長谷川 靖哉 (ハセガワ ヤスチカ)
工学研究院 応用化学部門 機能材料化学分野 | 教授 |
総合イノベーション創発機構化学反応創成研究拠点 | 教授 |
Last Updated :2025/02/13
■研究者基本情報
プロフィール情報
- 2010.4 北海道大学大学院工学研究院 教授
2005.4 奈良先端科学技術大学院大学 物質創成科学研究科 助教授 → 2006.4 准教授
1999.12 大阪大学大学院工学研究科 助手 → 2004.10 学内講師
1994.4 新日本理化株式会社 研究開発本部 研究員
Researchmap個人ページ
ホームページURL
研究者番号
- 80324797
J-Global ID
■経歴
経歴
学歴
委員歴
- 2022年04月 - 現在
複合系の光機能研究会, 理事, 学協会 - 2014年05月 - 現在
日本希土類学会, 理事, 学協会 - 2018年01月 - 2021年12月
光化学協会, 理事, 学協会 - 2016年05月 - 2020年05月
高分子学会, 理事, 学協会 - 2015年04月 - 2019年12月
錯体化学会, 将来計画委員会委員, 学協会 - 2015年04月 - 2016年03月
日本化学会, 代議員, 学協会 - 2014年04月 - 2016年03月
高分子学会, 「高分子」編集委員会委員, 学協会 - 2014年04月 - 2016年03月
複合系の光機能研究会, 会長, 学協会 - 2012年04月 - 2016年03月
日本化学会, 化学フェスタ実行委員, 学協会 - 2014年01月 - 2015年12月
光化学協会, 理事, 学協会 - 2012年04月 - 2014年03月
複合系の光機能研究会, 副会長, 学協会 - 2012年01月 - 2013年12月
光化学協会, 常任理事, 学協会 - 2009年04月 - 2012年12月
日本化学会, 「Chemistry Letters」Associate Editor, 学協会 - 2008年04月 - 2010年03月
複合系の光機能研究会, 役員会世話人・会計, 学協会 - 2006年04月 - 2008年03月
複合系の光機能研究会, 役員会世話人・事務局, 学協会 - 2003年09月 - 2006年03月
複合系の光機能研究会, 役員会世話人・庶務, 学協会
学内役職歴
■研究活動情報
受賞
- 2021年05月, 日本希土類学会, 日本希土類学会賞(塩川賞)
希土類配位空間の設計と光機能化 - 2017年04月, 文部科学省, 文部科学大臣表彰 科学技術賞
強発光を示す希土類分子ナノ材料に関する研究
長谷川靖哉 - 2016年06月, 日本画像学会, コニカミノルタ科学技術振興財団研究奨励賞
希土類錯体の光機能創出と画像技術応用
長谷川靖哉 - 2014年03月, 日本化学会, 日本化学会第31回学術賞
光機能を示す希土類ナノ物質に関する研究
長谷川靖哉 - 2013年09月, 光化学協会, 光化学協会賞
希土類物質のナノ構造制御と光機能に関する研究
長谷川靖哉 - 2010年03月, 平成21年度NAIST学術賞
希土類を基盤とした光機能ナノ物質の創成
長谷川靖哉 - 2006年09月, 光化学協会, 光化学協会奨励賞
希土類元素を基盤とする光機能材料の開拓
長谷川靖哉 - 2004年05月, 日本希土類学会, 第9回・日本希土類学会奨励賞
光機能を有する希土類錯体および希土類ナノ結晶の創成
長谷川靖哉
論文
- Full Picture of Energy Transfer in a Trivalent Europium Complex with Bidentate β-Diketonate Ligand
Shiori Miyazaki, Motoaki Gotanda, Yuichi Kitagawa, Yasuchika Hasegawa, Kiyoshi Miyata, Ken Onda
Journal of Physical Chemistry Letters, 2024年10月24日, [査読有り]
研究論文(学術雑誌) - Luminescence changeable CO2‐storage cylinder: Triple‐stranded helical Eu(III)/Tb(III) fluorinated MOFs with amide linkers
Joe Hayashi, Shinichiro Iwamura, Yuta Nakasaka, Mengfei Wang, Sunao Shoji, Yuichi Kitagawa, Koji Fushimi, Shin R. Mukai, Yasuchika Hasegawa
Chemistry – A European Journal, Wiley, 2024年09月09日
研究論文(学術雑誌), Triple‐stranded helical lanthanide MOFs with CO2 adsorption properties were investigated. Lanthanide MOFs ([Eu0.1Tb0.9(hfa)3(dpa)]n) are composed of lanthanide luminophores (Eu(III) and/or Tb(III) ions), fluorinated antenna ligands (hfa: hexafluoroacetylacetonate), and polyamide‐type linker ligands (dpa: 4‐(diphenylphosphoryl)‐N‐(4‐(diphenylphosphoryl)phenyl)benzamide). The cylindrical structure was characterized by single‐crystal X‐ray analysis, thermogravimetric analysis, and gas adsorption measurements. The inner surfaces of the cylindrical channels were covered with the fluorine atoms of the hfa ligands. The emission intensity ratio (IEu / ITb) in [Eu0.1Tb0.9(hfa)3(dpa)]n is affected by the CO2 gas adsorption behavior. The change in IEu / ITb value was caused by the intermolecular interactions between the CO2 gas molecules and the fluorinated ligands, resulting in an electronic structural change of the lowest triplet excited state in the photosensitized hfa ligands. - π-4f charge-transfer emission in a trivalent europium complex
Yuichi Kitagawa, Toranosuke Tomikawa, Kota Aikawa, Shiori Miyazaki, Tomoko Akama, Masato Kobayashi, Mengfei Wang, Sunao Shoji, Koji Fushimi, Kiyoshi Miyata, Yuichi Hirai, Takayuki Nakanishi, Ken Onda, Tetsuya Taketsugu, Yasuchika Hasegawa
2024年05月29日 - Chiral Tetrakis Eu(III) Complexes with Ammonium Cations for Improved Circularly Polarized Luminescence.
Makoto Tsurui, Ryohei Takizawa, Yuichi Kitagawa, Mengfei Wang, Masato Kobayashi, Tetsuya Taketsugu, Yasuchika Hasegawa
Angewandte Chemie (International ed. in English), e202405584, 2024年05月26日, [国際誌]
英語, 研究論文(学術雑誌), Large dissymmetry factor of the circularly polarized luminescence (gCPL) was observed in ligand and coordination tuned chiral tetrakis europium (Eu(III)) complexes with ammonium cations. The gCPL value was estimated to be -1.54, which is the largest among chiral luminescent molecules. Through photophysical measurements, single crystal X-ray structural analyses and quantum chemical calculations, changes in the geometric and electronic structures were observed for a series of chiral tetrakis Eu(III) complexes which enhanced the gCPL value. The emission quantum yield and photosensitized energy transfer efficiencies of chiral Eu(III) complexes with ammonium cations were also larger than that with previous Cs+. Based on the systematic modifications and analyses for chiral tetrakis Eu(III) complex, effect of the ammonium cation on enhanced CPL brightness is reported. - Effective photosensitized emission of a Tb(III) complex using a β-diketonate photosensitizer and an oxygen barrier system in a thermally populated triplet state.
Kota Inage, Mengfei Wang, Yasuchika Hasegawa, Yuichi Kitagawa
Dalton transactions (Cambridge, England : 2003), 53, 20, 8555, 8562, 2024年05月21日, [国際誌]
英語, 研究論文(学術雑誌), Photosensitizer design of luminescent terbium (Tb(III)) complexes with narrow bandwidths is important for advancing luminescent materials. In this study, we report an effective photosensitizer model in a thermally populated lowest excited triplet (T1) state during Tb(III) emission. The Tb(III) complex comprises a Tb(III) ion (serving as an emission center), hexafluoroacetylacetonates (acting as photosensitizer ligands), and bulky cyclohexyl group-attached phosphine-oxide-type ligands (functioning as an oxygen barrier system). Emission properties including emission and excitation spectra, ligand-excited emission quantum yields, and emission lifetimes were evaluated in the absence and presence of oxygen. Coordination geometry structures were determined through analysing single-crystal structures. The electronic structure based on 4f-orbitals was estimated from radiative rate constants and quantum chemical calculations. The bulky phosphine oxide ligand not only provides an oxygen barrier system but also induces an electronic structural modulation based on 4f-orbitals, allowing for effective photosensitized Tb(III) emission in a thermally populated ligand T1 state in air. - Guest-Responsive Near-Infrared-Luminescent Metal–Organic Cage Organized by Porphyrin Dyes and Yb(III) Complexes
Shota Hosoya, Sunao Shoji, Takayuki Nakanishi, Masato Kobayashi, Mengfei Wang, Koji Fushimi, Tetsuya Taketsugu, Yuichi Kitagawa, Yasuchika Hasegawa
Inorganic Chemistry, American Chemical Society (ACS), 2024年05月21日
研究論文(学術雑誌) - Highly Efficient and Thermally Durable Luminescence of 1D Eu3+ Coordination Polymers with Arsenic Bridging Ligands
Haruki Shimoji, Yuto Aoyama, Kota Inage, Masashi Nakamura, Takumi Yanagihara, Kazuhiro Yuhara, Yuichi Kitagawa, Yasuchika Hasegawa, Shunichiro Ito, Kazuo Tanaka, Hiroaki Imoto, Kensuke Naka
Chemistry – A European Journal, Wiley, 2024年04月09日
研究論文(学術雑誌), In this work, bisarsine oxides were evaluated as novel bridging ligands, aiming to develop practical and efficient luminescent lanthanide coordination polymers. We have synthesized one‐dimensional (1D) Eu3+ coordination polymers that incorporate bisarsine oxide bridging ligands and hexafluoroacetylacetonate anions. These polymers exhibited a denser packing of chains compared to analogous polymers bridged with bisphosphine oxides. The coordination polymers demonstrated exceptional thermal stability and substantial emission quantum yields. Additionally, the bisarsine oxides induced a pronounced polarization effect, facilitating a sensitive electric dipole transition that yields considerably narrow band red emission. Remarkably, the Eu3+ coordination polymers with bisarsine oxides maintained intense emission even at 550 K. A distinctive feature of these polymers is their heating‐induced emission enhancement observed when the temperature was increased from 300 K to 400 K. - Circularly polarized luminescence and high photoluminescence quantum yields from rigid 5,10-dihydroindeno[2,1-a]indene and 2,2'-dialkoxy-1,1'-binaphthyl conjugates and copolymers.
Keisuke Iwata, Makoto Tsurui, Kosuke Itaya, Naoto Hamaguchi, Yasunobu Egawa, Yuichi Kitagawa, Yasuchika Hasegawa, Hayato Tsuji
RSC advances, 14, 11, 7251, 7257, 2024年02月29日, [国際誌]
英語, 研究論文(学術雑誌), 5,5,10,10-Tetramethyl-5,10-dihydroindeno[2,1-a]indene (COPV1(Me)) was installed into either the 3,3'- or 6,6'-positions of chiral 2,2'-dioctyloxy-1,1'-binaphthyl to afford 2 : 1 conjugates (monomeric compounds) and 1 : 1 copolymers. These compounds showed high photoluminescence quantum yields of >0.95 whilst also exhibiting circular dichroism (CD) and circularly polarized luminescence (CPL). The dissymmetry factors of CPL (gCPL) for the 3,3'- and 6,6'-monomeric compounds in THF were 6.6 × 10-4 and 3.3 × 10-4, respectively. The 3,3'-isomer has a higher g value than the 6,6'-isomer, which was attributed to the difference in the extent of π-conjugation and the angle between electronic and magnetic transition moments. The gCPL values of the 3,3'-linked and 6,6'-linked copolymers were 1.1 × 10-3 and 6.8 × 10-4, respectively. The structural rigidity of the COPV units is beneficial to achieve relatively high g values whilst maintaining a photoluminescence quantum yield that is close to unity by using a single type of fluorophore. - Current Development of Lanthanide Complexes for Biomedical Applications.
Mengfei Wang, Yuichi Kitagawa, Yasuchika Hasegawa
Chemistry, an Asian journal, e202400038, 2024年02月13日, [国際誌]
英語, 研究論文(学術雑誌), Luminescent molecule-based bioimaging system is widely used for precise localization and distinction of cancer/tumor cells. Luminescent lanthanide (Ln(III)) complexes offer long-lived (sub-millisecond time scale) and sharp (FWHM <10 nm) emission, arising from the forbidden 4f-4f electronic transitions. Luminescent Ln(III) complex-based bioimaging has emerged as a promising option for both in vitro and in vivo visualizations. In this mini-review, the historical development and recent significant progress of luminescent Ln(III) probes for bioapplications are introduced. The recent studies are mainly focused on three points: (i) the structural modifications of Ln(III) complexes in both macrocyclic and small ligands, (ii) the acquirement of high resolution luminescence images of cancer/tumor cells and (iii) the constructions of ratiometric biosensors. Furthermore, our recent study is explained as a new Cancer GPS (cancer grade probing for determining tumor grade through photophysical property analyses of intracellular Eu(III) complex. - Passive Film Formed on Si-Mn Steel in Boric Acid-Borate Buffer at 6.5
Koji Fushimi, Kanta Higa, Akihiro Fujimura, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Hideki Katayama
Journal of The Electrochemical Society, 171, 2, 021502, 021502, The Electrochemical Society, 2024年02月01日
研究論文(学術雑誌), Passivity-maintaining current of high-strength (Si-Mn) steel in boric acid-borate buffer at pH 6.5 was larger than that of ferrite/pearlite (F/P) steel. Charge transfer resistance of the Si-Mn steel surface passivated at 1.10 V vs SHE in pH 6.5 buffer was smaller than that of F/P steel surface. Nano-analyses using AES and STEM revealed the details of the structure and components of the passive film on the Si-Mn steel. The inferiorities of passivity of Si-Mn steel were suggested to be due to the alloying components and metallurgical structure to increase the strength of the steel. - Structure-changeable luminescent Eu(III) complex as a human cancer grade probing system for brain tumor diagnosis.
Mengfei Wang, Masaya Kono, Yusaku Yamaguchi, Jahidul Islam, Sunao Shoji, Yuichi Kitagawa, Koji Fushimi, Sora Watanabe, Go Matsuba, Akihisa Yamamoto, Motomu Tanaka, Masumi Tsuda, Shinya Tanaka, Yasuchika Hasegawa
Scientific reports, 14, 1, 778, 778, 2024年01月22日, [国際誌]
英語, 研究論文(学術雑誌), Accurate determination of human tumor malignancy is important for choosing efficient and safe therapies. Bioimaging technologies based on luminescent molecules are widely used to localize and distinguish active tumor cells. Here, we report a human cancer grade probing system (GPS) using a water-soluble and structure-changeable Eu(III) complex for the continuous detection of early human brain tumors of different malignancy grades. Time-dependent emission spectra of the Eu(III) complexes in various types of tumor cells were recorded. The radiative rate constants (kr), which depend on the geometry of the Eu(III) complex, were calculated from the emission spectra. The tendency of the kr values to vary depended on the tumor cells at different malignancy grades. Between T = 0 and T = 3 h of invasion, the kr values exhibited an increase of 4% in NHA/TS (benign grade II gliomas), 7% in NHA/TSR (malignant grade III gliomas), and 27% in NHA/TSRA (malignant grade IV gliomas). Tumor cells with high-grade malignancy exhibited a rapid upward trend in kr values. The cancer GPS employs Eu(III) emissions to provide a new diagnostic method for determining human brain tumor malignancy. - Composition Analysis of Corrosion Products on Steel by Machine Learning of Optical Microscopic Images
Yuki Tsuji, Kota Hirasawa, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Koji Fushimi
Tetsu-to-Hagane, 2024年
研究論文(学術雑誌) - Quantitative evaluation of hydrogen absorption by detecting non-absorbed hydrogen in electrochemical hydrogen permeation test
Yuya Mizushiri, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Koji Fushimi
International Journal of Hydrogen Energy, Elsevier BV, 2024年01月
研究論文(学術雑誌) - Size-Control Synthesis and Luminescence Properties of Eu(III) Coordination Particles
Masaki Enokido, Kensei Sasaki, Sunao Shoji, Mengfei Wang, Koji Fushimi, Yuichi Kitagawa, Yasuchika Hasegawa
The Journal of Physical Chemistry C, 127, 49, 23785, 23791, American Chemical Society (ACS), 2023年12月01日
研究論文(学術雑誌) - Sandglass-Typed Single Chameleon Luminophore for Water Mapping Measurements: Intramolecular Energy Migrations in the Hydrophilic Tb(III)/Sm(III) Cluster
Yasuchika Hasegawa, Yuki Konishi, Masaki Enokido, Sunao Shoji, Mengfei Wang, Koji Fushimi, Yuichi Kitagawa
Inorganic Chemistry, 62, 41, 16794, 16800, American Chemical Society (ACS), 2023年09月21日
研究論文(学術雑誌) - Investigation of the dissolution/passivation mechanisms on Fe-Cr alloys in acidic Na2SO4 solution using online ICP-OES
Akihiro Fujimura, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Takashi Doi, Koji Fushimi
Electrochimica Acta, 463, 142843, 142843, Elsevier BV, 2023年09月
研究論文(学術雑誌) - Thermally-assisted photosensitized emission in a trivalent terbium complex
Yuichi Kitagawa, Kaori Shima, Takuma Nakai, Marina Kumagai, Shun Omagari, Pedro Paulo Ferreira da Rosa, Sunao Shoji, Koji Fushimi, Yasuchika Hasegawa
Communications Chemistry, 6, 1, Springer Science and Business Media LLC, 2023年06月22日
研究論文(学術雑誌), Abstract
Luminescent lanthanide complexes containing effective photosensitizers are promising materials for use in displays and sensors. The photosensitizer design strategy has been studied for developing the lanthanide-based luminophores. Herein, we demonstrate a photosensitizer design using dinuclear luminescent lanthanide complex, which exhibits thermally-assisted photosensitized emission. The lanthanide complex comprised Tb(III) ions, six tetramethylheptanedionates, and phosphine oxide bridge containing a phenanthrene frameworks. The phenanthrene ligand and Tb(III) ions are the energy donor (photosensitizer) and acceptor (emission center) parts, respectively. The energy-donating level of the ligand (lowest excited triplet (T1) level = 19,850 cm−1) is lower than the emitting level of the Tb(III) ion (5D4 level = 20,500 cm−1). The long-lived T1 state of the energy-donating ligands promoted an efficient thermally-assisted photosensitized emission of the Tb(III) acceptor (5D4 level), resulting in a pure-green colored emission with a high photosensitized emission quantum yield (73%). - Highly efficient light harvesting of a Eu(iii) complex in a host–guest film by triplet sensitization
Shiori Miyazaki, Kenichi Goushi, Yuichi Kitagawa, Yasuchika Hasegawa, Chihaya Adachi, Kiyoshi Miyata, Ken Onda
Chemical Sciences, Royal Society of Chemistry (RSC), 2023年05月, [査読有り]
研究論文(学術雑誌), Very high photoluminescence intensity of a Eu(iii) complex is achieved using a host–guest system. The intensity is 400 times larger than that of the Eu(iii) complex itself. - Characteristic stacked structures and luminescent properties of dinuclear lanthanide complexes with pyrene units
Takuma Nakai, Kaori Shima, Sunao Shoji, Koji Fushimi, Yasuchika Hasegawa, Yuichi Kitagawa
Frontiers in Chemistry, 11, Frontiers Media SA, 2023年04月14日
研究論文(学術雑誌), A novel design strategy of stacked organic fluorophores using dinuclear lanthanide (Ln(III)) complexes is demonstrated for the formation of excimer. The dinuclear Ln(III) complexes are composed of two Ln(III) (Eu(III) or Gd(III)) ions, six hexafluoroacetylacetonate (hfa), and two pyrene-based phosphine oxide ligands. Single-crystal analysis revealed a rigid pyrene-stacked structure via CH-F (pyrene/hfa) intramolecular interactions. The rigid aggregation structures of the two-typed organic ligands around Ln(III) resulted in high thermal stability (decomposition temperature: 340°C). The aggregated ligands exhibited excimer-type green emission from the stacked pyrene-center. The change in the Ln(III) ion promotes effective shifts of excimer emissions (Gd(III):500 nm, Eu(III):490 nm). The organic aggregation system using red-luminescent Eu(III) also provides temperature-sensitive ratiometric emission composed of π-π* and 4f-4f transitions by energy migration between aggregated ligands and Eu(III). - Initiation of Sulfide Stress Cracking Using Potentiostatic Liquid-Phase Ion Gun
K. Fushimi, H. Yanagimoto, S. Nakatsuji, S. Shoji, Y. Kitagawa, Y. Hasegawa, K. Baba
Journal of The Electrochemical Society, 170, 4, 041508, 041508, The Electrochemical Society, 2023年04月01日
研究論文(学術雑誌), A liquid-phase ion gun (LPIG) was used to create a local H2S enriched environment near Cr-containing steel surface in Na2S solutions in attempt to induce sulfide stress cracking on the specimen surface. In a 1.5 mM Na2S solution, anodic polarization of LPIG Pt microelectrode at a potential of 1.90 V vs SHE resulted in that local solution was successfully acidified to below pH 4, a pseudo-sour environment. When Cr-containing steels were potentiostatically polarized under this pseudo-sour environment by LPIG, sulfides were formed on the specimen surface depending on Cr-concentration, specimen potential, and chloride ion in solution. When LPIG was operated on Cr-containing steels subjected to tensile stress using a four-point bending tester, cracks were formed on the steel surface. - Structural metamorphosis and photophysical properties of thermostable nano- and microcrystalline lanthanide polymer with flexible coordination chains
Takayuki Nakanishi, Yuichi Hirai, Jian Xu, Takashi Takeda, Shunsuke Watanabe, Atsuo Yasumori, Shou Hakamada, Yuichi Kitagawa, Yasuchika Hasegawa
Science and Technology of Advanced Materials, 24, 1, Informa UK Limited, 2023年03月03日
研究論文(学術雑誌) - Bright Lanthanide III Triboluminescence despite Low Photoluminescence, and Dual Triboluminescence and Mechano‐Responsive Photoluminescence
Yuichi Hirai, Stann Van Baaren, Takahito Ohmura, Takayuki Nakanishi, Takashi Takeda, Yuichi Kitagawa, Yasuchika Hasegawa, Rémi Métivier, Clémence Allain
Advanced Optical Materials, 11, 9, Wiley, 2023年02月08日
研究論文(学術雑誌) - Synthesis of BCP-Based Straight-Shaped Diphosphine Ligands
Hideaki Takano, Hitomi Katsuyama, Hiroki Hayashi, Miyu Harukawa, Makoto Tsurui, Sunao Shoji, Yasuchika Hasegawa, Satoshi Maeda, Tsuyoshi Mita
American Chemical Society (ACS), 2023年01月12日
[1.1.1]Propellane, which is structurally simple and compact, exhibits promising potential for the synthesis of disubstituted straight-shaped bicyclo[1.1.1]pentane (BCP) compounds by manipulation of its highly reactive internal C–C bond. BCPs are considered to be isosteres of 1,4-disubstituted benzenes, which have found broad applications in the areas of functional molecules and drug discovery. The internal C–C single bond of [1.1.1]propellane is regarded as a change-shift bond, which can be readily cleaved by radical or ionic means to construct BCPs. We herein report a novel synthetic method for (un)symmetric diphosphines based on the BCP motif, which can be interpreted as isosteres of 1,4-bis(diphenylphosphino)benzenes. The obtained BCP-diphosphine derivatives were used to generate a straight-shaped Au complex and a Eu-based coordination polymer. - Intensive emission of Eu(
iii ) β-diketonate complexes with arsine oxide ligands
Haruki Shimoji, Toshiki Fujii, Akifumi Sumida, Yuichi Kitagawa, Yasuchika Hasegawa, Hiroaki Imoto, Kensuke Naka
Journal of Materials Chemistry C, Royal Society of Chemistry (RSC), 2023年
研究論文(学術雑誌), Europium(iii) hexafluoroacetylacetonates incorporating arsine oxides were synthesized. Tris(1-naphthyl)arsine oxide yielded a notably more intense emission and higher thermal stability than triphenylphosphine oxide, which is conventionally used. - Enhanced circularly polarized luminescence of chiral Eu(
iii ) coordination polymers with structural strain
Makoto Tsurui, Yuichi Kitagawa, Sunao Shoji, Koji Fushimi, Yasuchika Hasegawa
Dalton Transactions, 52, 3, 796, 805, Royal Society of Chemistry (RSC), 2023年
研究論文(学術雑誌), Three types of Eu(iii) coordination polymers with distorted chiral ligands were prepared for elucidating the relationship between their structural distortions, ligand-to-metal charge transfer, and circularly polarized luminescence properties. - A switchable system between magnetic and natural circularly polarised luminescence via J-aggregation using photosynthetic antenna model compounds
T. Tomikawa, Y. Kitagawa, K. Yoshioka, K. Murata, T. Miyatake, Y. Hasegawa, K. Ishii
J. Mater. Chem. C, 11, 8, 2831, 2835, Royal Society of Chemistry (RSC), 2023年, [査読有り]
英語, 研究論文(学術雑誌), Using zinc-chlorin, the switching of MCPL/CPL via J-aggregation has been clearly demonstrated for the first time. - Luminescent Lanthanide Complexes for Effective Oxygen-Sensing and Singlet Oxygen Generation
Y. Kitagawa, T. Nakai, S. Hosoya, S. Shoji, Y. Hasegawa
ChemPlusChem, e20220045, Wiley, 2023年, [査読有り]
英語, 研究論文(学術雑誌) - Controlled molecular assemblies of chiral boron dipyrromethene derivatives for circularly polarized luminescence in the red and near-infrared regions
Hayato Sakai, Yudai Suzuki, Makoto Tsurui, Yuichi Kitagawa, Takuya Nakashima, Tsuyoshi Kawai, Yuta Kondo, Go Matsuba, Yasuchika Hasegawa, Taku Hasobe
Journal of Materials Chemistry C, 11, 8, 2889, 2896, 2023年, [査読有り]
英語, 研究論文(学術雑誌), Chiral 1,1′-bi-2-naphthol (BINOL)-substituted boron dipyrromethene (BODIPY) derivatives with different numbers of phenyl groups at the 2 and 6 positions (denoted as nPh-B-BODIPY; n = 0, 1, 2) were newly synthesized to examine the aggregation-enhanced emission and circularly polarized luminescence (CPL) in the red and near-infrared (NIR) regions. Upon injection of THF solution of nPh-B-BODIPY into H2O, 0Ph-B-BODIPY underwent controlled self-assembly to produce fibrous nanoarchitectures, whereas spherical nanoparticles were formed in 1Ph-B-BODIPY and 2Ph-B-BODIPY. Absorption and CD spectra of 0Ph-B-BODIPY nanofibers demonstrated a red-shifted and split spectrum corresponding to the 0-0 band, suggesting strong interaction between neighbouring 0Ph-B-BODIPY units. Such fibrous assemblies exhibited a broad emission spectrum with multiple bands ranging from the visible to the near-infrared (NIR) region due to the multiple aggregate states. Consequently, 0Ph-B-BODIPY nanofibers demonstrated a broad circularly polarized luminescence (CPL) spectrum in the red to NIR regions together with the enhanced dissymmetry factors (glum) relative to 0Ph-B-BODIPY (monomer) and 1Ph-B-BODIPY nanoparticles. - Development of a quasi-on-time ICP-OES for analyzing electrode reaction products
Akihiro Fujimura, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa, Takashi Doi, Koji Fushimi
Electrochimica Acta, 433, 141246, 141246, Elsevier BV, 2022年11月, [査読有り]
英語, 研究論文(学術雑誌) - Emission Properties of Eu(III) Complexes Containing Arsine and Phosphine Ligands with Annulated Structures
Toshiki Fujii, Yuichi Kitagawa, Yasuchika Hasegawa, Hiroaki Imoto, Kensuke Naka
Inorganic Chemistry, 61, 17662, 17672, American Chemical Society (ACS), 2022年10月27日, [査読有り]
英語, 研究論文(学術雑誌) - Plant growth acceleration using a transparent Eu3+-painted UV-to-red conversion film
Sunao Shoji, Hideyuki Saito, Yutaka Jitsuyama, Kotono Tomita, Qiang Haoyang, Yukiho Sakurai, Yuhei Okazaki, Kota Aikawa, Yuki Konishi, Kensei Sasaki, Koji Fushimi, Yuichi Kitagawa, Takashi Suzuki, Yasuchika Hasegawa
Scientific Reports, 12, 1, 17155, Springer Science and Business Media LLC, 2022年10月26日, [査読有り]
英語, 研究論文(学術雑誌), Abstract
The stimulation of photosynthesis is a strategy for achieving sustainable plant production. Red light is useful for plant growth because it is absorbed by chlorophyll pigments, which initiate natural photosynthetic processes. Ultraviolet (UV)-to-red wavelength-converting materials are promising candidates for eco-friendly plant cultures that do not require electric power. In this study, transparent films equipped with a UV-to-red wavelength-converting luminophore, the Eu3+ complex, were prepared on commercially available plastic films for plant growth experiments. The present Eu3+-based films absorb UV light and exhibit strong red luminescence under sunlight. Eu3+-painted films provide significant growth acceleration with size increment and biomass production for vegetal crops and trees in a northern region. The plants cultured with Eu3+-painted films had a 1.2-fold height and 1.4-fold total body biomass than those cultures without the Eu3+ luminophores. The present film can promote the plant production in fields of agriculture and forestry. - Preparation of photonic molecular trains via soft-crystal polymerization of lanthanide complexes
Pedro Paulo Ferreira da Rosa, Yuichi Kitagawa, Sunao Shoji, Hironaga Oyama, Keisuke Imaeda, Naofumi Nakayama, Koji Fushimi, Hidehiro Uekusa, Kosei Ueno, Hitoshi Goto, Yasuchika Hasegawa
Nature Communications, 13, 1, 3660, Springer Science and Business Media LLC, 2022年07月, [査読有り], [最終著者, 責任著者]
研究論文(学術雑誌), Abstract
Soft-crystals are defined as flexible molecular solids with highly ordered structures and have attracted attention in molecular sensing materials based on external triggers and environments. Here, we show the soft-crystal copolymerization of green-luminescent Tb(III) and yellow-luminescent Dy(III) coordination centers. Soft-crystal polymerization is achieved via transformation of monomeric dinuclear complexes and polymeric structures with respect to coordination number and geometry. The structural transformation is characterized using single-crystal and powder X-ray diffraction. The connected Tb(III) crystal-Dy(III) crystal show photon energy transfer from the Dy(III) centre to the Tb(III) centre under blue light excitation (selective Dy(III) centre excitation: 460 ± 10 nm). The activation energy of the energy transfer is estimated using the temperature-dependent emission lifetimes and emission quantum yields, and time-dependent density functional theory (B3LYP) calculations. Luminescence-conductive polymers, photonic molecular trains, are successfully prepared via soft-crystal polymerization on crystal media with remarkable long-range energy migration. - Asymmetric Lumino-Transformer: Circularly Polarized Luminescence of Chiral Eu(III) Coordination Polymer with Phase-Transition Behavior
Makoto Tsurui, Yuichi Kitagawa, Sunao Shoji, Hitomi Ohmagari, Miki Hasegawa, Masayuki Gon, Kazuo Tanaka, Masato Kobayashi, Tetsuya Taketsugu, Koji Fushimi, Yasuchika Hasegawa
The Journal of Physical Chemistry B, 126, 20, 3799, 3807, American Chemical Society (ACS), 2022年05月26日, [査読有り], [最終著者, 責任著者]
研究論文(学術雑誌) - Amorphous lanthanide complexes for organic luminescent materials
J. Hayashi, S. Shoji, Y. Kitagawa, Y. Hasegawa
Coord. Chem. Rev., 214607, 2022年05月, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Application of a new film for horticultural use to convert UV-light to photosynthetic active radiation
Satoshi Kitaoka, Tauro Shinano, Takashi Suzuki, Sunao Shoji, Yasuchika Hasegawa
Eurasian Journal of Forests Research, 22, 73, 77, 2022年04月, [査読有り], [招待有り]
英語, 研究論文(大学,研究機関等紀要) - Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework
Y. Kitagawa, A. Naito, K. Aikawa, K. Shima, S. Shoji, K. Fushimi, Y. Hasegawa
Chem. Eur. J., 28, 16, e202104401, WILEY-V C H VERLAG GMBH, 2022年04月, [査読有り], [最終著者]
英語, 研究論文(学術雑誌), A spin-selective tribo-chemical reaction using a dinuclear lanthanide complex is demonstrated for the first time. The dinuclear complex is composed of two Eu-III ions, hexafluoroacetylacetonato ligands, and anthracene-based phosphine oxide bridges. Single-crystal analysis revealed a face-to-face-type anthracene dimer structure in the dinuclear Eu-III complex. Mechanical stimulus on the dinuclear Eu-III complex induced selective formation of oxidized anthracene. The tribo-chemical reaction is based on a characteristic energy-transfer pathway for the selective formation of an excited triplet state. - Luminescent Lanthanide Coordination Polymers with Transformative Energy Transfer Processes for Physical and Chemical Sensing Applications
Y. Hasegawa, Y. Kitagawa
J. Photochem. Photobio. C, Photochem. Rev., 100485, 2022年03月, [査読有り], [筆頭著者, 責任著者]
英語, 研究論文(学術雑誌) - Bright red emission with high color purity from Eu(III)complexes with Pai-cinjugated polycyclic aromatic loigands and their sensing applications
Y. Kitagawa, M. Tsurui, Y. Hasegawa
RSC Adv., 12, 810, 821, 2022年02月, [査読有り], [最終著者]
英語, 研究論文(学術雑誌) - Luminescent Eu(III)-based Coordination Polymers for Photonic Materials
Y. Hasegawa, S. Shoji, Y. Kitagawa
Chem. Lett., 51, 185, 196, 2022年02月, [査読有り], [筆頭著者, 責任著者]
英語, 研究論文(学術雑誌) - Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework
Kitagawa, Y., Naito, A., Aikawa, K., Shima, K., Shoji, S., Fushimi, K., Hasegawa, Y.
Chemistry (Weinheim an der Bergstrasse, Germany), 28, 16, 2022年
研究論文(学術雑誌) - Effective Photosensitization in Excited‐State Equilibrium: Brilliant Luminescence of Tb III Coordination Polymers Through Ancillary Ligand Modifications
Yuichi Kitagawa, Ryoma Moriake, Tomoko Akama, Koki Saito, Kota Aikawa, Sunao Shoji, Koji Fushimi, Masato Kobayashi, Tetsuya Taketsugu, Yasuchika Hasegawa
ChemPlusChem, e202200151, Wiley, 2022年, [査読有り]
英語, 研究論文(学術雑誌) - Charge-transfer excited states of π- and 4f-orbitals for development of luminescent Eu(III) complexes
Y. Kitagawa, P.-P. Ferreira da Rosa, Y. Hasegawa
Dalton Trans., 50, 14978, 14984, 2021年09月, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Hybrid Eu(III) Coordination luminophore Standing on Silica Nanoparticles By Two Legs for Enhanced Luminescence
T. Zhang, Y. Kitagawa, R. Moriake, P. P. Ferreira da Rosa, Md J. Islam, T. Yoneda, Y. Inokuma, K. Fushimi, Y. Hasegawa
Chem. Eur. J., in press, WILEY-V C H VERLAG GMBH, 2021年09月, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌), In this study, we have demonstrated a two-legged, upright molecular design method for monochromatic and bright red luminescent Ln(III)-silica nanomaterials. A novel Eu-III-silica hybrid nanoparticle was developed by using a doubly binding TPPO-Si(OEt)(3) (TPPO: triphenyl phosphine oxide) linker. The TPPO-Si(OEt)(3) was confirmed by H-1, P-31, Si-29 NMR spectroscopy and single-crystal X-ray analysis. Luminescent Eu(hfa)(3) and Eu(tfc)(3) moieties (hfa: hexafluoroacetylacetonate, tfc: 3-(trifluoromethylhydroxymethylene)camphorate) were fixed onto TPPO-Si(OEt)(3)-modified silica nanoparticles, producing Eu(hfa)(3)(TPPO-Si)(2)-SiO2 and Eu(tfc)(3)(TPPO-Si)(2)-SiO2, respectively. Eu(hfa)(3)(TPPO-Si)(2)-SiO2 exhibited the higher intrinsic luminescence quantum yield (93 %) and longer emission lifetime (0.98 ms), which is much larger than those of previously reported Eu-III-based hybrid materials. Eu(tfc)(3)(TPPO-Si)(2)-SiO2 showed an extra-large intrinsic emission quantum yield (54 %), although the emission quantum yield for the precursor Eu(tfc)(3)(TPPO-Si(OEt)(3))(2) was found to be 39 %. These results confirmed that the TPPO-Si(OEt)(3) linker is a promising candidate for development of Eu-III-based luminescent materials. - Long-lived emission beyond 1000 nm: control of excited-state dynamics in a dinuclear Tb(III)-Nd(III) complex
Y. Kitagawa, K. Matsuda, P. P. Ferreira da Rosa, K. Fushimi, Y. Hasegawa
Chem. Comm., 57, 65, 8047, 8050, ROYAL SOC CHEMISTRY, 2021年07月, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌), A long-lived near-infrared Nd(iii) emission is demonstrated using a Tb(iii) donor. The observed emission lifetime of 290 mu s at 1057 nm for a Tb(iii)-Nd(iii) dinuclear complex is attributed to the long-lived Tb(iii) donor and the appropriate spacing between the lanthanide ions. This design strategy leads to novel lanthanide photophysics. - Drastic Enhancement of Photosensitized Energy Transfer Efficiency of a Eu(III) Complex Driven by Arsenic
Toshiki Fujii, Yuichi Kitagawa, Yasuchika Hasegawa, Hiroaki Imoto, Kensuke Naka
Inorganic Chemistry, 60, 12, 8605, 8612, American Chemical Society (ACS), 2021年06月21日
研究論文(学術雑誌) - Active-passive transition of an fe-6 mass% cr surface in acidic sodium sulfate solutions under a laminar flow condition evaluated by ellipso-microscopy and channel flow electrode method
Akihiro Fujimura, Yuichi Kitagawa, Yasuchika Hasegawa, Takashi Doi, Koji Fushimi
Journal of the Electrochemical Society, 168, 5, 2021年05月
研究論文(学術雑誌), Electrochemical ellipso-microscopy was combined with the channel flow triple electrode method to evaluate the active-passive transition behavior of Fe-6 mass% Cr in acidic sodium sulfate solutions under the control of mass-transport reaction. During potentiodynamic polarization of the Fe-6 mass% Cr specimen electrode (SE), the SE surface was monitored by ellipso-microscopy and generated Fe(II) and Cr(III) species from the SE were detected at two detector electrodes arranged downstream in parallel. Forced convection of the electrolyte solution affected the mass-transport process of Cr(III) species on the SE surface in the latter half of the active region. In addition, the electrolyte solution flow resulted in enhancement of the passivation process and Cr enrichment on the passive surface. The effects of the electrolyte solution flow on active-passive transition and improvement of the passive film resistance are discussed. - Isopyrazole-Masked Tetraketone: Tautomerism and Functionalization for Fluorescent Metal Ligands
H. Shirakura, Y. Manabe, C. Kasai, Y. Inaba, M. Tsurui, Y. Kitagawa, Y. Hasegawa, T. Yoneda, Y. Ide, Y. Inokluma
Eur. J. Inorg. Chem., 4345, 4349, 2021年05月, [査読有り]
英語, 研究論文(学術雑誌) - Amide-bridged Eu(III) coordination polymer for stable luminescent glass material
J. Hayashi, S. Shoji, Y. Kitagawa, K. Fushimi, Y. Hasegawa
Mater. Lett., 297, 130012, 2021年05月, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Strong circularly polarized luminescence of mixed lanthanide coordination polymers with control of 4f electronic structur
Md Jahidal Islam, Y. Kitagawa, S. Tsurui, K. Fushimi, Y. Hasegaw
Dalton Trans, 50, 5433, 5436, 2021年05月, [査読有り], [責任著者]
英語, 研究論文(学術雑誌) - Thermo-Sensitive EuIII Coordination Polymers with Amorphous Networks
Y. Hasegawa, N. Sato, J. Hayashi, Y. Kitagawa, K. Fushimi
ChemistrySelect, 6, 2812, 2816, 2021年04月, [査読有り], [筆頭著者, 責任著者]
英語, 研究論文(学術雑誌) - Long-wavelength visible to near infrared photoluminescence from carbon-bridged styrylstilbene and thiadiazole conjugates in organic and aqueous media
Takeru Inoue, Makoto Tsurui, Hiroshi Yamagishi, Yuma Nakazawa, Naoto Hamaguchi, Shoya Watanabe, Yuichi Kitagawa, Yasuchika Hasegawa, Yohei Yamamoto, Hayato Tsuji
RSC Advances, 11, 11, 6008, 6013, Royal Society of Chemistry (RSC), 2021年03月, [査読有り]
研究論文(学術雑誌),Efficient long-wavelength visible to NIR-emitting materials have been synthesized by use of rigid planar styrylstilbene as a donor component.
- Bright sky-blue fluorescence with high color purity: assembly of luminescent diphenyl-anthracene lutetium-based coordination polymer
Yuichi Kitagawa, Ayu Naito, Koji Fushimi, Yasuchika Hasegawa
RSC Advances, 11, 12, 6604, 6606, Royal Society of Chemistry (RSC), 2021年03月, [査読有り]
研究論文(学術雑誌),Pure sky-blue fluorescence (FWHM: 50 nm) from lutetium-based coordination polymer with diphenyl-anthracene derivative is demonstrated for the first time.
- First Tribo‐Excited Chemical Reaction of a Stacked Lanthanide Coordination Polymer with an in Situ Reaction Monitor
Yuichi Kitagawa, Ayu Naito, Koji Fushimi, Yasuchika Hasegawa
Chemistry – A European Journal, 27, 7, 2279, 2283, Wiley, 2021年02月, [査読有り]
研究論文(学術雑誌), A tribo-excited chemical reaction using a stacked lanthanide coordination polymer is demonstrated for the first time. The polymer is composed of a EuIII ion, hexafluoroacetylacetonato ligands, and an anthracene-based phosphine oxide bridge. The tightly stacked structure with hydrogen bonding was characterized by X-ray crystal structure analysis. The mechanical stimulus leads to tribo-excited oxidation in the EuIII coordination polymer. Electron ionization mass spectroscopy and photo-spectroscopic analysis reveal that the chemical product afforded by tribo-oxidation is different from that obtained by photo-oxidation. - Coordination Geometrical Effect on Ligand-to-Metal Charge Transfer-Dependent Energy Transfer Processes of Luminescent Eu(III) Complexes
Pedro Paulo Ferreira da Rosa, Shiori Miyazaki, Haruna Sakamoto, Yuichi Kitagawa, Kiyoshi Miyata, Tomoko Akama, Masato Kobayashi, Koji Fushimi, Ken Onda, Tetsuya Taketsugu, Yasuchika Hasegawa
The Journal of Physical Chemistry A, 125, 1, 209, 217, American Chemical Society (ACS), 2021年01月14日, [査読有り]
研究論文(学術雑誌), Photophysical properties of europium (Eu(III)) complexes are affected by ligand-to-metal charge transfer (LMCT) states. Two luminescent Eu(III) complexes with three tetramethylheptadionates (tmh) and pyridine (py), [Eu(tmh)3(py)1] (seven-coordinated monocapped-octahedral structure) and [Eu(tmh)3(py)2] (eight-coordinated square antiprismatic structure), were synthesized for geometrical-induced LMCT level control. Distances between Eu(III) and oxygen atoms of tmh ligands were estimated using single-crystal X-ray analyses. The contribution percentages of π-4f mixing in HOMO and LUMO at the optimized structure in the ground state were calculated using DFT (LC-BLYP). The Eu-O distances and their π-4f mixed orbitals affect the energy level of LMCT states in Eu(III) complexes. The LMCT energy level of an eight-coordinated Eu(III) complex was higher than that of a seven-coordinated Eu(III) complex. The energy transfer processes between LMCT and Eu(III) ion were investigated using temperature-dependent and time-resolved emission lifetime measurements of 5D0 → 7FJ transitions of Eu(III) ions. In this study, the LMCT-dependent energy transfer processes of seven- and eight-coordinated Eu(III) complexes are demonstrated for the first time. - Long‐Range LMCT Coupling in Eu III Coordination Polymers for an Effective Molecular Luminescent Thermometer**
Yuichi Kitagawa, Marina Kumagai, Pedro Paulo Ferreira da Rosa, Koji Fushimi, Yasuchika Hasegawa
Chemistry – A European Journal, 27, 1, 264, 269, Wiley, 2021年01月04日, [査読有り]
研究論文(学術雑誌), A design for an effective molecular luminescent thermometer based on long-range electronic coupling in lanthanide coordination polymers is proposed. The coordination polymers are composed of lanthanide ions EuIII and GdIII, three anionic ligands (hexafluoroacetylacetonate), and a chrysene-based phosphine oxide bridges (6,12-bis(diphenylphosphoryl)chrysene). The zig-zag orientation of the single polymer chains induces the formation of packed coordination structures containing multiple sites for CH-F intermolecular interactions, resulting in thermal stability above 350 °C. The electronic coupling is controlled by changing the concentration of the GdIII ion in the EuIII-GdIII polymer. The emission quantum yield and the maximum relative temperature sensitivity (Sm) of emission lifetimes for the EuIII-GdIII polymer (Eu:Gd=1:1, Φtot=52 %, Sm=3.73 % K−1) were higher than those for the pure EuIII coordination polymer (Φtot=36 %, Sm=2.70 % K−1), respectively. Enhanced temperature sensing properties are caused by control of long-range electronic coupling based on phosphine oxide with chrysene framework. - <i>In-situ</i> Observation of Corrosion Initiation Occurring on NaCl Nanoparticles-deposited Carbon Steel Surfaces
Koji Fushimi, Haruka Okuyama, Kai Ohshimizu, Sunao Shoji, Yuichi Kitagawa, Yasuchika Hasegawa
Tetsu-to-Hagane, 107, 12, 1011, 1019, Iron and Steel Institute of Japan, 2021年
研究論文(学術雑誌) - Photolithographic fabrication of a micro-electrode surface on a carbon steel sheet for local hydrogen permeation measurements
Fushimi Koji, Ishii Nozomi, Nakajima Ayako, Kitagawa Yuichi, Hasegawa Yasuchika, Matsuo Yasutaka
ISIJ International, 61, 4, 1112, 1119, 2021年
研究論文(学術雑誌), Microelectrodes for hydrogen permeation measurements were fabricated by photolithography. Although the application of a positive-type photoresist coating was effective for the formation of a circle-shaped pattern with a diameter of several tens of micrometers on an iron surface, the coating had poor adhesion to the iron surface and poor durability in an H2SO4 solution. However, the addition of a silica coating derived from tetraethoxysilane (TEOS) on the iron surface as an inner layer resulted in improvement of durability as well as resistance of the coating. Furthermore, the introduction of a layer derived from a mixture of TEOS and glycidyl 3-trimethoxysilylpropyl ether (GPTMS) between the inner layer derived from TEOS and the photoresist coating resulted in long durability showing a large impedance of more than 109 Ω cm2 for 4×105 s in an H2SO4 solution. Cathodic polarization of the microelectrode on the iron surface revealed that the hydrogen evolution reaction (HER) rate is dependent on the plane orientation of the surface. HER rate on an SCM435 steel surface also strongly depended on the microstructure and hardness of the local surface. - Rapid method to measure hydrogen diffusion coefficient in metal using a multi-sine wave signal
Yamamoto Yudai, Kitagawa Yuichi, Hasegawa Yasuchika, Fushimi Koji
ISIJ International, 61, 4, 1064, 1070, 2021年
研究論文(学術雑誌), The electrochemical hydrogen penetration measurement technique, to which a sinusoidal perturbation method was applied, was modified using a signal containing multiple frequency components. The technique was successfully applied to measurement of the hydrogen diffusion coefficient in a ferric sheet specimen. A series of numerical calculations for the technique, in which the constituent frequencies of the signal were selected from the measurement result, also provided the same diffusion coefficient and verified the validity of the technique. The use of this technique enables rapid determination of the hydrogen diffusion coefficient in a specimen. - An Europium (III) Luminophore with Pressure-Sensing Units: Effective Back Energy Transfer in Coordination Polymers with Hexadentate Porous Stable Networks
Y. Hasegawa, T. Sawanobori, Y. Kitagawa, S. Shoji, K. Fushimi, Y. Nakadaka, T. Masuda, I. Hisaki
ChemPlusChem., 85, 9, 1989, 1993, 2020年12月, [査読有り], [筆頭著者, 責任著者], [国際誌]
英語, 研究論文(学術雑誌), A luminescent EuIII coordination polymer with O2 -sensing units under air, EuIII -hcpt (hcpt: 2,3,6,7,10,11-hexakis(4-carboxy-phenyl)triphenylene), is reported. The hexadentate carboxylic acids in hcpt ligands play an important role in the formation of tight-packed three-dimensional networks in EuIII -hcpt, giving hyper thermo-stable structures (decomposition temperature=420 °C). The three-dimensional porous network promotes bright luminescence (4f-4f emission quantum yield=70 %). The emission lifetime of EuIII -hcpt under vacuum (0.86 ms) was twice as large as that under O2 (0.48 ms, 1 atom:101.3 kPa). The Arrhenius analysis of the emission decay profile indicates that the back energy transfer (BEnT) from the emitting level of the europium(III) ion to the excited T1 state of the hcpt ligand should be activated at room temperature. The gradual decrease of emission lifetime is caused by the BEnT process in EuIII -hcpt. Finally, an advanced pressure-sensitive luminophore is demonstrated. - Circularly polarized absorption and luminescence of semiconductor Eu-OCN nanocrystals in blue light region
Y. Hasegawa, K. Koide, M. Tsurui, Y. Kitagawa, T. Nakanishi, Y. Doi, Y. Hinatsu, K. Fushimi
ChemPhysChem, 21, 2019, 2024, 2020年12月, [査読有り], [筆頭著者, 責任著者]
研究論文(学術雑誌) - Dual Energy Transfer Pathways from an Antenna Ligand to Lanthanide Ion in Trivalent Europium Complexes through Phosphine-Oxide Bridges
S. Miyazaki, K. Miyata, H. Sakamoto, F. Suzue, Y. Kitagawa, Y. Hasegawa, K. Onda
J. Phys. Chem. A, 124, 6601, 6606, 2020年12月, [査読有り]
研究論文(学術雑誌) - Chiral lanthanide lumino-glass for a circularly polarized light security device
Y. Kitagawa, S. Wada, MD J. Islam, K. Saita, M. Gon, K. Fushimi, K. Tanaka, S. Maeda, Y. Hasegawa
Communications Chemistry, 3, 1, 119, 2020年12月, [査読有り], [最終著者, 責任著者]
研究論文(学術雑誌), Artificial light plays an essential role in information technologies such as optical telecommunications, data storage, security features, and the display of information. Here, we show a chiral lanthanide lumino-glass with extra-large circularly polarized luminescence (CPL) for advanced photonic security device applications. The chiral lanthanide glass is composed of a europium complex with the chiral (+)-3-(trifluoroacetyl)camphor ligand and the achiral glass promoter tris(2,6-dimethoxyphenyl)phosphine oxide ligand. The glass phase transition behavior of the Eu(III) complex is characterized using differential scanning calorimetry. The transparent amorphous glass shows CPL with extra-large dissymmetry factor of gCPL = 1.2. The brightness of the lumino-glass is one thousand times larger than that of Eu(III) luminophores embedded in polymer films of the same thickness at a Eu(III) concentration of 1 mM. The application of the chiral lanthanide lumino-glass in an advanced security paint is demonstrated. - Stacked nanocarbon photosensitizer for efficient blue light excited Eu(III) emission
Yuichi Kitagawa, Fumiya Suzue, Takayuki Nakanishi, Koji Fushimi, Tomohiro Seki, Hajime Ito, Yasuchika Hasegawa
Communications Chemistry, 3, 1, 3, 2020年12月01日, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌), © 2020, The Author(s). Photosensitizer design to allow effective use of low-energy light is important for developing photofunctional materials. Herein, we describe a rational photosensitizer design for effective use of low-energy light. The developed photosensitizer is a stacked nanocarbon based on a rigid polyaromatic framework, which allows efficient energy transfer from the low-energy T1 level to the energy acceptor. We prepared an Eu(III) complex consisting of a luminescent center (Eu(III)) and stacked-coronene photosensitizer. The brightness of photosensitized Eu(III) excited using low-energy light (450 nm) is more than five times higher than the maximum brightness of previously reported Eu(III) complexes. - Effect of intentional convection on the passivity of an Fe–6Cr surface in pH 4.5 Na2SO4 solution
K. Fushimi, T. Kanazawa, A. Fujimura, Y. Kitagawa, Y. Hasegawa, T. Doi
Electrochimica Acta, 346, 136237, 136237, Elsevier BV, 2020年06月, [査読有り]
研究論文(学術雑誌) - Electronic strain effect on Eu(iii) complexes for enhanced circularly polarized luminescence
Makoto Tsurui, Yuichi Kitagawa, Koji Fushimi, Masayuki Gon, Kazuo Tanaka, Yasuchika Hasegawa
Dalton Trans., 49, 5352, 5361, 2020年04月07日, [査読有り], [国際誌]
英語, Luminescent Eu(iii) complexes with point-chiral phosphine oxide ligands, [Eu(hfa)3((R,R)-B2QPO)] (hfa: hexafluoroacetylacetonato, B2QPO: 2,3-bis(tert-butylmethylphosphine oxide)quinoxaline) and [Eu(hfa)3((R)-B3QPO)] (B3QPO: 2-tert-butylmethylphosphine oxide-3-(di-tert-butylphosphineoxide)quinoxaline), are reported for the investigation of the electronic strain effect on the coordination sphere. Single crystal X-ray crystallography reveals the strong structural strain of the hfa ligands in [Eu(hfa)3((R,R)-B2QPO)]. The emission quantum yields of [Eu(hfa)3((R,R)-B2QPO)] in solution (55%) and solid (63%) are comparable to those of previously reported bright luminescent Eu(iii) complexes. The chiroptical properties of [Eu(hfa)3((R,R)-B2QPO)] and [Eu(hfa)3((R)-B3QPO)] were characterized using circular dichroism (CD) and circularly polarized luminescence (CPL) spectra. The dissymmetry factor of [Eu(hfa)3((R,R)-B2QPO)] was estimated to be 0.08. The chiroptical phenomena of the Eu(iii) complexes are closely related to their structural (geometry) and electronic (LMCT: ligand-to-metal charge transfer) strains. - First demonstration of the π–f orbital interaction depending on the coordination geometry in Eu(III) luminophores
Y. Kitagawa, M. Kumagai, P. P. Ferreira da Rosa, K. Fushimia and Y. Hasegawa
Dalton Trans., 49, 10, 3098, 3101, 2020年03月09日, [査読有り], [最終著者, 責任著者], [国際誌]
英語, 研究論文(学術雑誌), Herein, the π-f orbital interaction depending on the coordination geometry in the Eu(iii) complex is demonstrated. Thermal analysis and computational calculations showed the phase transition of the Eu(iii) complex based on the change in the coordination geometry. A red-shifted LMCT band and radiative rate changes associated with the phase transition were found in the Eu(iii) complex. - The Role of π−f Orbital Interactions in Eu(III) Complexes for an Effective Molecular Luminescent Thermometer
Y. Kitagawa, M. Kumagai, T. Nakanishi, K. Fushimia and Y. Hasegawa
Inorg. Chem., 59, 5865, 5871, 2020年03月06日, [査読有り], [最終著者, 責任著者], [国際誌]
英語, 研究論文(学術雑誌), Luminescent Eu(III) complexes with a ligand-to-metal charge transfer (LMCT) state were demonstrated for the development of a molecular thermometer. The Eu(III) complex was composed of three anionic ligands (hfa: hexafluoroacetylacetonate) and a phosphine oxide derivative containing a chrysene framework (diphenylphosphorylchrysene (DPCO)). The chrysene framework induced a rigid coordination structure via intermolecular interactions, resulting in a high thermal stability (decomposition point: 280 °C). The Eu(III) complex also exhibited an extremely high molar absorption coefficient (490000 cm-1 M-1), high intrinsic emission quantum yields (73%), and temperature-dependent energy migration between ligands and Eu(III) ion. The characteristic energy migration system was explained by the presence of the LMCT state based on π-f orbital interactions. - Steric and Electronic Control of Chiral Eu(III) Complexes for Effective Circularly Polarized Luminescence.
Yuichi Kitagawa, Makoto Tsurui, Yasuchika Hasegawa
ACS omega, 5, 8, 3786, 3791, 2020年03月03日, [査読有り], [招待有り], [最終著者, 責任著者], [国際誌]
英語, 研究論文(学術雑誌), Circularly polarized luminescence (CPL) is characterized by the differential emission of right and left circularly polarized light by a chiral molecule. This mini-review describes the recent developments in chiral trivalent europium (Eu(III)) complexes with effective CPL. CPL has many potential applications in security tags, lasers, and three-dimensional organic electroluminescence devices, which is one of the most intensely investigated topics in molecular luminophores. Eu(III) complexes have attracted considerable attention as effective CPL luminophores for the above-mentioned applications. In this review, recent studies on the Eu(III) CPL, including the steric (dimer, tetramer, aggregates, and coordination polymers) and electronic control (mononuclear) of Eu(III) complexes for the construction of a luminophore with effective CPL, are discussed. The characteristic CPL applications employing the chiral mononuclear Eu(III) complexes are also described. Chiral Eu(III) complexes with well-designed organic ligands can result in the establishment of new research areas in the fields of photochemistry and materials science. - First aggregation-induced emission of a Tb(III) luminophore based on modulation of ligand– ligand charge transfer bands
Y. Kitagawa, M. Kumagai, T. Nakanishi, K. Fushimia and Y. Hasegawa
Dalton Trans., 49, 8, 2431, 2436, 2020年02月25日, [査読有り], [最終著者, 責任著者], [国際誌]
英語, 研究論文(学術雑誌), Herein the aggregation-induced emission (AIE) of a Tb(iii) complex is reported for the first time. The Tb(iii) complex is composed of three anionic ligands (acac: acetylacetonate) and one large hetero-π-conjugated neutral ligand (dpq: dipyrido[3,2-f:2',3'-h]quinoxaline). The formation of a crystalline J-aggregate of the Tb(iii) complex (CJ-Tb(iii)) was characterized by X-ray crystal structure analysis and absorption spectra. A crystalline H-aggregate (CH-Tb(iii)) was also prepared using the ligand steric effect (tmh: 2,2,6,6-tetramethyl-3,5-heptanedionate). The emission and AIE properties of CJ-Tb(iii) were evaluated using emission spectra, lifetime, and quantum yields, whereas CH-Tb(iii) did not emit photons. Density functional theory calculations predict that the AIE originates from the modulation of ligand-to-ligand charge transfer bands through J-aggregation. - Aggregation-induced emission of a Eu(III) complex via ligand-to-metal charge transfer
Yuichi Kitagawa, Marina Kumagai, Koji Fushimia, Yasuchika Hasegawa
Chemical Physics Letters, 749, 137437, 137437, Elsevier BV, 2020年, [査読有り]
研究論文(学術雑誌) - Dithieno[3,4-b:3′,4′-d]arsole: A Novel Class of Hetero[5]radialenes
Aya Urushizaki, Takashi Yumura, Yuichi Kitagawa, Yasuchika Hasegawa, Hiroaki Imoto, Kensuke Naka
Eur. J. Org. Chem., 2020年, [査読有り] - Characteristic Evaluation of Chameleon Luminophore Dispersed in Polymer
M. Kasai, Y. Sugioka, M. Yamamoto, T. Nagata, T. Nonomura, K. Asai, Y. Hasegawa
Sensors, 20, 2623, s20092623, 2623, 2020年, [査読有り]
研究論文(学術雑誌) - Splitting and Reorientation of π-Conjugation by an Unprecedented Photo-Rearrangement Reaction
Yuya Inaba, Tomoki Yoneda, Yuichi Kitagawa, Kiyoshi Miyata, Yasuchika Hasegawa, Yasuhide Inokuma
CHEMICAL COMMUNICATIONS, 56, 3, 348, 351, ROYAL SOC CHEMISTRY, 2020年, [査読有り]
英語, 研究論文(学術雑誌), A dodecahexaene analogue cross-conjugated with four carbonyl groups was prepared from an aliphatic tetraketone. Exposure to LED light (>420 nm) led to the splitting of the dodecahexaene conjugation into two hexatriene subunits, connected through a stereogenic carbon atom. The two triene subunits exhibited excitonic coupling in the UV-Vis absorption and CD spectra. - Luminescent Coordination Polymers Constructed from Flexible, Tetradentate Diisopyrazole Ligand and Copper(I) Halides
Tomoki Yoneda, Chika Kasai, Yumehiro Manabe, Makoto Tsurui, Yuichi Kitagawa, Yasuchika Hasegawa, Parantap Sarkar, Yasuhide Inokuma
Chemistry–An Asian Journal, 15, 5, 601, 605, WILEY-V C H VERLAG GMBH, 2020年, [査読有り]
英語, 研究論文(学術雑誌), One- and two-dimensional coordination polymers composed of a structurally flexible, tetradentate diisopyrazole ligand and copper(I) halides were synthesized as crystalline solids. Complexation with copper(I) chloride or bromide resulted in the formation of infinite coordination chains through connecting each diisopyrazole ligand with two copper(I) ions in a trigonal planar coordination geometry. Contrarily, the combination of a diisopyrazole ligand and copper(I) iodide gave a two-dimensional coordination network comprising Cu4I4 units with stair-step type geometry and diisopyrazoles that acted as both tetradentate and bidentate bridging ligands. All the coordination polymers exhibited visible photo-emission upon UV irradiation, and the Cu4I4 complex showed thermochromic behavior. - Luminescent lanthanide complex with seven-coordination geometry
P.-P. Ferreira da Rosa, Y. Kitagawa, Y. Hasegawa
Coordination Chemistry Reviews, 213153, 2020年, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Olefin-accelerated solid-state C–N cross-coupling reactions using mechanochemistry
K. Kubota, T. Seo, K. Koide, Y. Hasegawa, H. Ito
Nature Commun., 10, 1, doi.org/10.1038/s41467-018-080, Springer Science and Business Media {LLC}, 2019年12月, [査読有り]
英語, 研究論文(学術雑誌) - Near-IR Luminescent YbIII Coordination Polymers Composed of Pyrene Derivatives for Thermostable Oxygen Sensors
Yasuchika Hasegawa, Takafumi Matsui, Yuichi Kitagawa, Takayuki Nakanishi, Tomohiro Seki, Hajime Ito, Yuta Nakasaka, Takao Masuda, Koji Fushimi
Chemistry - A European Journal, 25, 53, 12308, 12315, 2019年09月20日, [査読有り]
英語, 研究論文(学術雑誌), © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Oxygen-sensitive and near-infrared (NIR) luminescent YbIII coordination polymers incorporating ligands based on pyrene derivatives were synthesized: YbIII–TBAPy and YbIII–TIAPy (TBAPy: 1,3,6,8-tetrakis(p-benzoate)pyrene; TIAPy: 1,3,6,8-tetrakis(3,5-isophthalic acid)pyrene). The coordination structures of these materials have been characterized by means of electrospray ionization mass spectrometry, X-ray diffraction analysis, and thermogravimetric analysis. Moreover, the porous structure of YbIII–TIAPy has been evaluated by measuring its N2 adsorption isotherm. The NIR luminescence properties of YbIII–TBAPy and YbIII–TIAPy have been examined by acquiring emission spectra and determining emission lifetimes under air or argon and in vacuo. YbIII–TIAPy exhibited high thermal stability (with a decomposition temperature of 400 °C), intense luminescence (with an emission quantum yield under argon of 6.6 %), and effective oxygen-sensing characteristics. These results suggest that NIR luminescent YbIII coordination polymers prepared using pyrene derivatives could have applications in novel thermo-stable oxygen sensors. - Thermo-sensitive luminescence of lanthanide complexes, clusters, coordination polymers and metal-organic frameworks with organic photosensitizers
Hasegawa Yasuchika, Kitagawa Yuichi
JOURNAL OF MATERIALS CHEMISTRY C, 7, 25, 7494, 7511, 2019年07月07日, [査読有り] - Perfluorophenyl-Directed Giant Porphyrin J-Aggregates
Mitsuhiko Morisue, Ikuya Ueno, Kunihiko Muraoka, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa, Takaaki Hikima, Sono Sasaki
Chemistry - A European Journal, 25, 30, 7322, 7329, 2019年05月28日, [査読有り]
英語, 研究論文(学術雑誌), © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Quadrupolar interactions of porphyrin bearing two pentafluorophenylethynyl terminals (1) drove the formation of a successive one-dimensional staircase structure, i.e., J-aggregates, to yield millimeter-length needles with a single-crystalline character in methylcyclohexane solution. In contrast, π-stacked interactions of porphyrin bearing two nonfluorinated phenyl terminals (2) formed no aggregates in solution. A spin-cast film of 1 also showed bathochromic shift of the Soret and Q bands, indicating the formation of J-aggregates. The molecular arrangement of the J-aggregates was revealed by microbeam glazing-incidence wide-angle X-ray diffraction (GIWAXD), and was in good agreement with the optimized structure generated by density functional theory (DFT) calculations. - Photoluminescence Properties of [Core+exo]‑Type Au6 Clusters: Insights into the Effect of Ligand Environments on the Excitation Dynamics
Y. Shichibu, M. Zhang, T. Iwasa, Y. Ono, T. Taketsugu, S. Omagari, T. Nakanishi, Y. Hasegawa, K. Konishi
J.Phys. Chem. C., 123, 11, 6934, 6939, 2019年03月21日, [査読有り]
英語, 研究論文(学術雑誌), © Copyright 2019 American Chemical Society. The use of multidentate chelating ligands enriches the geometric diversity of coordinated gold clusters, offering much knowledge to benefit the understanding of their unique electronic structures and optical properties. Herein we report different behaviors of [core+exo]-type Au6 clusters bearing C3- and C4-bridged diphosphines (1 and 2), highlighting profound effects of the steric constraints of the ligand environments on the excited-state structural dynamics. Although the Au6 geometries of 1 and 2 in the crystalline states were somewhat different, their absorption spectra in solution were almost similar. However, marked differences were found in the photoluminescence properties; phosphorescent-type emission was dominantly observed for 1, whereas 2 gave both fluorescence- and phosphorescence-type emissions. Theoretical calculations showed that the bridging chains influence the geometries of the Au6 unit in the excited states, leading to the observed differences in emission behaviors. - 価数制御した希土類ナノ結晶の発光特性評価
岩本 真帆, 神田 翔太, 川島 祥, 宮部 豪人, 長谷川 靖哉, 甲谷 繁
日本薬学会年会要旨集, 139年会, 2, 253, 253, (公社)日本薬学会, 2019年03月
日本語 - Hydrogen permeation into a carbon steel sheet observed by a micro-capillary combined with a devanathan-stachurski cell
Koji Fushimi, Misako Jin, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa
Tetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan, 105, 1, 64, 68, 2019年01月, [査読有り]
研究論文(学術雑誌), © 2019 Iron and Steel Institute of Japan. All Rights Reserved. Synopsis: A micro-capillary technique was applied to a Devanathan-Stachurski electrochemical cell for local measurement of hydrogen permeation into a steel sheet. An electrolyte-flowing design for the hydrogen entry side of the Devanathan-Stachurski cell successfully allowed the detection of hydrogen permeation response on hydrogen exit side electrode in a micro-capillary cell with a diameter of 250 μm. Phase shift of the detected permeation current from a sinusoidal perturbation of the electrolyte flow rate in the hydrogen entry cell was strongly dependent on the metallographic structure of the steel sheet. A local structure, in which two single grains form grain boundaries, led to hydrogen permeation more frequently than did a local structure of single grains. The results suggested that the diffusion coefficient of the boundaries was at least two-times larger than that of the grains. - Evaluation of Zn2+ Coordination Structures in Chiral Zn2+ Complexes Based on Shape Measurement Factors: Relationships between Catalytic Activity and the Coordination Structure
S. Aoki, Y. Kitagawa, Y. Hasegawa, S. Sonoike, Y. Saga, M. Hatanaka
Eur. J. Inorg. Chem., 2019, 44, 4740, 4751, Wiley, 2019年, [査読有り]
英語, 研究論文(学術雑誌) - Thermal and crystallographic investigation of luminescent Eu(III) coordination polymers with dithiane and dioxane hexyl rings
Y. Hirai, P. P. Ferreira da Rosa, Y. Kitagawa, Y. Hasegawa
Chem. Lett., 48, 1544, 1546, 2019年, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Lifetimes of lanthanide(III) Triboluminescence Excited by Aerodynamic Shock Waves
Y. Hirai, A. Kotani, H. Sakaue, Y. Kitagawa, Y. Hasegawa
J. Phys. Chem. C, 123, 27251, 27256, 2019年, [査読有り], [最終著者, 責任著者]
英語, 研究論文(学術雑誌) - Micro- and nano-scopic aspects of passive surface on pearlite structure of carbon steel in pH 8.4 boric acid-borate buffer
Koji Fushimi, Ryogo Nakagawa, Yuichi Kitagawa, Yasuchika Hasegawa
J. Electrochem. Soc., 166, C3409, C3416, 2019年, [査読有り]
英語, 研究論文(学術雑誌) - Luminescent Lanthanide Complexes, Clusters, Coordination Polymers and Metal-organic Frameworks with Temperature-sensing properties
Y. Hasegawa, Y. Kitagawa
J. Mater. Chem. C., 7, 7494, 7511, 2019年, [査読有り]
英語, 研究論文(学術雑誌) - Photophysical investigation of near infrared emitting lanthanoid complexes incorporating tris (2-naphthoyl)methane as a new antenna ligand
La. A. Galán, S. Wada, L. Cameron, A. N. Sobolev, Y. Hasegawa, E. Zysman-Colman, M. I. Ogden, M. Massi
Dalton Trans., 48, 3768, 3776, 2019年, [査読有り]
英語, 研究論文(学術雑誌) - Visualization of icing of supercooled water using Tb(III)-basedtemperature-sensitive paint
Y. Hirai, A. Mallette, Y. Nishio, W. Patterson, Y. Hasegawa, H. Sakaue
Sensors and Actuators: A. Physical, 285, 599, 602, 2019年, [査読有り]
英語, 研究論文(学術雑誌) - Structural Manipulation of Triboluminescent Lanthanide Coordination Polymers by Side-Group Alteration
Hajime Ito, Yuichi Hirai, Pedro Paulo Ferreira da Rosa, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Yasuchika Hasegawa
Inorganic Chemistry, 58, 14653, 14659, American Chemical Society ({ACS}), 2018年12月03日, [査読有り]
英語, 研究論文(学術雑誌) - Ligand-Assisted Back Energy Transfer in Luminescent Tb-III Complexes for Thermosensing Properties
Yamamoto, Masanori, Kitagawa, Yuichi, Nakanishi, Takayuki, Fushimi, Koji, Hasegawa, Yasuchika
CHEMISTRY-A EUROPEAN JOURNAL, 24, 67, 17719, 17726, WILEY-V C H VERLAG GMBH, 2018年12月, [査読有り]
英語, 研究論文(学術雑誌), A luminescent Tb-III complex with a hexafluoroacetylacetone (hfa) ligand shows a characteristic back energy transfer (BEnT), which leads to high temperature sensitivity and potential application as a thermosensitive paint. Ligand-assisted BEnT was observed when a phosphine oxide ligand was introduced into Tb(hfa)(3) complex, which was shown to affect the activation energy (Delta E-a) and frequency factor (A) in the BEnT process between Tb-III ion and hfa ligands. According to temperature-dependent emission-lifetime measurements of mononuclear Tb(hfa)(3) complexes with monodentate phosphine oxides and polynuclear Tb(hfa)(3) complexes with bidentate phosphine oxides, the Delta E-a and A values of polynuclear Tb-III complexes were smaller than those of mononuclear Tb-III complexes. Phosphorescence spectra and lifetimes of each Gd(hfa)(3) complex revealed that excited states of hfa ligands in Tb(III)complexes differed from those of the polynuclear Tb-III complexes and mononuclear Tb-III complexes. The differences in the Delta E-a and A values between polynuclear and mononuclear Tb-III complexes were caused by the formation of different excited states, such as delocalization of the excited state in the polynuclear Tb-III complexes and localization of excited states in the mononuclear Tb-III complexes. In particular, small Delta E-a and A values of polynuclear Tb-III complexes provided high, effective activation of the BEnT at low temperature, which resulted in high-sensitive temperature-dependent phosphor materials over a wide temperature range. - Electronic chirality inversion of lanthanide complex induced by achiral molecules
Wada, Satoshi, Kitagawa, Yuichi, Nakanishi, Takayuki, Gon, Masayuki, Tanaka, Kazuo, Fushimi, Koji, Chujo, Yoshiki, Hasegawa, Yasuchika
SCIENTIFIC REPORTS, 8, 16395, NATURE PUBLISHING GROUP, 2018年11月, [査読有り]
英語, 研究論文(学術雑誌), 3A novel mechanism for chiroptical activity inversion based on the electronic structure of metal complexes without Lambda- or Delta-type structure change was demonstrated spectroscopically and theoretically. To demonstrate the mechanism, a europium (Eu(III)) complex with chiral (+)-3-(trifluoroacetyl) camphor (+tfc) and achiral triphenylphosphine oxide (tppo) was prepared. The steric and electronic structures of the Eu(III) complex were adjusted by additional achiral tppo and coordinating acetone molecules, and were characterised by H-1 NMR, photoluminescence, and emission lifetime measurements. The optical activity of the Eu(III) complex in solution was evaluated by circularly polarized luminescence (CPL) measurements. CPL sign inversion, which was independent of Lambda- or Delta-type structure changes from the spectroscopic viewpoint, and a drastic CPL intensity enhancement were observed depending on the external achiral molecules around Eu(III) ion. These phenomena provide the first clarification of optical activity change associated with electronic structure rather than chiral coordination structure-type (Lambda or Delta) under external environments. - Spin-orbit coupling dependent energy transfer in luminescent nonanuclear Yb-Gd / Yb-Lu clusters
Shun Omagari, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Koji Fushimi, Hajime Ito, Andries Meijerink, Yasuchika Hasegawa
Journal of Luminescence, 201, 170, 175, 2018年09月, [査読有り]
英語, 研究論文(学術雑誌), © 2018 Elsevier B.V. In luminescent lanthanide (Ln(III)) complexes, the yield and the lifetime of triplet excited state of organic ligands are crucial factors that affect the ligands-to-Ln(III) energy transfer efficiency. Such factors are dependent on spin-orbit coupling induced by the Ln(III) ions that mixes different multiplicity states through heavy atom and paramagnetic effects. We investigated the role of these effects on the energy transfer efficiency in synthesized nonanuclear Yb-Gd / Yb-Lu clusters ([Ln9(µ-OH)10(butyl salicylate)16]NO3, Ln9 = YbnGd9-n or YbnLu9-n, n = 0, 1, 3, 7, and 9). Based on the intensity of the fluorescence and phosphorescence of the ligands, the spin-orbit coupling strength was in the order of Yb(III) > Gd(III) > Lu(III). Various photophysical processes affecting the energy transfer efficiency in YbnGd9-n and YbnLu9-n clusters are discussed from the perspective of spin-orbit coupling and give insight in how to optimize energy transfer efficiencies. - Red Luminescent Eu(III) Coordination Bricks Excited on Blue LED Chip
Toru Koizuka, Kei Yanagisawa, Yuichi Hirai, Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
Inorganic Chemistry, 57, 12, 7097, 7103, American Chemical Society, 2018年06月18日, [査読有り]
英語, 研究論文(学術雑誌), Three types of red luminescent Eu(III) complexes with Schiff base and hfa ligands (hfa: hexafluoroacetylacetonate), mononuclear [Eu(hfa)2(OAc)(salen)2] (OAc: acetate anion, salen: N,N′-bis(salicylidene)ethylenediamine), brick-type [Eu2(hfa)4(OAc)2(salbn)2] (salbn: N,N′-bis(salicylidene)-1,4-butanediamine), and polynuclear [Eu(hfa)2(OAc)(salhen)]n (salhen: N,N′-bis(salicylidene)-1,6-hexanediamine) are reported for white light-emitting diode (LED) devices. Among these complexes, brick-type [Eu2(hfa)4(OAc)2(salbn)2] excited by blue light (460 nm) exhibits the photosensitized quantum yield (φπ-π∗ = 47%) and remarkably high efficiency of sensitization (ηsens = 96%). The efficiency of sensitization is caused by the excited state based on ligand-ligand interaction between the Schiff base and hfa ligands in Eu(III) complexes. To fabricate LED devices, the red luminescent [Eu2(hfa)4(OAc)2(salbn)2] was mounted on an InGaN blue LED chip. - Thermosensitive Seven-Coordinate TbIII Complexes with LLCT Transitions
Pedro Paulo Ferreira da Rosa, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Hajime Ito, Koji Fushimi, Yasuchika Hasegawa
European Journal of Inorganic Chemistry, 2018, 19, 2031, 2037, Wiley-VCH Verlag, 2018年05月24日, [査読有り]
英語, 研究論文(学術雑誌), Seven-coordinate TbIII complexes with strong luminescence and thermosensing properties are reported. Mononuclear [Tb(tmh)3(PEB)] [tmh: 2,2,6,6-tetramethyl-3,5-heptanedione, PEB: (diphenylphosphoryl)ethynyl]benzene and dinuclear [Tb2(tmh)6(m-BPEB)] [m-BPEB: 1,3-bis(diphenylphosphoryl)ethynyl]benzene were characterized by single-crystal X-ray analysis. The quantum yields of [Tb(tmh)3(PEB)] and [Tb2(tmh)6(m-BPEB)] were estimated to be 71 and 39 %, respectively. Thermosensing properties are evaluated by temperature-dependent emission lifetime measurements (Arrhenius analysis), which are affected by the presence of ligand-to-ligand charge transfer (LLCT) bands. The LLCT bands are confirmed by DFT calculations. - Effective Europium Coordination Luminophores Linked with Bi- and Tridentate Carbazole Phosphine Oxides for Organic Electroluminescent Devices
Yasuchika Hasegawa, Shiori Natori, Jun Fukudome, Takashi Nagase, Takashi Kobayashi, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Hiroyoshi Naito
Journal of Physical Chemistry C, 122, 17, 9599, 9605, 2018年05月03日, [査読有り]
英語, 研究論文(学術雑誌), © Copyright 2018 American Chemical Society. Lanthanide coordination polymers with charge combination parts, hole and electron transport units, [Eu(ntfa)3(dppcz)]n and [Eu3(ntfa)9(tpcz)2]n [ntfa = 3-(2-naphthoyl)-1,1,1-trifluoroacetonate, dppcz = 3,6-bis(diphenylphosphoryl)-9-phenylcarbazole), tpcz = 3,6-bis(diphenylphosphoryl)-9-[4-(diphenylphosphoryl)phenyl]carbazole], are reported as an emitting material for organic electroluminescent (EL) devices. The intrinsic emission quantum yields φ4f-4f of [Eu(ntfa)3(dppcz)]n and [Eu3(ntfa)9(tpcz)2]n in the solid state were calculated to be 32% and 45%, respectively. The photosensitized energy-transfer efficiencies ηsens from organic ntfa ligands to luminescent Eu(III) ions in [Eu(ntfa)3(dppcz)]n and [Eu3(ntfa)9(tpcz)2]n were found to be 84% and 39%, respectively. The energy-transfer efficiency ηsens from ntfa to Eu(III) ion is dependent on the network structure in Eu(III) coordination polymers in the solid state. The ηsens values and characteristic structures of Eu(III) coordination polymers are directly linked to maximum luminances and current efficiencies in solid EL devices, respectively. The luminance of an EL device containing [Eu(ntfa)3(dppcz)]n was estimated to be 188 cd/m2 at 15 V, which is greater than that of previously reported EL devices with Eu(III) complexes. - Solid-State and Nanoparticle Synthesis of EuSxSe1−x Solid Solutions
H. A. Dalafu, N. Rosa, D. James, D. R. C. Asuigui, M. McNamara, A. Kawashima, S. Omagari, T. Nakanishi, Y. Hasegawa, S. L. Stoll
Chem. Mater., 30, 9, 2954, 2964, AMER CHEMICAL SOC, 2018年05月, [査読有り]
英語, 研究論文(学術雑誌), Europium chalcogenide alloys, EuSxSe1-x, have been synthesized both in the solid-state and as colloidal nanoparticles; the composition, structure, magnetism, and optical band gaps have been characterized. The goal was to observe the consequences of selenium concentration on the electronic structure as evidenced by the optical and magnetic properties and whether these properties are maintained in the nanomaterials. Both solid-state and nanoparticle alloys obey Vegard's law with a systematic change in cell constant as confirmed by the powder X-ray diffraction. The bulk materials form homogeneous alloys that exhibit a linear change in both magnetic and optical properties as a function of composition. A synthetic method to prepare nanoalloys with a wide range of S:Se ratio has been developed. The nanoalloys are homogeneous, and EDS mapping of single nanoparticles indicates relatively uniform S and Se composition across the nanocrystals. The magnetic properties of the nanoparticles appear to parallel those in the solid-state. Although the composition is an effective tool to tune to the optical band gap in the solid-state alloys with a linear change in E-g with composition, the nanoparticle optical band gaps appeared to be shifted, which we attribute to the presence of an amorphous selenium phase. The study of the properties of colloidal alloys highlights the importance of the mechanism of nanoparticle formation to control composition and purity. - An Estimation Method of Metal-Ligand Orbital Mixing in Lanthanide(III) Complexes Using Magnetic Circular Dichroism
Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
ChemistrySelect, 3, 9, 2646, 2648, Wiley-Blackwell, 2018年03月07日, [査読有り]
英語, 研究論文(学術雑誌), The photophysical properties of lanthanide(III) complexes depend on the magnitude of orbital mixing between the lanthanide(III) and ligands. Herein, an estimation method of orbital mixing in lanthanide(III) complexes is reported using LnCl3⋅nH2O (Ln=Pr, Gd, Tb) and Ln(tfa)3(H2O)2 (tfa: trifluoroacetylacetonate, Ln=Pr, Gd, and Tb) for the first time. The electronic state properties were assessed from the electronic absorption and magnetic circular dichroism (MCD) spectra. The MCD spectra revealed the energy levels of the spin-allowed and spin-forbidden 4 f–5d transitions of the Tb(III) complex that is hidden by the intense π–π* transition of the ligands. This energy gap corresponds to the exchange splitting energy between the 5d and 4fn−1 electrons, which provides information regarding the orbital mixing between the Tb(III) ion and the ligands. - A Luminescent Dinuclear EuIII/TbIII Complex with LMCT Band as a Single-Molecular Thermosensor
Kei Yanagisawa, Yuichi Kitagawa, Takayuki Nakanishi, Tomohiro Seki, Koji Fushimi, Hajime Ito, Yasuchika Hasegawa
Chemistry - A European Journal, 24, 8, 1956, 1961, Wiley-VCH Verlag, 2018年02月06日, [査読有り]
英語, 研究論文(学術雑誌), Temperature-dependent luminescence of a dinuclear EuIII/TbIII complex with a seven-coordinate structure is demonstrated. The dinuclear complex is composed of two lanthanide ions, six tetramethylheptanedionate ligands, and a bidentate phosphine oxide linker ligand. The dinuclear structure of the complex was characterized by single-crystal XRD. Intrinsic 4f–4f emission quantum yields of the dinuclear EuIII and TbIII complexes were 66 and 61 %, respectively. The luminescence color of the dinuclear EuIII/TbIII complex changed from red to green with increasing temperature. The thermosensing range based on the ratio of luminescence intensity (AEu/ATb) was 100–450 K. The temperature-dependent luminescence is due to the presence of a ligand-to-metal charge-transfer state. - Origin of Concentration Quenching in Ytterbium Coordination Polymers: Phonon-Assisted Energy Transfer
Shun Omagari, Takayuki Nakanishi, Yuichi Hirai, Yuichi Kitagawa, Tomohiro Seki, Koji Fushimi, Hajime Ito, Yasuchika Hasegawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 5, 561, 567, WILEY-V C H VERLAG GMBH, 2018年02月, [査読有り]
英語, 研究論文(学術雑誌), Phonons are important in energy transfer for compensating the energy mismatch between a donor and an acceptor. In inorganic hosts doped with lanthanides, phonon-assisted energy transfer can lead to quenching by a direct transfer of the energy to the phonon mode of the acceptor lanthanide. We demonstrate that this also applies to lanthanide coordination polymers and is the reason for the weak concentration quenching in this type of material. [YbxGd1-x(hfa)(3)dpbp](n) [x = 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1; hfa: hexafluoroacetylacetonate, dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl] coordination polymers have been synthesized and their photophysical properties investigated. The single-exponential emission lifetimes of Yb3+ gradually decreased with increasing concentration of Yb3+. Qualitative agreement was achieved between the experimental and theoretical lifetimes by using the phonon-assisted energy-transfer-induced quenching model, which indicates that the origin of the concentration quenching in the coordination polymers is phonon-assisted energy transfer. - Three-dimensional coordination polymers composed of luminescent lanthanide element blocks
Hasegawa, Y., Nakanishi, T., Kitagawa, Y.
New Polymeric Materials Based on Element-Blocks, 2018年
研究論文(学術雑誌) - Synthesis and photophysical properties of Eu(III) complexes with phosphine oxide ligands including metal ions
Masanori Yamamoto, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Hajime Ito, Koji Fushimi, Yasuchika Hasegawa
Bulletin of the Chemical Society of Japan, 91, 1, 6, 11, Chemical Society of Japan, 2018年, [査読有り]
英語, 研究論文(学術雑誌), Lanthanide (Ln3+) complexes composed of luminescent Eu3+ complex and joint metal blocks (Al3+, Zn2+ and Pd2+ complexes) are reported. The Eu3+ complexes [Eu(hfa)3- (dppy)2PdCl2]n (Eu-Pd), [Eu(hfa)3(dppy)2ZnCl2]n (Eu-Zn) and [Eu(hfa)3(dppy)4AlCl3]n (Eu-Al) (hfa: hexafluoroacetylacetonato, dppy: 4-pyridyldiphenylphosphine oxide) were synthesized by the complexation of [Eu(hfa)3(H2O)2] with [MCln-(dppy)m] (M = Pd2+, Zn2+ and Al3+). These predicted structures were estimated using single-crystal X-ray structural analyses and DFT calculations. Photophysical properties of these complexes were evaluated based on the emission lifetimes and emission quantum yields. The emission quantum yields are dependent on the moiety of the joint metal blocks. Eu-Al complex shows the largest emission quantum yield (Φff = 72%). In contrast, the emission quantum yield of Eu-Pd is found to be 1.3%. The structures and photophysical properties of Eu3+ complexes linked with joint metal blocks are demonstrated. - Highly luminescent tetranuclear Eu(III) complex with characteristic cavity Space
T. Koizuka, Y. Kitagawa, T. Nakanishi, K. Fushimi, Y. Hasegawa
Inorg. Chim. Acta, 486, 240, 244, 2018年, [査読有り]
英語, 研究論文(学術雑誌) - Time-dependent measurement of hydrogen penetration into iron sheets from borate buffer solution using FFT analysis
Yudai Yamamoto, Yuichi Kitagawa, Yasuchika Hasegawa, Koji Fushimi
J. Electrochem. Soc., 165, 13, C900, C906, ELECTROCHEMICAL SOC INC, 2018年, [査読有り]
英語, 研究論文(学術雑誌), Hydrogen penetration into iron sheets from a borate buffer solution (pH 8.4) was investigated using a modified Devanathan-Stachurski cell with flow paths. A sinusoidal perturbation method was applied to evaluate the hydrogen-diffusion coefficient D and its dependence on specimen thickness, polarization potential, and electrolyte flow rate. A fast Fourier transform (FFT) technique was employed to achieve automated derivation of the diffusion coefficient with precision and rapid screening of the experimental conditions. The obtained value of D increased with an increase in the specimen thickness or with an increase in the overpotential of the hydrogen evolution reaction, indicating the effect of a surface barrier layer-like oxide film on the hydrogen-entry side. On the other hand, D is not dependent on the electrolyte flow rate in the entry-side cell. From the viewpoint of hydrogen penetration, the properties of the barrier layer are almost immune to the flow rate, though it is affected by the polarization potential. The sinusoidal perturbation method combined with FFT allows the time-dependent evaluation of the hydrogen-penetration behavior in specimens with temporal changes, such as oxide-film formation and corrosion. (c) 2018 The Electrochemical Society. - Chiral α-Hydroxy Acid-Coadsorbed TiO2 Photocatalysts for Asymmetric Induction in Hydrogenation of Aromatic Ketones
S. Kohtani, A. Kawashima, F. Masuda, M. Sumi, Y. Kitagawa, E. Yoshioka, Y. Hasegawa, H. Miyabe
Chem. Comm., 54, 12610, 12613, 2018年, [査読有り]
英語, 研究論文(学術雑誌) - Liquid-Phase Ion Gun for Local Acidification of Na2S Aqueous Solution and Local Sulfidation of Fe-Cr Alloy Surface
K. Fushimi, S. Nakatsuji, J. Lee, Y. Kitagawa, T. Nakanishi, Y. Hasegawa, K. Baba, S. Tsuri
J. Electrochem. Soc., 165, C618, C623, 2018年, [査読有り]
英語, 研究論文(学術雑誌) - Asymmetric color-changeable luminophore with donor-acceptor-donor structure for solvent and temperature sensitive properties
Y. Kitagawa, R.Yachi, T. Nakanishi, K. Fushimi, Y. Hasegawa
ChemistrySelect, 39, 10905, 10908, 2018年, [査読有り]
英語, 研究論文(学術雑誌) - Spiral Eu(III) Coordination Polymers with Circularly Polarized Luminescence
Y. Hasegawa, Y. Miura, Y. Kitagawa, S. Wada, T. Nakanishi, K. Fushimi, T. Seki, H. Ito, T. Iwasa, T. Taketsugu, M. Gon, K. Tanaka, Y. Chujo, S. Hattori, M. Karasawa, K. Ishii
Chem. Comm., 54, 10695, 10697, 2018年, [査読有り]
英語, 研究論文(学術雑誌) - A highly luminescent Eu(iii) complex based on an electronically isolated aromatic ring system with ultralong lifetime
Yuichi Kitagawa, Fumiya Suzue, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
Dalton Transactions, 47, 21, 7327, 7332, Royal Society of Chemistry, 2018年, [査読有り]
英語, 研究論文(学術雑誌), A luminescent Eu(iii) complex with a large electronically isolated aromatic ring system, Eu(hfa)3(DPPTO)2 (where hfa denotes hexafluoroacetylacetonate and DPPTO denotes 2-diphenylphosphoryltriphenylene), is reported. The light-harvesting efficiency of the Eu(iii) complex was assessed from electronic absorption spectra. Luminescence properties were evaluated from luminescence spectra, excitation spectra, luminescence quantum yields, and luminescence lifetimes. A remarkably brilliant luminescence was observed because of the strong light absorption and the high luminescence quantum yield of the Eu(iii) complex. Density functional theory calculations indicated an electronic separation between the energy-donating large π-conjugated orbital and the energy-accepting Eu(iii) orbital. These findings demonstrate that novel Eu(iii) photophysics can be induced by large electronically isolated aromatic ring systems. - Fully Conjugated Porphyrin Glass: Collective Light-Harvesting Antenna for Near-Infrared Fluorescence beyond 1 µm
M. Morisue, S. Omagari, I. Ueno, T. Nakanishi, Y. Hasegawa, S. Yamamoto, J. Matsui, S. Sasaki, T. Hikima, S. Sakurai
ACS Omega, 3, 4, 4466, 4474, American Chemical Society, 2018年, [査読有り]
英語, 研究論文(学術雑誌), Expanded π-systems with a narrow highest occupied molecular orbital-lowest unoccupied molecular orbital band gap encounter deactivation of excitons due to the "energy gap law" and undesired aggregation. This dilemma generally thwarts the near-infrared (NIR) luminescence of organic π-systems. A sophisticated cofacially stacked π-system is known to involve exponentially tailed disorder, which displays exceptionally red-shifted fluorescence even as only a marginal emission component. Enhancement of the tail-state fluorescence might be advantageous to achieve NIR photoluminescence with an expected collective light-harvesting antenna effect as follows: (i) efficient light-harvesting capacity due to intense electronic absorption, (ii) a long-distance exciton migration into the tail state based on a high spatial density of the chromophore site, and (iii) substantial transmission of NIR emission to circumvent the inner filter effect. Suppression of aggregation-induced quenching of fluorescence could realize collective light-harvesting antenna for NIR-luminescence materials. This study discloses an enhanced tail-state NIR fluorescence of a self-standing porphyrin film at 1138 nm with a moderate quantum efficiency based on a fully π-conjugated porphyrin that adopts an amorphous form, called "porphyrin glass". - Effective Photo-, Electro- and Mechano-sensitized Luminescence of Lanthanide Complexes
Y. Hasegawa, Y. Kitagawa, T. Nakanishi
NPG Asia Mater., 10, 52, 70, 2018年, [査読有り], [招待有り]
英語, 研究論文(学術雑誌) - Photosensitized luminescence of highly thermostable mononuclear Eu (III) complexes with π-expanded β-diketonate ligands
T. Koizuka, M. Yamamoto, Y. Kitagawa, T. Nakanishi, K. Fushimi, Y. Hasegawa
Bull. Chem.Soc. Jpn., 90, 12, 1287, 1292, CHEMICAL SOC JAPAN, 2017年12月, [査読有り]
英語, 研究論文(学術雑誌), Thermostable mononuclear Eu(III) complexes with a pi-expanded system, [Eu(btfa)(3)(DPEPO)] and [Eu(ntfa)(3)(DPEPO)] (DPEPO: bis[2-(diphenylphosphino) phenyl] ether oxide, btfa: benzoyltrifluoroacetonate, ntfa: 3-(2-naphthoyl)-1,1,1-trifluoro-acetonate), are reported. Decomposition temperature (dp) of [Eu(btfa)(3)(DPEPO)] and that of [Eu(ntfa) 3(DPEPO)] are estimated to be 320 degrees C and 318 degrees C, respectively. These values are higher than that of the previous [Eu(hfa)(3)(DPEPO)] (hfa: hexa-fluoroacetylacetonate, dp = 228 degrees C). The photosensitized emission quantum yield Phi(pi-pi*) and photosensitized energy transfer efficiency eta(sens) of [Eu(ntfa)(3)(DPEPO)] (eta(pi-pi*) = 45%, eta(sens) = 77%) are larger than those of [Eu(btfa)(3)(DPEPO)] (Phi(pi-pi*) = 38%, eta(sens) = 55%). The thermostable Eu(III) complex with a p-expanded system is expected to be useful for fabrication of LED devices. - Enhanced Luminescence of Asymmetrical Seven-Coordinate Eu-III Complexes Including LMCT Perturbation
Kei Yanagisawa, Yuichi Kitagawa, Takayuki Nakanishi, Tomoko Akama, Masato Kobayashi, Tomohiro Seki, Koji Fushimi, Hajime Ito, Tetsuya Taketsugu, Yasuchika Hasegawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 32, 3843, 3848, WILEY-V C H VERLAG GMBH, 2017年09月, [査読有り]
英語, 研究論文(学術雑誌), Luminescent mononuclear seven-coordinate Eu-III complexes, with monocapped-octahedral (point group: C-3v), monocapped-trigonal-prismatic (C-2v), and pentagonal-bipyramidal (D-5h) coordination structures, are reported. The complexes each consist of a Eu-III ion, three tetramethylheptanedionates, and a phosphine oxide derivative. Controlling steric hindrance by means of introducing methyl groups into the phosphine oxide ligands resulted in the formation of three types of coordination polyhedral structures. The coordination geometrical structures of the Eu-III complexes were evaluated by single-crystal X-ray diffraction analysis and shape-factor calculations. The radiative rate constant of the Eu-III complex with a monocapped-octahedral structure was larger than those with monocapped-trigonal-prismatic and pentagonal-bipyramidal structures. Characteristic photophysical properties of the seven-coordinate Eu-III complexes are discussed with TD-DFT calculations and Arrhenius analysis of the ligand-to-metal charge transfer. - J-Type Heteroexciton Coupling Effect on an Asymmetric Donor-Acceptor-Donor-Type Fluorophore
Yuichi Kitagawa, Ryuto Yachi, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
JOURNAL OF PHYSICAL CHEMISTRY A, 121, 24, 4613, 4618, AMER CHEMICAL SOC, 2017年06月, [査読有り]
英語, 研究論文(学術雑誌), The novel donor acceptor donor (D-A-D)-type fluorophore with an asymmetric structure is reported. The twisted-induced charge transfer (TICT) luminescence was observed. The degree of charge transfer and radiative rate constant in the luminescence increased simultaneously with increase in orientational polarizability of solvents. In contrast to the numerous CT fluorophore researches, this behavior has never been previously observed. This characteristic behavior reveals the existence of an effective exciton coupling between the CT states in the donor-acceptor-donor-type fluorophore for the first time. - Triboluminescence of Lanthanide Coordination Polymers with Face-to-Face Arranged Substituents
Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Yasuchika Hasegawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 56, 25, 7171, 7175, WILEY-V C H VERLAG GMBH, 2017年06月, [査読有り]
英語, 研究論文(学術雑誌), Luminescence upon the grinding of solid materials (triboluminescence, TL) has long been a puzzling phenomenon in natural science and has also attracted attention because of its broad application in optics. It has been generally considered that the TL spectra exhibit similar profiles as those of photoluminescence (PL), although they occur from distinct stimuli. Herein, we describe for the first time a large spectral difference between these two physical phenomena using lanthanide(III) coordination polymers with efficient TL and PL properties. They are composed of emission centers (Tb-III and Eu-III ions), antenna (hexafluoroacetylacetonate=hfa), and bridging ligands (2,5-bis(diphenylphosphoryl)furan=dpf). The emission color upon grinding (yellow TL) is clearly different from that upon UV irradiation (reddish-orange PL) in Tb-III/Eu-III-mixed coordination polymers [Tb,Eu(hfa)(3)(dpf)](n) (Tb/Eu=1). The results directly indicate the discrete excitation processes of PL and TL. - Luminescent Mechanochromic 9-Anthryl Gold(I) Isocyanide Complex with an Emission Maximum at 900 nm after Mechanical Stimulation
Tomohiro Seki, Noriaki Tokodai, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa, Takeshi Iwasa, Tetsuya Taketsugu, Hajime Ito
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 139, 19, 6514, 6517, AMER CHEMICAL SOC, 2017年05月, [査読有り]
英語, 研究論文(学術雑誌), Upon mechanical stimulation, 9-anthryl gold(I) isocyanide complex 3 exhibited a bathochromic shift of its emission color from the visible to the infrared (IR) region, which is unprecedented in its magnitude. Prior to exposure to the mechanical stimulus, the polymorphs 3 alpha and 3 beta exhibit emission wavelength maxima (lambda(em,max)) at 448 and 710 nm, respectively. Upon grinding, the lambda(em,max) of 3 alpha(ground) and 3 beta(ground) are bathochromically shifted to 900 nm, i.e., Delta lambda(em,max) (3 alpha) = 452 nm or 1.39 eV. Polymorphs 3 alpha and 3 beta thus represent the first examples of mechanochromic luminescent materials with lambda(em,max) in the IR region. - Eu(III) Chiral Coordination Polymer with a Structural Transformation System
Naoyuki Koiso, Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
INORGANIC CHEMISTRY, 56, 10, 5741, 5747, AMER CHEMICAL SOC, 2017年05月, [査読有り]
英語, 研究論文(学術雑誌), A luminescent En(III) chiral coordination, polymer with a structural transformation system, [Eu(hfa)(3)((R)-bidp](n), (hfa: haxafltiorOacetylacetonato, (R)-bidp : (R)-1,1'-binapthyl-2,2'-bis- (diphenylphosphinate), is reported. Single-crystal X-ray analysis revealed a. characteristic helical polymer structure of [Eu(hfa)(3)((R)- bidp](n) with hydrogen-fluotine/pi interactions. [Eu(hfa)(3)((R)-bidp)](n) shows high thermostability (decomposition temperature = 320 degrees C) and strong luminescence properties (the 4f-4f emission quantum yield = 76%) in the solid State due to its tight packing and asymmetric structure. [Eu(hfa)(3)((R)-bidp)](n) is also transformed from a polymer to monomer structure in liquid media. The chiroptical properties of the monomer form in liquid media were characterized by using circular dichroism and circularly polarized luminescence spectra. In this study, structural and photophysical properties of a luminescent Eu(III) chiral coordination polymer with a structural transformation system were demonstrated. - Solvent-Dependent Dual-Luminescence Properties of Europium Complex with Helical π-Conjugated Ligands
Y. Kitagawa, R. Ohno, T. Nakanishi, K. Fushimi, Y. Hasegawa
Photochem. & Photosci., 16, 5, 683, 689, ROYAL SOC CHEMISTRY, 2017年05月, [査読有り]
英語, 研究論文(学術雑誌), A europium(III) complex with a large p-conjugated helical ligand, tris(hexafluoroacetylacetonato) europium(III) bis((pentahelicenyl) diphenylphosphine oxide) (Eu(hfa) (HPO)(2)), exhibits dual luminescence excited at the pi-pi* transition band. In this study, the solvent-dependent photophysical properties of Eu(hfa)(3)(HPO)(2) are reported. The ground-state properties of the ligand and the Eu(III) complex are assessed from electronic absorption spectra, magnetic circular dichroism spectra, and density functional theory calculations. The excited-state properties of these compounds are evaluated using luminescence spectra, excitation spectra, luminescence lifetimes, and luminescence quantum yields depending on solvents, which are CHCl3, C2H5Br, C2H5I, CH3COCH3, and CD3COCD3. Under all of the examined conditions, the intensity ratios of dual luminescence originating from the ligand and the Eu(III) ion were strongly dependent on the properties of the solvent. The solvent dependence of the luminescence ratio is discussed in terms of the external heavy atom effect. - Supramolecular Polymer of Near-Infrared Luminescent Porphyrin Glass
Mitsuhiko Morisue, Yuki Hoshino, Masaki Shimizu, Takayuki Nakanishi, Yasuchika Hasegawa, Md Amran Hossain, Shinichi Sakurai, Sono Sasaki, Shinobu Uemura, Jun Matsui
MACROMOLECULES, 50, 8, 3186, 3192, AMER CHEMICAL SOC, 2017年04月, [査読有り]
英語, 研究論文(学術雑誌), A comprehensive study of supramolecular polymerization of ditopic zinc (2-pyridylethynyl)porphyrin dimer 1 in toluene and thin films was performed. A glass-forming porphyrin bearing 3,4,5-tri((S)-3,7-dimethyloctyloxy)phenyl groups, named "porphyrin glass", was introduced with the 2-pyridylethynyl group as a supramolecular organizing unit; two zinc (2-pyridylethynyl)porphyrins were held together by self-complementary pyridyl-tozinc coordination bonds to form a slipped-cofacial stack. Then, ditopic zinc (2-pyridylethynyl)porphyrin could be extended to a linear supramolecular polymer. The small binding constant limited the degree of supramolecular polymerization of 1 in toluene solution. In spin-cast film, on the other hand, 1 adopted a form of supramolecular polymer of porphyrin glass, which was effective enough to display a large bathochromic shift of the absorption bands exceeding the narrowest limit of the optical band gap extrapolated from the electronic structures in solution. The supramolecularly polymerized porphyrin glass formed excimer,which exhibited solid-state near-infrared (NIR) luminescence at approximately 1025 nm. - Development of Ion-Conductive and Vapoluminescent Porous Coordination Polymers Composed of Ruthenium(II) Metalloligand
Ayako Watanabe, Atsushi Kobayashi, Erika Saitoh, Yuki Nagao, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa, W. M. C. Sameera, Masaki Yoshida, Masako Kato
INORGANIC CHEMISTRY, 56, 5, 3005, 3013, AMER CHEMICAL SOC, 2017年03月, [査読有り]
英語, 研究論文(学術雑誌), We synthesized two new porous coordination polymers (PCPs) {Ln(7)(OH)(5)[Ru(dcbpy)(3)](4).4nH(2)O} (Ln(7)-Ru-4; Ln = Ce, Nd) composed of the luminescent ruthenium (II) metalloligand [Ru(4,4'-dcbpy)(3)](4-) ([4Ru]; 4,4'-dcbpy = 4,4'-dicarboxy-2,2'-bipyridine) and lanthanide ions Ln(3+) (Ln = Ce, Nd). These two PCPs Ln7-Ru4 are isomorphous with the previously reported PCP La-7-Ru-4, and the lattice constants (a, c, and unit cell volume V) changed systematically according to the lanthanide contraction. All three Ln(7)-Ru-4 compounds have OW anion containing porous structures and a large number of hydrate water molecules within the pores, resulting in moderate ion conductivities (10(-6)-10(-7) S cm(-1)) at 90% relative humidity Wavelength / nm (RH) and 298 K. In contrast, the structural transformation of Ln(7)-Ru-4 associated with water-vapor adsorption/desorption strongly depends on the lanthanide ion; the Ln(7)-Ru-4 compounds with larger Ln(3+) ions recover the original porous structure at lower relative humidities (RH). A similar trend was observed for the ion conduction activation energy, suggesting that the bridging Ln(3+) ion plays an important role in the formation of the ion conductive pathways. La-7-Ru-4 and Ce-7-Ru-4 exhibit vapochromic luminescence associated with water vapor adsorption/desorption, arising from the (MLCT)-M-3 emission of [4Ru]. This vapochromic behavior is also affected by the replacement of the Ln3(+) ion; the vapochromic shift of Ce-7-Ru-4 was observed at RH values (near 100% RH) higher than that of La-7-Ru-4. (MLCT)-M-3 emissions of the [4Ru] metalloligand in Nd-7-Ru-4 were barely observable in the visible region, but sharp emission bands characteristic of 4f-4f transitions of the Nd3+ ion were observed in the near -infrared (NIR) region (arising from the (MLCT)-M-1 transition of [4Ru]), suggesting the transfer of energy from the [4Ru] (MLCT)-M-3 excited state to the 4f-4f transition state of the Nd3+ ions. - Amorphous Formability and Temperature-Sensitive Luminescence of Lanthanide Coordination Glasses Linked by Thienyl, Naphthyl, and Phenyl Bridges with Ethynyl Groups
Yuichi Hirai, Pedro Paulo Ferreira da Rosa, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 90, 3, 322, 326, CHEMICAL SOC JAPAN, 2017年03月, [査読有り]
英語, 研究論文(学術雑誌), The glass-transition properties and temperature-sensitive luminescence of lanthanide (Ln(III)) coordination compounds are reported. The glass formability was systematically provided by incorporation of bent-angled phosphine oxide (2,5-bis(diphenylphosphorylethynyl)thiophene: dpet, 2,7-bis(diphenylphosphorylethynyl) naphthalene: dpen, 1,3-bis(diphenylphosphorylethynyl) benzene: m-dpeb) ligands with thienyl, naphthyl, phenyl cores, and ethynyl groups. The glass-transition points were clearly identified for all Ln(III) coordination compounds (T-g = 65-87 degrees C). The Tb(III)/Eu(III) mixed coordination glass [Tb,Eu(hfa)(3)(m-dpeb)](3) (hfa: hexafluoroacetylacetonate) also showed green, yellow, orange, and red photoluminescence depending on temperature. - Effective Photo- and Triboluminescent Europium(III) Coordination Polymers with Rigid Triangular Spacer Ligands
Yasuchika Hasegawa, Shiori Tateno, Masanori Yamamoto, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Hajime Ito, Koji Fushimi
CHEMISTRY-A EUROPEAN JOURNAL, 23, 11, 2666, 2672, WILEY-V C H VERLAG GMBH, 2017年02月, [査読有り]
英語, 研究論文(学術雑誌), Luminescent Eu-III coordination polymers with rigid triangular spacer ligands are reported. The Eu-III coordination polymer, [Eu-3(hfa)(9)(tppb)(2)](n) (hfa: hexafluoroacetylacetonate, tppb: tris(4-diphenylphosphorylphenyl) benzene), shows high thermo-stability (decomposition temperature= 354 degrees C) and photoluminescence quantum yield (Phi(4f-4f)= 82%, photosensitized energy transfer efficiency= 78%). The tribolumines-cence efficiency of Eu-III coordination polymer with triangular spacers under laser pulse irradiation (Nd:YAG, lambda= 1064 nm, pulse width= 5 ns, pulse energy= 0.1 mJ) is calculated to be 49%. Characteristic triangular structure, high emission quantum yield, effective photosensitized energy transfer, and remarkable triboluminescence properties of Eu-III coordination polymers are demonstrated for the first time. - Time-dependent measurement of hydrogen penetration in ferric metal materials
Yudai Yamamoto, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers, 2017年
英語, 研究論文(国際会議プロシーディングス), Hydrogen diffusion in metal sheet has conventionally been investigated using a double electrochemical cell, so-called Devanathan-Stachurski (DS) cell. The authors reported that, when a flow-rate of electrolyte in an entry side cell is sinusoidally perturbed, an entry side current and an exit side current flow with sinusoidal waveforms and the latter shows a latency of phase shift θ depending on the alternation frequency, specimen thickness and hydrogen diffusion coefficient DH in the sheet. In this study, the emphasis was put on a time-dependence of θ. Utilization of fast-Fourier-transform enabled the evaluation of θ in real-time. Hydrogen penetration measurement under potentiostatic polarization with sinusoidal flow-rate perturbation was applied to a ferric metal sheet. Under a standard ambient condition, the value of θ showed a circadian change, which was similar to the change in temperature of the experimental system. However, an Arrhenius-type analysis for the thermo-response of θ resulted in abnormally large values of activation energy and maximal diffusion coefficient, suggesting that the value of θ is dependent on not only temperature but also other parameters. - Non-uniform distribution of passive film formed on carbon steel
Koji Fushimi, Ryogo Nakagawa, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa
EUROCORR 2017 - The Annual Congress of the European Federation of Corrosion, 20th International Corrosion Congress and Process Safety Congress 2017, Asociace koroznich inzenyru z.s.- AKI - Czech Association of Corrosion Engineers, 2017年
英語, 研究論文(国際会議プロシーディングス), Passive film of S45C carbon steel formed in pH 8.4 boric acid-borate buffer solution was investigated by using scanning electrochemical microscopy (SECM). Passivity-maintaining current of the carbon steel was about 3 times as large as that of pure iron. Current of electron-transfer reaction (ETR) of redox mediator through the passive film was strongly dependent on metallographic structure of the carbon steel. For example, the passive film formed on perlite eutectic phase in the carbon steel allowed larger ETR current than that formed on primary phase ferrite. Raman spectroscopy revealed that the surface of carbon steel was covered with non-uniform magnetite and amorphous carbon. It was suggested that cementite in the perlite affected not only the formation of oxide but also the semi-conductive property of the film. - Effect of Cylinder Height on Directional Photoluminescence from Highly Luminous Thin Films on Periodic Plasmonic Arrays
Motoharu Saito, Shunsuke Murai, Hiroyuki Sakamoto, Masanori Yamamoto, Ryosuke Kamakura, Takayuki Nakanishi, Koji Fujita, Yasuchika Hasegawa, Katsuhisa Tanaka
MRS Advances, 2, 3, 173, 178, Materials Research Society, 2017年, [査読有り]
英語, 研究論文(国際会議プロシーディングス), Periodic array of metallic nanocylinder combined with the highly luminous dielectric layer is a good platform to control the intensity, spectral shape and directionality of photoluminescence (PL). In spite of its importance, the effect of cylinder height on the PL properties has not been verified experimentally. Here we investigate the effect of cylinder height on the PL properties both experimentally and numerically. The system consisted of a highly luminous layer made of Eu(III) complex and a series of periodic array of aluminum nanocylinders with different heights. The strongest directional PL was achieved when the height is similar to the diameter, i.e., the aspect ratio close to unity. Our finding is useful for designing the compact and efficient luminescence source with directional output. - Grain Dependency of a Passive Film Formed on Polycrystalline Iron in pH 8.4 Borate Solution
Y. Takabatake, Y. Kitagawa, T. Nakanishi, Y. Hasegawa, K. Fushimi
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 164, 7, C349, C355, ELECTROCHEMICAL SOC INC, 2017年, [査読有り]
英語, 研究論文(学術雑誌), Passivating behavior of polycrystalline iron in pH 8.4 borate buffer solution was investigated by using two-dimensional (2D) ellipsometry and a micro-capillary cell (MCC) technique. In situ 2D ellipsometry of the passivating process of polycrystalline iron clearly demonstrated formation and growth of a passive film, though differences in growth rate and thickness of the film among substrate grains was observed less in ellipsometric images. Potentiostatic polarization and electrochemical impedance spectroscopy with the MCC showed that charge transfer resistance R-ct and donor density N-D of the passive film depended on the substrate orientation, though a clear correlation between these parameters was not observed. It was thought that several factors such as anisotropic growth, dissolution, and aging of oxides gave the grain-dependent defect structure of the passive film, depending on the surface crystallographic orientation of the substrate iron. (C) 2017 The Electrochemical Society. All rights reserved. - Amorphous porphyrin glasses exhibit near-infrared excimer luminescence
Mitsuhiko Morisue, Ikuya Ueno, Takayuki Nakanishi, Takafumi Matsui, Sono Sasaki, Masaki Shimizu, Jun Matsui, Yasuchika Hasegawa
RSC ADVANCES, 7, 37, 22679, 22683, ROYAL SOC CHEMISTRY, 2017年, [査読有り]
英語, 研究論文(学術雑誌), The amorphous nature of a series of zinc-porphyrins bearing two 3,4,5-tri((S)-3,7-dimethyloctyloxy) phenyl groups at the meso-positions, named "porphyrin glass", were tolerant of pi-conjugation engineering in ethynylene-linked dimers. The butadiyne-linked dimeric porphyrin glass formed an intermolecular excimer, which exhibited bright and exceptionally long-lived, near-infrared (NIR) luminescence at approximately 970 nm in the solid state. Therefore, porphyrin glasses overcame a general bottleneck for NIR-luminescence, such as an undesired pi-stacked aggregation of a large porphyrin plane in addition to the energy gap law. The formation of amorphous molecular glasses from a series of meso-ethynylene-conjugated zinc-porphyrins, named "porphyrin glass", is described. The butadiyne-linked dimeric porphyrin glass formed an intermolecular excimer, which exhibited solid-state, near-infrared (NIR) luminescence at approximately 970 nm. - Directional outcoupling of photoluminescence from Eu(III)-complex thin films by plasmonic array
S. Murai, M. Saito, H. Sakamoto, M. Yamamoto, R. Kamakura, T. Nakanishi, K. Fujita, M. A. Verschuuren, Y. Hasegawa, K. Tanaka
APL Photonics, 2, 026104, 2017年, [査読有り] - Initiation of Localized Corrosion of Ferritic Stainless Steels by Using the Liquid-Phase Ion Gun Technique
Jun-Seob Lee, Takashi Kawano, Tomohiro Ishii, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 164, 2, C1, C7, ELECTROCHEMICAL SOC INC, 2017年, [査読有り]
英語, 研究論文(学術雑誌), The initiation of localized corrosion of types 430 and 443J1 ferritic stainless steels was evaluated in 0.15 mol dm(-3) Na2SO4 solution. A liquid-phase ion gun (LPIG), a silver microelectrode covered with a silver chloride layer, was cathodically polarized to generate Cl- in the vicinity of the stainless steel polarized at 0.4 V-SSE. Contact of the stainless steel surface with the Cl- -concentrated environment by the LPIG operation induced a rapid increase in anodic current flow through the stainless steel electrode after the induction period t(d) and consumption of the cathodic electric charge Q(d) by the LPIG microelectrode. Numerical modeling using the LPIG microelectrode current for t(d) gave a critical Cl- concentration [Cl-](d) needed for the initiation of localized corrosion. These parameters obtained by LPIG tests showed that type 443J1 stainless steel was superior to type 430 stainless steel in localized corrosion resistance. AES depth profiling of the stainless steel surfaces after the LPIG operation revealed enrichment of Cl in the outermost oxide film as well as decreased film thickness. The mechanism of degradation of the stainless steel surface due to contact with the Cl- -concentrated solution is discussed. The adsorption of Cl- on the oxide surface is thought to be a trigger of the oxide degradation. (C) The Author(s) 2016. Published by ECS. - Organic linkers control the thermosensitivity of the emission intensities from Tb(III) and Eu(III) in a chameleon polymer
Miho Hatanaka, Yuichi Hirai, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Keiji Morokuma
CHEMICAL SCIENCE, 8, 1, 423, 429, ROYAL SOC CHEMISTRY, 2017年01月, [査読有り]
英語, 研究論文(学術雑誌), Thermometers whose emission color gradually changes with temperature are called chameleon emitters. In this study, we discuss the mechanism of the thermosensitivity of the emission color of polymers that contain two lanthanides (Ln(3+)), e. g., [Tb0.99Eu0.01(hfa)(3)(linker)](n), where the Ln(3+)(hfa)(3) complexes (hfa: hexafluoro acetylacetonato) are connected by a phosphine oxide "linker"molecule. First, the difference in the thermosensitivities of the emissions from Tb3+ and Eu3+ are discussed. With increasing temperature, the green-emission intensity from Tb3+ decreases whereas the red-emission intensity from Eu3+ does not change. This was found to originate from the different reaction barriers for the quenching of the Ln(3+) excited state via the intersystem crossing (ISC) between the hfa-centered triplet state and the ground state. Next, the excitation energy transfer (EET) from Tb3+ to Eu3+ is discussed. Although the direct EET between Ln(3+) atoms is negligible because of the long distance between them, stepwise EET is found to occur via the linker-centered triplet state with a reasonable barrier. Thus, we propose a new idea-thermosensitivity can be controlled by the linker as well as by the ligand (hfa). To confirm the role of the linker, four phosphine oxides were examined. The thermosensitivity dependence on the linker is validated via experimental measurements. - Passivation Behavior of Type-316L Stainless Steel in the Presence of Hydrogen Sulfide Ions Generated from a Local Anion Generating System
Jun-Seob Lee, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
ELECTROCHIMICA ACTA, 220, 304, 311, PERGAMON-ELSEVIER SCIENCE LTD, 2016年12月, [査読有り]
英語, 研究論文(学術雑誌), The passivity of type 316L stainless steel was studied in a pH 8.4 boric acid-borate buffer solution containing hydrogen sulfide ions (HS-) by using a local anion-generating system. During potentiostatic polarization of the stainless steel at a primary passive potential of 0.4V(SSE) and at a secondary passive potential of 0.9 V-SSE in solutions with and without HS-, the current density flowing for passive film formation was increased by the presence of HS- at both potentials, while 15 Hz impedance at 0.9 V-SSE in the solution with HS- was larger than that in the solution without HS-. It was thought that the presence of HS- in the solution during film formation made the film less resistive and affected the film capacitance depending on the polarization potential. X-ray photoelectron spectroscopy (XPS) showed an increase in metal cation and oxygen anion vacancies in the passive film formed at the primary passive state in the solution containing HS-. Auger electron spectroscopy (AES) and Raman spectroscopy revealed that a sulfide layer was deposited on the stainless steel surface that was oxidized at the secondary passive state in the solution containing HS-. It is thought that application of a high potential changes the passivity of the stainless steel surface in the solution containing HS-. (C) 2016 Elsevier Ltd. All rights reserved. - Critical Role of Energy Transfer Between Terbium Ions for Suppression of Back Energy Transfer in Nonanuclear Terbium Clusters
Shun Omagari, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Koji Fushimi, Hajime Ito, Andries Meijerink, Yasuchika Hasegawa
SCIENTIFIC REPORTS, 6, 37008, NATURE PUBLISHING GROUP, 2016年11月, [査読有り]
英語, 研究論文(学術雑誌), Lanthanide (Ln(III)) complexes form an important class of highly efficient luminescent materials showing characteristic line emission after efficient light absorption by the surrounding ligands. The efficiency is however lowered by back energy transfer from Ln(III) ion to the ligands, especially at higher temperatures. Here we report a new strategy to reduce back energy transfer losses. Nonanuclear lanthanide clusters containing terbium and gadolinium ions, TbnGd9-n clusters ([TbnGd9-n(mu-OH)(10)(but ylsalicylate)(16)](+) NO3-, n = 0, 1, 2, 5, 8, 9), were synthesized to investigate the effect of energy transfer between Tb(III) ions on back energy transfer. The photophysical properties of TbnGd9-n clusters were studied by steady-state and time-resolved spectroscopic techniques and revealed a longer emission lifetime with increasing number of Tb(III) ions in TbnGd9-n clusters. A kinetic analysis of temperature dependence of the emission lifetime show that the energy transfer between Tb(III) ions competes with back energy transfer. The experimental results are in agreement with a theoretical rate equation model that confirms the role of energy transfer between Tb(III) ions in reducing back energy transfer losses. The results provide a new strategy in molecular design for improving the luminescence efficiency in lanthanide complexes which is important for potential applications as luminescent materials. - Luminescent Europium(III) Coordination Zippers Linked with Thiophene-Based Bridges
Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Yasuchika Hasegawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 55, 39, 12059, 12062, WILEY-V C H VERLAG GMBH, 2016年09月, [査読有り]
英語, 研究論文(学術雑誌), Novel Eu-III coordination polymers [Eu(hfa)(3)(dpt)](n)(dpt: 2,5-bis(diphenylphosphoryl)thiophene) and [Eu(hfa)(3)(dpedot)](n) (dpedot: 2,5-bis(diphenylphosphoryl)ethylenedioxythiophene) with hydrogen-bonded zipper structures are reported. The coordination polymers are composed of Eu-III ions, hexafluoroacetylacetonato ligands, and thiophene-based phosphine oxide bridges. The zig-zag orientation of single polymer chains induced the formation of densely packed coordination structures with multiple intermolecular interactions, resulting in thermal stability above 300 degrees C. They exhibit a high intrinsic emission quantum yield (ca. 80%) due to their asymmetrical and low-vibrational coordination structures around Eu-III ions. Furthermore, the characteristic alternative orientation of substituents also contributes to the dramatically high ligand-to-metal energy transfer efficiencies of up to 80% in the solid state. - Three-photon-induced Luminescence of Europium Acetylacetonate-type Complexes
Yasutaka Suzuki, Hiroki Moritomo, Akinari Fuji, Koichiro Satomi, Jun Kawamata, Masanori Yamamoto, Yasuchika Hasegawa
CHEMISTRY LETTERS, 45, 5, 538, 540, CHEMICAL SOC JAPAN, 2016年05月, [査読有り]
英語, 研究論文(学術雑誌), We measured the three-photon absorption spectra of two europium acetylacetonate-type complexes. The three-photon absorption peak wavelengths of tris(hexafluoroacetylacetonato)-europium(III) (Eu(hfa)) and tris(2-naphthoyltrifluoroacetonato)-europium(IE) (Eu(ntfa)) were 925 and 1025 nm, respectively. The peak values of the 3PA cross-sections of Eu(hfa) and Eu(ntfa) were 1.9 and 13.9 GM (1 GM = 10(-82) cm(6) s(2)), respectively. Using Eu(ntfa) as a probe, a three-photon microscope image of a living cell was obtained using a 1030 nm operating femto-second fiber laser as the light-source. Thus, Eu(ntfa) is a fiber laser excitable luminescent probe useful for three-photon microscopy. - Synthesis of Dipyridinogermole-Copper Complex as Soluble Phosphorescent Material
Kazuya Murakami, Yousuke Ooyama, Seiji Watase, Kimihiro Matsukawa, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa, Kei Inumaru, Joji Ohshita
CHEMISTRY LETTERS, 45, 5, 502, 504, CHEMICAL SOC JAPAN, 2016年05月, [査読有り]
英語, 研究論文(学術雑誌), The reaction of diphenyldipyridinogermole with [Cu2I2-(PPh3)(3)] in THE afforded a complex with high thermal stability. Crystals with linear polymeric structures (determined by single crystal X-ray diffraction study) emitted orange phosphorescence with the quantum yield of 25%. The sufficient solubility of the complex permitted the fabrication of a complex-doped poly(methyl methacrylate) (PMMA) self-standing phosphorescent film. - Hyper-stable organo-Eu-III luminophore under high temperature for photo-industrial application
Ayako Nakajima, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Hajime Ito, Koji Fushimi, Yasuchika Hasegawa
SCIENTIFIC REPORTS, 6, 24458, NATURE PUBLISHING GROUP, 2016年04月, [査読有り]
英語, 研究論文(学術雑誌), Novel organo-Eu-III luminophores, Eu(hfa)(x)(CPO)(y) and Eu(hfa)(x)(TCPO)(y) (hfa: hexafluoroacetylacetonate, CPO: 4-carboxyphenyl diphenyl phosphine oxide, TCPO: 4,4',4 ''- tricarboxyphenyl phosphine oxide), were synthesized by the complexation of Eu-III ions with hfa moieties and CPO or TCPO ligands. The thermal and luminescent stabilities of the luminophores are extremely high. The decomposition temperature of Eu(hfa)(x)(CPO)(y) and Eu(hfa)(x)(TCPO)(y) were determined as 200 and 450 degrees C, respectively. The luminescence of Eu(hfa)(x)(TCPO)(y) under UV light irradiation was observed even at a high temperature, 400 degrees C. The luminescent properties of Eu(hfa)(x)(CPO)(y) and Eu(hfa)(x)(TCPO)(y) were estimated from emission spectra, quantum yields and lifetime measurements. The energy transfer efficiency from hfa moieties to EuIII ions in Eu(hfa)(x)(TCPO)(y) was 59%. The photosensitized luminescence of hyper-stable Eu(hfa)(x)(TCPO)(y) at 400 degrees C is demonstrated for future photonic applications. - Molecular Design Guidelines for Large Magnetic Circular Dichroism Intensities in Lanthanide Complexes
Yuichi Kitagawa, Satoshi Wada, Kei Yanagisawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
CHEMPHYSCHEM, 17, 6, 845, 849, WILEY-V C H VERLAG GMBH, 2016年03月, [査読有り]
英語, 研究論文(学術雑誌), Magneto optical devices based on the Faraday effects of lanthanide ion have attracted much attention. Recently, large Faraday effects were found in nano-sized multinuclear lanthanide complexes. In this study, the Faraday rotation intensities were estimated for lanthanide nitrates [Ln(III)(NO3)(3)nH(2)O: Ln=Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm) and Eu-III complexes with -diketone ligands, using magnetic circular dichroism. Eu ions exhibit the largest Faraday rotation intensity for (F0D1)-F-7-D-5 transitions, and high-symmetry fields around the Eu ions induce larger Faraday effects. The molecular design for the enhancement of Faraday effects in lanthanide complexes is discussed. - The relationship between magneto-optical properties and molecular chirality
Satoshi Wada, Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuhiro Morisaki, Koji Fujita, Katsuaki Konishi, Katsuhisa Tanaka, Yoshiki Chujo, Yasuchika Hasegawa
NPG ASIA MATERIALS, 8, e251, NATURE PUBLISHING GROUP, 2016年03月
英語, 研究論文(学術雑誌), The chiral nonanuclear Tb(III) clusters [Tb-9(sal-(R)-Bt)(16)(mu-OH)(10)]+[NO3]-(Tb-(R)-Bt: sal-(R)-Bt=(R)-2-butyl salicylate) and [Tb9 (sal-(S)-Bt)(16)(mu-OH)(10)](+)[NO3](-)(Tb-(S)-Bt: sal-(S)-Bt=(S)-2-butyl salicylate) were found to exhibit a unique magneto-optical property: the Faraday effect. The clusters were composed of 9 Tb(III) ions bridged by 10 mu-OHs and 16 chiral salicylic acid esters. The Faraday rotation angle of Tb-(R)-Bt was greater than that of Tb-(S)-Bt, indicating that the Faraday effect was affected by the chirality of the Tb(III) clusters. The chiroptical properties of the Tb(III) clusters were estimated using circular dichroism and circularly polarized luminescence. In this study, a new finding concerning chiral magneto-optical properties was investigated. - Luminescent Eu(III) coordination polymer cross-linked with Zn(II) complexes
Masanori Yamamoto, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
MATERIALS LETTERS, 167, 183, 187, ELSEVIER SCIENCE BV, 2016年03月
英語, 研究論文(学術雑誌), A structural design of new luminescent lanthanide coordination polymers composed of Eu3+ complex and Zn2+ complexes are introduced. The Eu3+ coordination polymer [Eu(hfa)(3)(dppy)(2)ZnCI2](n), (Eu-Zn) (hfa: hexafluoroacetylacetonato, dppy: 4-pyridyldiphenylphosphane oxide) were synthesized by the complexation of Eu(hfa)(3)(H2O)(2) with ZnCl2(dppy)(2). The structure was characterized using XRD and TG-DTA. The photophysical properties were estimated using the emission spectra, the emission lifetimes, and the emission quantum yields. The emission quantum yields are larger then that of precursor Eu (hfa)(3)(H2O)(2). The emission quantum yield of Eu-Zn was found to be 59%. The preparations, structures and photophysical properties of Eu-Zn are demonstrated as a new luminescent Eu3+ coordination polymer for the first time. (C) 2015 Elsevier B.V. All rights reserved. - Organo-lanthanide luminophores bridged by phosphine oxide ligands
Yuichi Hirai, Takayuki Nakanishi, Yasuchika Hasegawa
JOURNAL OF LUMINESCENCE, 170, 801, 807, ELSEVIER SCIENCE BV, 2016年02月
英語, 研究論文(学術雑誌), Organo-lanthanide luminophores composed of lanthanide ions and specific phosphine oxide ligands exhibit characteristic photo- and thermo-properties for future photonic applications. In this review, lanthanide coordination polymers with strong luminescence, thermostability, and thermo-responsive emission properties are introduced. We also present a strategy for luminescent lanthanide compounds with amorphous formability. Photofunctional organo-lanthanide luminophores are expected to contribute to the development of new and better performing materials and devices. (C) 2015 Elsevier B.V. All rights reserved. - Luminescent Thin Films Composed of Nanosized Europium Coordination Polymers on Glass Electrodes
Yasuchika Hasegawa, Takeshi Sugawara, Takayuki Nakanishi, Yuichi Kitagawa, Makoto Takada, Akitsugu Niwa, Hiroyoshi Naito, Koji Fushimi
CHEMPLUSCHEM, 81, 2, 187, 193, WILEY-V C H VERLAG GMBH, 2016年02月
英語, 研究論文(学術雑誌), Luminescent thin films composed of thermostable lanthanide coordination polymers on glass electrodes were prepared using a novel combination of micelle reactions and electrochemical deposition techniques. The micelle-encapsulated luminescent polymers were obtained by the polymerization of [Eu(hfa)(3)] (hfa=hexafluoroacetylacetonate) with bridging phosphine oxide ligands in micelles using a redox-active ferrocenyl-containing surfactant in water. Films were electrochemically deposited on indium tin oxide coated glass electrodes by potentiostatic polarization of micelle-encapsulated Eu-III coordination polymers. The luminescence properties of the electrochemically deposited films were characterized by measuring their emission spectra, emission lifetimes and emission quantum yields. - Ellipso-Microscopic Observation of Titanium Surface under UV-Light Irradiation
Fushimi K, Kurauchi K, Nakanishi T, Hasegawa Y, Ueda M, Ohtsuka T
2016年, [査読有り]
研究論文(学術雑誌) - Heterogeneity of a Thermal Oxide Film Formed on Polycrystalline Iron Observed by Two-Dimensional Ellipsometry
Y. Takabatake, Y. Kitagawa, T. Nakanishi, Y. Hasegawa, K. Fushimi
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 163, 14, C815, C822, ELECTROCHEMICAL SOC INC, 2016年, [査読有り]
英語, 研究論文(学術雑誌), Heterogeneity of the thermally oxidized surface of a polycrystalline iron substrate was investigated by using two-dimensional (2D) ellipsometry and a micro-capillary cell (MCC). Thickness mapping of a bi-layered oxide film (inner Fe3O4 layer/outer alpha-Fe2O3 layer) on the iron substrate was performed by 2D ellipsometry, and it was demonstrated that the grain-dependency of the thickness of Fe3O4 determined the heterogeneity of oxide thickness on the polycrystalline iron. Degradation behavior of the thermally oxidized surface during galvanostatic polarization was observed by in situ 2D ellipsometry. The transients of ellipsometric parameters showed different trajectories depending on the substrate orientation, indicating that the magnitude of degradation of the oxide by the cathodic current differed depending on the heterogeneous oxide structure. EIS measurements with the MCC revealed that donor density N-D of the oxide was greater in the order of {0 0 1} > {1 1 1} > {1 0 1}. It was concluded that the grain-dependency of the oxide thickness and N-D was attributed to the anisotropic growth of the two oxide layers. (C) 2016 The Electrochemical Society. All rights reserved. - Visible luminescent lanthanide ions and large π-conjugated ligand system shake hands
Y. Kitagawa, R. Ohno, T. Nakanishi, K. Fushimi, Y. Hasegawa
Phys. Chem. Chem. Phys., 18, 45, 31012, 31016, ROYAL SOC CHEMISTRY, 2016年, [査読有り]
英語, 研究論文(学術雑誌), Visible luminescence europium(III) complexes with large pi-conjugated systems were theoretically and experimentally studied. A strategy for extending the pi-conjugation of a ligand for use with europium(III) ions was found on the basis of fragment molecular orbital and density functional theory calculations. Using this method, a novel europium complex was designed and synthesized. Its excited state properties were assessed from the luminescence spectrum, excitation spectrum, luminescence lifetime, and luminescence quantum yield. In this study, the novel photophysics induced by the combination of visible luminescent europium(III) ions and large pi-conjugated systems are described. - Thermosensitive Luminescent Lanthanide Complex with Two Photosensitized Ligands
Ayako Nakajima, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
SENSORS AND MATERIALS, 28, 8, 845, 850, MYU, SCIENTIFIC PUBLISHING DIVISION, 2016年, [査読有り]
英語, 研究論文(学術雑誌), A novel thermosensitive luminescent lanthanide coordination compound was successfully synthesized. The coordination compound consists of Eu, Tb, and two photosensitized organic ligands [hexafluoroacetylacetone (hfa) and tris(p-carboxyphenyl) phosphine oxide (TPO)]. The Eu/Tb mixed coordination compound shows different luminescent colors depending on the temperature (green luminescence at 300 K and yellow luminescence at 450 K). In this study, emission spectra were measured at 300, 350, 400, and 400 K, and the ratio of (Eu/Tb) luminescence intensity at each temperature was estimated. The temperature-dependent luminescence is caused by the two differentially photosensitized organic ligands, hfa and TPO. These results may lead to the development of novel thermosensing devices using lanthanide luminescence. - Photophysical properties of luminescent silicon nanoparticles surface-modified with organic molecules via hydrosilylation
Mari Miyano, Yuichi Kitagawa, Satoshi Wada, Akira Kawashima, Ayako Nakajima, Takayuki Nakanishi, Junya Ishioka, Tamaki Shibayama, Seiichi Watanabe, Yasuchika Hasegawa
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES, 15, 1, 99, 104, ROYAL SOC CHEMISTRY, 2016年
英語, 研究論文(学術雑誌), Luminescent silicon nanoparticles have attracted considerable attention for their potential uses in various applications. Many approaches have been reported to protect the surface of silicon nanoparticles and prevent their easy oxidation. Various air-stable luminescent silicon nanoparticles have been successfully prepared. However, the effect of interactions of the pi-electron system with the silicon surface on the excited state properties of silicon nanoparticles is unclear. In this study, we have successfully prepared silicon nanoparticles protected with three organic compounds (styrene, 1-decene, and 1-vinyl naphthalene) and have examined their photophysical properties. The ligand pi-electron systems on the silicon surface promoted the light harvesting ability for the luminescence through a charge transfer transition between the protective molecules and silicon nanoparticles and also enhanced the radiative rate of the silicon nanoparticles. - Acid-protected Eu(III) coordination nanoparticles covered with polystyrene
Hiromitsu Onodera, Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
JOURNAL OF MATERIALS CHEMISTRY C, 4, 1, 75, 81, ROYAL SOC CHEMISTRY, 2016年
英語, 研究論文(学術雑誌), Acid-protected Eu(III) coordination nanoparticles composed of Eu(III) complexes, joint ligands, terminate ligands and a protection layer are reported. The prepared acid-protected Eu(III) coordination nanoparticles [Eu(hfa)(3)(dpbp)(x)(SDPO)(y)](n)-PS and Eu(III) coordination nanoparticles [Eu(hfa)(3)(dpbp)(x)(SDPO)(y)](n) were characterized using ESI-mass spectrometry (ESI-MS), X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS) measurements, and thermogravimetric analysis (TGA). [Eu(hfa)(3)(dpbp)(x)(SDPO)(y)](n)-PS shows an effective acid-resistance property based on the polystyrene layer on its nanoparticle surface. The emission intensity is retained under 3000 s in an acidic condition (pH = 0.92). In this study, acidprotected Eu(III) coordination nanoparticles are demonstrated. - Drastically Improved Durability and Efficiency of Silicon Solar Cells Using Hyper-Stable Lanthanide Coordination Polymer Beads
Hisataka Kataoka, Takayuki Nakanishi, Shun Omagari, Yu Takabatake, Yuichi Kitagawa, Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 89, 1, 103, 109, CHEMICAL SOC JAPAN, 2016年01月
英語, 研究論文(学術雑誌), Remarkable improvements of environmental durability and energy conversion efficiency in silicon solar cells were achieved using ethylene vinyl acetate (EVA) protection film containing poly(methyl methacrylate) (PMMA) polymer beads (PB), which includes hyper-stable luminescent lanthanide coordination polymer [Eu(hfa)(3)(dpbp)](n) (hfa: hexafluoroacetylacetonate, dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl). The shape of PB including [Eu(hfa)(3)(dpbp)](n) (PB-[Eu(hfa)(3)(dpbp)](n)) was observed with SEM. Luminescence performance of EVA protection films including PB-[Eu(hfa)(3)(dpbp)] or related lanthanide complexes (previously reported [Eu(hfa)(3)(dpbp)](n) powder, Tb(hfa)(3)(TPPO)(2), Eu(hfa)(3)(TPPO)(2), and Yb(hfa)(3)(TPPO)(2), TPPO: triphenylphosphine oxide) were characterized using emission spectroscopy, quantum yields, and lifetimes. Their durability were evaluated using photophysical measurements after degradation test (85 degrees C 85% RH). The durability of PB[Eu(hfa)(3)(dpbp)] in EVA film was estimated to be twenty-five years, which is much longer than those of previous lanthanide complexes. The temperature dependency of emission spectra of PB-[Eu(hfa)(3)(dpbp)], confirmed that the luminescence properties are maintained even at high temperatures up to 120 degrees C. Increased value of the solar cell short-circuit current efficiency using EVA protection film containing PB-[Eu(pfa)(3)(dpbp)(n) was found to be 1.1%, which is a drastic increase as a photovoltaic solar system. The EVA protection films with PB-[Eu(hfa)(3)(dpbp)(n) are effective for enhancing the performance of silicon solar cells. - Photoswitchable Faraday effect in EuS-Au nanosystems
Akira Kawashima, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 213, 1, 178, 182, WILEY-V C H VERLAG GMBH, 2016年01月
英語, 研究論文(学術雑誌), Effective photoswitchable europium sulfide nanocrystals with gold nanoparticles using dithiol (DDT: 1,10-decanedithiol) joint molecules, EuS-Au nanosystems, are demonstrated. The TEM image indicates the formation of EuS-Au nanosystems composed of cube-shaped EuS nanocrystals and spherical Au nanoparticles. Under visible-light irradiation, a drastic change of absorption band of EuS-Au nanosystems at around 600 nm was observed. The Faraday effects of EuS-Au nanosystems were estimated using magnetic circular dichroism (MCD) measurements. The effective change of the MCD spectra of EuS-Au nanosystems under visible-light irradiation was successfully observed at around 670 nm for the first time. The effective reversible changes in MCD spectra with the alternative irradiation cycles of visible light (>440 nm) and dark are also presented. The decrease rate of rotation angle at 670 nm of EuS-Au nanosystems is larger than that of absorbance. These results indicate that the effective change of MCD spectra of EuS-Au nanosystems would be dominated not only by a drastic change of absorption band related to enhanced LSPR of Au nanoparticles but also by specific interaction between EuS and Au in nanosystem under irradiation. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim - FEM Analysis for Sinusoidal Perturbation of Hydrogen Permeation into a Steel Sheet
Yudai Yamamoto, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
ISIJ INTERNATIONAL, 56, 3, 472, 477, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 2016年
英語, 研究論文(学術雑誌), Numerical calculation for the diffusion problem of hydrogen absorbed in a steel sheet during hydrogen permeation measurement using a double electrochemical cell was carried out. The finite element method (FEM) was applied to obtain the concentration distribution of hydrogen expressed by one- or two-dimensional Fick's laws in the sheet, assuming that hydrogen concentration at the hydrogen entry interface was perturbed sinusoidally and both the hydrogen entry and exit reactions were in a mass-transport controlled process. From a comparison with experimental results reported previously, in which a phase shift from entry current to exit current waves observed on a single grain of the specimen sheet was at least two-times larger than that on two grains, it was estimated that the diffusion coefficient at a grain boundary located between two grains was five orders in magnitude larger than that on a single grain. - Hydrogen Permeation into a Carbon Steel Sheet Observed by a Micro-capillary Combined with a Devanathan-Stachurski Cell
Koji Fushimi, Misako Jin, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa
ISIJ INTERNATIONAL, 56, 3, 431, 435, IRON STEEL INST JAPAN KEIDANREN KAIKAN, 2016年
英語, 研究論文(学術雑誌), A micro-capillary technique was applied to a Devanathan-Stachurski electrochemical cell for local measurement of hydrogen permeation into a steel sheet. An electrolyte-flowing design for the hydrogen entry side of the Devanathan-Stachurski cell successfully allowed the detection of hydrogen permeation response on hydrogen exit side electrode in a micro-capillary cell with a diameter of 250 pm. Phase shift of the detected permeation current from a sinusoidal perturbation of the electrolyte flow rate in the hydrogen entry cell was strongly dependent on the metallographic structure of the steel sheet. A local structure, in which two single grains form grain boundaries, led to hydrogen permeation more frequently than did a local structure of single grains. The results suggested that the diffusion coefficient of the boundaries was at least two-times larger than that of the grains. - Titanium surface anodized under UV light irradiation observed by ellipso-microscopy
K. Fushimi, K. Kurauchi, H. Ikeyama, Y. Kitagawa, T. Nakanishi, Y. Hasegawa, M. Ueda, T. Ohtsuka
JOURNAL OF SOLID STATE ELECTROCHEMISTRY, 19, 12, 3579, 3587, SPRINGER, 2015年12月
英語, 研究論文(学術雑誌), Photo-corrosion of an anodized titanium surface in 0.05 mol dm(-3) sulfuric acid solution was investigated by using an in situ electrochemical ellipso-microscope. Irradiation of ultra-violet (UV) light on an anodized surface, which showed a patch-like bright image on an ellipso-microscopic view due to non-uniform growth of the oxide film, under potentiostatic polarization allowed the flow of a photo-induced anodic current and changed the brightness and patch pattern in the image. This indicates that the irradiation promotes photo-electrochemical reaction, resulting in a change in the thickness and/or structure of the oxide film on the surface. The film change was dependent not only on power density of the irradiation light but also on applied potential during the irradiation and crystallographic orientation of the substrate. Pitting initiation during potentiodynamic polarization in the acid with bromide ions was also monitored using the ellipso-microscope. The irradiation resulted in pitting initiation at lower potentials than those in a non-irradiated condition. - Thermostable Eu(III)-nanorod luminophores with effective photosensitized energy transfer
Hiromitsu Onodera, Ayako Nakajima, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
JOURNAL OF ALLOYS AND COMPOUNDS, 648, 651, 657, ELSEVIER SCIENCE SA, 2015年11月
英語, 研究論文(学術雑誌), The thermostable Eu(III)-doped nanorod aggregates composed of luminescent Eu(III) complexes and diphenylphosphinic acids (DPP) are reported. Prepared Eu(III)-nanorod aggregates [Eu(hfa)(x)(TPPO)(y)(DPP)(z)](n) (hfa: hexafluoroacetylacetionate, TPPO: triphenylphosphine oxide), Eu(III)-nanoparticle aggregates [Eu(hfa) x(DPP) y] n, and standard Eu(III)-nanoparticles [Eu(DPP)(x)](n) were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements. The decomposition temperatures of [Eu(hfa)(x)(DPP)(y)](n) and [Eu(hfa)(x)(TPPO)(y)(DPP)(z)](n) for thermogravimetric analysis (TGA) were found to be over > 500 degrees C. Photosensitized luminescence was successfully observed for Eu(III)-nanorod and Eu(III)-nanoparticle aggregates excited at the specific pi-pi* transition band for organic hfa ligands (lambda = 340 nm), which is similar to the inter-ligand charge transfer (ILCT) band in the solid-state, were successfully observed. The photosensitized energy transfer efficiency of Eu(III)-nanorod aggregates of [Eu(hfa)(x)(TPPO)(y)(DPP)(z)](n) was estimated to be 91%. In this study, thermostable Eu(III)-nanorod aggregate luminophore composed of Eu(III) complexes and DPP joint compounds are demonstrated. (C) 2015 Elsevier B.V. All rights reserved. - Emission Modulation of Poly(vinyl acetate)–Tetrabutylphosphonium Tetrafluoroborate Hybrid Film Doped with 4-[Bis(4-methylphenyl)amino]benzaldehyde
K. Ogura, Z. Hoshi, E. Nagata, R. Ichikawa, T. Nakanoshi, Y. Hasegawa, H. Nakano
J. Photopolym. Sci. Tech., 28, 4, 601, 604, Tokai University, 2015年10月05日, [査読有り]
英語, 研究論文(学術雑誌), A hybrid film of poly(vinyl acetate) and tetrabutylphosphonium tetrafluoroborate together with 4-[bis(4-methylphenyl)amino]benzaldehyde as a fluorescent dopant was fabricated. It was found that the film exhibited thermally reversible phase-separation and dissolution transitions and that both homogeneous and phase-separated states could be obtained at room temperature by appropriate thermal treatments. In addition, emission modulation of the film was achieved by using the phase-separation–dissolution transitions. Fluorescence properties including fluorescence life times and quantum yields in homogeneous film seemed to be unchanged by phase separation, suggesting that no significant change in the surrounding environment of the dopant molecules took place by phase-separation– dissolution cycles. Therefore, the emission modulation observed here was suggested to be due to mainly the change in the light-scattering effect caused by phase transitions. - Mechanofluorochromism of 1-Alkanoylaminopyrenes
Eisuke Nagata, Shugo Takeuchi, Takayuki Nakanishi, Yasuchika Hasegawa, Yasuteru Mawatari, Hideyuki Nakano
CHEMPHYSCHEM, 16, 14, 3038, 3043, WILEY-V C H VERLAG GMBH, 2015年10月
英語, 研究論文(学術雑誌), To create a new series of mechanofluorochromic materials and to elucidate the mechanism of the phenomenon of mechanofluorochromism, 1-alkanoylaminopyrenes including 1-acetylaminopyrene (AAPy), 1-octanoylaminopyrene (OAPy), and 1-stearoylaminopyren (SAPy) were prepared. It was found that these materials exhibited mechanofluorochromism with emission colors in the crystalline samples changing reversibly from bluish purple to yellowish green, which could be induced by mechanical grinding. X-ray crystal structure analysis, electronic absorption, and fluorescence spectroscopies, as well as fluorescence lifetime analysis and powder X-ray diffraction analysis of AAPy suggested that the present mechanofluorochromism was caused by developing crystal defects through grinding. Intermolecular hydrogen bonds were suggested to play an important role in the occurrence of mechanofluorochromism, suppressing the face-to-face overlapping of pyrene moieties to form excimers in the pristine crystal. - Seven-Coordinate Luminophores: Brilliant Luminescence of Lanthanide Complexes with C-3v Geometrical Structures
Kei Yanagisawa, Takayuki Nakanishi, Yuichi Kitagawa, Tomohiro Seki, Tomoko Akama, Masato Kobayashi, Tetsuya Taketsugu, Hajime Ito, Koji Fushimi, Yasuchika Hasegawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 162, 28, 4769, 4774, WILEY-V C H VERLAG GMBH, 2015年10月
英語, 研究論文(学術雑誌), Enhanced luminescence properties of mononuclear lanthanide complexes with asymmetric seven-coordination structures are reported for the first time. The lanthanide complexes are composed of a lanthanide ion (Eu-III or Tb-III), three tetramethyl heptanedionato ligands, and one triphenylphosphine oxide ligand. The coordination geometries of the lanthanide complexes have been evaluated by using single-crystal X-ray analyses and shape-measurement calculations. The complexes are categorized to be seven-coordinate monocapped octahedral structures (point group C-3v). The seven-coordinate lanthanide complexes show high intrinsic emission quantum yields, extra-large radiative rate constants, and unexpected small nonradiative rate constants. The brilliant luminescence properties have been elucidated in terms of the asymmetric coordination geometry and small vibrational quanta related to thermal relaxation. - Terbium Oxide, Fluoride, and Oxyfluoride Nanoparticles with Magneto-optical Properties
Akira Kawashima, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fujita, Katsuhisa Tanaka, Koji Fushimi, Mohammad A. Malik, Paul O'Brien, Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 88, 10, 1453, 1458, CHEMICAL SOC JAPAN, 2015年10月
英語, 研究論文(学術雑誌), Novel terbium nanoparticles (TbX: terbium oxide (Tb2O3), terbium fluoride (TbF3), and terbium oxyfluoride (TbOF)) have been prepared and their magneto-optical properties reported. The TbX nanoparticles were synthesized by the thermolysis of Tb(III) complexes, used as single-source precursors, in oleylamine. The temperature used for the decomposition was estimated from using the thermogravimetric analysis (TGA) measurements. The as-prepared TbX nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDS), and X-ray photoelectron spectroscopy (XPS). Large Faraday rotations were observed from poly(methyl methacrylate) (PMMA) thin films containing TbX nanoparticles under magnetic field (15000 Oe). TbX nanoparticles with magneto-optical properties have been prepared for the first time. - Enhanced Electric Dipole Transition in Lanthanide Complex with Organometallic Ruthenocene Units
Yasuchika Hasegawa, Nao Sato, Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Atsushi Kobayashi, Masako Kato, Tomohiro Seki, Hajime Ito, Koji Fushimi
JOURNAL OF PHYSICAL CHEMISTRY A, 119, 20, 4825, 4833, AMER CHEMICAL SOC, 2015年05月, [査読有り]
英語, 研究論文(学術雑誌), Enhanced luminescence of a lanthanide complex with dynamic polarization of the excited state and molecular motion is introduced. The luminescent lanthanide complex is composed of one Eu(hfa)(3) (hfa, hexafluoroacetylacetonate) and two phosphine oxide ligands with ruthenocenyl units Rc, [Eu(hfa)(3)(RcPO)(2)] (RcPO = diphenylphosphorylruthenocene). The ruthenocenyl units in the phosphine oxide ligands play an important role of switching for dynamic molecular polarization and motion in liquid media. The oxidation states of the ruthenocenyl unit (Rc(1+)/Rc(1+)) are controlled by potentiostatic polarization. Eu(III) complexes attached with bidentate phosphine oxide ligands containing ruthenocenyl units, [Eu(hfa)(3)(RcBPO)] (RcBPO = 1,1'-bis(diphenylphosphoryl)ruthenocene), and with bidentate phosphine oxide ligands, [Eu(hfa)(3)(BIPHEPO)] (BIPHEPO =1,1'-biphenyl-2,2'-diylbis(diphenylphosphine oxide), were also prepared as references. The coordination structures and electrochemical properties were analyzed using single crystal X-ray analysis, cyclic voltammetry, and absorption spectroscopy measurements. The luminescence properties were estimated using an optoelectrochemical cell. Under potentiostatic polarization, a significant enhancement of luminescence was successfully observed for [Eu(hfa)(3)(RcPO)(2)], while no spectral change was observed for [Eu(hfa)(3)(RcBPO)]. In this study, the remarkable enhanced luminescence phenomena of Eu(III) complex based on the dynamic molecular motion under potentiostatic polarization have been performed. - Luminescent Coordination Glass: Remarkable Morphological Strategy for Assembled Eu(III) Complexes
Yuichi Hirai, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Tomohiro Seki, Hajime Ito, Hiroyuki Fueno, Kazuyoshi Tanaka, Toshifumi Satoh, Yasuchika Hasegawa
INORGANIC CHEMISTRY, 54, 9, 4364, 4370, AMER CHEMICAL SOC, 2015年05月
英語, 研究論文(学術雑誌), Syntheses of novel luminescent Eu(III) coordination glasses 1 ([Eu(hfa)(3)(o-dpeb)](2)), 2 ([Eu(hfa)(3)(m-dpeb)](3)), and 3 ([Eu(hfa)(3)(p-dpeb)](n)) are reported. They are composed of Eu(III) ions, hexafluoroacetylacetonato (hfa) ligands, and unique bent-angled phosphine oxide (o-, m-, p-dpeb) ligands with ethynyl groups. Their coordination structures and glass formability are dependent on the regiochemistry of substitution in regard to the internal benzene core. Single-crystal X-ray analyses and DFT calculation reveals dinuclear, trinuclear, and polymer structures for Eu(III) coordination glasses 1, 2, and 3, respectively. Those compounds show characteristic glass-transition (T-g = 25-96 degrees C) and strong luminescence properties (phi(Ln) = 72-94%). - Magneto-optical property of lantanide cluster with Ln-O lattice structure
Takayuki Nakanishi, Yasuchika Hasegawa
Kobunshi, 64, 4, 203, 204, Society of Polymer Science, 2015年04月01日
日本語, 研究論文(学術雑誌), Lanthanide(Ln)-complexes with organic ligands have attracted much interest for optical, electronic and magnetic applications. In particular, poly-nuclear lanthanide complexes with a Ln-O inorganic lattice have been reported to show characteristic chemical and physical properties such as catalytic reactions, acting as single-molecular magnets, and photo-sensitized luminescence. The molecular design and synthesis of poly-nuclear lanthanide complexes is expected to open up a new field of advanced molecular science. In this article, we describe the magneto-optical properties of novel terbium nona-nuclear complexes with a sandglass shaped Tb-O lattice structure. Effective Faraday rotation was observed in nona-nuclear terbium complexes in the visible region for the first time. - EVA thin film with thermo- and moisture-stable luminescent copolymer beads composed of Eu(III) complexes for improvement of energy conversion efficiency on silicon solar cell
Hisataka Kataoka, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa
OPTICAL MATERIALS, 42, 411, 416, ELSEVIER SCIENCE BV, 2015年04月
英語, 研究論文(学術雑誌), Luminescent beads composed of Eu(hfa)(3)(TPPO)(2) (hfa: hexafluoroacetylacetonate, TPPO: triphenylphosphine oxide) in PMMA copolymer (polymethylmethacrylate- styrene and polymethylmethacrylate-tri-fluoromethylmethacrylate copolymers), PMMA-St-Eu and PMMA-TF-Eu have been reported for improvement of energy conversion efficiency on silicon solar cell. The PMMA-St-Eu and PMMA-TF-Eu beads are prepared using radical initiator AIBN (2,2-azobisisobutyronitrile) without BPO (Benzoyl peroxide) which promotes decomposition of Eu(hfa)(3)(TPPO)(2). The emission properties of EVA (ethylene vinyl acetate) film with PMMA-St-Eu or PMMA-TF-Eu beads are characterized by the emission spectra and lifetimes. Thermo- and moisture-stabilities of the EVA films are performed under high temperature and high moisture condition (85 degrees C85%RH). Increase percentage the solar cell short circuit current efficiency in the solar cell modulation using with EVA film containing PMMA-St-Eu beads with size in 70 mu m was estimated to 1.2%. Thermo- and moisture-stable PMMA-St-Eu and PMMA-TF-Eu beads for solar sealing film are demonstrated for the first time. (C) 2015 Elsevier B.V. All rights reserved. - Effective Photosensitized Energy Transfer of Nonanuclear Terbium Clusters Using Methyl Salicylate Derivatives
Shun Omagari, Takayuki Nakanishi, Tomohiro Seki, Yuichi Kitagawa, Yumie Takahata, Koji Fushimi, Hajime Ito, Yasuchika Hasegawa
JOURNAL OF PHYSICAL CHEMISTRY A, 119, 10, 1943, 1947, AMER CHEMICAL SOC, 2015年03月
英語, 研究論文(学術雑誌), The photophysical properties of the novel nonanuclear Tb(III) clusters Tb-L1 and Tb-L2 involving the ligands methyl 4-methylsalicylate (L1) and methyl 5-methylsalicylate (L2) are reported. The position of the methyl group has an effect on their photophysical properties. The prepared nonanuclear Tb(III) clusters were identified by fast atom bombardment mass spectrometry and powder X-ray diffraction. Characteristic photophysical properties, including photoluminescence spectra, emission lifetimes, and emission quantum yields, were determined. The emission quantum yield of Tb-L1 (Phi(pi pi)* = 31%) was found to be 13 times larger than that of Tb-L2 (Phi(pi pi)* = 2.4%). The photophysical characterization and DFT calculations reveal the effect of the methyl group on the electronic structure of methylsalicylate ligand. In this study, the photophysical properties of the nonanuclear Tb(III) clusters are discussed in relation to the methyl group on the aromatic ring of the methylsalicylate ligand. - Chiroptical properties of nonanuclear Tb(III) clusters with chiral champhor derivative ligands
Satoshi Wada, Yuichi Kitagawa, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
e-Journal of Surface Science and Nanotechnology, 13, 31, 34, Surface Science Society of Japan, 2015年02月14日
英語, 研究論文(国際会議プロシーディングス), The chiroptical properties of nonanuclear Tb(III) clusters are reported. The nonanuclear Tb(III) clusters are composed of nine Tb(III) ions, ten μ-OH parts, and sixteen chiral organic ligands, (±)-bornyl salicylate. Their chiroptical properties were estimated by circular dichroism (CD) and circularly polarized luminescence (CPL). Their electronic structures were calculated using TD-DFT (B3LYP/6-31G(d)) method. - Synthesis and photoluminescence properties of nonanuclear Tb(III) clusters with long alkyl chain group
Shun Omagari, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
e-Journal of Surface Science and Nanotechnology, 13, 27, 30, Surface Science Society of Japan, 2015年02月14日
英語, 研究論文(国際会議プロシーディングス), Series of nonanuclear Tb(III) clusters with ligands of different length of alkyl chain groups and their photophysical properties are demonstrated. The nonanuclear Tb(III) clusters (Tb9 clusters) are composed of nine oxygen-bridged Tb(III) ions and sixteen alkyl salicylate ligands, where alkyl chain are ethyl (Tb9-Et), propyl (Tb9-Pr), butyl (Tb9-Bu), and hexyl (Tb9-Hex) groups. The luminescence properties of the Tb9 clusters are characterized by absorption spectra, emission quantum yields, and emission lifetimes. The radiative (kr) and nonradiative (knr) rate constants were calculated from their photophysical properties. Tb9-Hex have shown the highest kr (859 s-1) and lowest knr(137 s-1), owing to the tight packing due to CH-π interaction by long alkyl chains. - Synthesis of TbOx nanoparticles from the thermal decomposition of TB(III) complexes
Akira Kawashima, Takayuki Nakanishi, Yuichi Kitagawa, Koji Fushimi, Yasuchika Hasegawa
e-Journal of Surface Science and Nanotechnology, 13, 23, 26, Surface Science Society of Japan, 2015年02月07日
英語, 研究論文(国際会議プロシーディングス), Terbium oxide nanoparticles, TbOx nanoparticles, were synthesized by the thermal reaction of Tb(III) complexes as a single-source precursor with acetylacetone (acac) or hexafluoroacetylacetone (hfa). Thermal decomposition processes of Tb(III) complexes for preparation of TbOx nanoparticles were characterized by the thermogravimetric analysis (TGA). The prepared TbOx nanoparticles were identified using XRD and TEM measurements. - Luminescent silicon nanoparticles covered with ionic liquid
Mani Miyano, Satoshi Wada, Takayuki Nakanishi, Yasuchika Hasegawa
MATERIALS LETTERS, 141, 359, 361, ELSEVIER SCIENCE BV, 2015年02月
英語, 研究論文(学術雑誌), Red-, yellow- and green-luminescent silicon nanoparticles covered with ionic liquid AMImTFSI (1-Allyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide) are reported. Red luminescent silicon nanoparticles (Si-Red), yellow luminescent silicon nanoparticles (Si-Yellow) and green luminescent silicon nanoparticles (Si-Green) were prepared under the acid-etching process using hydrofluoric acid/nitric acid for 50 s, 75 s, and 90 s, respectively. Their surface protection using ionic liquid was carried out by the injection of bare silicon nanoparticles into AMImTFSI, resulting in formation of Si-Red-I, Si-Yellow-I and Si-Green-I. The Si-Red-I, Si-Yellow-I and Si-Green-I show effective luminescence after 17 days. In this study, luminescent silicon nanoparticles covered with ionic liquid are performed for the first time. (C) 2014 Elsevier B.V. All rights reserved. - Hydrodynamic effect of entry side cell on hydrogen permeation into steel sheet
K. Fushimi, M. Jin, Y. Yamamoto, Y. Kitagawa, T. Nakanishi, Y. Hasegawa
European Corrosion Congress, EUROCORR 2015, 1, 548, 551, Austrian Society for Metallurgy and Materials (ASMET), 2015年
英語, 研究論文(国際会議プロシーディングス), Devanathan-Stachurski (DS) double electrochemical cell for measurement of hydrogen-permeation into a steel sheet was extended to an electrolyte-flowing design. Increase in flow rate of electrolyte in a hydrogen-entry side cell induced an increase in hydrogen-evolution current at the entry side electrode and a decrease in hydrogen-detection current at the hydrogen-exit side electrode. Hydrogen-permeation was actualized by a sinusoidal perturbation of the entry-flow rate. The hydrogen-permeation response, i.e., phase shift of the detection current from the evolution current, was proportional to the square root of flow rate frequency and was dependent on the sheet thickness. - Europium Chalcogenide Nanoparticles
Yasuchika Hasegawa, Takayuki Nakanishi
Handbook on the Physics and Chemistry of Rare Earths, 47, 101, 146, Elsevier, 2015年, [査読有り]
英語, 論文集(書籍)内論文, Intrinsic magnetic semiconductor nanoparticles containing europium chalcogenides EuX (X. = O, S, Se, and Te) are now being targeted from the viewpoints of fundamental condensed matter science and also of practical application for spintronics and magneto-optic devices. At the present stage, various types of magnetic dopants in II-VI or III-V semiconductor nanoparticles have been investigated. It turns out that the quantum-size and quantum-confinement effects found in europium chalcogenides is providing new photophysics arising from both ferro- and antiferromagnetic spin configurations. Preparation methods of europium chalcogenide nanoparticles are linked to the progress of modern nanoscience and technology. They have been dramatically improved by several research groups during the past decade. In particular, high-quality nanoscale EuO, EuS, and EuSe materials were successfully prepared by the reaction of an Eu(III) complex used as single-source precursor. Nano-size structures of magnetic semiconductor europium chalcogenides lead to the formation of single domains of magnetic moment in the nanocrystal. Aggregates of sphere-shaped EuX nanoparticles exhibit superparamagnetic and super-antiferromagnetic behaviors. Moreover, enhancement of ferromagnetic properties for aggregates of cube-shaped EuS nanoparticles has been observed. EuX nanoparticles with giant magneto-optical efficiency are expected to be useful in applications such as optical isolators and spintronic devices. In conclusion, intrinsic magnetic semiconductor nanocrystals containing Eu(II) ions under the form of EuX are therefore promising materials for next-generation photonic devices. © 2015 Elsevier B.V. - Cluster-π electronic interaction in a superatomic Au13 cluster bearing σ-bonded acetylide ligands
M. Sugiuchi, Y. Shichibu, T. Nakanishi, Y. Hasegawa, K. Konishi
CHEMICAL COMMUNICATIONS, 51, 70, 13519, 13522, ROYAL SOC CHEMISTRY, 2015年, [査読有り]
英語, 研究論文(学術雑誌), An organometallic Au-13 cluster having two sigma-bonded acetylide ligands was synthesized and its structure was determined by X-ray crystallography. Absorption spectral studies indicated the presence of electronic coupling between the superatomic Au-13 core and the acetylide pi-orbitals, which was supported by theoretical considerations. - Passivity of Dual-Phase Carbon Steel with Ferrite and Martensite Phases in pH 8.4 Boric Acid-Borate Buffer Solution
Kei Yanagisawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 162, 7, C322, C326, ELECTROCHEMICAL SOC INC, 2015年, [査読有り]
英語, 研究論文(学術雑誌), Passivity of a dual-phase carbon steel with ferrite and martensite phases was investigated in pH 8.4 boric acid-borate buffer solution. The corrosion potential of the dual-phase steel was higher than that of pure martensitic steel and lower than that of pure ferritic steel. In dynamic polarization measurements, the passivity-maintaining current of the dual-phase steel was an intermediate value of those of pure ferritic and martensitic steels. EIS revealed that both the charge transfer resistance and capacitance of the oxide film formed on the dual-phase steel were intermediate between those of pure ferritic and martensitic steels. Although the donor density in the oxide film of the dual-phase steel was similar to that of pure ferritic steel, it was smaller than that of pure martensitic steel. SECM showed that the passive film formed on the martensite phase of the dual-phase steel had better electronic conductivity than that of the passive film formed on the ferrite phase. These differences in local passivity of the dual-phase steel suggested that the passive film formed on the ferrite phase has better passivity but larger scattering of the property than that of the passive film on the martensite phase. The local passivity of the dual-phase steel was strongly dependent on the texture of the substrate material. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/.), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved. - Luminescent Silicon Nanoparticles Surface-Modified with Chiral Molecules
Mari Miyano, Takayuki Nakanishi, Satoshi Wada, Yuichi Kitagawa, Akira Kawashima, Koji Fushimi, Yasuhiro Morisaki, Yoshiki Chujo, Yasuchika Hasegawa
JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY, 28, 2, 255, 260, TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN, 2015年, [査読有り]
英語, 研究論文(学術雑誌), Active surface of luminescent silicon nanoparticles was terminated by the photochemical reaction of chiral molecules, (S)- or (R)-5-allyl-2-oxabicyclo[3,3,0]oct-8-ene ((S) - or (R) - AOBE) under UV light. The particle size and shapes were characterized using Transmission Electron Microscope (TEM). The average particle size was found to be 5.7 nm. Circular dichroism (CD) signals with large dissymmetry factors from silicon nanoparticles terminated with (S) - and (R) - AOBE were observed at around 300 nm and 500 nm, which were much larger than those of (S)- and (R)-AOBE molecules. The silicon nanoparticles covered with (S)- or (R)-AOBE provided red luminescence based on the indirect electronic transition. Effective circular polarized luminescence (CPL) was not observed from indirect transition band. - Effect Of Hydrogen Sulfide Ions on the Passive Behavior of Type 316L Stainless Steel
Jun-Seob Lee, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa, Koji Fushimi
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 162, 14, C685, C692, ELECTROCHEMICAL SOC INC, 2015年
英語, 研究論文(学術雑誌), The effect of hydrogen sulfide ions (HS-) on the passivity of type 316L stainless steel was investigated in pH 8.4 boric acid-borate buffer solution. Galvanostatic polarization of a silver microelectrode covered with Ag2S generated both OH- and HS- above the stainless steel surface. During potentiostatic polarization of the stainless steel, the passivity-maintaining current density increased with increase in the concentration of HS- in the vicinity of the surface. The impedance of the stainless steel at a constant frequency decreased during polarization in the presence of HS-, while it was sustained after dilution of HS-. Electrochemical impedance spectroscopy (EIS), Mott-Schottky (M-S) analysis and scanning electrochemical microscopy (SECM) showed that a defective and n-type semiconductive passive film was formed in the solution containing HS-. Auger electron spectroscopy (AES) revealed that metal cations and oxygen vacancies in the passive film on the stainless steel increased when it was formed in a HS- -conoining solution. The series of changes in passive film properties is thought to be due to adsorption of HS- on the film surface during the polarization. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licensestby/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved. - Photo-degradation Analysis of Luminescent Polymers with Lanthanide Complexes
Hisataka Kataoka, Shun Omagari, Takayuki Nakanishi, Yasuchika Hasegawa
JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY, 28, 2, 247, 254, TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN, 2015年
英語, 研究論文(学術雑誌), UV durability of luminescent Eu(III) complexes for future solar cell application is estimated using Fourier transform infrared spectroscopy (FT-IR). Sandwich-typed glass cells containing Eu(III) complexes powders under UV irradiation are used for the carbonyl index analysis (calculation of decomposition percentage of organic ligands) using FT-IR measurements. The durability of Eu(hfa)(3)(TPPO)(2) (hfa: hexafluoroacetylacetonate, TPPO: triphenylphospine oxide) is five times larger than that of Eu(tta)(3)(phen) (tta: trifluoromethylthienylacetylacetonate, phen: phenanthroline). Photophysical performance of Eu(III) complexes under UV irradiation is also evaluated using emission lifetimes and external quantum efficiency measurements of the solar cell module using EVA films with Eu(III) complexes. Photo-degradation analysis of luminescent polymer thin films with Eu(III) complexes are demonstrated for the first time. - Thermostable nano luminophores composed of europium ions and organic ligands
Hiromitsu Onodera, Ayako Nakajima, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
e-Journal of Surface Science and Nanotechnology, 13, 219, 222, Surface Science Society of Japan, 2015年
英語, 研究論文(国際会議プロシーディングス), The luminescent nanoparticles with Eu(III) ions are reported. Standard nanoparticles are prepared by the reaction of europium chloride with dpp (diphenylphospinic acid) joint ligands. The size-controlled nanoparticles are synthesized by the reaction of Eu(hfa)<
inf>
3<
/inf>
(H<
inf>
2<
/inf>
O)<
inf>
2<
/inf>
(hfa: hexafluoroacetylacetonate) with bidentate dpbp ligands (dpbp: 4,4′-bis(diphenylphosphoryl)biphenyl) and monodentate ligands (TPPO: triphenylphosphine oxide). Their particle sizes were characterized using TEM and dynamic light scattering (DLS) measurements. Their luminescence properties were estimated by the emission spectra and lifetimes. - Synthesis of binary solid solution Cu-Pd nanoparticles by DMF reduction for enhanced photoluminescence properties
Masashi Chiba, Mai Nguyen Thanh, Yasuchika Hasegawa, Yasushi Obora, Hideya Kawasaki, Tetsu Yonezawa
JOURNAL OF MATERIALS CHEMISTRY C, 3, 3, 514, 520, ROYAL SOC CHEMISTRY, 2015年
英語, 研究論文(学術雑誌), We report the use of a DMF reduction method for straightforward synthesis of binary solid solution Cu-Pd nanoparticles (NPs) over the entire range of composition. The resulting NPs were uniform in size (less than 2.5 nm), tunable in composition, and exhibited photoluminescence properties that were nonlinear in composition. These binary solid solution NPs showed enhanced photoluminescence intensity and quantum yield compared to those of the single-metal NPs and their mixtures. The highest quantum yield of 3.10% for Cu-Pd alloy NPs synthesized using equimolar feeding ratio versus 2.75% for Cu and 0.71% for Pd NPs was obtained. These enhancements make the alloy NPs promising materials for optical applications. - Development of a Liquid-Phase Ion Gun and Its Application for Sulfidation of Silver Surface
Jun-Seob Lee, Koji Fushimi, Yuichi Kitagawa, Takayuki Nakanishi, Yasuchika Hasegawa
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 162, 4, C115, C120, ELECTROCHEMICAL SOC INC, 2015年
英語, 研究論文(学術雑誌), A system for safe generation of sulfide ions was established by using the microelectrode technique in order to investigate sulfidation of the metal surface of silver. Both silver microelectrode sulfidation and silver sulfide reduction on the microelectrode were reversible in Na2S solution and corresponded to Ag2S formation and HS- generation, respectively. Cathodic polarization of Ag2S, which covered the silver microelectrode, in pH 8.4 boric-borate buffer solution successfully generated HS- above a glass or silver substrate. Concentration of HS- in the vicinity of the substrate was dependent on the distance between the microelectrode and the substrate. The silver substrate was locally sulfidated by HS- generated from the microelectrode. However, at potentials higher than 0.14 V-RHE, local sulfidation of the silver substrate was independent of the substrate potential. It is thought that mass transport of HS- is dominant for sulfidation of the silver substrate. (C) The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved. - Luminescent lanthanide coordination polymers for photonic applications
Y. Hasegawa, T. Nakanishi
RSC ADVANCES, 5, 1, 338, 353, ROYAL SOC CHEMISTRY, 2015年
英語, Luminescent lanthanide coordination polymers composed of lanthanide ions and organic joint ligands exhibit characteristic photophysical and thermostable properties that are different from typical organic dyes, luminescent metal complexes, and semiconductor nanoparticles. Various types of luminescent Eu(III) and Tb(III) coordination polymers have been reported to date. One-, two-, and three-dimensional alternating sequences of lanthanide ions and organic ligands exhibit remarkable characteristics as novel organic materials with various structures, and unique physical properties. In this review, the characteristic structures, photophysical properties, and photonic applications for organic display devices, triboluminescent materials, thermosensors, color and brightness tuning, new type organogels, future magneto-optical materials, luminescent organo-nanoparticles, and energy transfer process of lanthanide coordination polymers are introduced. - Enhanced light storage of SrAl
2 O4 glass-ceramics controlled by selective europium reduction
Takayuki Nakanishi, Kazune Watanabe, Jumpei Ueda, Koji Fushimi, Setsuhisa Tanabe, Yasuchika Hasegawa
Journal of the American Ceramic Society, 98, 2, 423, 429, 2014年12月03日
研究論文(学術雑誌), © 2014 The American Ceramic Society. A luminescent Eu, Dy: SrAl2O4 glass-ceramics with high transparency in the visible region was successfully synthesized using the frozen sorbet technique with the control of O2 partial pressure (PO2) for the oxidation of Eu2+ ions. The glass-ceramics include Eu2+, Eu3+, and Dy3+ ions, and thus exhibits three characteristic types of emission bands, 4f-5d at around 520 nm (Eu2+ ions), 4f-4f at 610 nm (Eu3+ ions), and 480 nm (Dy3+ ions). The Eu, Dy: SrAl2O4 glass-ceramics provide remarkable long-persistent luminescence under dark condition. The glass-ceramics also exhibits color-changing luminescence in the visible region based on their remarkable light storage properties. The luminescent Eu, Dy: SrAl2O4 glass-ceramics using the frozen sorbet technique with control of PO2 are promising materials for application in novel photonic and light storage materials. - Corrosion behaviour of ferrite and austenite phases on super duplex stainless steel in a modified green-death solution
Jun-Seob Lee, Koji Fushimi, Takayuki Nakanishi, Yasuchika Hasegawa, Yong-Soo Park
CORROSION SCIENCE, 89, 111, 117, PERGAMON-ELSEVIER SCIENCE LTD, 2014年12月
英語, 研究論文(学術雑誌), Corrosion behaviour of super duplex stainless steel (SDSS) in acidic chloride solution was investigated electrochemically. Potentiostatic polarisations of SDSS at -0.377 and -0.447 V-SHE resulted in selective dissolution of gamma- and alpha-phases, respectively, and were utilized for fabricating single-phase electrodes. Potentiodynamic polarisation curve of SDSS could be calculated from those of single-phase electrodes. The higher corrosion current density and less noble corrosion potential of alpha-phase characterised by galvanic connection with gamma-phase indicated that alpha- and gamma-phases were functioned as the anode and the cathode, respectively, in the corrosion of SDSS. (C) 2014 Elsevier Ltd. All rights reserved. - Thermo-stable Lanthanoid Coordination Nanoparticles Composed of Luminescent Eu(III) Complexes and Organic Joint Ligands Using Micelle Techniques in Water
Onodera Hiromitsu, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 87, 12, 1386, 1390, CHEMICAL SOC JAPAN, 2014年12月
英語, 研究論文(学術雑誌), Strong luminescent nanoparticles composed of lanthanoid coordination polymers using micelle reaction techniques, lanthanoid coordination nanoparticles, are reported. Size of the nanoparticles estimated using dynamic light-scattering measurements were found to be approximately 66 urn. Lanthanoid coordination nanoparticles were characterized using ESI-MS spectrometry, XRD measurements, and thermogravimetric analyses (TGA). Emission properties of lanthanoid coordination nanoparticles were estimated using emission spectra and emission lifetimes. These results indicate that nanoparticles composed of lanthanoid coordination polymers show effective luminescent properties and thermal stability such as bulk powders of lanthanoid coordination polymers. - Distibylation of Acetylenes with Ph2Sb-SbPh2: Synthesis, Crystal Structures and Phosphorescence Properties of Bis(diphenylstibyl)ethenes
Joji Ohshita, Toshiyuki Tsuchida, Kazuya Murakami, Yousuke Ooyama, Takayuki Nakanishi, Yasuchika Hasegawa, Norifumi Kobayashi, Hideyuki Higashimura
ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES, 69, 11-12, 1181, 1187, VERLAG Z NATURFORSCH, 2014年11月
英語, 研究論文(学術雑誌), Treatment of tetraphenyldistibine (1) with terminal arylacetylenes, XC6H5C equivalent to CH (2a-c, X = H, F, OMe), gave the corresponding anti-addition products (E)-aryl-1,2-bis(diphenylstibyBethenes 3a-c in 11-17 % yields. A similar reaction of 1 with 1,4-diphenylbutadiyne provided (E)-1,4-diphenyl-1,2-bis(diphenylstibyl)but- 1-en-3-yne (3d) in 28% yield. X-Ray diffraction studies on crystals of 3a, 3b and 3d revealed a congested configuration around the ethylene core. The optical properties of the adducts 3a-d were examined by measuring UV absorption and photoluminescence spectra. Interestingly, 3d showed phosphorescence in the solid state, which was enhanced at low temperature. - Growth and Degradation of an Anodic Oxide Film on Titanium in Sulphuric Acid Observed by Ellipso-microscopy
K. Fushimi, K. Kurauchi, Y. Yamamoto, T. Nakanishi, Y. Hasegawa, T. Ohtsuka
ELECTROCHIMICA ACTA, 144, 56, 63, PERGAMON-ELSEVIER SCIENCE LTD, 2014年10月
英語, 研究論文(学術雑誌), The surface of polycrystalline titanium polarised anodically in 0.05 mol dm(-3) sulphuric acid was monitored using an ellipso-microscope. During dynamic polarisation, a patch-like bright image was seen on an ellipso-microscopic view, and the brightness and image changed with increase in potential. The change in the brightness and image mainly corresponded to growth of an anodic oxide film on the surface. An in situ monitoring using the ellipso-microscope revealed that the film formation rate was dependent on the crystallographic orientation of the substrate. Breakdown of the film induced in a solution containing bromide ions was also monitored using the microscope. Prior to the pitting propagation, the surface was partially changed with flow of a large anodic current. AES measurement revealed that the formation of bromo-oxide resulted in localised film degradation followed by pitting corrosion. (C) 2014 Elsevier Ltd. All rights reserved. - Photofunctional Lanthanoid Complexes, Coordination Polymers, and Nanocrystals for Future Photonic Applications
Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 87, 10, 1029, 1057, CHEMICAL SOC JAPAN, 2014年10月
英語, In this account, lanthanoid complexes, coordination polymers, and nanocrystals with photofunctional properties are introduced. To maintain the effective emission of Nd(III), Sm(III), Eu(III), TWIT), and Yb(III) ions in organic media, the coordination sphere of the lanthanoid ions should consist of strong, bulky, and asymmetric ligands with low vibrational frequencies, that is, there are three criteria for luminescence: 1) suppression of vibrational relaxation, 2) prevention of nonradiative cross relaxation at diffusional collision, and 3) introduction of asymmetric coordination geometry for enhancing electric dipole transition. Lanthanoid coordination compounds with characteristic photosensitizing properties, photochromic properties, circularly polarized luminescence (CPL), metal ion sensing properties, solvent sensing properties, energy-conversion properties, thermostable properties, triboluminescent properties, and thermosensing properties are also described for the development of photofunctional materials. In the second half, the synthesis, photophysical magnetic, and magneto-optical properties of lanthanoid nanocrystals, EuO, EuS, and EuSe, are reported. In particular, the remarkable photophysical properties of nanoaggregates composed of EuS nanocrystals are presented. Photofunctional lanthanoid(III) complexes, coordination polymers, and nanocrystals are expected to open up a frontier field of materials science. - Thermo-sensitive luminescent materials composed of Tb(III) and Eu(III) complexes
Yuichi Hirai, Takayuki Nakanishi, Kohei Miyata, Koji Fushimi, Yasuchika Hasegawa
MATERIALS LETTERS, 130, 91, 93, ELSEVIER SCIENCE BV, 2014年09月
英語, 研究論文(学術雑誌), Thermo-stable lanthanide coordination polymers [Tb,Eu(hfa)(3)(dpbp)](n) composed of Tb(III) ion, Eu(III) ion, bidentate phosphine oxide (dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl), and low-vibrational frequency hexafiuoroacetylacetonate (hfa) ligand are reported. The lanthanide coordination polymers [Tb,Eu(hfa)(3)(dpbp)](n) (Tb/Eu=1, 10, 250, 500, and 750) are characterized by XRD, emission spectra and emission lifetime measurements. The energy transfer efficiencies among lanthanide ions are estimated using the emission lifetimes of solid-state coordination polymers. Characteristic emission properties of lanthanide coordination polymers composed of Tb(III) ions and a small amount of Eu(III) ions (Tb/Eu=750) have been observed for the first time. The energy transfer between lanthanide ions in coordination polymers is described in terms of solid-state materials. (C) 2014 Elsevier B.V. All rights reserved. - Novel Synthesis and Effective Surface Protection of Air-Stable Luminescent Silicon Nanoparticles
Mari Miyano, Shinobu Endo, Hideaki Takenouchi, Satoshi Nakamura, Yoshinori Iwabuti, Osamu Shiino, Takayuki Nakanishi, Yasuchika Hasegawa
JOURNAL OF PHYSICAL CHEMISTRY C, 118, 34, 19778, 19784, AMER CHEMICAL SOC, 2014年08月
英語, 研究論文(学術雑誌), Air-stable luminescent silicon nanoparticles with effective surface protection are reported as a quantum dot material with high emission quantum yield. The silicon nanoparticles are prepared by a novel reaction of SiO2 with phenol resins and characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average particle size of the silicon nanoparticles is controlled by an acid-etching process with hydrofluoric and nitric adds in methanol. The particle size estimated from emission spectra was less than 5 nm. The surfaces of the silicon nanoparticles are protected using a photoassisted reaction with styrene molecules after the acid-etching process. The surface-protected silicon nanoparticles exhibit luminescence at around 650 nm, and their emission quantum yield is estimated to be 55%. - Enhancement of Optical Faraday Effect of Nonanuclear Tb(III) Complexes
Takayuki Nakanishi, Yuki Suzuki, Yoshihiro Doi, Tomohiro Seki, Hitoshi Koizumi, Koji Fushimi, Koji Fujita, Yukio Hinatsu, Hajime Ito, Katsuhisa Tanaka, Yasuchika Hasegawa
INORGANIC CHEMISTRY, 53, 14, 7635, 7641, AMER CHEMICAL SOC, 2014年07月
英語, 研究論文(学術雑誌), The effective magneto optical properties of novel nonanuclear Tb(III) complexes with Tb-O lattice (specifically, [Tb-9(sal-R)(16)(mu-OH)(10)]+NO3-, where sal-R = alkyl salicylate (R = -CH3 (Me), -C2H5 (Et), -C3H7 (Pr), or -C4H9 (Bu)) are reported. The geometrical structures of these nonanudear Tb(III) complexes were characterized using X-ray single-crystal analysis and shape-measure calculation. Optical Faraday rotation was observed in nonanuclear Tb(III) complexes in the visible region. The Verdet constant per Tb(III) ion of the Tb-9(sal-Me) complex is 150 times larger than that of general Tb(III) oxide glass. To understand their large Faraday rotation, electron paramagnetic resonance measurements of Gd(III) complexes were carried out. In this Report, the magneto optical relation to the coordination geometry of Tb ions is discussed. - Photo- and thermo-stable luminescent beads composed of Eu(III) complexes and PMMA for enhancement of silicon solar cell efficiency
Hisataka Kataoka, Tetsuo Kitano, Toshiki Takizawa, Yuichi Hirai, Takayuki Nakanishi, Yasuchika Hasegawa
JOURNAL OF ALLOYS AND COMPOUNDS, 601, 293, 297, ELSEVIER SCIENCE SA, 2014年07月
英語, 研究論文(学術雑誌), Photo-and thermo-stable luminescent beads composed of Eu(hfa)(3)(TPPO)(2) (hfa: hexafluoroacetylacetonate, TPPO: triphenylphosphine oxide) and PMMA (polymethylmethacryrate), Eu(hfa)(3)(TPPO)(2)-beads, have been reported for improvement of energy conversion efficiency on silicon solar cell. The photophysical properties of Eu(hfa)(3)(TPPO)(2) and compared Eu(tta)(3)(TPPO)(2) (tta: trifluoromethyl- thienylacetylacetonate) are characterized by the emission quantum yield, the emission lifetime, the radiative and the non-radiative rate constants. Photo-and thermo-stability of the beads with Eu(III) complexes in EVA (Ethylene Vinyl Acetate) are estimated under UV irradiation (Xenon lamp: 60 W/m(2)) and highly temperature (120 degrees C). The stability of the Eu(hfa)(3)(TPPO)(2)-beads for industrial application was calculated to be ten years under air condition. Energy conversion efficiency of silicon solar cells attached EVA films with Eu(hfa)(3)(TPPO)(2)-beads increased approximately 2%(10% -> 10.2%) compared with EVA films contained with UV absorber. Photo-and thermo-stable Eu(hfa)(3)(TPPO)(2)-beads for silicon solar cells are demonstrated for the first time. (C) 2014 Elsevier B.V. All rights reserved. - Ratiometric luminescence thermometry based on crystal-field alternation at the extremely narrow D-5(0) -> F-7(2) transition band of europium(III)
Junpei Yuasa, Ryusuke Mukai, Yasuchika Hasegawa, Tsuyoshi Kawai
CHEMICAL COMMUNICATIONS, 50, 59, 7937, 7940, ROYAL SOC CHEMISTRY, 2014年
英語, 研究論文(学術雑誌), A dinuclear europium(III) complex with a structure of [BP-(Eu-III)(2)-(ODA)(3)] (BP = 2,2'-bipyridine-6,6'-dicarboxylic acid bis(N-hydroxy-succinimide) ester, ODA = diglycolic acid) shows a fully reversible emission spectral change at the extremely narrow D-5(0) -> F-7(2) transition band in response to temperature changes ranging from 283 K to 333 K. - Synthesis of Group 14 Dipyridinometalloles with Enhanced Electron-Deficient Properties and Solid-State Phosphorescence
Joji Ohshita, Kazuya Murakami, Daiki Tanaka, Yousuke Ooyama, Tomonobu Mizumo, Norifumi Kobayashi, Hideyuki Higashimura, Takayuki Nakanish, Yasuchika Hasegawa
ORGANOMETALLICS, 33, 2, 517, 521, AMER CHEMICAL SOC, 2014年01月
英語, 研究論文(学術雑誌), Silicon- and germanium-bridged bipyridyls were prepared, and their optical and electrochemical properties were investigated. It was found that they exhibited enhanced electron deficiency and phosphorescence properties in comparison to parent bipyridyl. The single-crystal structure of a dipyridinosilole and results of DFT calculations on models are also described. - Grain-Dependent Passivation of Iron in Sulfuric Acid Solution
Y. Takabatake, K. Fushimi, T. Nakanishi, Y. Hasegawa
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 161, 14, C594, C600, ELECTROCHEMICAL SOC INC, 2014年
英語, 研究論文(学術雑誌), Passive films formed on single grains of a polycrystalline pure iron substrate were investigated in 0.05 mol dm(-3) sulfuric acid with a micro-capillary cell (MCC). Passivation behavior under the condition of potentiostatic polarization was strongly dependent on the crystallographic orientation of the substrate surface. Electrochemical impedance spectroscopy revealed that the charge transfer resistance of the passivated surface was determined by the substrate orientation. Galvanostatic reduction and XPS analysis of the surface passivated using the MCC showed that the substrate orientation affected the chemical state of iron in the oxide. The results suggested that the aging of the passive film formed on the iron substrate depended on its crystallographic orientation due to the differences in surface energy of the substrate surface that has a bcc lattice structure. It was concluded that the grain dependency on the electric property of the passive film arose from the compositional differences of the oxide film. (C) The Author(s) 2014. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License (CC BY, http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse of the work in any medium, provided the original work is properly cited. All rights reserved. - Convection-Dependent Hydrogen Permeation into a Carbon Steel Sheet
K. Fushimi, M. Jin, T. Nakanishi, Y. Hasegawa, T. Kawano, M. Kimura
ECS ELECTROCHEMISTRY LETTERS, 3, 6, C21, C23, ELECTROCHEMICAL SOC INC, 2014年
英語, 研究論文(学術雑誌), The Devanathan-Stachurski electrochemical cell for measurement of hydrogen-permeation into a steel sheet was extended to an electrolyte-flowing design. Increase in flow rate of the entry cell induces increase in hydrogen-evolution current at the entry electrode but decrease in hydrogen-permeation current at the hydrogen-exit electrode. Hydrogen-permeation is actualized by a sinusoidal perturbation of the entry-flow rate. The hydrogen-permeation response, i.e., phase shift of the detection current from the evolution current, was proportional to the square root of flow rate frequency and was dependent on sheet thickness. The sinusoidal perturbation of entry-flow rate is a new factor influencing hydrogen-permeation into the sheet. (C) 2014 The Electrochemical Society. All rights reserved. - Microelectrochemistry of dual-phase steel corroding in 0.1 M sulfuric acid
K. Fushimi, K. Yanagisawa, T. Nakanishi, Y. Hasegawa, T. Kawano, M. Kimura
ELECTROCHIMICA ACTA, 114, 83, 87, PERGAMON-ELSEVIER SCIENCE LTD, 2013年12月
英語, 研究論文(学術雑誌), Corrosion behavior of high-purity dual-phase carbon steel composed of only ferrite and martensite phases in 0.1 M sulfuric acid was investigated by both macro- and micro-electrochemical methods. The dual-phase steel corrodes non-uniformly due to galvanic coupling between its microstructures as well as self-corrosion of each phase. Hydrogen evolution reaction on galvanic-coupled martensite accelerates iron dissolution reaction of ferrite, though the corrosion rate of martensite was three-times larger than that of ferrite due to the self-corrosion in the acid. Totally, ferrite phases corrode selectively and the degree of selective corrosion was about two-times larger than martensite phases. (C) 2013 Elsevier Ltd. All rights reserved. - Effect of Ligand Polarization on Asymmetric Structural Formation for Strongly Luminescent Lanthanide Complexes
Yasuchika Hasegawa, Tomoki Ohkubo, Takayuki Nakanishi, Atsushi Kobayashi, Masako Kato, Tomohiro Seki, Hajime Ito, Koji Fushimi
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 2013, 34, 5911, 5918, WILEY-V C H VERLAG GMBH, 2013年12月
英語, 研究論文(学術雑誌), The effect of ligand polarization on the formation of strongly luminescent lanthanide complexes with asymmetric structures is described for the first time. The lanthanide complexes are composed of Eu-III ions, three hexafluoroacetylacetonate (hfa) ligands, and two monodentate phosphine oxide ligands, namely, triphenylphosphine oxide (TPPO), p-tolyldiphenylphosphine oxide (TPPO-Me), tri-p-tolylphosphine oxide (TPPO-3Me) or o-phenoxyphenyldiphenylphosphine oxide (TPPO-OPh). The luminescence properties of the Eu-III complexes are characterized by their emission quantum yields, emission lifetimes, and their radiative (k(r)) and nonradiative (k(nr)) rate constants. The Eu-III complex with TPPO-OPh ligands offers a markedly high emission quantum yield (72% in [D-6]acetone, 85% in the solid state) owing to enhancement of the electric dipole transition and suppression of vibrational relaxation, which are directly related to k(r) and k(nr). The coordination geometries of the Eu-III complexes are categorized by shape-measure calculations. The Eu-III complexes exhibit characteristic square-antiprismatic or trigonal-dodecahedral structures, depending on the ligand polarization. Strongly luminescent Eu(hfa)(3)(TPPO-OPh)(2) has an asymmetric dodecahedron structure. The formation of distorted dodecahedral structures with low vibrational frequencies for the enhancement of luminescence is elucidated in terms of the ligand polarization of the monodentate phosphine oxide ligands in the Eu-III complexes. - Microelectrode techniques for corrosion research of iron
K. Fushimi, Y. Takabatake, T. Nakanishi, Y. Hasegawa
ELECTROCHIMICA ACTA, 113, 741, 747, PERGAMON-ELSEVIER SCIENCE LTD, 2013年12月
英語, 研究論文(学術雑誌), Two micro-electrode techniques, scanning electrochemical microscopy (SECM) and the micro-capillary cell (MCC) technique, were used to investigate corrosion behaviour of a polycrystalline iron surface in acidic sulphate media. Local corrosion reactivity was found to be strongly dependent on crystallographic orientation of the surface as well as measurement conditions. Results obtained by using microelectrode techniques are expected to reveal all aspects of corrosion behaviour of the surfaces of polycrystalline materials including iron. (C) 2013 Elsevier Ltd. All rights reserved. - trans-Bisglycoconjugation is an Efficient and Robust Architecture for PDT Photosensitizers Based on 5,10,15,20-Tetrakis(pentafluorophenyl)porphyrin Derivatives
Shiho Hirohara, Kohei Sharyo, Yuji Kawasaki, Masayasu Totani, Ayumi Tomotsuka, Ryota Funasako, Nobutaka Yasui, Yasuchika Hasegawa, Junpei Yuasa, Takuya Nakashima, Tsuyoshi Kawai, Chio Oka, Masashi Kawaichi, Makoto Obata, Masao Tanihara
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 86, 11, 1295, 1308, CHEMICAL SOC JAPAN, 2013年11月
英語, 研究論文(学術雑誌), To examine the versatility of the trans-bisglycoconjugation architecture for 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (TFPP) derivative-based photodynamic therapy (PDT), 25 porphyrin derivatives bearing D-glucopyranose moieties were prepared, and their in vitro photocytotoxicities were examined. trans-Bisglycoconjugated TFPP derivatives exerted the best photocytotoxicity among TFPP derivatives in the same category, regardless of the central metal ion and the type of glycoconjugation. trans-Bisglycoconjugated free-base TFPP bearing beta-D-glucopyranosylthio groups (trans-H(2)2(SG1c)) was found to be the most potent photosensitizer, not only in HeLa cells (EC50 < 5 nM), but also in highly metastatic cancer cell lines such as B16-BL6 melanoma cells (EC50 < 10 nM). UV vis and dynamic light-scattering measurements suggested that trans-bisglycoconjugated TFPP derivatives formed relatively large I-aggregates in an aqueous solution. trans-Bisglycoconjugated TFPP derivatives exhibited greater uptake by HeLa cells than those with different glycoconjugation patterns, with the exception of Zn(II) complexes. trans-Bisglycoconjugated TFPP derivatives efficiently generated hydrogen peroxide and hydroxyl radical by a type I photoreaction, while no significant differences were found in the efficiency of singlet oxygen generation by a type II photoreaction. These unique characteristics of transbisglyeoconjugated TFPP derivatives support the conclusion that trans-bisglycoconjugation is a highly efficient and robust architecture for TFPP-based PDT development. - Enhanced Magneto-optical Properties of Semiconductor EuS Nanocrystals Assisted by Surface Plasmon Resonance of Gold Nanoparticles
Akira Kawashima, Takayuki Nakanishi, Tamaki Shibayama, Seiichi Watanabe, Koji Fujita, Katsuhisa Tanaka, Hitoshi Koizumi, Koji Fushimi, Yasuchika Hasegawa
CHEMISTRY-A EUROPEAN JOURNAL, 19, 43, 14438, 14445, WILEY-V C H VERLAG GMBH, 2013年10月
英語, 研究論文(学術雑誌), Remarkable magneto-optical properties of a new isolator material, that is, europium sulfide nanocrystals with gold (EuS-Au nanosystem), has been demonstrated for a future photo-information technology. Attachment of gold particles that exhibit surface plasmon resonance leads to amplification of the magneto-optical properties of the EuS nanocrystals. To construct the EuS-Au nanosystems, cubic EuS and spherical Au nanocrystals have been joined by a variety of organic linkers, that is, 1,2-ethanedithiol (EDT), 1,6-hexanedithiol (HDT), 1,10-decanedithiol (DDT), 1,4-bisethanethionaphthalene (NpEDT), or 1,4-bisdecanethionaphthalene (NpDDT). Formation of these systems was observed by XRD, TEM, and absorption spectra measurements. The magneto-optical properties of the EuS-Au nanosystem have been characterized by using Faraday rotation spectroscopy. The Faraday rotation angle of the EuS-Au nanosystem is dependent on the Au particle size and interparticle distance between EuS and Au nanocrystals. Enhancement of the Faraday rotation of EuS-Au nanosystems was observed. The spin configuration in the excited state of the EuS-Au nanosystem was also investigated using photo-assisted electron paramagnetic resonance. - EuS Nano-assembles Linked with Photo-functional Naphthalenedithiols
Akira Kawashima, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 579, 1, 69, 76, TAYLOR & FRANCIS LTD, 2013年09月
英語, 研究論文(学術雑誌), Novel photo-functional naphthalenedithiol (NpDDT) as a linker molecule for formation of EuS nanocrystal assembles (EuS nano-assembles) has been reported. NpDDT is synthesized by the reaction of 1,4-dihydroxynaphthalene with 1,10-decanedithiol in benzene at 80 degrees C for 1hour.
Formation of EuS nano-assembles with NpDDT is observed by TEM measurement. Photophysical properties of EuS nano-assembles with NpDDT are characterized using the emission spectra and the emission quantum yields. The emission quantum yields of naphthalene units in NpDDT are depended on the aggregation size of EuS nano-assembles. Novel luminescent NpDDT has been reported as an effective linker material for formation and observation of semiconductor EuS nano-assembles for the first time. - Synthesis, Optical Properties, and Crystal Structures of Dithienostannoles
Daiki Tanaka, Joji Ohshita, Yousuke Ooyama, Norifumi Kobayashi, Hideyuki Higashimura, Takayuki Nakanishi, Yasuchika Hasegawa
ORGANOMETALLICS, 32, 15, 4136, 4141, AMER CHEMICAL SOC, 2013年08月
英語, 研究論文(学術雑誌), Reactions of dichlorodiphenylstannane with 3,3'-dilithio-5,5'-bis(trimethylsilyl)-2,2'-bithiophene and 3,3'-dilithio-2,2'-di(benzo[b]thiophene) gave 1,1-diphenyl-3,6-bis(trimethylsilyl)dithienostannole (DTSn1) and di(benzo[b]thieno)-1,1-diphenylstannole (DTSn2), respectively. Optical properties of the dithienostannoles and the results of DFT calculations on a model suggested an in-phase interaction between Sn sigma* and bithiophene pi* orbitals, stabilizing the LUMO. Interestingly, DTSn1 showed crystallization-enhanced emission and the photoluminescence (PL) quantum yield of the crystals was determined to be higher by about 20 times than that in the amorphous and solution phase, while DTSn2 exhibited moderate PL efficiency both as crystals and in solution. Crystal structures of the dithienostannoles were determined by X-ray diffraction studies, which showed the differences in the molecular packing between DTSn1 and DTSn2, being responsible for their different PL properties in the crystal state. - Novel opto-magnetic silicate glass with semiconductor EuS nanocrystals
Takayuki Nakanishi, Masashi Maeda, Akira Kawashima, Shogo Kamiya, Koji Fushimi, Koji Fujita, Katsuhisa Tanaka, Yasuchika Hasegawa
Journal of Alloys and Compounds, 562, 123, 127, 2013年06月15日
英語, 研究論文(学術雑誌), Novel magneto-optical silica glass with semiconductor EuS nanocrystals (NCs) has been reported. The silica glass with EuS NCs is synthesized by the hydrolysis reaction with a ligand exchange process (from NH2-group to OH-group). The silica framework around EuS NCs provides thermo-stable structure under 500 °C. The glass material also shows effective magneto-optical properties, Faraday rotation, in the visible region (400-700 nm). The positive peak of Faraday rotation spectrum is blue-shifted in comparison with traditional EuS NCs in PMMA polymer. The effective peak-shift of Faraday rotation is caused by ligand change on EuS NCs surface (Nephelauxetic effect). The EuS-silica nanoglass composite with thermally stable structure would have potential applications as an optical isolator with a high-power laser. © 2013 Elsevier B.V. All rights reserved. - A luminescent single-molecule magnet: Observation of magnetic anisotropy using emission as a probe
Kei Yamashita, Rie Miyazaki, Yumiko Kataoka, Takayuki Nakanishi, Yasuchika Hasegawa, Motohiro Nakano, Tomoo Yamamura, Takashi Kajiwara
Dalton Transactions, 42, 6, 1987, 1990, Royal Society of Chemistry, 2013年02月14日
英語, 研究論文(学術雑誌), An assemblage of a Tb(iii) ion and two mononuclear [Zn<
sup>
II<
/sup>
(L)] complexes as antenna chromophores (H<
inf>
2<
/inf>
L: Schiff base ligand) afforded a luminescent single-molecule magnet. The f-f emission spectrum had partially resolved fine structure which provides detailed information on the magnetic anisotropy of the <
sup>
7<
/sup>
F<
inf>
6<
/inf>
ground multiplet of the Tb(iii) ion. © The Royal Society of Chemistry 2013. - Effective Optical Faraday Rotations of Semiconductor EuS Nanocrystals with Paramagnetic Transition-Metal Ions
Yasuchika Hasegawa, Masashi Maeda, Takayuki Nakanishi, Yoshihiro Doi, Yukio Hinatsu, Koji Fujita, Katsuhisa Tanaka, Hitoshi Koizumi, Koji Fushimi
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 135, 7, 2659, 2666, AMER CHEMICAL SOC, 2013年02月
英語, 研究論文(学術雑誌), Novel EuS nanocrystals containing paramagnetic Mn(II), Co(II), or Fe(II) ions have been reported as advanced semiconductor materials with effective optical rotation under a magnetic field, Faraday rotation. EuS nanocrystals with transition-metal ions, EuS:M nanocrystals, were prepared by the reduction of the Eu(III) dithiocarbamate complex tetraphenylphosphonium tetrakis(diethyldithiocarbamate)europium(III) with transition-metal complexes at 300 degrees C. The EuS:M nanocrystals thus prepared were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroanalysis (ICP-AES), and a superconducting quantum interference device (SQUID) magnetometer. Enhanced Faraday rotations of the EuS:M nanocrystals were observed around 550 nm, and their enhanced spin polarization was estimated using electron paramagnetic resonance (EPR) measurements. In this report, the magneto-optical relationship between the Faraday rotation efficiency and spin polarization is discussed. - Fingerprint signatures of lanthanide circularly polarized luminescence from proteins covalently labeled by a β-diketonate europium(III) chelate
J. Yuasa, T. Ohno, H. Tsumatori, R. Shiba, H. Kamikubo, M. Kataoka, Y. Hasegawa, T. Kawai
Chem. Commun., 49, 41, 4604, 4606, ROYAL SOC CHEMISTRY, 2013年
英語, 研究論文(学術雑誌), Fingerprint signatures of circularly polarized luminescence (CPL) are observed from Staphylococcus aureus nuclease (SNase), bovine serum albumin (BSA), and insulin (Ins) labeled with europium(III) complexes containing a beta-diketonate ligand, where SNase shows a virtually opposite CPL sign compared to those of BSA and Ins. - Chameleon Luminophore for Sensing Temperatures: Control of Metal-to-Metal and Energy Back Transfer in Lanthanide Coordination Polymers
Kohei Miyata, Yuji Konno, Takayuki Nakanishi, Atsushi Kobayashi, Masako Kato, Koji Fushimi, Yasuchika Hasegawa
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 52, 25, 6413, 6416, WILEY-V C H VERLAG GMBH, 2013年
英語, 研究論文(学術雑誌) - Magnetic Semiconductor EuO, EuS, and EuSe Nanocrystals for Future Optical Devices
Yasuchika Hasegawa
CHEMISTRY LETTERS, 42, 1, 2, 7, CHEMICAL SOC JAPAN, 2013年01月
英語, Magnetic semiconductor nanocrystals composed of lanthanoid ions, europium chalcogenide nanocrystals (EuX: EuO, EuS, and EuSe nanocrystals), are characterized by the narrow 4f orbitals that exist as degenerate levels between the conduction band [5d orbitals of Eu(II)] and the valence band (p orbitals of O2-, S2-, and Se2-). In this review, syntheses and characteristic photophysical properties of EuX nanocrystals are introduced. EuX nanocrystals are expected to be useful in applications such as future optical isolators, optomagnetic and spintronic devices. - First Synthesis of EuS Nanoparticle Thin Film with a Wide Energy Gap and Giant Magneto-Optical Efficiency on a Glass Electrode
Yasuchika Hasegawa, Mina Kumagai, Akira Kawashima, Takayuki Nakanishi, Koji Fujita, Katsuhisa Tanaka, Koji Fushimi
JOURNAL OF PHYSICAL CHEMISTRY C, 116, 36, 19590, 19596, AMER CHEMICAL SOC, 2012年09月
英語, 研究論文(学術雑誌), Novel magneto-optical thin films composed of europium sulfide (EuS) nanoparticles on a glass electrode exhibit large magneto-optical efficiency and a wide energy gap. EuS nanoparticle thin films are prepared by the electrochemical reduction of a single-source precursor, a Eu(III) dithiocarbamate complex (tetraphenylphosphonum tetrakis(diethyldithiocarbamate) europium(III)). The EuS nanoparticle thin films were prepared on indium-tin oxide (ITO)-coated glass electrodes and characterized by electrochemical analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, laser scanning microscopy, and absorption spectroscopy. Faraday rotation spectra for estimation of the magneto-optical efficiency have clear positive and negative peaks, which are attributed to the 4f-5d transitions of the EuS thin films. The positive and negative peaks of the Faraday rotation spectrum are 525 and 680 nm, which are directly related to the energy gap of the EuS nanoparticle thin film (2.4 eV). That spectrum indicates that the EuS nanoparticle thin films are blue shifted in comparison with 7 nm diameter EuS nanoparticles (2.2 eV). The Verdet constant of the thin film was 11 mdeg/cm Oe at 525 nm, which is approximately 10 times larger than that of previously reported EuS nanoparticles. - Nona-Coordinated Chiral Eu(III) Complexes with Stereoselective Ligand-Ligand Noncovalent Interactions for Enhanced Circularly Polarized Luminescence
Takashi Harada, Hiroyuki Tsumatori, Katsura Nishiyama, Junpei Yuasa, Yasuchika Hasegawa, Tsuyoshi Kawai
INORGANIC CHEMISTRY, 51, 12, 6476, 6485, AMER CHEMICAL SOC, 2012年06月
英語, 研究論文(学術雑誌), Circularly polarized luminescence (CPL) of chiral Eu(III) complexes with nona- and octa-coordinated structures, [Eu(R/S-iPr-Pybox)-(D-facam)(3)] (1-R/1-S; R/S-iPr-Pybox, 2,6-bis(4R/4S-isopropyl-2-oxazolin-2yl)pyridine; D-facam, 3-trifluoroacetyl-d-camphor), [Eu(S,S-Me-Ph-Pybox) (D-facam)(3)] (2-SS; S,S-Me-Ph-Pybox, 2,6-bis(4S-methyl-5S-phenyl-2-oxazolin-2yl)pyridine), and [Eu(Phen)(D-facam)(3)] (3; Phen, 1,10-phenanthroline) are reported, and their structural features are discussed on the basis of X-ray crystallographic analyses. These chiral Eu(III) complexes showed relatively intense photoluminescence due to their D-5(0) -> F-7(1) (magnetic-dipole) and D-5(0) -> F-7(2) (electric-dipole) transition. The dissymmetry factors of CPL (g(CPL)) at the former band of 1-R and 1-S were as large as -1.0 and -0.8, respectively, while the g(CPL) of 3 at the D-5(0) -> F-7(1) transition was relatively small (g(CPL) = -0.46). X-ray crystallographic data indicated specific ligand-ligand hydrogen bonding in these compounds which was expected to stabilize their chiral structures even in solution phase. CPL properties of 1-R and 1-S were discussed in terms of transition nature of lanthanide luminescence. - Solvent-dependent luminescence of eight-coordinated Eu(III) complexes with bidentate phosphine oxide
Kohei Miyata, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, 235, 35, 39, ELSEVIER SCIENCE SA, 2012年05月
英語, 研究論文(学術雑誌), Solvent-dependent luminescence of Eu(III) complexes composed of oxo-linked bidentate phosphine oxide ligands, 4,5-bis(diphenylphosphoryl)-9,9-dimethylxanthene (xantpo). 4,5-bis(di-tert-butylphosphoryl)-9,9-dimethylxanthene (tBu-xantpo) and low-vibrational frequency hexafluoroacetylacetonato (hfa) ligands is reported. The Eu(III) complexes. Eu(hfa)(2)(xantpo)(2) and Eu(hfa)(3)(tBu-xantpo), exhibit eight-coordinated square antiprism and trigonal dodecahedron structure, respectively. Their emission quantum yield, emission lifetime, and radiative and non-radiative rate constant are characterized using acetone, acetone-d(6), toluene, chloroform, and DMF. The relationship between photophysical properties and coordination structures of eight-coordinated Eu(III) complexes is discussed for the first time. (C) 2012 Elsevier B.V. All rights reserved. - Synthesis of PbS/EuS Core/Shell Nanocrystals
Takuya Nakashima, Hiroki Nakao, Atsushi Tanaka, Yasuchika Hasegawa, Tsuyoshi Kawai
CHEMISTRY LETTERS, 41, 4, 412, 414, CHEMICAL SOC JAPAN, 2012年04月
英語, 研究論文(学術雑誌), The synthesis of nonmagnetic/magnetic PbS/EuS core/shell nanocrystals (NCs) has been demonstrated. PbS NCs were deposited by EuS layer via thermal decomposition of the single-source precursor, Eu(III)-dithiocarbamate complex, giving PbS/EuS core/shell NCs. - Thermostable Organo-phosphor: Low-Vibrational Coordination Polymers That Exhibit Different Intermolecular Interactions
Kohei Miyata, Tadashi Ohba, Atsushi Kobayashi, Masako Kato, Takayuki Nakanishi, Koji Fushimi, Yasuchika Hasegawa
CHEMPLUSCHEM, 77, 4, 277, 280, WILEY-V C H VERLAG GMBH, 2012年04月
英語, 研究論文(学術雑誌) - フロー型微小液滴セルを用いたチタン表面の微細加工
伏見公志, 渡邊治憲, 中西貴之, 長谷川靖哉
表面技術, 63, 6, 375, 380, 一般社団法人 表面技術協会, 2012年
日本語, Flowing-type micro-droplet cells (f-MDC) were applied to the anodic polarization of titanium surface in sodium-chloride-containing ethylene glycol solution. Anodic current attributable to removal of the surface oxide and the dissolving substrate flowed locally at the area limited with f-MDC, forming a hole on the surface. The hole shape and morphology were dependent on the applied voltage, polarization time, flowing volume rate, and the capillary employed for the f-MDC. Suitable conditions for polarization to obtain an ordered hole with f-MDC were discussed. - Eu(III) emission band changes caused by peripheral C-H/O hydrogen bonding
Yusuke Kuramochi, Tetsuya Nakagawa, Toshiaki Yokoo, Junpei Yuasa, Tsuyoshi Kawai, Yasuchika Hasegawa
DALTON TRANSACTIONS, 41, 22, 6634, 6640, ROYAL SOC CHEMISTRY, 2012年
英語, 研究論文(学術雑誌), We synthesized Eu(III) and Sm(III) complexes with tridentate phosphine oxide ligands, Eu(hfa)(3)(TPPM) and Sm(hfa)(3)(TPPM) (hfa: hexafluoroacetylacetonato, TPPM: tris(diphenylphosphinyl) methane), and we then examined their luminescent properties. In the complexes the Eu(III) and Sm(III) centres were fully surrounded by low-vibrational frequency ligands, which led to relatively high emission quantum yields (Phi(Eu) = 30%, Phi(Sm) = 4.7%). The X-ray single crystal structures of the Eu(hfa)(3)(TPPM) revealed nonacoordinated Eu(III) complexes and C-H/O hydrogen bonding formations between the acidic hydrogen atom of the TPPM ligand and oxygen atoms of solvent molecules. The C-H/O hydrogen bonding slightly affected the coordination structure around the Eu(III) ion. Despite the seemingly small effect on the structural change, because the emission band profile of the D-5(0) -> F-7(2) transition is sensitive to changes in the coordination environment of the Eu(III) complex, we observed a red shift in the emission spectral line. - Brilliant Triboluminescence of a Lanthanide Coordination Polymer with Low-Vibrational-Frequency and Non-Centrosymmetric Structural Networks
Yasuchika Hasegawa, Ryo Hieda, Kohei Miyata, Tetsuya Nakagawa, Tsuyoshi Kawai
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 32, 4978, 4984, WILEY-V C H VERLAG GMBH, 2011年11月
英語, 研究論文(学術雑誌), Characteristic triboluminescence from a lanthanide coordination polymer with a non-centrosymmetric structure is reported. The lanthanide coordination polymer is composed of luminescent Eu-III ions and bidentate phosphane oxides, poly[3,3 '-bis(diphenylphosphoryl)-2,2 '-bipyridine][tris(hexafluoroacetylacetonate)]europium (poly-Eu-BIPYPO) crystals. The coordination geometry of poly-Eu-BIPYPO is categorized as an asymmetric eight-coordinate square antiprism (8-SAP). The space group of the crystal is also classified as the non-centrosymmetric Cc, which is suitable for piezoelectricity and triboluminescence. The photoluminescence quantum yield of poly-Eu-BIPYPO crystals excited at 380 nm is found to be 61%. Triboluminescence of the lanthanide coordination polymer is observed upon breaking, even at ambient temperature and in daylight. The remarkable triboluminescence phenomenon and geometrical structure of lanthanide coordination polymer are demonstrated. - Shielding effect of double microelectrode tips in a scanning electrochemical microscope
Koji Fushimi, Ken-ichiro Matsushita, Yasuchika Hasegawa
ELECTROCHIMICA ACTA, 56, 26, 9602, 9608, PERGAMON-ELSEVIER SCIENCE LTD, 2011年11月
英語, 研究論文(学術雑誌), Electrochemical interaction of coaxial double microelectrodes, in which a ring microelectrode was surrounded by another ring microelectrode, was investigated. Mass-transfer reactions that occurred on both inner and outer microelectrodes interfered with each other and showed a "shielding" effect depending on potentials and geometries of microelectrodes. Application of the inner microelectrode of the double microelectrodes for a probing tip of a scanning electrochemical microscope (SECM) revealed that the shielding effect by the outer microelectrode affected the electrochemistry on the inner microelectrode in the vicinity of the substrate surface. The effect was intensified above the insulator but attenuated above the conductor as the microelectrodes approached in feedback mode of the SECM. Approach to a critical interelectrode distance also intensified the shielding effect in the substrate generation/tip collection mode. An SECM line-scan using a platinum/epoxy resin-model substrate was carried out to investigate the shielding effect on current sensitivity and lateral resolution of an SECM image. (C) 2011 Elsevier Ltd. All rights reserved. - Noncovalent Ligand-to-Ligand Interactions Alter Sense of Optical Chirality in Luminescent Tris(β-diketonate) Lanthanide(III) Complexes Containing a Chiral Bis(oxazolinyl) Pyridine Ligand
J. Yuasa, T. Ohno, K. Miyata, H. Tsumatori, Y. Hasegawa, T. Kawai
J. Am. Chem. Soc., 133, 25, 9892, 9902, AMER CHEMICAL SOC, 2011年06月
英語, 研究論文(学術雑誌), Highly luminescent tris[beta-diketonate (HFA, 1,1,1,5,5,5-hexafluoropentane-2,4-dione)] europium(III) complexes containing a chiral bis(oxazolinyl) pyridine (pybox) ligand-[ (Eu(III)R)-Ph-pybox) (HFA)(3)], [ (Eu(III)(R)-i-Pr-pybox)(HFA)(3)], and [ (Eu(III)(R)-Me-Ph-pybox)(HFA)(3)])-exhibit strong circularly polarized luminescence (CPL) at the magnetic-dipole ((5)D(0)->(7)F(1)) transition, where the [ (Eu(III)(R)-Ph-pybox)-(HFA)(3)] complexes show virtually opposite CPL spectra as compared to those with the same chirality of [ (Eu(III)(R)-i-Pr-pybox)(HFA)(3)] and [ (Eu(III)(R)-Me-Ph-pybox) (HFA)(3)]. Similarly, the [ (Tb(III)(R)-Ph-pybox)(HFA)(3)] complexes were found to exhibit CPL signals almost opposite to those of [ (Tb(III)(R) -i-Pr-pybox)(HFA)(3)] and [ (Tb(III)m(R)-M-Ph-pybox)(HFA)(3)] complexes with the same pybox chirality. Single-crystal X-ray structural analysis revealed ligand ligand interactions between the pybox ligand and the HFA ligand in each lanthanide(III) complex: pi-pi stacking interactions in the Eum and Tb(III) complexes with the Ph-pybox ligand, CH/F interactions in those with the i-Pr-pybox ligand, and CH/pi interactions in those with the Me-Ph-pybox ligand. The ligand ligand interactions between the achiral HFA ligands and the chiral pybox results in an asymmetric arrangement of three HFA ligands around the metal center. The metal center geometry varies depending on the types of ligand ligand interaction. - Enhanced Near-Infrared Luminescence of Yb(III) Complexes with Phosphine Oxide and Hexafluoroacetylacetonate Ligands
Shin-ichiro Kishimoto, Tetsuya Nakagawa, Tsuyoshi Kawai, Yasuchika Hasegawa
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 84, 2, 148, 154, CHEMICAL SOC JAPAN, 2011年02月
英語, 研究論文(学術雑誌), Near-infrared (NIR) luminescent Yb(III) complexes composed of low-vibrational frequency (LVF) fluorinated acetylacetonate and phosphine oxide ligands are reported. Their structures are determined using X-ray single-crystal analyses and categorized as eight-coordinated square antiprisin. The radiative rate constants (k(r)), the nonradiative rate constants (k(nr)), and the 4f-4f emission quantum efficiency (Phi(Em)) are estimated using their absorption spectra of magnetic dipole transition in Yb(III) complexes (F-2(5/2) -> F-2(7/2)) and the observed emission lifetimes. Characteristic NIR luminescence properties of Yb(III) complexes with LVF phosphine oxide and fluorinated acetylacetonate ligands are elucidated in terms of the radiative and nonradiative rate constants. - Heterogeneous dissolution of polycrystalline pure iron in sulphuric acid solution
K. Fushimi, K. Matsushita, K. Miyamoto, Y. Hasegawa
Proceedings of EUROCORR 2011 (CD-ROM), 4747, 2011年, [査読有り]
英語, 研究論文(国際会議プロシーディングス) - Circularly Polarized Light from Chiral Lanthanide(III) Complexes in Single Crystals
Hiroyuki Tsumatori, Takashi Harada, Junpei Yuasa, Yasuchika Hasegawa, Tsuyoshi Kawai
APPLIED PHYSICS EXPRESS, 4, 1, 11601, JAPAN SOC APPLIED PHYSICS, 2011年01月
英語, 研究論文(学術雑誌), A circularly polarized emission (CPE) microscope system was designed for measuring circularly polarized light (CPL) from small single crystals of lanthanide(III) complexes with different crystal structures. CPL under excitation with 370-nm laser light was successfully observed from the crystals, and the CPL spectra were significantly different from those observed in solution. Dependence of the CPL spectra on the lattice plane of the crystals was also demonstrated. (C) 2011 The Japan Society of Applied Physics - Size-Controlled Aggregation of Cube-Shaped EuS Nanocrystals with Magneto-Optic Properties in Solution Phase
Atsushi Tanaka, Hironari Kamikubo, Mikio Kataoka, Yasuchika Hasegawa, Tsuyoshi Kawai
LANGMUIR, 27, 1, 104, 108, AMER CHEMICAL SOC, 2011年01月
英語, 研究論文(学術雑誌), Size-controlled formation of colloidal aggregates composed of cube-shaped EuS nanocrystals, EuS NCs, in solution phase are reported and their optical and magneto-optical properties are studied. The average size of the colloidal particles of the EuS NCs-aggregates formed in 1-pentanol, 1-hexanol, and 1-octanol were ca. 800, 500, and 100 nm, respectively. Self-organized cubic-type superlattice structure was evaluated in the colloidal aggregates by means of the small-angle X-ray diffraction measurements, which is similar to those in the macroscopic 3D superlattice structures. The distances between NCs in the EuS NCs-aggregates are dependent on alkyl chain length of the solvent alcohol. Magneto-optic properties of EuS NCs-aggregates and the monomeric EuS nanocrystals in liquid media are characterized with magnetic circular dichroism spectra. The active wavelength of EuS NCs-aggregates is considerably longer than that of the monomeric EuS nanocrystals. - Remarkable Luminescence Properties of Lanthanide Complexes with Asymmetric Dodecahedron Structures
Kohei Miyata, Tetsuya Nakagawa, Ryuhei Kawakami, Yuki Kita, Katsufumi Sugimoto, Takuya Nakashima, Takashi Harada, Tsuyoshi Kawai, Yasuchika Hasegawa
CHEMISTRY-A EUROPEAN JOURNAL, 17, 2, 521, 528, WILEY-BLACKWELL, 2011年
英語, 研究論文(学術雑誌), The distorted coordination structures and luminescence properties of novel lanthanide complexes with oxo-linked bidentate phosphane oxide ligands-4,5-bis(diphenylphosphoryl)-9,9-dimethylxanthene (xantpo), 4,5-bis(di-tert-butylphosphoryl)-9,9-dimethylxanthene (tBu-xantpo), and bis[ (2-diphenylphosphoryl)phenyl] ether (dpepo)-and low-vibrational frequency hexafluoroacetylacetonato (hfa) ligands are reported. The lanthanide complexes exhibit characteristic square antiprism and trigonal dodecahedron structures with eight-coordinated oxygen atoms. The luminescence properties of these complexes are characterized by their emission quantum yields, emission lifetimes, and their radiative and nonradiative rate constants. Lanthanide complexes with dodecahedron structures offer markedly high emission quantum yields (Eu: 55-72%, Sm: 2.4-5.0% in [D(6)]acetone) due to enhancement of the electric dipole transition and suppression of vibrational relaxation. These remarkable luminescence properties are elucidated in terms of their distorted coordination structures. - Recent advances in instrumentation for absolute emission quantum yield measurements
Hitoshi Ishida, Seiji Tobita, Yasuchika Hasegawa, Ryuzi Katoh, Koichi Nozaki
COORDINATION CHEMISTRY REVIEWS, 254, 21-22, 2449, 2458, ELSEVIER SCIENCE SA, 2010年11月
英語, 研究論文(学術雑誌), The fluorescence and phosphorescence quantum yields (Phi) of standard solutions have been re-evaluated based on an absolute method using an integrating sphere equipped with a multichannel spectrometer. We have examined in detail the Phi value of ruthenium(II) tris(2,2'-bipyridine) complex which have been often used as the standards in the determination of quantum yields of transition-metal complexes. This revealed that the Phi values for [Ru(bpy)(3)](2+) were 0.063 in deaerated H(2)O, 0.040 in aerated H(2)O, 0.095 in deaerated CH(3)CN. and 0.018 in aerated CH(3)CN, respectively, which are significantly higher than the previously accepted values.
We have also examined the technical aspects in the determination of absolute emission quantum yields for lanthanide complexes and those of organic crystals of anthracene. For the accurate determination for lanthanide complexes, special care must be taken in the spectroscopic measurements because of their narrow absorption and emission bands. For organic crystals, the fluorescence quantum yields are reduced due to reabsorption, chemical impurities and structural defects. Our observations for highly purified anthracene crystals revealed that the lower limit value of Phi was 0.64. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved. - Recent progress of luminescent metal complexes with photochromic units
Yasuchika Hasegawa, Tetsuya Nakagawa, Tsuyoshi Kawai
COORDINATION CHEMISTRY REVIEWS, 254, 21-22, 2643, 2651, ELSEVIER SCIENCE SA, 2010年11月
英語, 研究論文(学術雑誌), Photo-responsive molecules have been studied extensively because of their light irradiation abilities that enable modulation of certain physical and chemical properties in emerging molecular electronic and photonic devices. For advanced photonic applications, photochromic metal complexes that have photochromic units as the photo-responsive ligand are highly desirable, as they allow improvement of the photochromic properties and their photo-switching functionality. This article focuses on recent progress in luminescent metal complexes with photochromic units. Luminescence-switching properties of photochromic metal complexes depend on characteristic electronic transitions. The electronic transitions of photochromic metal complexes can be divided into three categories: (1) pi-pi* transition of the ligand, (2) metal to ligand charge transfer (MLCT) in transition-metal complex, and (3) f-f transition in lanthanide complex. Luminescence modulation using various metal complexes with photochromic units has been studied extensively in recent years, and various applications for future molecular switching devices are expected in the field of advanced photonics. Based on the literature and our studies on luminescent metal complexes with photochromic units, we report on the recent progress of luminescent metal complexes with photochromic units. (C) 2010 Elsevier B.V. All rights reserved. - Self-Assembly and Enhanced Magnetic Properties of Three-Dimensional Superlattice Structures Composed of Cube-Shaped EuS Nanocrystals
Atsushi Tanaka, Hironari Kamikubo, Yoshihiro Doi, Yukio Hinatsu, Mikio Kataoka, Tsuyoshi Kawai, Yasuchika Hasegawa
CHEMISTRY OF MATERIALS, 22, 5, 1776, 1781, AMER CHEMICAL SOC, 2010年03月
英語, 研究論文(学術雑誌), Superlattice structures (SLSs) assembled with cube-shaped EuS nanocrystals (NCs) and their remarkable magnetic properties are reported. The cube-shaped EuS NCs are prepared by the thermal reduction of single source precursor, tetra(diethyldithiocarbamate) europium complex with oleylamine as a surface modified regent. The fine structures of the three-dimensional (3D) SLSs assembled with EuS NCs are characterized by TEM, small-angle XRD, and electron transmission tomographic analysis. Magnetic measurements of the SLSs on polymer films with SQUID show that the coercive field of the SLSs assembled with cube-shaped EuS NCs are twice larger than those of cube-shaped EuS NCs powder. The enhanced magnetic properties are attributed to magnetic dipole interaction between cube-shaped EuS NCs in SLS structures. - Absorption cross-section control of Eu(III) complexes for increase of amplified spontaneous emission excited by third harmonic of nanosecond Nd:YAG laser
Yasuchika Hasegawa, Kazuki Nakamura, Hideki Kawai, Naoki Yasuda, Yasunori Tsukahara, Yuji Wada
Journal of Alloys and Compounds, 488, 2, 578, 581, 2009年12月04日
研究論文(学術雑誌), The amplified spontaneous emission (ASE) properties of polymer thin-films containing Eu(III) complexes were demonstrated by observating emissions from the edge of excited polymer thin-films. The amplification of the ASE components of Eu(III) complexes was increased in proportion to the absorption cross-sections. In particular, the amplitude percentages of the ASE component of Eu(III) complexes having naphthyl groups (absorption cross-section at 355 nm: 850 × 10-19 cm2) were estimated to be over 60% under 10 mJ excitation. © 2008 Elsevier B.V. All rights reserved. - Circularly Polarized Luminescence of Eu(III) Complexes with Point- and Axis-Chiral Ligands Dependent on Coordination Structures
Takashi Harada, Yoko Nakano, Michiya Fujiki, Masanobu Naito, Tsuyoshi Kawai, Yasuchika Hasegawa
INORGANIC CHEMISTRY, 48, 23, 11242, 11250, AMER CHEMICAL SOC, 2009年12月, [査読有り]
英語, 研究論文(学術雑誌), Circularly polarized luminescence (CPL) of Eu(III) complexes with point- and axis-chiral ligands, [Eu((R/S)-BINAPO) (D-facam)(3)] ((R/S)-BINAPO, (R/S)-2,2'-bis(diphenylphosphoryl)-1,1'-binaphthyl; D-facam, 3-trifluoroacetyl-d-camphor), [Eu(BIPHEPO)(D-facam)(3)] (BIPHEPO, 2,2'-bis(diphenylphosphoryl)-biphenyl), [Eu(TPPO)(2)(D-facam)(3)] (TPPO, triphenylphosphine oxide), and [Eu((R)-BINAPO)(hfa)(3)] (hfa, 1,1,1,5,5,5-hexafluoropentane-2,4-dione) are reported. The photophysical properties of chiral Eu(III) complexes were characterized by circular dichroism spectra, emission spectra, emission quantum yields, emission lifetimes, and CPL spectra. The dissymmetry factors of their CPL (vertical bar g(CPL)vertical bar) at the magnetic-dipole transition of [Eu((R)-BINAPO)(D-facam)(3)], [Eu((S)-BINAPO)(D-facam)(3)], [Eu(BIPHEPO)(D-facam)(3)], and [Eu(TPPO)(2)(D-facam)(3)] were as high as 0.44, 0.34, 0.24, and 0.47, respectively, while [Eu((R)-BINAPO)(hfa)(3)] exhibited a relatively smaller dissymmetry factor (vertical bar g(CPL)vertical bar=0.03). Their coordination structures were determined by the X-ray single-crystal analyses with shape-measure estimations. The photophysical relationship between the CPL properties and the electric transition probabilities of the chiral Eu(III) complexes is elucidated in terms of the coordination structures. - Emission properties of Sm(III) complexes having remarkably deep-red emission band
Hideki Kawai, Chen Zhao, Shin-ichi Tsuruoka, Takahiko Yoshida, Yasuchika Hasegawa, Tsuyoshi Kawai
JOURNAL OF ALLOYS AND COMPOUNDS, 488, 2, 612, 614, ELSEVIER SCIENCE SA, 2009年12月
英語, 研究論文(学術雑誌), Novel Sm(III) complexes were synthesized by the reaction of hexafluoroacetylacetonato (hfa) and triphenylphosphine oxide (TPPO), 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen). Emission bands were observed at "deep-red" region and were attributed to f-f transitions. The branching ratio (electric-dipole transitions 644 nm vs. magnetic dipole transition 598 nm) of the Sm(hfa)(3)(TPPO)(2) was much larger than that of Sm(hfa)(3)(bpy)(2), Sm(hfa)(3)(phen)(2). Those emission properties are due to coordination number and asymmetrical structures of novel Sm(III) complexes. (C) 2008 Elsevier B.V. All rights reserved. - Crystal growth of nanoscaled europium selenide having characteristic crystal shapes
Atsushi Tanaka, Taka-aki Adachi, Yasuchika Hasegawa, Tsuyoshi Kawai
JOURNAL OF ALLOYS AND COMPOUNDS, 488, 2, 538, 540, ELSEVIER SCIENCE SA, 2009年12月
英語, 研究論文(学術雑誌), Tetrapod-shaped EuSe nanocrystals were prepared through the thermal reduction of europium chloride an organic selenide complex, n-hexadecylamine, and two additives oleic acid and oleylamine. The obtained EuSe nanoparticles were characterized by X-ray diffraction (XRD). The crystal grain size from the XRD spectrum was estimated to be 50 nm. In contrast, observation of the transmission electron microscope (TEM) gave larger sized EuSe (average size: 200 nm). Anisotropic crystal-growth of EuSe nanocrystals was achieved by addition of a small amount of oleic acid in the crystal growth process. (C) 2008 Elsevier B.V. All rights reserved. - Circularly polarized luminescence from chiral Eu(III) Complex with high emission quantum yield
Takashi Harada, Yasuchika Hasegawa, Yoko Nakano, Michiya Fujiki, Masanobu Naito, Takehiko Wada, Yoshihisa Inoue, Tsuyoshi Kawai
JOURNAL OF ALLOYS AND COMPOUNDS, 488, 2, 599, 602, ELSEVIER SCIENCE SA, 2009年12月
英語, 研究論文(学術雑誌), Luminescent Eu(III) complex with axis-chiral ligand, [Eu((R)-BINAPO)(hfa)(3)] ((R)-BINAPO: (R)-2,2'-bis(diphenylphosphoryl)-1,1'-binaphthyl, hfa: 1,1,1,5,5,5-hexa-fluoropentanedione) was synthesized. Its emission quantum yield and the emission lifetime in acetone-d(6) were found to be 0.53 and 2.1 ms, respectively. The circularly polarized luminescence of the Eu(III) complex was also measured. The dissymmetry factor at the magnetic dipole transition (vertical bar g(lum)vertical bar) of [Eu((R)-BINAPO)(hfa)(3)] was found to be 0.03. (C) 2008 Elsevier B.V. All rights reserved. - Characteristic Structures and Photophysical Properties of Nine-Coordinate Europium(III) Complexes with Tandem-Connected Tridentate Phosphane Oxide Ligands
Kohei Miyata, Yasuchika Hasegawa, Yusuke Kuramochi, Tetsuya Nakagawa, Toshiaki Yokoo, Tsuyoshi Kawai
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 32, 4777, 4785, WILEY-V C H VERLAG GMBH, 2009年11月
英語, 研究論文(学術雑誌), Structures and photophysical properties of f-block metal complexes with tandem-connected tridentate phosphane oxide ligands, {bis[o-(diphenylphosphoryl)phenyl]phenylphosphane oxide}tris (hexafluoroacetylacetonato) europium (III) [Eu(hfa)(3)(DPPPO)], {bis[o-(diphenylphosphoryl)pyridyl]-phenylphosphane oxide}tris (hexafluoroacetylacetonato)europium(III) [Eu(hfa)(3)(DPPYPO)] and {bis[o-(diphenylphosphoryl]benzothienyliphenylphosphane oxide[tris(hexafluoroacetylacetonato)europium (III) [Eu(hfa)(3)(DPBTPO)], are reported. The coordination geometries of Eu(hfa)(3)(DPPPO) and Eu(hfa)(3)(DPBTPO) provide characteristic distorted, capped square antiprism structures with nine-coordinate oxygen atoms. The emission properties related to the electric transition are characterized by the emission spectra, the emission quantum yields, the emission lifetimes, and the radiative and non-radiative rate constants. Eu(III) complexes with tridentate phosphane oxide ligands offer relatively high emission quantum yields (> 60 % in [D(6)]acetone) due to their low-symmetric and low-frequency vibrational structures. The electric dipole transition intensities in the emission spectra depend on the chemical structures of tridentate phosphane oxides. The characteristic photophysical properties of polyhedral f-block metal complexes, nine-coordinate Eu(III) complexes with tridentate phosphane oxide, are demonstrated for the first time. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) - Self-aggregation of magnetic semiconductor EuS nanocrystals
Atsushi Tanaka, Yasuchika Hasegawa, Hironari Kamikubo, Mikio Kataoka, Tsuyoshi Kawai
THIN SOLID FILMS, 518, 2, 870, 872, ELSEVIER SCIENCE SA, 2009年11月
英語, 研究論文(学術雑誌), Controlled formation of aggregates having organized structure of cube-shaped EuS nanocrystals is reported. The EuS aggregates in liquid media (methanol) were obtained by means of van der Waals interaction between EuS nanocrystals. The packing structure of the EuS aggregates is characterized with transmission electron microscopy (TEM) and small angle X-ray scattering measurements (SAXS). TEM image indicates the EuS nanocrystals form self-aggregated 2D orthogonal lattice structure. The diffraction peak of (111) of SAXS profile shows that the cube-shaped EuS form 3D cubic superlattice. We successfully demonstrated that the aggregates of cube-shaped EuS nanocrystals formed cubic stacking structure. (C) 2009 Elsevier B.V. All rights reserved - Circularly Polarized Luminescence of Eu(III) Complex Depended on the Electric-dipole Transition Probability
T. Harada, Y. Hasegawa, Y. Nakano, M. Fujiki, M. Naito, T. Kawai
Inorg. Chem., 48, 11242, 11250, 2009年 - Systematic Investigation of Molecular Arrangements and Solid-State Fluorescence Properties on Salts of Anthracene-2,6-disulfonic Acid with Aliphatic Primary Amines
Yuji Mizobe, Tomoaki Hinoue, Atsushi Yamamoto, Ichiro Hisaki, Mikiji Miyata, Yasuchika Hasegawa, Norimitsu Tohnai
CHEMISTRY-A EUROPEAN JOURNAL, 15, 33, 8175, 8184, WILEY-V C H VERLAG GMBH, 2009年
英語, Organic salts of anthracene-2,6-disulfonic acid (ADS) with a wide variety of primary amines have been fabricated, and their arrangements of anthracene molecules and solid-state fluorescence properties investigated. Single-crystal X-ray studies reveal that the salts show seven types of crystal forms and corresponding molecular arrangements of anthracene moieties depending on the amine, while anthracene shows only one form and arrangement in the solid state. Depending on the molecular arrangements, the ADS salts exhibit various solid-state fluorescence properties: spectral shift (30 nm) and suppression and enhancement of the fluorescence intensity. Especially the ADS salt with n-heptylamine (nHepA), which shows discrete anthracene moieties in the crystal, exhibits the highest quantum yield (Phi(F)=46.1 +/- 0.2%) in the series of ADS salts, which exceeds that of anthracene crystal (Phi(F)=42.9 +/- 0.2%). From these systematic investigations on the arrangements and the solid-state properties, the following factors are essential for high fluorescence quantum yield in the solid state: prevention of contact between pi planes of anthracene moieties and immobilization of anthracene rings. In addition, such organic salts have potential as a system for modulating the molecular arrangements of fluorophores and the concomitant solid-state properties. Thus, systematic investigation of this system constructs a library of arrangements and properties, and the library leads to remarkable strategies for the development of organic solid materials. - Nondestructive luminescence intensity readout of a photochromic lanthanide(III) complex
Tetsuya Nakagawa, Yasuchika Hasegawa, Tsuyoshi Kawai
CHEMICAL COMMUNICATIONS, 37, 37, 5630, 5632, ROYAL SOC CHEMISTRY, 2009年
英語, 研究論文(学術雑誌), A photochromic Eu(III) complex was synthesized and its emission intensity change could be readout using wavelength-divided luminescence modulation. - Metal-Ion Sensing Europium(III) Complexes with Bidentate Phosphine Oxide Ligands Containing a 2,2 '-Bipyridine Framework
Yasuchika Hasegawa, Ryo Hieda, Tetsuya Nakagawa, Tsuyoshi Kawai
HELVETICA CHIMICA ACTA, 92, 11, 2238, 2248, WILEY-V C H VERLAG GMBH, 2009年
英語, 研究論文(学術雑誌), Novel Eu(III) complexes with bidentate phosphine oxide ligands containing a bipyridine framework, i.e., [3,3'-bis(diphenylphosphoryl)-2,2'-bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu-(hfa)(3)(BIPYPO)]) and [3,3'-bis(diphenylphosphoryl)-6,6'-dimethyl-2,2'-bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)(3)(Me-BIPYPO)]), were synthesized for lanthanide-based sensor materials having high emission quantum yields and effective chemosensing properties. The emission quantum yields of [Eu(hfa)(3)(BIPYPO)] and [Eu(hfa)(3)(Me-BIPYPO)] were 71 and 73%, respectively. Metal-ion sensing properties of the Eu(III) complexes were also studied by measuring the emission spectra of Eu(III) complexes in the presence of Zn(II) or Cu(II) ions. The metal-ion sensing and the photophysical properties of luminescent Eu(III) complexes with a bidentate phosphine oxide containing 2,2'-bipyridine framework are demonstrated for the first time. - Enhancement of Amplified Spontaneous Emission of Eu(III) Complexes by Increase of Absorption Cross Section
Y. Hasegawa, K. Nakamura, H. Kawai, N. Yasuda, Y. Tsukahara, Y. Wada
J. Alloy. Compd., 488, 578, 581, 2009年 - Octadehydrodibenzo[12]annulene-Based Organogels: Two Methyl Ester Groups Prevent Crystallization and Promote Gelation
Ichiro Hisaki, Hajime Shigemitsu, Yuu Sakamoto, Yasuchika Hasegawa, Yasuo Okajima, Kazunori Nakano, Norimitsu Tohnai, Mikiji Miyata
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 48, 30, 5465, 5469, WILEY-V C H VERLAG GMBH, 2009年
英語, 研究論文(学術雑誌) - Remarkable chiral and luminescent properties of novel Yb(III) and Eu(III) complexes containing BINAPO ligand
Md. Abdus Subhan, Yasuchika Hasegawa, Takayoshi Suzuki, Sumio Kaizaki, Yanagida Shozo
INORGANICA CHIMICA ACTA, 362, 1, 136, 142, ELSEVIER SCIENCE SA, 2009年01月
英語, 研究論文(学術雑誌), Lanthanide complexes are of great importance for their prospective applications in wide range of science and technology. Chiral lanthanide complexes can constitute stereo-discriminating probes in biological media, owing to the luminescent properties of the rare-earth ions. Sensitized emission with narrow bandwidth, having fast radiation rate and high emission quantum efficiency are the main perspective for synthesizing the complexes. Attention has been given on remarkable chirality with high dissymmetry factors (g = Delta epsilon(ext)/epsilon(max)) of the complexes. For this purpose, beta-diketonato ligands with chiral BINAPO (1,1'-binapthyl phosphine oxide) ligand were chosen to achieve the goal. The complexes [Ln(TFN)(3)-(S-BINAPO)](TFN = 4,4,4- trifluoro-1(2-napthyl)-1,3-butanedione), [Ln(HFT)(3)(S-BINAPO)] (HFT = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione) and [Ln(HFA)(3)(S-BINAPO)](hfa = hexafluoroacetylacetonate) (where Ln = Yb, Eu) were synthesized. The complex, [Eu(TFN)(3)(S-BINAPO)] gives strong red emission at 615 nm with narrow emission band (< 10 nm) when excited by 465 nm light with quantum efficiency 86%. The dissymmetry factors (g = Delta epsilon(ext)/epsilon(max)) corresponding to the F-7(1) -> D-5(0) transition at 590 nm is 0.091 for [Eu(TFN)(3)(S-BINAPO)] and for [Yb(hfa)(3)(S-BINAPO)](hfa = hexafluoroacetylacetonate) corresponding to the F-2(7/2) -> F-2(5/2) transitions is 0.12, are among the largest values for both Eu and Yb complexes to date, respectively. The Eu complexes, [Eu(HFT)(3)(S-BINAPO)] and [Eu(TFN)(3)(S-BINAPO)] are found to be spontaneously emissive, showing bright red emission, when placed in sunlight or even in the laboratory when light is switched on. (c) 2008 Elsevier B.V. All rights reserved. - Near-infrared luminescent polymer thin films containing Yb(III) complex and photosensitized dye
Shin-ichiro Kishimoto, Atsushi Tanaka, Yasuchika Hasegawa, Tsuyoshi Kawai
THIN SOLID FILMS, 517, 4, 1497, 1499, ELSEVIER SCIENCE SA, 2008年12月
英語, 研究論文(学術雑誌), Polymethylmethacrylate (PMMA) thin films containing Yb(pms)(3)(H(2)O)(8) (pms: bis(perfluoromethanesulfonyl)imide) and dipyridophenazine with DMSO and DMSO-d(6) were fabricated on the glass substrates. The films show photosensitized near-IR luminescence under UV light irradiation of 370 nm in wavelength. The emission quantum yields of Yb(III) complex in PMMA (film 1), PMMA containing DMSO (film 2), and PMMA containing DMSO-d(6) (film 3) thin films are 0.18,0.26, and 0.26%, respectively. The emission quantum yields of films 1 and 2 were considerably enhanced after the annealing at 80 degrees C. (c) 2008 Elsevier B.V. All rights reserved - Photoresponsive europium(III) complex based on photochromic reaction
Tetsuya Nakagawa, Yasuchika Hasegawa, Tsuyoshi Kawai
JOURNAL OF PHYSICAL CHEMISTRY A, 112, 23, 5096, 5103, AMER CHEMICAL SOC, 2008年06月
英語, Luminescence properties and their photoinduced control of the electric dipole transitions of a Eu(III) complex that has photochromic triangle terarylenes ligands, tris(hexafluoroacetylacetonato)bis[4,5- bis(5-methyl-2-phenylthiazol-4-yl)-2-phenylthiazole]europium(III) (Eu(hfa)(3)(THIA)(2)), were studied. Fairly high photochromic reactivity of the ligand between the open-ring and closed-ring forms were found to be maintained even in the complex, and reversible color change could be observed many times. The photocyclization and the cycloreversion quantum yields of the Eu(hfa)(3)(THIA)(2) were found to be 37% and 3.4%, respectively. The thermal stability of the closed-ring form of THIA ligand is significantly improved in the Eu(III) complex. The D-5(0)-F-7(2) transition intensity of the Eu(III) complex with open-ring form ligands (Eu(hfa)(3)(THIA)2-O) is larger than that of the Eu(III) complex with closed-ring form ligands (Eu(hfa)(3)(THIA)2-C). The radiative rate constants of Eu(hfa)(3)(THIA)2-O and Eu(hfa)(3)(THIA)2-C are estimated to be 1.7 x 10(2) and 1.5 x 10(2) s(-1), respectively. The reversible control of the emission properties of the Eu(III) complex by the photochromic reactions is demonstrated for the first time. - Remarkable magneto-optical properties of europium selenide nanoparticles with wide energy gaps
Yasuchika Hasegawa, Taka-Aki Adachi, Atsushi Tanaka, Mohammad Afzaal, Paul O'Brien, Takahiro Doi, Yukio Hinatsu, Koji Fujita, Katsuhisa Tanaka, Tsuyoshi Kawai
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 130, 17, 5710, 5715, AMER CHEMICAL SOC, 2008年04月
英語, 研究論文(学術雑誌), The enhanced magneto-optical properties of nanoscaled lanthanide chalogenide semiconductors which have a wide energy gap were observed at around 500 nm for the first time. The nanoscaled semiconductors, Eu(1-x)Se nanoparticles 1 (cubic shapes) and 2 (spherical shapes), were synthesized by the thermal reduction of Eu(III) ion with organic ligands containing Se atoms. The resulting Eu(1-x)Se nanoparticles were characterized by X-ray diffraction, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, superconducting quantum interference devices magnetometer, and microwave induced plasma atomic emission spectroscopy measurements. The particle grain sizes of 1 and 2 were estimated to be 11 and 20 nm, respectively. The concentration-normalized Veldet constants (the magnitude of the Faraday effect) of Eu(1-x)Se nanoparticles were much larger than those of corresponding bulk EuSe and EuS nanoparticles. - Optical and electroluminescent properties of samarium complex-based organic light-emitting diodes
Zenken Kin, Hirotake Kajii, Yasuchika Hasegawa, Tsuyoshi Kawai, Yutaka Ohmori
THIN SOLID FILMS, 516, 9, 2735, 2738, ELSEVIER SCIENCE SA, 2008年03月
英語, 研究論文(学術雑誌), The optical and electroluminescent (EL) properties of newly synthesized tris(hexafluoroacethylacetonato)(phenanthroline)samarium(III)mono-methanol [Sm(hfa)(3)(phen)(2)MeOH]-based organic light-emitting diodes (OLEDs) were investigated. The as-prepared photoluminescence (PL) spectrum of Sm(hta)(3)(phen)(2)MeOH-doped PMMA film exhibits the peaks at the wavelength around 564, 598, 645 and 710 nm which correspond to the 4G(5/2) ->(7)H5(/2), (4)G(7/2) -> H-7(7/2), (4)G(5/2) -> H-7(9/2) and (4)G(5/2) -> H-7(11/2) transitions of the Sm3+ ion, respectively. The best organic light-emitting device performance is obtained for a device using 8 wt.% Sm(hfa)(3)(phen)(2)MeOH and 40 wt.% 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4,oxadiazole doped in poly(N-vinylcarbazole) as a emitting layer. The optimal device exhibits maximum luminance of 135 candela (cd)/m(2) at the current density of 0. 16 A/cm(2), with current efficiency of 0. 1 cd/A at the current density of 0.08 A/cm(2). The EL spectrum from optimal device has the Commission Internationale De L'Eclairage (CIE) coordinate of (0.60, 0.36). (C) 2007 Elsevier B.V. All rights reserved. - Preparation of EuSe nanoparticles from Eu(III) complex containing selenides
Taka-aki Adachi, Atsushi Tanaka, Yasuchika Hasegawa, Tsuyoshi Kawai
THIN SOLID FILMS, 516, 9, 2460, 2462, ELSEVIER SCIENCE SA, 2008年03月
英語, 研究論文(学術雑誌), The EuSe nanoparticles were prepared by the thermal reduction of Europium nitrate with new organic selenium compound, tetraphenylphosphonium diphenylphosphinediselenide (PPh4)(Se2P(C6H5)(2)), for the first time. EuSe nanoparticles were identified by the X-ray diffraction (XRD), the transmission electron microscope (TEM) and the energy dispersive X-ray spectroscopy (EDX) measurements. The average size of the EuSe nanoparticles was found to be 19 nm. The energy gap in EuSe nanoparticles of 19 nm was estimated by edge of absorption band, giving the energy gap of 1.86 eV. (C) 2007 Elsevier B.V. All fights reserved. - Emission properties of Sm(III) complex having ten-coordination structure
Yasuchika Hasegawa, Shin-ichi Tsuruoka, Takahiko Yoshida, Hideki Kawai, Tsuyoshi Kawai
THIN SOLID FILMS, 516, 9, 2704, 2707, ELSEVIER SCIENCE SA, 2008年03月
英語, 研究論文(学術雑誌), Sammarium(III) complex having ten-coordination structure, bis-(1, 10-phenanthroline)tris-(hexafluoroacetylacetonato)samarium(III) (Sm(hfa)(3) (phen)(2)) was prepared by chelation of tris-(hexafluoroacetylacetonato) samarium(III) (Sm(hfa)(3)(H2O)(2)) with 1,10-phenantroline (phen). The characteristic ten-coordination structure of Sm(hfa)(3)(phen)(2) was determined by H-1 NMR and elemental analyses. Strong deep-red emission (lambda(max)=643 nm) and narrow emission band (FWHM=5 nm) of Sm(hfa)(3)(phen)(2) originated from electronic allowed transition from characteristics ten coordinate structure. The emission quantum yields Sm(hfa)(3)(phen)(2) excited at absorption bands of ligands and Sm(III) ion were found to be 0.36 and 1.4%, respectively. (c) 2007 Elsevier B.V. All rights reserved. - Improvement of lasing properties of europium (III) complexes by increase of emission quantum yield
Kazuki Nakamura, Yasuchika Hasegawa, Hideki Kawai, Naoki Yasuda, Yasunori Tsukahara, Yuji Wada
THIN SOLID FILMS, 516, 9, 2376, 2381, ELSEVIER SCIENCE SA, 2008年03月
英語, 研究論文(学術雑誌), Deuterated Eu(III) complexes of tris-(hexafluoroacetylacetonato)europium(III) dehydrates (Eu(hfa-H)(3)(H2O)(2)), tris-(hexafluoroacetylacetonato) europium(III) bis(triphenylphospine oxide) (Eu(hfa-H)(3)(TPPO)(2)), tris(hexafluoroacetylacetonato) europium(III) 1,1'-biphenyl-2,2-diylbis (diphenylphosphine oxide) (Eu(hfa-H)(3)(BIPHEPO)) were prepared by the exchange reaction via keto-enol tautomerism of the Eu(III) complexes with CD3OD. The emission quantum yields of the deuterated Eu(III) complexes were higher than those of corresponding non-deuterated Eu(III) complexes. The lasing properties of Eu(III) complexes in polymer thin film were measured by photo-pumping of Nd: YAG laser (355 nm). Percentages of ASE components in whole emission were increased by deuteration of the Eu(III) complexes. (C) 2007 Elsevier B.V. All rights reserved. - Photosensitized near-infrared luminescence of Yb(III) complexes containing phenanthroline derivatives
Yasuchika Hasegawa, Takuma Yasuda, Kazuki Nakamura, Tsuyoshi Kawai
JAPANESE JOURNAL OF APPLIED PHYSICS, 47, 2, 1192, 1195, JAPAN SOC APPLIED PHYSICS, 2008年02月
英語, 研究論文(学術雑誌), Near-IR emission of novel Yb(III) complexes with phenanthroline derivertives, bis(phenanthroline)-tris(bis-perfluoromethanesurfonyliminate)ytterbium [Yb(PmS)(3)(phen)(2)] and dipyridophenazine-tris(bis-perfluoromethanesurfonyliminate)ytterbium [Yb(pms)(3)(dip)] are studied in dimethylsulfoxide [DMSO-d(6)]. The emission quantum yields of Yb(PMS)(3)(phen)(2) and Yb(pms)(3)(dipy-phenazine) excited at 940nm ((2)F(7/2)-(2)F(5/2) transition) were found to be 7.4 and 9.1%, respectively. We successfully observed the photosensitized near-infrared emission from the Yb(III) complexes upon excitation of the aromatic ligands. The energy transfer efficiencies of Yb(pms)(3)(phen)(2) and Yb(pms)(3)(dip) excited at 310 nm (pi-pi* transition) were evaluated to be 9.1 and 4.0%, respectively. - Enhanced deep-red luminescence of tris(hexafluoroacetylacetonato)samarium(III) complex with phenanthroline in solution by control of ligand coordination
Yasuchika Hasegwa, Shin-ichi Tsuruoka, Takahiko Yoshida, Hideki Kawai, Tsuyoshi Kawai
JOURNAL OF PHYSICAL CHEMISTRY A, 112, 5, 803, 807, AMER CHEMICAL SOC, 2008年02月
英語, 研究論文(学術雑誌), The effect of solvent molecule on the emission properties of Sm(hfa)(3)(phen)(2) (hfa = hexafluoroacetylacetonato, phen = phenanthoroline) was investigated using acetone, acetonitrile, and-pyridine. (5)G(5/2) -> H-5(9/2) transition intensities in pyridine were found to be larger than those in corresponding acetone and acetonitrile. The radiative rate constant in pyridine (4.8 x 10(2) s(-1)) was 2 times larger than those in acetonitrile (2.6 x 10(2) s(-1)) and acetone (2.3 x 10(2) s(-1)), although the nonradiative transition via vibrational relaxation (k(nr) = 1.7 x 10(4) s(-1)) in pyridine was the same as those in acetone and acetonitrile (k(nr) = 1.8 x 10(4) s(-1)), resulting in the enhanced emission quantum yield of Sm(III) complex in pyridine (2.7%). The coordination structures of Sm(hfa)(3)(phen)(2) in acetonitrile, acetone, and pyridine were estimated by X-ray single-crystal analyses. These results indicate that enhancement of the emission properties in pyridine is due to faster radiative rate related to formation of asymmetrical nine-coordinated structure, Sm(hfa)(3)(phen)(py) (py = pyridine). - Enhanced Faraday rotation of cube-shaped EuS nanocrystals with a magnetic coercive field
Y. Hasegawa, A. Tanaka, Y. Doi, Y. Hinatsu, K. Fujita, K. Tanaka, T. Kawai
IUMRS-ICA 2008 SYMPOSIUM AA. RARE-EARTH RELATED MATERIAL PROCESSING AND FUNCTIONS, 1, 1, 7, IOP PUBLISHING LTD, 2008年
英語, 研究論文(国際会議プロシーディングス), Enhanced Faraday effect of cube-shaped EuS nanocrystals (average crystal size = 12 nm) with a coercive field is demonstrated for the fast time. The coercive field and the remanent magnetization of cube-shaped EuS nanocrystals were found to be 0.011 T and 0.05 mu(B), respectively, using a SQUID (superconducting quantum interface device). Consideration of the volume percentages of cube-shaped EuS nanocrystals in polymer thin film gives a large Verdet constant (0.071 deg/cm Oe), which is 3.7 times larger than that of the polymer thin films containing sphere-shaped EuS nanocrystals (average crystal size = 14 nm). Cube-shaped EuS nanocrystals with a coercive field are expected to be used as active magneto-optical materials. - Energy-transfer mechanism in photoluminescent Terbium(III) complexes causing their temperature-dependence
Shinya Katagiri, Yasunori Tsukahara, Yasuchika Hasegawa, Yuji Wada
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 80, 8, 1492, 1503, CHEMICAL SOC JAPAN, 2007年08月
英語, 研究論文(学術雑誌), Photoluminescence of Terbium(III) complexes was investigated as a function of temperatures in the range of 80-280 K for [Tb(bfa)(3)(H2O)(2)] (bfa: 4,4,4-trifluoro-1-phenyl-1,3-butanedionato), [Tb(hfa)(3)(H2O)(3)] (hfa: hexafluoroacetylacetonato), [Tb(tfa)(3)(H2O)(2)] (tfa: trifluoroacetylacetonato), [Tb(acaC)(3)(H2O)(3)] (acac: acetylacetonato), and [Tb(hfa)(3)(tppo)(2)] (tppo: triphenylphosphine oxide). These complexes were classified into the two groups with different temperature-dependences. The first group consisting of [Tb(bfa)(3)(H2O)(2)], [Tb(tfa)(3)(H2O)(2)], and [Tb(acac)(3)(H2O)(3)] showed a dependence determined by the energy gap between the excited triplet state of the ligand and the emitting level of terbium(III) ion. In contrast, for [Tb(hfa)3(H2O)(3)] and [Tb(hfa)(3)(tppo)(2)] containing hfa as a ligand, not only the energy gap but also the energy barriers of the "Forward energy transfer" from the ligand to terbium(III) ion and "Back energy transfer" from terbium(III) ion to the ligand were taken into account for understanding their dependences. These results are discussed based on the re-orientation of the complexes accompanied by the forward and back energy transfer processes using DFT calculations. - Photochromism of thiazole-containing triangle terarylenes
Takuya Nakashima, Kazuhiko Atsumi, Shigekazu Kawai, Tetsuya Nakagawa, Yasuchika Hasegawa, Tsuyoshi Kawai
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 19, 19, 3212, 3218, WILEY-V C H VERLAG GMBH, 2007年07月
英語, 研究論文(学術雑誌), Triangle terarylene derivatives based on the 4,5-diarylthiazole structure have been synthesized and their photochromic properties have been studied both in solution and in the crystalline state. The thiazolyl-substituted terarylenes displayed reversible photochromism in solution, with photocyclization quantum yields as high as 60%, while a 4,5-dithienylthiazole derivative underwent photochromic reaction even in the single-crystal state, although a 4,5-dithiazolylthiazole (terthiazole) showed no photochromic reaction in the crystalline phase. The difference in photochromic reactivity between the 4,5-dithienylthiazole and the 4,5-dithiazolylthiazole was found by X-ray crystallographic analyses to originate from conformational differences in the crystalline state. The thermal cycloreversion activation energies in the solution phase were measured for thiazolyl-substituted terarylenes and for a corresponding terthiophene derivative. The activation energy for the transition from photogenerated closed-ring isomer to open-ring isomer increased with the number of substitutions of thiazole unit for thiophene. The lower aromatic stabilization energy of thiazole in relation to that of thiophene was considered to be responsible for the thermal stability of the closed-ring isomers of thiazolyl-substituted terarylenes. - Distinct guest-dependent changes in arrangements of a fluorophore and the corresponding emission modes in a ternary system: Transcription and translation of guest molecular information
Yuji Mizobe, Tornoaki Hinoue, Mikiji Miyata, Ichiro Hisaki, Yasuchika Hasegawa, Norimitsu Tohnai
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 80, 6, 1162, 1172, CHEMICAL SOC JAPAN, 2007年06月
英語, 研究論文(学術雑誌), In order to prepare novel molecular arrangements of a fluorophore that result in new solid-state fluorescence properties, we fabricated a ternary system consisting of anthracene-2,6-disulfonic acid (ADS), aliphatic primary amines and guest molecules as a fluorophore, arrangement-controlling parts and molecular information sources, respectively. The system consisting of ADS, (rac)-s-butylamine and 1,4-dioxane yielded a novel zigzag arrangement of anthracene moieties that gave rise to a rare emission mode. Subsequent screening of the amines and guests in the ternary system suggested that a relationship exists among the molecular information source, the zigzag arrangement and the rare emission mode. Namely, molecular information of 1,4-dioxane is transcribed to the zigzag arrangement, and the arrangement is translated into the excimer-like emission. Interestingly, the relationship appears to mimic that found in DNA. In addition, transcription of the molecular information requires the appropriate shape and size of void spaces formed by ADS and (rac)-s-butylamine. From these observations, the zigzag arrangement and the corresponding rare emission mode is specific for the system of ADS, (rac)-s-butylamine and 1,4-dioxane. - Enhanced lasing properties of dissymmetric Eu(III) complex with bidentate phosphine ligands
Kazuki Nakamura, Yasuchika Hasegawa, Hideki Kawai, Naoki Yasuda, Nobuko Kanehisa, Yasushi Kai, Toshihiko Nagamura, Shozo Yanagida, Yuji Wada
JOURNAL OF PHYSICAL CHEMISTRY A, 111, 16, 3029, 3037, AMER CHEMICAL SOC, 2007年04月
英語, The luminescent and lasing properties of Eu(III) complexes were enhanced by using an dissymmetric Eu(III) complex. The photophysical properties (the emission spectral shapes, the emission lifetimes, the emission quantum yields, and the stimulated emission cross section (SEC)) were found to be dependent on the geometrical structures of Eu(III) complexes. The geometrical structures of Eu(III) complexes were determined by X-ray single crystal analyses. The symmetrical group of Eu(hfa)(3)(BIPHEPO) (tris(hexafluoroacetylacetonato)europium(III) 1,1'-biphenyl-2,2'-diylbis(diphenylphosphine oxide)) was found to be C-1, which was more dissymmetric than Eu(hfa)(3)(TPPO)(2) (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C-2 symmetry) and Eu(hfa)(3)(OPPO)(2) (tris(hexafluoroacetylacetonato)europium(III) 1,2-phenylenebis(diphenylphosphine oxide): C-2 symmetry). The analytical data were supported by Judd-Ofelt analysis. The most dissymmetrical Eu(III) complex, Eu(hfa)(3)(BIPHEPO), showed large electron transition probability and large SEC (4.64 x 10(-20) cm(2)). The SEC of Eu(hfa)(3)(BIPHEPO) was superior to even the values of Nd-glass laser for practical use (1.6-4.5 x 10(-20) cm(2)). The lasing properties of Eu(III) complexes in polymer thin film were measured by photopumping of a Nd:YAG laser (355 nm). The threshold energy of lasing oscillation was found to be 0.05 mJ. The increasing rate of the lasing intensity of Eu(hfa)(3)(BIPHEPO) as a function of the excitation energy was much larger than that of Eu(hfa)(3)(TPPO)(2) and Eu(hfa)(3)(OPPO)(2). The dissymmetrical structure of Eu(hfa)(3)(BIPHEPO) promoted the enhancement of the lasing property. - Reversible luminescence modulation in photochromic europium(III) complex having triangle terthiazole ligands
Tetsuya Nakagawa, Kazuhiko Atsumi, Takuya Nakashima, Yasuchika Hasegawa, Tsuyoshi Kawai
CHEMISTRY LETTERS, 36, 3, 372, 373, CHEMICAL SOC JAPAN, 2007年03月, [査読有り]
英語, 研究論文(学術雑誌), Luminescent Eu-III complex having photochromic ligand is synthesized, and its reversible control of the luminescent properties based on photochromic reaction was demonstrated. - Three-dimensional optical trapping and arrangements of magnetic semiconductor EuS nanoaggregations
Atsushi Tanaka, Tadao Sugiura, Tsuyoshi Kawai, Yasuchika Hasegawa
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS, 46, 8-11, L259, L261, JAPAN SOC APPLIED PHYSICS, 2007年03月
英語, 研究論文(学術雑誌), Cubic-shaped EuS nanocrystals of about 14 nm were prepared by the thermal reduction of an Eu(III) complex and their aggregations in methanol were observed by dynamic light scattering (DLS) measurements. The average size of the aggregations was 488 39 nm. Three-dimensional (3D) optical trapping and the arrangements of EuS aggregations were demonstrated using a Nd:YAG laser for the first time. - Reversible luminescent control of novel Eu(III) complex having photochromic ligand
T. Nakagawa, K. Atsumi, T. Nakashima, Y. Hasegawa, T. Kawai
Chem. Lett., 36, 372, 378, 2007年 - Photoluminescence and electroluminescence in combination of rare-earth metal complexes and phosphorescent molecules
Z. Kin, Y. Hino, H. Kajii, Y. Hasegawa, T. Kawai, Y. Ohmori
Mater. Res. Soc. Sump. Proc., 965, S04-02, 2007年 - Visible and near-infrared luminescence from self-assembled lanthanide(III) clusters with organic photo sensitizers
Kazuhiro Manseki, Yasuchika Hasegawa, Yuji Wada, Hideki Ichida, Yasuo Kanematsu, Takashi Kushida
JOURNAL OF LUMINESCENCE, 122, 262, 264, ELSEVIER SCIENCE BV, 2007年01月
英語, 研究論文(学術雑誌), Synthesis and photophysical properties of nonanuclear lanthanide(III) clusters, H-10[Ln(9)(hesa)(16)(mu-O)(10)(NO3)] (hesa = hexylsalicylate, Ln = Gd, Tb and Yb) were investigated. By the ligand excitation at 380 nm in methanol, the Tb cluster exhibited luminescence due to the 4f-4f transitions of Tb(III) around 487, 549, 580, 621, 646, 670, and 680 nm (D-5(4) -> 7F(i): i = 6, 5, 4, 3, 2, 1, 0). The Yb cluster also showed the photosensitized luminescence at around 980 nm (F-2(7/2) -> F-5/2). Especially, the Tb cluster gave a high emission quantum yield (Phi(s) > 0.90) in methanol. (c) 2006 Elsevier B.V. All rights reserved. - Anomalous anthracene arrangement and rare excimer emission in the solid state: Transcription and translation of molecular information
Yuji Mizobe, Mikiji Miyata, Ichiro Hisaki, Yasuchika Hasegawa, Norimitsu Tohnai
ORGANIC LETTERS, 8, 19, 4295, 4298, AMER CHEMICAL SOC, 2006年09月
英語, 研究論文(学術雑誌), A novel molecular arrangement of anthracene moieties and the corresponding rare solid-state excimer emission is obtained by utilization of a ternary system. The system consists of ammonium anthracene disulfonate and adducts, and shows the modulation of the solid-state emission mode depending on the adducts. The adducts act as molecular information sources that are transcribed to the arrangement, and the arrangement is translated into the emission mode. This series of processes might be mimicry of central dogma. - Synthesis and photophysical properties of EuS nanoparticles from the thermal reduction of novel Eu(III) complex
Y Hasegawa, Y Okada, T Kataoka, T Sakata, H Mori, Y Wada
JOURNAL OF PHYSICAL CHEMISTRY B, 110, 18, 9008, 9011, AMER CHEMICAL SOC, 2006年05月
英語, 研究論文(学術雑誌), EuS nanoparticles were synthesized by the thermal reduction of single source precursor (SSP), (PPh4)[Eu(S2CNEt2)4]center dot 2H(2)O, under microwave irradiation. The average size of the EuS nanoparticles was found to be 8 nm (3-16 nm in size). The organic products on the EuS surface were observed by using FT-IR, NMR, and MS analyses. We have found that these are resulted from the chemical reactions of SSP and cover the nanocrystal surface. A thermal reaction of SSP gave EuS nanoparticles and the organic product ((SCN)-S-center dot(Et)(2)). The organic product would make a dimmer, (Et)(2)NC(S)-(S)CN(Et)(2), by the couping of the radicals formed in the thermal reaction and/or thiopolymer in the solution through the polymerization of the radicals. The effective surface modification by the organic products led to protection of the EuS surface, resulting in the formation of the strongly luminescent EuS nanoparticles at room temperature (emission peak = 350 nm, fwhm = 58 nm, emission quantum yield = 27 +/- 5%). - A novel strategy for fluorescence enhancement in the solid-state: affording rigidity to fluorophores packing
Yuji Mizobe, Hiromichi Ito, Ichiro Hisaki, Mikiji Miyata, Yasuchika Hasegawa, Norimitsu Tohnai
CHEMICAL COMMUNICATIONS, 20, 2126, 2128, ROYAL SOC CHEMISTRY, 2006年05月
英語, 研究論文(学術雑誌), Solid-state fluorescence enhancement was achieved by preparation of rigid packing that was afforded by disposition of benzylamine into tubulate spaces, serving as a powerful and useful strategy for the enhancement. - Syntheses, structures, near-infrared and visible luminescence, and magnetic properties of lanthanide-organic frameworks with an imidazole-containing flexible ligand
ZH Zhang, Y Song, T Okamura, Y Hasegawa, WY Sun, N Ueyama
INORGANIC CHEMISTRY, 45, 7, 2896, 2902, AMER CHEMICAL SOC, 2006年04月
英語, 研究論文(学術雑誌), Reactions of tripodal ligand 1,3,5-tris(imidazole-1-ylmethyl)-2,4,6-trimethylbenzene (L) with lanthanide metal salts and triethyl orthoformate led to the formation of six bowl-like dinuclear compounds [Ln(2)(L)(HL)(NO3)(6)(HCOO)](.)3CH(3)OH (Ln = Gd 1, Tb 2, Dy 3, Er 4, Yb 5, and Eu 6). The single-crystal X-ray diffraction analysis revealed that six complexes are isomorphous and isostructural and that the dinuclear molecules are further connected by hydrogen bonds and pi-pi interactions, resulting in 3D channel-like structures. The luminescence properties have been studied, and the results showed that the Tb(III) (2) and Eu(III) (6) complexes exhibited sensitized luminescence in the visible region and their luminescence lifetimes in powder and DMSO-d(6) solution are in the range of milliseconds. The Yb(III) complex (5) emits typical near-infrared luminescence in DMSO-d6 solution. Variable-temperature magnetic susceptibility measurements of 1-6 showed that complex 1 (Gd) is nearly a paramagnet and complexes 2 (Tb), 3 (Dy), and 4 (Er) show the ferromagnetic coupling between magnetic centers, whereas the depopulation of the Stark levels in complexes 5 (Yb) and 6 (Eu) leads to a continuous decrease in XmT when the sample is cooled from 300 to 1.8 K. - The first observation of the magnetic circular dichroism in EuS nanocrystals
Y Tsukahara, T Kataoka, Y Hasegawa, S Kaizaki, Y Wada
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 203, 206, ELSEVIER SCIENCE SA, 2006年02月, [査読有り]
英語, 研究論文(学術雑誌), EuS nanocrystals were prepared by the liquid ammonia method. measurements, the absorption spectra and the MCD spectra. (c) 2005 Elsevier B.V. All rights reserved. - Photophysical properties of tetranuclear Eu(III) complexes in polyphenylsilsesqioxane (PPSQ)
K Manseki, Y Hasegawa, Y Wada, S Yanagida
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 805, 808, ELSEVIER SCIENCE SA, 2006年02月
英語, 研究論文(学術雑誌), The tetranuclear europium(III) complexes, [Eu-4(mu-O)(L-1)(10)] (L-1=2-hydroxy-4-octyloxybenzophenone, 1) and [Eu-4(mu-O)(L-2)(10)] (L-2=2-hydroxy-4-dodecyloxybenzophenone, 2), were incorporated into the thermostable polyphenylsilsesqioxane (PPSQ) which had a high transparency. The emission bands of both Eu(III) complexes in PPSQ were observed at 578, 590, 615, 653 and 700 nm by the excitation of the ligands at 380 nm. The emission lifetimes were determined to be 0.38 ms for I and 0.39 ms for 2, which were found to be longer than those in THF-d(8) (0.10 ms for 1 and 0.11 ms for 2). The tetranuclear Eu(HI) complexes doped in the PPSQ polymers were stable up to the condition of 250 degrees C. (c) 2005 Elsevier B.V. All rights reserved. - Temperature-dependent energy transfer in photo-sensitized luminescence of rare earth complexes
S Katagiri, Y Hasegawa, Y Wada, K Mitsuo, S Yanagida
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 809, 812, ELSEVIER SCIENCE SA, 2006年02月
英語, 研究論文(学術雑誌), We have fabricated polymer thin films containing bis(triphenylphosphineoxide)-tris(hexafluoroacetylacetonato) terbium(III) [Tb(HFA)(3)(TPPO)(2)] as a thermo-sensor. The thermo-sensitivity of the thin film containing the Tb(III) complex was found to be 13.5%/degrees C. The emission intensity ratio normalized according to that at 0 degrees C observed for Tb(HFA)(3)(TPPO)(2) in the thin film was not affected by pressure. The thermo-sensing thin film is expected to be useful in measuring surface-temperatures of bodies in wind-tunnel experiments. (c) 2005 Elsevier B.V. All rights reserved. - High lasing oscillation efficiency of Eu(III) complexes having remarkably sharp emission band
K Nakamura, Y Hasegawa, H Kawai, N Yasuda, Y Wada, S Yanagida
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 771, 775, ELSEVIER SCIENCE SA, 2006年02月
英語, 研究論文(学術雑誌), Luminescent Eu(III) complexes with bis-phosphine oxide ligands were synthesized. Geometric structures of novel Eu(III) complexes were determined by single-crystal X-ray diffraction. One of the Eu(III) complexes showed remarkably sharp red emission and large stimulated emission cross-section (full width at half maximum (FWHM) = 2.1 nm, stimulated emission cross-section = 1.80 x 10(-20) cm(2)). The sharpness of the emission bands of the Eu(III) complexes was discussed in terms of the symmetry of the geometrical structure. (c) 2005 Elsevier B.V. All rights reserved. - EPR spectra analysis of photo-magnetic properties of EuO nanocrystals
Y Hasegawa, Y Wada, S Yanagida
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 207, 211, ELSEVIER SCIENCE SA, 2006年02月
英語, 研究論文(学術雑誌), The temperature dependencies of magnetic susceptibility c of the europium oxide (EuO) nanocrystals were examined. The experimental Bohr magnetons (p) for EuO nanocrystals agreed well with the theoretical p for the 4f(7) configuration (Eu(II)). A dramatic increase in magnetization of the EuO nanocrystals under UV irradiation at room temperature was observed by photo-magnetic measurements superconducting quantum interface device (SQUID with optical fiber). This increase in magnetization under UV irradiation can be explained by the occurrence of a d-f exchange interaction of conductive electrons in the 5d band (magnetic exciton). We suggest a mechanism in which the photo-magnetization increases by the presence of an exciton band in the UV region for the polyurea-modified EuO nanocrystals. In order to confirm the magnetic exciton of EuO nanocrystals, we carried out the electron paramagnetic resonance (EPR) measurements under UV irradiation, showing the formation of photo-active species in EuO nanocrystals. (c) 2005 Elsevier B.V. All tights reserved. - Molecular design of luminescent Eu(III) complexes as lanthanide lasing material and their optical properties
Y Hasegawa, H Kawai, K Nakamura, N Yasuda, Y Wada, S Yanagida
JOURNAL OF ALLOYS AND COMPOUNDS, 408, 669, 674, ELSEVIER SCIENCE SA, 2006年02月
英語, 研究論文(学術雑誌), Luminescent polymer (PMMA) containing a Eu(III) complex with a fast radiation rate and a high luminescence quantum efficiency (75 +/- 5%), (bis-triphenylphosphineoxide)(tris-hexafluoroacetylacetonato)europium (III) (Eu(hfa)(3)(TPPO)(2)), was fabricated. The quantum yield and the radiation rate of the luminescent polymer were found to be 75 +/- 5% and 1.1 x 10(3) s(-1), respectively. An Eu(III) complex-doped polymer thin-film was also prepared by use of polyphenylsilsesquioxane (PPSQ) to construct a waveguide lanthanide laser. We propose a strategy for the molecular design of luminescent Eu(III) complexes aiming at lanthanide lasing. (c) 2005 Elsevier B.V. All rights reserved. - The first observation of the MCD analysis of EuS nanocrystals
Y. Tsukahara, T. Kataoka, Y. Hasegawa, S. Kaizaki, Y. Wada
J. Alloy Compd., 408-412, 203, 2006年 - Syntheses, structures, and luminescent and magnetic properties of novel three-dimensional lanthanide complexes with 1,3,5-benzenetriacetate
ZH Zhang, T Okamura, Y Hasegawa, H Kawaguchi, LY Kong, WY Sun, N Ueyama
INORGANIC CHEMISTRY, 44, 18, 6219, 6227, AMER CHEMICAL SOC, 2005年09月
英語, 研究論文(学術雑誌), Five novel lanthanide complexes with the formulas [Nd(bta)(H2O)2(.)4.35H(2)O]n (1), [Sm(bta)(H2O)(2)(.)4.5H(2)O](n), (2), [Eu(bta)(H2O)(.)1.48H(2)O](n) (3), [Tb(bta)(H2O)(.)1.31 H2O](n) (4), and [Yb(bta)(H2O)(H2O)-H-.](n) (5) (H(3)bta = 1,3,5-benzenetriacetic acid) have been prepared by using the corresponding lanthanide salt and H3bta. The results of an X-ray crystallographic analysis revealed that all the complexes have three-dimensional channel-like structures, in which the bta(3-) ligands adopt different coordination modes: monodentate and mu(2)-eta(2):eta(1)-bridging coordination modes in 1, 2, and 5 and mu(2)-eta(1):eta(1) -bridging and mu(2)-eta(2):eta(1)-bridging coordination modes in 3 and 4, respectively. Complexes 1 and 2, as well as 3 and 4, are isostructural, respectively, in which all the Ln(III) (Ln = Nd, Sm, Eu, and Tb) atoms are nine-coordinated, while the Yb-III atoms in complex 5 are eight-coordinated. Both complexes 3 and 4 showed strong luminescence upon excitation, and their luminescence decay curves fit well with single exponential decays of which the lifetime is 0.45 ms for 3 and 1.0 ms for 4. The magnetic properties of the complexes were investigated in the temperature range of 1.8-300 K. - Photosensitized luminescence of thermostable polynuclear Eu(III) complexes
K Manseki, Y Hasegawa, Y Wada, S Yanagida
JOURNAL OF LUMINESCENCE, 111, 3, 183, 189, ELSEVIER SCIENCE BV, 2005年02月
英語, 研究論文(学術雑誌), Tetranuclear europium(III) complexes, [Eu-4(mu-O)(L-1)(10)] (L-1 = 2-hydroxy-4-octyloxybenzophenone,1) and [Eu-4(mu-O)(L-2)(10)] (L-2 = 2-hydroxy-4-dodecyloxybenzophenone,2) were synthesized by the reaction of lanthanide nitrates with L or L, in the presence of triethylamine in methanol. The photosensitized emission bands of the both Eu(III) complexes in THF-d(8) were observed around 579, 590, 615, 653, and 699 nm by the excitation of the ligands at 380 nm, whereas the emission from the mononuclear complex 3 containing ethanol molecules was almost quenched. The emission efficiencies were determined to be 3.1 +/- 0.1% for 1 and 3.9 +/- 0.1% for 2, respectively. The differential scanning calorimetry (DSC) measurements demonstrated that the decomposition points of 1 and 2 were 309 degreesC and 320 degreesC, respectively, indicating high thermostability of these complexes compared to the mononuclear Eu(III) complex 3 (250degreesC). New strategy for designing stable rare earth compounds giving strong emission would be emphasized by introducing polynuclear complexes. Polynuclear complexes should open a wide range of molecular design for photosensitized luminescence and thermal stability. (C) 2004 Elsevier B.V. All rights reserved. - Size-controlled synthesis of quantum-sized EuS nanoparticles and tuning of their Faraday rotation peak
T Kataoka, Y Tsukahara, Y Hasegawa, Y Wada
CHEMICAL COMMUNICATIONS, 14, 48, 6038, 6040, ROYAL SOC CHEMISTRY, 2005年
英語, 研究論文(学術雑誌), Size-controlled EuS nanoparticles were synthesized by the reaction of europium metal with thiourea as a sulfur source in liq. NH3, whose surface was confirmed to be modified with thiourea by FT-IR measurement, and the opto-magnetic properties (Faraday effect) of the EuS nanoparticles were investigated by using PMMA films containing the nanoparticles, showing that their Faraday rotation peaks were adjustable by control of their particle size. - pH-dependent reversible transformation of TPPS4 anchored on mesoporous TiO2 film between monomers and J-aggregates
Y Fujii, Y Hasegawa, S Yanagida, Y Wada
CHEMICAL COMMUNICATIONS, 14, 24, 3065, 3067, ROYAL SOC CHEMISTRY, 2005年
英語, 研究論文(学術雑誌), Protonated TPPS4 monomer and its J-aggregate were formed simultaneously from TPPS4 adsorbed through its sulfonic acid groups on TiO2 porous film by decreasing the pH of the surrounding water and this behavior on TiO2 film can be reversibly repeated depending on pH, indicating a flexible and stable arrangement of TPPS4 through chemical bonds between the sulfonic acid groups and the TiO2 surface. - A tunable solid-state fluorescence system consisting of organic salts of anthracene-2,6-disulfonic acid with primary amines
Y Mizobe, N Tohnai, M Miyata, Y Hasegawa
CHEMICAL COMMUNICATIONS, 14, 14, 1839, 1841, ROYAL SOC CHEMISTRY, 2005年
英語, 研究論文(学術雑誌), A dramatic change of solid-state fluorescence properties triggered by molecular arrangements of anthracene moieties was obtained by using organic salts of ADS with primary amines, indicating that modification of the amines enables us to tune the properties. - A novel method for synthesizing EuS nanocrystals from a single-source precursor under white LED irradiation
Y Hasegawa, M Afzaal, P O'Brien, Y Wada, S Yanagida
CHEMICAL COMMUNICATIONS, 14, 2, 242, 243, ROYAL SOC CHEMISTRY, 2005年
英語, 研究論文(学術雑誌), EuS nanocrystals, with an average diameter of 9 nm, have been synthesized by the photolysis of Na[Eu(S2CEt2)(4)].3.5H(2)O; the first quantum confined particles of EuS to be reported. - Strategies for the design of luminescent lanthanide(III) complexes and their photonic applications
Y Hasegawa, Y Wada, S Yanagida
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS, 5, 3, 183, 202, ELSEVIER SCIENCE BV, 2004年12月
英語, Strategies for the design of luminescent lanthanide complexes, especially Nd(III) complexes are introduced in this review. The relatively low efficiency of Nd(III) emission in solution has been attributed to: (1) the radiationless transition process via vibrational excitation of the surrounding medium; (2) dipole-dipole non-radiative energy transfer processes via cross-relaxation and excitation migration; and (3) characteristics of perturbation of Nd(III) f orbitals by the surrounding environment. A Nd(III)-doped organic medium could be used as a strong luminescent material if these contributions could be controlled via the design of ligands for the Nd(III) complexes. Furthermore, recent photonic applications using Nd(III), Eu(III) and Tb(III) complexes are demonstrated in this paper. The design of lanthanide(III) complexes and luminescence-based applications, including the fabrication of devices, are expected to open up pioneering fields in materials science. (C) 2004 Japanese Photochemistry Association. Published by Elsevier B.V. All rights reserved. - Novel luminescent Eu(III) complex with remarkably narrow emission band
K Nakamura, Y Hasegawa, Y Wada, S Yanagida
CHEMICAL PHYSICS LETTERS, 398, 4-6, 500, 504, ELSEVIER SCIENCE BV, 2004年11月
英語, 研究論文(学術雑誌), In order to fabricate a high-power laser medium using Eu(III) complex, strong-luminescent Eu(III) complexes with low vibrational ligands were synthesized. One of the Eu(III) complex showed remarkably sharp red emission and large stimulated emission cross-section. The value of stimulated emission cross-section was the same order as the values of Nd-glass laser for practical use. (C) 2004 Elsevier B.V. All rights reserved. - Thermo-sensitive luminescence based on the back energy transfer in terbium(III) complexes
S Katagiri, Y Hasegawa, Y Wada, S Yanagida
CHEMISTRY LETTERS, 33, 11, 1438, 1439, CHEMICAL SOC JAPAN, 2004年11月
英語, 研究論文(学術雑誌), The emission intensities of Tb(hexafluoroacetylacetonato)(3)(H2O)(2) [Tb(HFA)(3)(H2O)(2)] and Tb(HFA)(3)(triphenyl-phosphine oxide)(2) [Tb(HFA)(3)(TPPO)(2)] in acetone-d(6) dramatically decreased with increasing temperature in contrast to no change observed for Tb(NO3)(3). The high thermal sensitivity is attributed to the back energy transfer from Tb(III) ion to triplet state of HFA having the energy barrier. - Lanthanide heterometallic molecular squares Ru-2-Ln(2) exhibiting sensitized near-infrared emission
D Guo, CY Duan, F Lu, Y Hasegawa, QJ Meng, S Yanagida
CHEMICAL COMMUNICATIONS, 13, 1486, 1487, ROYAL SOC CHEMISTRY, 2004年07月
英語, 研究論文(学術雑誌), New lanthanide heterometallic molecular squares functionalized with Ru-bipy antenna chromophore Ru-2-Ln(2) exhibit sensitized near-infrared emission upon photo-excitation of the Ru-centered antenna at 420 nm. - Photo-sensitizing ruthenium complexes for solid state dye solar cells in combination with conducting polymers as hole conductors
Y Saito, T Azechi, T Kitamura, Y Hasegawa, Y Wada, S Yanagida
COORDINATION CHEMISTRY REVIEWS, 248, 13-14, 1469, 1478, ELSEVIER SCIENCE SA, 2004年07月
英語, Pyrrole- or thiophene-bearing pyridine ligands were designed to synthesize ruthenium complexes with pyrrole or thiophene groups as sensitizing dye molecules. Solid state dye sensitized solar cells (sDSCs) were fabricated using the newly designed ruthenium complexes as sensitizers and conducting polymers, polypyrrole and poly (3,4-ethylenedioxythiophene) as solid-state hole transport materials. The polymers were introduced into the void of mesoporous dye sensitized TiO2 electrodes by in situ chemical- and photo-electrochemical polymerization. Employment of the novel ruthenium dyes with pyrrole or thiophene groups in the ligand systems improved the photovoltaic performance of the sDSCs. Electronic communication at the interface between the new ruthenium dyes and the conducting polymer coupled with ionic liquids was found to contribute to the improved photovoltaic performance of sDSCs. (C) 2004 Elsevier B.V. All rights reserved. - Preparation and physical properties of EuO nanocrystals using Eu(II)-exchanged zeolite X as a precursor
S Thongchant, S Katagiri, Y Hasegawa, Y Wada, S Watase, M Nakamoto, T Sakata, H Mori, S Yanagida
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 77, 4, 807, 812, CHEMICAL SOC JAPAN, 2004年04月
英語, 研究論文(学術雑誌), The cation-exchange of zeolite X with divalent europium has been achieved using a methanol solution containing Eu(II) prepared by photochemical reduction of Eu(III). Emission spectra have confirmed that the valence of europium ion in the ion-exchanged zeolite X was divalent. A blue shift of emission spectra was observed after exposing Eu(II)X to air at room temperature. TEM have revealed the formation of EuO nanocrystals with average size of 4.2 nm on the outer surface of Eu(II)X. EuO nanocrystals show ferromagnetism accompanied by photo-response magnetism under UV irradiation. - Blue phosphorescence of the novel dinuclear gold(I) complex bridged by 1,3-benzenedithiolate in solution
S Watase, T Kitamura, Y Hasegawa, N Kanehisa, M Nakamoto, Y Kai, S Yanagida
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 77, 3, 531, 536, CHEMICAL SOC JAPAN, 2004年03月
英語, 研究論文(学術雑誌), A novel dinuclear benzenedithiolatogold(I) complex was synthesized and characterized spectroscopically. This complex showed intense blue emission [quantum yield at 1.0 x 10(-4) mol dm(-3): phi = 0.026(2)] at room temperature in fluid solvents. This emission originates from a metal-perturbed ligand-centered transition. The relatively long life time of the excited state (tau(50) = ca. 2 musec) and the large stokes shift suggest that the emission is phosphorescence. The X-ray single crystal structural determination showed that the complex has a distorted 12-membered macrocyclic Structure bridged by two benzenedithiolate ligands, with no gold-old interactions. - Intrazeolite nanostructure of Nd(III) complex giving strong near-infrared luminescence
M Ryo, Y Wada, T Okubo, Y Hasegawa, S Yanagida
JOURNAL OF PHYSICAL CHEMISTRY B, 107, 41, 11302, 11306, AMER CHEMICAL SOC, 2003年10月
英語, 研究論文(学術雑誌), We investigated the variation of the emission properties of tetramethylammonium ion-containing faujasite zeolite treated with bis-(perfluoromethylsulfonyl)amide (PMS) as a function of the Nd(III)-loading level. The emission intensity increased with the Nd(III)-loading level. The emission decays did not follow simple first-order kinetics and the average lifetime became longer with increasing Nd(III)-loading level. It was found that at low Nd(III)-loading levels, Nd(PMS)(3) Complexes formed with coordinating water molecules in the supercage of the zeolite, resulting in rapid emission with a lifetime of less than 40 mus. On the other hand, the components with lifetimes longer than 100 mus observed at high loading levels were attributed to [Nd(PMS)] zeolite complexes without coordinating water molecules. The zeolites with high Nd(III)-loading levels gave more efficient emission due to the large contribution of the complex in the zeolite that emitted more efficiently. The suppression of energy migration among the Nd(III) ions by co-exchanging with La(III) led to more efficient near-IR emission of Nd(III) complexes encaged in the faujasite-type zeolite. - Polymer thin films containing Eu(III) complex as lanthanide lasing medium
Y Hasegawa, Y Wada, S Yanagida, H Kawai, N Yasuda, T Nagamura
APPLIED PHYSICS LETTERS, 83, 17, 3599, 3601, AMER INST PHYSICS, 2003年10月
英語, 研究論文(学術雑誌), Direct evidence of lanthanide(III) lasing using Eu(III) complex in polymer thin films (threshold level <0.05 mJ) is reported. The thin film consists of polystyrene containing Eu(III) complexes based on two criteria: (1) Higher emission quantum yield of Eu(III) complexes, which increases the r(s) (energy density), and (2) faster radiation rate at large B (Einstein coefficient). The microcavity was constructed by coating a glass substrate with a film having a high refractive index. The film thickness was found to be 1.71 mm. The threshold level for laser transmission was found to be <0.05 mJ. (C) 2003 American Institute of Physics. - Size selective synthesis of surface-modified EuS nanocrystals using pyridine and their physical properties
S Thongchant, Y Hasegawa, Y Wada, S Yanagida
CHEMISTRY LETTERS, 32, 8, 706, 707, CHEMICAL SOC JAPAN, 2003年08月
英語, 研究論文(学術雑誌), The particle size of EuS nanocrystals was gradually increased by addition of pyridine to the reaction mixture of europium metal and hydrogen sulfide in liquid ammonia. The size effect of EuS nanocrystals was found in the absorption spectra for the first time. The size effect on the magnetic properties of the nanocrystals was also observed. - First observation of Faraday effect of EuS nanocrystals in polymer thin films
S Thongchant, Y Hasegawa, K Tanaka, K Fujita, K Hira, Y Wada, S Yanagida
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS, 42, 7B, L876, L878, INST PURE APPLIED PHYSICS, 2003年07月
英語, 研究論文(学術雑誌), The semi-transparent EuS nanocrystal-embedded plastic films were prepared by casting the polymer solutions containing dispersed EuS nanocrystals on glass substrates. The resulting EuS-plastic films showed large Faraday effect at room temperature. The Faraday rotation peaks of the films,shifted toward longer wavelength with an increase of the crystal size of EuS. - Liquid-phase synthesis of EuS nanocrystals and their physical properties
Supitcha Thongchant, Yasuchika Hasegawa, Yuji Wada, Shozo Yanagida
Journal of Physical Chemistry B, 107, 10, 2193, 2196, 2003年03月13日, [査読有り]
英語, 研究論文(学術雑誌), The first EuS nanocrystals were prepared by the reaction of europium metal and HaS in liquid ammonia. X-ray diffraction (XRD) patterns and TEM images supported the formation of nanoscaled EuS crystals with average size of 20.4 nm. The nanocrystals showed blue shift compared with previously reported EuS films. The Curie point of EuS nanocrystals (16.6 K) was the same as that of the corresponding bulk compound, but a decreasing of magnetic moment was found because of the specific surface condition of the nanocrystals. - Low-vibrational luminescent polymers including tris(bis-perfluoromethane and ethanesulfonylaminate)neodymium(III) with 8 coordinated DMSO-d6
Y Hasegawa, K Sogabe, Y Wada, S Yanagida
JOURNAL OF LUMINESCENCE, 101, 3, 235, 242, ELSEVIER SCIENCE BV, 2003年03月
英語, 研究論文(学術雑誌), Novel Nd(III) complexes, tris(bis-perfluoromethane and ethanesulfonylaminato)neodymium(III)octa(deuterated dimethylsulfoxide) were designed and synthesized to apply to luminescent materials in plastic optical fiber. The IR and the near-IR spectra analyses has been done to estimate the radiationless transition via vibrational excitation of the Nd(III) complexes. [Nd(pms)(3)(DMSO-d(6))(8)] and [Nd(pes)(3)(DMSO-d(6))(8)] in polyhexafluoroisopropylmethacrylate gave a emission quantum yield of 1.3% and 1.6%, which was the largest in luminescent Nd(III) polymers. A research field for telecommunication network using 1.3 mum light would be achieved by luminescent Nd(III) materials encapsulated low-vibrational coordination sites. (C) 2002 Elsevier Science B.V. All rights reserved. - Liquid-phase synthesis of EuS nanocrystals and their physical properties
S Thongchant, Y Hasegawa, Y Wada, S Yanagida
JOURNAL OF PHYSICAL CHEMISTRY B, 107, 10, 2193, 2196, AMER CHEMICAL SOC, 2003年03月
英語, 研究論文(学術雑誌), The first EuS nanocrystals were prepared by the reaction of europium metal and H2S in liquid ammonia. X-ray diffraction (XRD) patterns and TEM images supported the formation of nanoscaled EuS crystals with average size of 20.4 nm. The nanocrystals showed blue shift compared with previously reported EuS films. The Curie point of EuS nanocrystals (16.6 K) was the same as that of the corresponding bulk compound, but a decreasing of magnetic moment was found because of the specific surface condition of the nanocrystals. - Luminescent polymer containing the Eu(III) complex having fast radiation rate and high emission quantum efficiency
Y Hasegawa, M Yamamuro, Y Wada, N Kanehisa, Y Kai, S Yanagida
JOURNAL OF PHYSICAL CHEMISTRY A, 107, 11, 1697, 1702, AMER CHEMICAL SOC, 2003年03月
英語, 研究論文(学術雑誌), Radiation rates and emission quantum yields of Eu(III) were modified using asymmetric deuterated Eu(Ill) complexes doped in poly(methyl methacrylate) (PMMA) deuterated tris-(hexafluoroacetylacetonato)europium-(III) with phospine oxide in order to produce lowthreshold levels for laser transmission and amplifier emissions. Geometric structures of asymmetric Eu(III) complexes were determined by single-crystal X-ray diffraction and Judd-Ofelt analysis. Luminescent polymers were fabricated by incorporating Eu(Ill) complexes in a PMMA matrix. Luminescent PMMA containing Eu(hfa-D)(3)(DPFBPO)(2) exhibited the highest quantum yield and fastest radiation rate (quantum yield = 78 +/- 6%, radiation rate =1.2 x 10(3) s(-1)) of the PMMA matrixes. Emission quantum yields of Eu(hfa-D)(3) (TPPO)(2) in acetone-d(6) were found to be >95%. This radiation rate is of the same order as values reported for Nd:YAG. Prepared luminescent polymers including Eu(hfa-D)(3)-(TPPO-F)(2) showed promising results for applications to novel organic Eu(III) devices, such as organic liquid lasers, plastic lasers, and optical fibers. - EuO Nanocrystal Formation under ArF Laser Irradiation
Hasegawa, Y., Thongchant, S., Kataoka, T., Wada, Y., Yatsuhashi, T., Nakashima, N., Yanagida, S.
Chemistry Letters, 32, 8, 708, 709, 2003年
研究論文(学術雑誌) - Polyphenylsilsesquioxane partially-substituted with germanium: Refractive index controllability and thermal stability
N Yasuda, S Yamamoto, Y Hasegawa, H Nobutoki, Y Wada, S Yanagida
CHEMISTRY LETTERS, 2, 244, 245, CHEMICAL SOC JAPAN, 2002年02月
英語, 研究論文(学術雑誌), The refractive index of a novel silicon-germanium ladder copolymer synthesized by partially substituting silicon in the main chain of polyphenylsilsesquioxane by germanium could be controlled between 1.558 and 1,573 by changing the content of germanium up to 10 mol%, without losing thermal stability over 500degreesC. - Enhanced luminescence and photomagnetic properties of surface-modified EuO nanocrystals
Y Hasegawa, S Thongchant, Y Wada, H Tanaka, T Kawai, T Sakata, H Mori, S Yanagida
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 41, 12, 2073, 2075, WILEY-V C H VERLAG GMBH, 2002年
英語, 研究論文(学術雑誌) - Spectroscopic study on strongly luminescent Nd(III) exchanged zeolite: TMA(+)-containing FAU type zeolite as a suitable host for ship-in-bottle synthesis
M Ryo, Y Wada, T Okubo, T Nakazawa, Y Hasegawa, S Yanagida
JOURNAL OF MATERIALS CHEMISTRY, 12, 6, 1748, 1753, ROYAL SOC CHEMISTRY, 2002年
英語, 研究論文(学術雑誌), Enhanced emission from intrazeolite Nd3+ was investigated by using bis(perfluoromethanesulfonyl)aminate (PMS) as a low vibrational ligand of the ion and TMA(+)-containing FAU zeolite nanocrystallite (TMA-nano-FAU) as a host matrix. Treatments such as deuteration, and thermal treatments at high temperatures were ineffective for the strong emission of Nd3+ within this zeolite. The high-resolution emission and excitation spectra suggested that the environment of Nd3+ in the zeolite was more homogeneous than that in a glass matrix, and intrazeolitic emissive Nd3+ ions consisted of at least two species. The diffuse reflectance spectra revealed that the strong emission was attributed to the PMS ligands that eliminated hydroxy groups from the vicinity of the ion. On the other hand, thermal treatment at high temperatures induced emission of Nd3+-exchanged Na-micro-FAU. Judd-Ofelt analysis revealed that the difference of the emission property between TMA-nano- and Na-micro-FAU zeolites depended on whether the cations migrated to the inner cages or not: in the former case, the ligation of PMS with the Nd3+ ion occurred easily, because the ions remained in the super cages without migrating into inner cages due to the hindrance of TMA(+) occupying in the sodalite cages. In the latter case, the ligation was suppressed because of the Nd3+ ions migrated into the inner cages from the supercages. - Novel synthesis of phase-pure nano-particulate anatase and rutile TiO2 using TiCl4 aqueous solutions
HB Yin, Y Wada, T Kitamura, T Sumida, Y Hasegawa, S Yanagida
JOURNAL OF MATERIALS CHEMISTRY, 12, 2, 378, 383, ROYAL SOC CHEMISTRY, 2002年
英語, 研究論文(学術雑誌), Phase-pure anatase TiO2 nanocrystallites ranging from 2 to 10 nm in size were synthesized directly from a TiCl4 aqueous solution using citric acid as an additive. Citric acid was found to play a decisive role in stabilizing the TiCl4 aqueous solution, leading to the selective formation of the anatase TiO2 nanocrystallites in hydrothermal autoclaving. On the other hand, hydrothermal autoclaving of the rutile TiO2 embryos prepared by room-temperature peptization of the TiCl4 aqueous solution gave rod-like rutile TiO2 nanocrystallites (14-17 x 22-33 nm) under neutral conditions. The presence of KCl or NaCl enhanced the crystal growth of the rutile embryos in the hydrothermal process. - Spindle-type EuO nanocrystals and their magnetic properties
S Thongchant, Y Hasegawa, Y Wada, S Yanagida
CHEMISTRY LETTERS, 12, 1274, 1275, CHEMICAL SOC JAPAN, 2001年12月
英語, 研究論文(学術雑誌), EuO nanocrystals were prepared by liquid phase reaction of europium metal in liquid ammonia for the first time. TEM revealed that the EuO nanocrystals had a spindle shape with mean length of 280 nm (a) by mean width of 95 nm (b). The SQUID measurement showed that the EuO nanocrystals turned into ferromagnetic phase at 70 K and 150 K. - High efficiency near-LR emission of Nd(III) based on low-vibrational environment in cages of nanosized zeolites
Y Wada, T Okubo, M Ryo, T Nakazawa, Y Hasegawa, S Yanagida
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 122, 35, 8583, 8584, AMER CHEMICAL SOC, 2000年09月
英語, 研究論文(学術雑誌) - A new one-pot synthesis of bisperfluoroalkanesulfonylamides and bispentafluorobenzenesulfonylamide as potassium salts
K Sogabe, Y Hasegawa, Y Wada, T Kitamura, S Yanagida
CHEMISTRY LETTERS, 8, 944, 945, CHEMICAL SOC JAPAN, 2000年08月, [査読有り]
英語, 研究論文(学術雑誌), Bisperfluoroalkanesulfonylamides were synthesized as potassium salts by one-pot reaction of perfluoroalkanesulfonyl halides with acctamide derivatives in the presence of K2CO3 in THF. - Remarkable luminescence of novel Nd(III) complexes with low-vibrational hexafluoroacetylacetone and DMSO-d(6) molecules
S Yanagida, Y Hasegawa, Y Wada
JOURNAL OF LUMINESCENCE, 87-9, 995, 998, ELSEVIER SCIENCE BV, 2000年05月
英語, 研究論文(学術雑誌), The structure of the Nd(III) complex with deuterated hexafluoroacetylacetone, Nd(HFA-D)(3)(D2O)(2), in DMSO-d(6) was investigated since the system gave a remarkable luminescence. The emission rate, Judd-Ofelt analysis, EXAFS, NMR and electrospray mass spectra suggested that the system should have the symmetrical bulky shell of six inner coordinating DMSO and three outer coordinating HFA molecules. This conjectured 12-coordinate structure with low-vibration C-D and C-F bondings and bulky shell well rationalized the enhanced emission of the Nd(HFA-D)(3)(D-2 O-2)(2) in DMSO-d(6). The incorporation of the Nd(HFA-D)(3)/DMSO-d(6) system into the methacrylate polymers was successfully attempted. Use of the polymethacrylate with low percentage of C-H bonds, i.e., P-FiPMA (polyhexafluoroisopropylmethacrylate) gave remarkable luminescence of Nd(III) in the organic polymer matrix. (C) 2000 Elsevier Science B.V. All rights reserved. - Preparation of perfluorosulfonylimides from convenient one pot synthesis
K. Sogabe, Y. Hasegawa, Y. Wada, T. Kitamura, S. Yanagida
Chem. Lett., 944, 945, 2000年 - Luminescence of novel neodymium sulfonylaminate complexes in organic media
Y Hasegawa, T Ohkubo, K Sogabe, Y Kawamura, Y Wada, N Nakashima, S Yanagida
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 39, 2, 357, +, WILEY-V C H VERLAG GMBH, 2000年
英語, 研究論文(学術雑誌) - Observation of neodymium electroluminescence
Y Kawamura, Y Wada, Y Hasegawa, M Iwamuro, T Kitamura, S Yanagida
APPLIED PHYSICS LETTERS, 74, 22, 3245, 3247, AMER INST PHYSICS, 1999年05月
英語, 研究論文(学術雑誌), Organic electroluminescence devices using a neodymium(III) complex as an emitting layer were fabricated. The cell structure of glass substrate/indium-tin-oxide/N,N'-diphenyl -N, N'- di(m-tolyl)-benzidine/tris(dibenzoylmethanato)(monobathophenanthroline)neodymium(III) complex/tris(8-quinolinolato)aluminum(III) complex/Mg:Ag was employed. Sharp near-infrared emission bands assigned to f - f transitions of neodymium ion were obtained at dc bias voltage of over 15 V. (C) 1999 American Institute of Physics. [S0003-6951(99)01422-9]. - Enhanced luminescence of lanthanide(III) complexes in polymer matrices
Y Hasegawa, K Sogabe, Y Wada, T Kitamura, N Nakashima, S Yanagida
CHEMISTRY LETTERS, 1, 35, 36, CHEMICAL SOC JAPAN, 1999年
英語, 研究論文(学術雑誌), Effectively luminescent organic polymers were successfully fabricated by incorporating deuterated hexafluoroacetylacetonato Nd(III) or Eu(III) complex and DMSO-d(6) in polyalkylmethacrylate matrices with low percentage of H atoms. - Enhanced emission of Nd3+ in liquid systems: Formation of symmetrical rigid shells of tightly solvated DMSO molecules and weakly coordinated low-vibrational beta-diketonato ligands
Y Hasegawa, M Iwamuro, K Murakoshi, Y Wada, R Arakawa, T Yamanaka, N Nakashima, S Yanagida
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 71, 11, 2573, 2581, CHEMICAL SOC JAPAN, 1998年11月
英語, 研究論文(学術雑誌), Coordination structures of neodymium(III) complexes with some beta-diketones were investigated in terms of their correlations with emission efficiency in deuterated dimethylsulfoxide (DMSO-d(6)). The analysis of UV-vis spectra, C-13 NMR, electrospray mass spectrometry (ES-MS) spectra, XANES and EXAFS analysis of tris(hexafluoroacetylacetonato)neodymium(III) complex, [Nd(hfa-H)(3)(H2O)(2)], and tris[bis(perfluorooctanoyl)methanato]neodymium(III), [Nd(pom-H)(3)], in DMSO indicated that the deuterated tris(hexafluoroacetylacetonato)neodymium(III), Nd(hfa-D)(3), and deuterated tris[bis(perfluorooctanoyl)methanato]neodymium(III) Nd(pom-D)(3), in DMSO-d(6) should have a symmetrical, rigid and bulky shell composed of six inner-coordinating DMSO molecules and three weakly coordinating hfa-D and pom-D molecules. The improvement in the emission efficiency of the neodymium complexes with the low vibrational and weakly coordinating beta-diketonates in DMSO-d(6) was ascribed to their symmetrical rigid coordination structures, which should suppress radiationless transition via vibrational excitation and energy migration in the fluid system. - Luminescence of Nd3+ complexes with some asymmetric ligands in organic solutions
M Iwamuro, Y Hasegawa, Y Wada, K Murakoshi, N Nakashima, T Yamanaka, S Yanagida
JOURNAL OF LUMINESCENCE, 79, 1, 29, 38, ELSEVIER SCIENCE BV, 1998年07月
英語, 研究論文(学術雑誌), A novel Nd3+ complex, Nd(POA-D)(3), with asymmetric ligands (POA: perfluorooctanoylacetic acid), was synthesized in order to enhance the transition probability in its f-f transition by reducing symmetry of the ligand field around Nd3+ This complex gives the 2.5 times higher oscillator strength of the hypersensitive transition in methanol-d(4) than the corresponding symmetrical complex, Nd(POM-D)(3) (POM: bisperfluorooctanoylmethane). The Stark splitting of the emitting level of Nd(POA-D)(3) was observed and the Judd-Ofelt analysis gave a large Ohm(2) value, clearly showing the asymmetric environment around Nd3+. C-13 NMR analysis, molecular orbital and molecular mechanics calculations and EXAFS analysis suggest that the asymmetric environment achieved in Nd(POA-D)(3) is ascribed mainly to the asymmetric distribution of electrons on the coordinating O atoms. The higher absorption coefficient of Nd(POA-D)(3) leads to 1.86 times stronger emission than Nd(POM-D)(3) when measured at the common concentration and conditions. It is stressed that introduction of asymmetric ligands is a promising way for promoting emission of Nd3+ in solutions when coupled with replacement of C-H bonds with C-D and C-F in the ligands. (C) 1998 Elsevier Science B.V. All rights reserved. - Strategies for enhancing photoluminescence of Nd3+ in liquid media
S Yanagida, Y Hasegawa, K Murakoshi, Y Wada, N Nakashima, T Yamanaka
COORDINATION CHEMISTRY REVIEWS, 171, 461, 480, ELSEVIER SCIENCE SA, 1998年04月
英語, 研究論文(学術雑誌), The excited state (F-4(3/2)) of Nd3+ readily undergoes radiationless energy transfer via vibrational excitation of surrounding medium and dipole-dipole energy transfer via cross relaxation and energy migration, which makes it difficult to observe luminescence of Nd3+ in a liquid matrix. In order to suppress such de-excitation of the F-4(3/2) stale, two kinds of beta-diketonato ligands which have no C-H and O-H bonds having high vibrational frequency were successfully designed for observing luminescence of Nd3+ in a liquid matrix. Luminescence of Nd3+ was observed for the first time by using deuteratcd tris-(hexafluoroacetylacetonato) neodymium(III), Nd(HFA-D)(3), in deuterated organic solvents. The luminescence intensity, lifetime and quantum yield of the complex were measured in methanol-d(4), acetone-d(6), THF-d(8), DMF-d(7) and DMSO-d(6). Deuterated tris(bis-(perfluorooactanoyl) methanato)neodymium(III), Nd(POM-D)(3), gave enhanced luminescence in DMSO-d(6) by minimizing energy migration during diffusional collisions in the liquid matrix. The intensity was independent of concentration in the micromolar range from 0.01 to 0.07M. The bulky perfluoroalkyl groups in the ligands effectively prevented de-excitation via vibrational excitation and cross relaxation in liquid media. (C) 1998 Elsevier Science S.A. - Luminescence properties of Nd3+ and Yb3+ complexes in organic solvents for liquid laser medium
J. Kim, N. Nakashima, Y. Hasegawa, Y. Wada, S. Yanagida, T. Yamanaka
Rev. Laser Eng., 26, 691, 1998年 - First observation of photosensitized luminescence of Nd3+ in organic solution
M Iwamuro, Y Hasegawa, Y Wada, E Murakoshi, T Kitamura, N Nakashima, T Yamanaka, S Yanagida
CHEMISTRY LETTERS, 10, 1067, 1068, CHEMICAL SOC JAPAN, 1997年
英語, 研究論文(学術雑誌), Photosensitized luminescence of Nd3+ in solution was successfully observed for the first lime by coordinating the metal cation with deuterated 4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-pentadecafluoro-1-pentafluorophenyl-1,3-decanedione as a ligand with a low vibrational chromophore. - Characteristic emission of beta-diketonato Nd3+ complexes dressed with perfluoroalkyl groups in DMSO-d(6)
Y Hasegawa, K Murakoshi, Y Wada, JH Kim, N Nakashima, T Yamanaka, S Yanagida
CHEMICAL PHYSICS LETTERS, 260, 1-2, 173, 177, ELSEVIER SCIENCE BV, 1996年09月
英語, 研究論文(学術雑誌), Tris(bis(perfluorooctanoyl)methanato)neodyium(III), Nd(POM-D)(3), was successfully synthesized to induce efficient emission in DMSO-d(6). While the emission quantum yield of the tris(hexafluoroacetylacetonato)neodymium(III), Nd(HFA-D)(3), system decreased as the concentration increased, the Nd(POM-D), system gave almost constant quantum yield (3.2%) in DMSO-d(6) ranging in concentration from 0.01 to 0.07 M, The enhanced and characteristic emission of the Nd(POM-D), system suggests that dipole-dipole energy transfer via cross-relaxation through collisions between Nd3+ complex molecules should be suppressed in the fluid system by use of the bulky diketonato complex of Nd3+. - Enhanced emission of deuterated tris(hexafluoroacetylacetonato)neodymium(III) complex in solution by suppression of radiationless transition via vibrational excitation
Y Hasegawa, Y Kimura, K Murakoshi, Y Wada, JH Kim, N Nakashima, T Yamanaka, S Yanagida
JOURNAL OF PHYSICAL CHEMISTRY, 100, 24, 10201, 10205, AMER CHEMICAL SOC, 1996年06月
英語, 研究論文(学術雑誌), The deuterated tris(hexafluoroacetylacetonato)neodymium(III) complex, Nd(HFA-D)(3), was obtained by ketoenol tautomerism reaction of Nd(HFA)3 in methanol-d(4). The emission of Nd(HFA-D)3 was observed in the following anhydrous deuterated organic solvents: methanol-d(4), acetone-d(6), THF-d(8), DMF-d(7), and DMSO-d(6). The intensity and lifetime of the emission in DMSO-d(6) are much superior to those in other deuterated solvents. The specific interaction of DMSO molecules with Nd(HFA)3 was confirmed by C-13 NMR and F-19 NMR analysis. The strong coordination ability of DMSO to Nd3+ ion in Nd(HFA-D)(3) led to the enhanced emission in DMSO owing to the suppression radiationless transition via vibrational excitation of D2O molecules in the vicinity of Nd(HFA-D)(3). - Enhancement of luminescence of Nd3+ complexes with deuterated hexafluoroacetylacetonato ligands in organic solvent
Y Hasegawa, K Murakoshi, Y Wada, S Yanagida, JH Kim, N Nakashima, T Yamanaka
CHEMICAL PHYSICS LETTERS, 248, 1-2, 8, 12, ELSEVIER SCIENCE BV, 1996年01月
英語, 研究論文(学術雑誌), Tris-(hexafluoroacetylacetonato)neodymium [Nd(HFA-D)(3)], was prepared by chelation of Nd3+ ion with deuterated hexafluoroacetylacetone in CD3OD. Luminescence of the Nd3+ complex was observed for the first time in organic solvents and the quantum yield was estimated to be of the order of 10(-2) in deuterated acetone solution. The-absorption spectrum of [Nd(HFA-D)(3)] dissolved in acetone was comparable with that of Nd3+ ion in Y3Al5O15 matrix (Nd:YAG). Splitting of the F-4(3/2) level was determined to be 82.3 cm(-1) in this system. These spectral characteristics suggest that the physical nature of Nd3+ coordination environments should be uniform and well defined by coordination of HFA in solution. - PREPARATION AND PROPERTIES OF (ETA(5)-PENTAMETHYLCYCLOPENTADIENYL) IRON CATIONIC COMPLEXES WITH LONG-CHAIN ALKYL-GROUPS
Y HASEGAWA, T FUJINAMI, S SAKAI
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 66, 10, 3116, 3119, CHEMICAL SOC JAPAN, 1993年10月
英語, Organo- transition metal surfactants, (eta5-pentamethylcyclopentadienyI)iron cationic complexes with long-chain alkyl groups were prepared and their characteristics such as surface tension, redox, and photo-decomposition are discussed. - OPTICAL CHARACTERIZATION OF DEEP LEVELS IN SINGLE-CRYSTALS OF CUGAS2 GROWN BY CHEMICAL VAPOR TRANSPORT
K TANAKA, K ISHII, S MATSUDA, Y HASEGAWA, K SATO
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 28, 1, 12, 15, JAPAN J APPLIED PHYSICS, 1989年01月
英語, 研究論文(学術雑誌) - HEXAAMMINECOBALT(III) HYDROGEN-ION EXCHANGE IN ALPHA-ZIRCONIUM AND THETA-ZIRCONIUM PHOSPHATES WITH VARIOUS PARTICLE-SIZE DISTRIBUTION
Y HASEGAWA, K FUJITA
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, 58, 5, 1535, 1538, CHEMICAL SOC JAPAN, 1985年, [査読有り]
英語, 研究論文(学術雑誌)
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大曲駿, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 応用物理学会春季学術講演会講演予稿集(CD-ROM), 64th, ROMBUNNO.14p‐411‐10, 2017年03月01日
日本語 - 希土類錯体の4f‐5d遷移とLMCT遷移に基づく磁気光学効果の検出
北川裕一, 和田智志, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2017, ROMBUNNO.1B17, 2017年
日本語 - ヘリセンを配位子として導入したユーロピウム錯体の発光特性とその溶媒依存性
大野良輔, 北川裕一, 中西貴之, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 66th, 235, 2016年08月30日
日本語 - 強発光を示すEu‐Polyoxometalateのフォトクロミック挙動
岡井翼, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 29th, ROMBUNNO.2C03, 2016年08月29日
日本語 - 希土類サイトバリエーションを持つSr3Al2O6:Ln(III)結晶の光物性
松井貴文, 中西貴之, 北川裕一, 伏見公志, 樋口幹雄, 長谷川靖哉, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 29th, ROMBUNNO.2PC18, 2016年08月29日
日本語 - 架橋および終端ホスフィンオキシドを含む発光性Eu(III)錯体ポリマー
中島綾子, 北川裕一, 中西貴之, 伏見公志, 長谷川靖哉, 高分子学会予稿集(CD-ROM), 65, 2, ROMBUNNO.2Pf066, 2016年08月24日
日本語 - 剛直な三次元骨格構造を有する耐熱性Eu(III)錯体ポリマー
中島綾子, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 28th, 26‐27, 2016年08月08日
日本語 - Jタイプ励起子相互作用を利用した配位型カルバゾール誘導体のCT性発光
矢地莉勇人, 北川裕一, 中西貴之, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 28th, 120‐121, 2016年08月08日
日本語 - 強発光を示す希土類錯体ポリマーのナノ粒子化と表面保護
長谷川靖哉, 小野寺宏光, 中西貴之, 北川裕一, 伏見公志, 高分子学会予稿集(CD-ROM), 65, 1, ROMBUNNO.3L17, 2016年05月10日
日本語 - アノード酸化チタンの皮膜厚分布に対するUV光照射の影響
金澤友美, 北川裕一, 中西貴之, 長谷川靖哉, 伏見公志, 電気化学会大会講演要旨集(CD-ROM), 83rd, ROMBUNNO.1D12, 2016年03月23日
日本語 - 炭素鋼の動電位分極曲線に対する添加アニオンの影響
西村基, 北川裕一, 中西貴之, 長谷川靖哉, 伏見公志, 電気化学会大会講演要旨集(CD-ROM), 83rd, ROMBUNNO.1D04, 2016年03月23日
日本語 - ユーロピウム錯体ポリマーを用いた有機発光ダイオードの作製
福留淳, 高田誠, 菅原猛司, 名取詩織, 長谷川靖哉, 永瀬隆, 永瀬隆, 小林隆史, 小林隆史, 内藤裕義, 内藤裕義, 応用物理学会秋季学術講演会講演予稿集(CD-ROM), 77th, 2016年 - 優れた耐熱性を有する希土類錯体ポリマーの合成とその応用
中島綾子, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 化学系学協会北海道支部冬季研究発表会講演要旨集(CD-ROM), 2016, ROMBUNNO.1C07, 2016年
日本語 - 酸性溶液中の鉄の腐食抑制反応における電極の幾何学の影響
西村基, 北川裕一, 中西貴之, 長谷川靖哉, 伏見公志, 材料と環境討論会講演集, 62nd, 463, 464, 2015年10月20日
日本語 - 不働態鉄表面のSECM観察用レドックスメディエータの検討と適用
後藤優明, 北川裕一, 中西貴之, 長谷川靖哉, 伏見公志, 材料と環境討論会講演集, 62nd, 457, 458, 2015年10月20日
日本語 - 多結晶純鉄上に形成した熱酸化皮膜の光学的および電気化学的解析
高畠勇, 北川裕一, 中西貴之, 長谷川靖哉, 伏見公志, 材料と環境討論会講演集, 62nd, 345, 346, 2015年10月20日
日本語 - EuS‐CaS全率固溶体ナノ結晶における磁気光学物性の検討
中西貴之, 中島綾子, 北川裕一, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2015, CD-ROM, ROMBUNNO.3P091, 2015年09月08日
日本語 - 希土類錯体の配位子に依存した磁気円偏光二色性強度
北川裕一, 和田智志, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2015, CD-ROM, ROMBUNNO.3C13, 2015年09月08日
日本語 - 四座型カルバゾールユニットを含むユウロピウム(III)配位ポリマーの合成と発光特性評価
名取詩織, 北川裕一, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2015, CD-ROM, ROMBUNNO.1P102, 2015年09月08日
日本語 - 有機配位子を含むEu(III)ポリオキソメタレートのフォトクロミック効果と発光特性
岡井翼, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2015, CD-ROM, ROMBUNNO.3P071, 2015年09月08日
日本語 - フッ化テルビウムナノ結晶の合成と光磁気特性
川島祥, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 28th, ROMBUNNO.2PN05, 2015年09月01日
日本語 - EuをドープしたCaSナノ結晶の発光および磁気光学特性
中島綾子, 中西貴之, 川島祥, 北川裕一, 伏見公志, 長谷川靖哉, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 28th, ROMBUNNO.2PN04, 2015年09月01日
日本語 - 高温領域で発光を示すEu(III)錯体ポリマー
中島綾子, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 27th, 130, 131, 2015年08月07日
日本語 - β‐ジケトナトを含むEu(III)ポリオキソメタレートのフォトクロミック挙動と光物性
岡井翼, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 27th, 104, 105, 2015年08月07日
日本語 - 発光性Eu(III)錯体におけるπ共役系を拡張した配位子の新規設計指針・合成とその光物性
大野良輔, 北川裕一, 中西貴之, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 27th, 134, 135, 2015年08月07日
日本語 - 流速正弦波制御を用いた鋼板中の水素拡散係数の測定
山本悠大, 神実紗子, 伏見公志, 中西貴之, 北川裕一, 長谷川靖哉, 材料と環境講演集, 2015, 273, 274, 2015年04月30日
日本語 - 酸性硫酸ナトリウム水溶液中の鉄不働態化挙動の電極サイズ依存性
西村基, 伏見公志, 中西貴之, 長谷川靖哉, 小寺史浩, 材料と環境講演集, 2015, 235, 236, 2015年04月30日
日本語 - 二種類の配位サイトで構成されるEu(III)錯体ポリマーの合成と発光特性
中島綾子, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 日本化学会講演予稿集, 95th, 2, 352, 2015年03月11日
日本語 - タングステン酸を骨格とするEu(III)クラスターの光増感発光
岡井翼, 中西貴之, 北川裕一, 伏見公志, 長谷川靖哉, 日本化学会講演予稿集, 95th, 2, 352, 2015年03月11日
日本語 - 赤外発光を示すアントラセン金(I)イソシアニド錯体の光学特性と結晶構造
戸子台遥光, 関朋宏, 大曲駿, 中西貴之, 長谷川靖哉, 伊藤肇, 日本化学会講演予稿集, 95th, 3, 643, 2015年03月11日
日本語 - 小規模微小電極アレイ上に形成される拡散層の数値計算
山本悠大, 伏見公志, 中西貴之, 北川裕一, 長谷川靖哉, 電気化学会大会講演要旨集(CD-ROM), 82nd, ROMBUNNO.1P10, 2015年03月09日
日本語 - 不働態鉄表面のSECM観察用レドックスメディエータの検討
後藤優明, 伏見公志, 北川裕一, 中西貴之, 長谷川靖哉, 電気化学会大会講演要旨集(CD-ROM), 82nd, ROMBUNNO.3P11, 2015年03月09日
日本語 - 多結晶純鉄上に形成した熱酸化皮膜の不均一性
高畠勇, 伏見公志, 北川裕一, 中西貴之, 長谷川靖哉, 電気化学会大会講演要旨集(CD-ROM), 82nd, ROMBUNNO.3P12, 2015年03月09日
日本語 - Auプラズモン電場増強効果によるEuSナノ結晶の光磁気特性変化
川島祥, 中西貴之, 藤田晃司, 田中勝久, 伏見公志, 長谷川靖哉, 日本セラミックス協会年会講演予稿集(CD-ROM), 2015, ROMBUNNO.1P085, 2015年03月06日
日本語 - 微小電気化学法を用いた炭素鋼板へ侵入・透過する水素の局部測定
神実紗子, 伏見公志, 山本悠大, 北川裕一, 中西貴之, 長谷川靖哉, 材料と環境討論会講演集, 61st, 411, 412, 2014年11月12日
日本語 - 私の自慢 希土類光化学の研究進化 : 様々な環境で研究を続ける
長谷川 靖哉, 化学と工業 = Chemistry & chemical industry, 67, 11, 993, 995, 2014年11月
日本化学会, 日本語 - 分極性の異なるホスフィンオキシド単座配位子を用いたEu(III)錯体の光物性検討
中西貴之, 大久保智樹, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 64th, 141, 2014年09月01日
日本語 - 位置異性配位子を有する発光性Eu(III)錯体の形態制御
平井悠一, 中西貴之, 関朋宏, 伊藤肇, 佐藤敏文, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 64th, 20, 2014年09月01日
日本語 - Tb‐Ybを含む九核希土類クラスターにおける近赤外発光
中西貴之, 鈴木勇喜, 伏見公志, 長谷川靖哉, 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 27th, ROMBUNNO.2PN12, 2014年08月25日
日本語 - テルビウムとガドリニウムで構成された九核ランタニドクラスターの発光メカニズム
大曲駿, 中西貴之, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 26th, 120, 121, 2014年08月06日
日本語 - キラル配位子を導入した九核Tb(III)クラスターの光物性とファラデー効果特性
和田智志, 中西貴之, 北川裕一, 森崎泰弘, 藤田晃司, 田中勝久, 中條善樹, 小西克明, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 26th, 102, 103, 2014年08月06日
日本語 - 金属錯体で架橋したEu(III)配位高分子の合成と光物性
山本昌紀, 中西貴之, 関朋宏, 伊藤肇, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 26th, 134, 135, 2014年08月06日
日本語 - 鋼板水素透過現象に対する水素発生面の物質輸送が及ぼす影響
神実紗子, 伏見公志, 中西貴之, 長谷川靖哉, 河野崇史, 木村光男, 材料と環境講演集, 2014, 371, 372, 2014年04月30日
日本語 - 紫外線照射したアノード酸化チタン表面の偏光反射顕微鏡観察
伏見公志, 倉内和則, 中西貴之, 長谷川靖哉, 上田幹人, 大塚俊明, 電気化学会大会講演要旨集, 81st, 139, 2014年03月29日
日本語 - キラル配位子を導入した九核Tb(III)クラスターの合成と光物性
和田智志, 中西貴之, 関朋宏, 伊藤肇, 小西克明, 伏見公志, 長谷川靖哉, 日本化学会講演予稿集, 94th, 2, 422, 2014年03月12日
日本語 - 平面四配位型Pd(II)錯体で架橋されたEu(III)配位高分子の合成と光物性
山本昌紀, 中西貴之, 関朋宏, 伊藤肇, 伏見公志, 長谷川靖哉, 日本化学会講演予稿集, 94th, 2, 420, 2014年03月12日
日本語 - 二相炭素鋼表面上に形成する不働態皮膜の不均一性
柳澤慧, 伏見公志, 中西貴之, 長谷川靖哉, 河野崇史, 木村光男, 表面技術協会講演大会講演要旨集, 129th, 61, 2014年03月03日
日本語 - 多チャンネル微小電極アレイの作製とその電極特性評価
山本悠大, 伏見公志, 中西貴之, 長谷川靖哉, 齋藤美紀子, 本間敬之, 表面技術協会講演大会講演要旨集, 129th, 210, 2014年03月03日
日本語 - メタロセン含有Eu(III)錯体の発光特性
佐藤奈緒, 伏見公志, 中西貴之, 長谷川靖哉, 化学系学協会北海道支部冬季研究発表会講演要旨集(CD-ROM), 2014, ROMBUNNO.1A08, 2014年01月28日
日本語 - 九核Tb(III)クラスターの合成と光磁気特性
鈴木勇喜, 土井貴弘, 日夏幸雄, 関朋宏, 伊藤肇, 小泉均, 中西貴之, 伏見公志, 長谷川靖哉, 化学系学協会北海道支部冬季研究発表会講演要旨集(CD-ROM), 2014, ROMBUNNO.1A09, 2014年01月28日
日本語 - 近赤外波長領域での吸収発光特性を示すポルフィリン積層π電子系の構築
星野佑紀, 清水正毅, 黒田裕久, 森末光彦, 松井淳, 中西貴之, 長谷川靖哉, 上村忍, 干場次朗, 佐々木園, 櫻井伸一, 光化学討論会要旨集(CD-ROM), 2014, 2014年 - 化学還元によるCu/Pdナノクラスターの合成と蛍光特性
千葉仁嗣, 中西貴之, 長谷川靖哉, NGUYEN Thanh Mai, 石田洋平, 米澤徹, 光化学討論会要旨集(CD-ROM), 2014, 2014年 - Eu(II):CaSナノ結晶の合成とその光機能評価
中西貴之, 渡邊和音, 川島祥, 伏見公志, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2014, ROMBUNNO.3P090, 2014年
日本語 - 自己集積型Eu(III)錯体の構造制御と光物性
平井悠一, 中西貴之, 関朋宏, 伊藤肇, 伏見公志, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2014, ROMBUNNO.1B10, 2014年
日本語 - 酸化テルビウムナノ結晶の合成と光磁気特性
川島祥, 中西貴之, 伏見公志, O’BRIEN Paul, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2014, ROMBUNNO.3P084, 2014年
日本語 - スタッキングにより高次集積化されたユウロピウム(III)配位ポリマーの特異な発光特性
立野栞, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2014, ROMBUNNO.3P082, 2014年
日本語 - 金属錯体で架橋されたEu(III)錯体ポリマーの光物性
山本昌紀, 中西貴之, 関朋宏, 伊藤肇, 伏見公志, 長谷川靖哉, 光化学討論会要旨集(CD-ROM), 2014, ROMBUNNO.3P091, 2014年
日本語 - ジチオカルバメイト錯体を用いた赤色蛍光体CaSナノ結晶の合成
渡邊和音, 川島祥, 中西貴之, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 63rd, 265, 2013年10月15日
日本語 - 集積型ユーロピウム(III)錯体から構成される結晶の相転移挙動と発光特性
立野栞, 中西貴之, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 63rd, 311, 2013年10月15日
日本語 - Eu(III)配位複合体の組織構造と発光特性
平井悠一, 中西貴之, 関朋宏, 伊藤肇, 佐藤敏文, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 63rd, 292, 2013年10月15日
日本語 - 九核Tb(III)クラスターの構造と光磁気機能の解明
鈴木勇喜, 土井貴弘, 日夏幸雄, 関朋宏, 伊藤肇, 小泉均, 中西貴之, 伏見公志, 長谷川靖哉, 錯体化学会討論会講演要旨集, 63rd, 138, 2013年10月15日
日本語 - Tb(III)とYb(III)を含む九核クラスターにおけるエネルギー移動と近赤外発光
中西貴之, 鈴木勇喜, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2013, 73, 2013年09月07日
日本語 - 二次元配位子を有するユーロピウム(III)配位ポリマーの光物性とトリボルミネッセンス
立野栞, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2013, 123, 2013年09月07日
日本語 - プラズモン電場増強下におけるEuS‐Auナノ複合体の光磁気特性変化
川島祥, 中西貴之, 藤田晃司, 田中勝久, 小泉均, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2013, 58, 2013年09月07日
日本語 - 光磁気特性を示す九核Tb(III)クラスターのスピン構造解析
鈴木勇喜, 土井貴弘, 日夏幸雄, 関朋宏, 伊藤肇, 小泉均, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2013, 187, 2013年09月07日
日本語 - 炭素鋼板上で発生した水素侵入分布の微小電極を用いた測定
神実紗子, 伏見公志, 中西貴之, 長谷川靖哉, 河野崇史, 木村光男, 電気化学会大会講演要旨集, 80th, 367, 2013年03月29日
日本語 - ケイ素およびゲルマニウム架橋ビピリジルの発光特性の評価
村上和也, 大下浄治, 水雲智信, 中西貴之, 長谷川靖哉, 小林憲史, 東村秀之, 日本化学会中国四国支部大会講演要旨集, 2013, 2013年 - 超分子型Eu(III)錯体の発光特性とアモルファス特性
平井悠一, 中西貴之, 佐藤敏文, 覚知豊次, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 25th, 104, 105, 2013年
日本語 - 九核テルビウム(III)クラスターの磁気光学特性
中西貴之, 鈴木勇喜, 関朋宏, 土井貴弘, 伏見公志, 日夏幸雄, 伊藤肇, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 25th, 54, 55, 2013年
日本語 - Eu2+:SrAl2O4ガラスハイブリッド合成と発光スペクトル時間変化挙動
渡部和音, 中西貴之, 上田純平, 伏見公志, 田部勢津久, 長谷川靖哉, ガラスおよびフォトニクス材料討論会講演要旨集, 53rd, 96-97, 2012年10月25日
日本語 - 偏光反射イメージングによる不働態チタン表面のin‐situ観察
倉内和則, 伏見公志, 中西貴之, 長谷川靖哉, 大塚俊明, 材料と環境討論会講演集, 59th, 215-216, 2012年09月10日
日本語 - 九核Tb(III)クラスターの合成および磁気光学特性
鈴木勇喜, 土井貴弘, 日夏幸雄, 伊藤肇, 中西貴之, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2012, 184, 2012年09月07日
日本語 - 外部環境に応答したキラル希土類錯体の円偏光発光特性の変化
上野紘史, 湯浅順平, 長谷川靖哉, 河合壯, 配位化合物の光化学討論会講演要旨集, 24th, 107-108, 2012年08月06日
日本語 - 3次元ネットワーク構造を有する希土類配位高分子の発光特性評価
宮田康平, 中西貴之, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 24th, 81-82, 2012年08月06日
日本語 - 残光性SrAl_2O_4含有透明ガラスコンポジットの作製と光学特性
中西 貴之, 渡邉 和音, 伏見 公志, 長谷川 靖哉, 希土類 = Rare earths, 0, 60, 140, 141, 2012年05月08日
日本語 - 金プラズモンによるEuSナノ結晶の光磁気特性変化
川島 祥, 宮田 康平, 中西 貴之, 伏見 公志, 長谷川 靖哉, 希土類 = Rare earths, 0, 60, 154, 155, 2012年05月08日
日本語 - 低分極性配位子を有するEu(III)錯体の強発光
大久保 智樹, 中西 貴之, 伏見 公志, 長谷川 靖哉, 希土類 = Rare earths, 0, 60, 168, 169, 2012年05月08日
日本語 - 微小キャピラリセルを用いた純鉄の0.05M硫酸中における動電位アノード分極
高畠勇, 伏見公志, 中西貴之, 長谷川靖哉, 電気化学会大会講演要旨集, 79th, 206, 2012年03月29日
日本語 - 残光性SrAl2O4結晶含有透明ガラスコンポジットの作製と光学特性評価
渡邊和音, 中西貴之, 伏見公志, 長谷川靖哉, 日本セラミックス協会年会講演予稿集, 2012, 92, 2012年03月19日
日本語 - Tb(III)クラスターの合成と光磁気特性評価
鈴木勇喜, 土井貴弘, 日夏幸雄, 伊藤肇, 中西貴之, 伏見公志, 長谷川靖哉, 日本化学会講演予稿集, 92nd, 2, 470, 2012年03月09日
日本語 - 遷移金属イオンドープしたEuSナノ結晶の磁気光学特性
前田将司, 中西貴之, 土井貴弘, 日夏幸雄, 伏見公志, 長谷川靖哉, 化学系学協会北海道支部冬季研究発表会講演要旨集, 2012, 37, 2012年01月31日
日本語 - 分子間相互作用を有する希土類配位高分子の発光特性
宮田康平, 大場惟史, 小林厚志, 加藤昌子, 中西貴之, 伏見公志, 長谷川靖哉, 化学系学協会北海道支部冬季研究発表会講演要旨集, 2012, 36, 2012年01月31日
日本語 - Secm observation of polycrystalline iron corroding in sulphuric acid solution
K. Fushimi, K. Matsushita, H. Tachikawa, Y. Hasegawa, 18th International Corrosion Congress 2011, 2, 1223, 1230, 2011年12月01日
In order to investigate the non-uniform corrosion behaviour of polycrystalline pure iron in sulphuric acid, SECM of multi grains and a dynamic polarization test of single grains were carried out. SECM successfully visualized the difference in dissolution activity between 0 0 1 and 3 2 5 grains. The corrosion potential and corrosion current of the single grain were found to be dependent on the orientation. The grain showing a noble corrosion potential allowed a high corrosion current to flow. The sequence of corrosion activity of the lower Miller indices grains was in the order of 1 0 1 < 1 1 1 < 0 0 1, although both cathodic and anodic Tafel slopes were independent of the crystallographic orientation. The results indicated that hydrogen evolution reaction (HER) coupling with iron dissolution reaction governed the corrosion reaction on iron grains. A grain on which HER is more active than that on others, such as a 0 0 1 grain, plays an important role as cathodic parts for the heterogeneous corrosion of polycrystalline iron at corrosion potential. The dependence of relaxed surface on orientation is discussed from the viewpoint of HER activity using the results of ab initio calculation. - ホスフィンオキシドで架橋された希土類配位高分子の構造と発光特性
宮田康平, 大場惟史, 小林厚志, 加藤昌子, 伏見公志, 長谷川靖哉, 光化学討論会講演要旨集, 2011, 39, 2011年09月01日
日本語 - 分極性の異なった単座型ホスフィンオキシド配位子を有するEu(III)錯体の光物性評価
大久保智樹, 岸本眞一郎, 宮田康平, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 23rd, 82, 83, 2011年08月04日
日本語 - 様々な有機溶媒中における8配位型Eu(III)錯体の発光特性評価
宮田康平, 中西貴之, 伏見公志, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 23rd, 38, 39, 2011年08月04日
日本語 - 9配位構造を有するキラルEu(III)錯体の円偏光発光特性の評価
原田聖, 妻鳥紘之, 西山桂, 湯浅順平, 長谷川靖哉, 河合壯, 配位化合物の光化学討論会講演要旨集, 23rd, 120, 121, 2011年08月04日
日本語 - 遷移金属イオンを含むEuSナノ結晶の合成と機能評価
前田将司, 宮田康平, 中西貴之, 伏見公志, 長谷川靖哉, 日本化学会北海道支部夏季研究発表会講演要旨集, 2011, 77, 2011年07月01日
日本語 - ジチオールで結合したEuS/Auナノ結晶複合体の光磁気特性
川島祥, 宮田康平, 中西貴之, 伏見公志, 長谷川靖哉, 日本化学会北海道支部夏季研究発表会講演要旨集, 2011, 76, 2011年07月01日
日本語 - キラル希土類錯体の光学キラリティー
原田聖, 妻鳥紘之, 湯浅順平, 長谷川靖哉, 河合壯, シンポジウム「モレキュラー・キラリティー」講演要旨集, 2011, (JA)66,(EN)65, 2011年05月20日
日本語 - 架橋型ホスフィンオキシド配位子を有する希土類配位高分子の合成と発光特性
宮田 康平, 大場 惟史, 小林 厚志, 加藤 昌子, 伏見 公志, 長谷川 靖哉, 希土類 = Rare earths, 0, 58, 102, 103, 2011年05月05日
日本語 - pH2.3の硫酸ナトリウム水溶液中の多結晶鉄の不均一腐食挙動
伏見公志, 松下兼一郎, 長谷川靖哉, 電気化学会大会講演要旨集, 78th(CD-ROM), ROMBUNNO.1H21, 2011年03月29日
日本語 - キラルな9配位Eu(III)錯体の配位構造に依存した円偏光発光特性
原田聖, 妻鳥紘之, 湯浅順平, 長谷川靖哉, 河合壯, 日本化学会講演予稿集, 91st, 2, 248, 2011年03月11日
日本語 - キラルEu(III)錯体単結晶の結晶構造と円偏光発光計測
妻鳥紘之, 原田聖, 湯浅順平, 長谷川靖哉, 河合壯, 応用物理学関係連合講演会講演予稿集(CD-ROM), 58th, ROMBUNNO.26P-BK-9, 2011年03月09日
日本語 - 磁性半導体EuXナノ結晶の合成と光磁気機能(<特集>ナノ結晶の成長と新機能)
長谷川 靖哉, 河合 壯, 日本結晶成長学会誌, 37, 4, 273, 280, 2011年01月
磁性半導体EuX(ユーロピウムカルコゲナイド:EuO,EuSなど)ナノ結晶は伝導帯と荷電子帯の間に縮退した4f軌道を有する.この4f軌道から伝導帯への許容遷移は特徴的な光磁気特性を誘起することから,新しい光磁気材料として興味深い.ここでは,この特徴的な磁性半導体EuXナノ結晶の合成および光磁気特性について紹介する.さらに,レーザートラッピング法および自己組織化法を用いたEuXの会合体形成および配列について解説する.EuXナノ結晶は新規な光アイソレーターや光磁気デバイスへの応用が期待される., 日本結晶成長学会, 日本語 - キラルEu(III)錯体の配位構造の対称性に依存した円偏光発光特性
原田聖, 妻鳥紘之, 湯浅順平, 河合壯, 長谷川靖哉, 光化学討論会講演要旨集, 2010, 151, 2010年09月08日
日本語 - キラルなビスオキサゾリンピリジン配位子を有するユーロピウム錯体の円偏光発光
湯浅順平, 大野智子, 宮田康平, 妻鳥紘之, 原田聖, 長谷川靖哉, 河合壯, 日本化学会講演予稿集, 90th, 2, 190, 2010年03月12日
日本語 - 非対称型リン酸三座配位子を有するEu(III)錯体の合成と発光特性
宮田 康平, 長谷川 靖哉, 河合 壯, 希土類 = Rare earths, 0, 54, 74, 75, 2009年05月21日
日本語 - スルフォン置換基を有するフォトクロミックEu(III)錯体の合成と発光特性
中川 哲也, 長谷川 靖哉, 河合 壯, 希土類 = Rare earths, 0, 54, 76, 77, 2009年05月21日
日本語 - 発光素子への展開を目指した強発光希土類錯体の創製
中村一希, 長谷川靖哉, 小林範久, 日本写真学会秋季研究報告会講演要旨集, 2009, 2009年 - 新しい機能材料創成を目指したフォトクロミック希土類錯体の開発 (特集 材料機能の多様化と新展開)
長谷川 靖哉, 中川 哲也, 河合 壯, 化学工業, 59, 11, 879, 883,892, 2008年11月
化学工業社, 日本語 - キラルなβ‐diketonato配位子を有するEu(III)錯体の配位構造による円偏光発光特性制御
原田聖, 河合壯, 中野陽子, 藤木道也, 内藤昌信, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 21st, 28, 29, 2008年08月05日
日本語 - 配位構造制御によるキラルEu(III)錯体の円偏光発光特性制御
原田聖, 河合壯, 中野陽子, 藤木道也, 内藤昌信, 長谷川靖哉, 日本化学会講演予稿集, 88th, 1, 289, 2008年03月12日
日本語 - 新規Sm(III)錯体の深赤色発光特性
川井 秀記, 趙 晨, 鶴岡 真一, 吉田 孝彦, 長谷川 靖哉, 河合 壯, 電気学会研究会資料. EDD, 電子デバイス研究会, 2008, 1, 77, 80, 2008年01月24日
種々の新規なサマリウム錯体を合成し、その赤色発光特性について検討を行った。配位子を配位することにより、長波長域の644nmの発光が著しく増加した。磁気双極子遷移(598nm)に対する電気双極子遷移(644nm)の発光強度比は、ビピリジン(bpy),フェナントロリン(phen)を配位させたものに比べて、トリフェニルホスフィンオキシド(TPPO)を配位させたものが高い値を示した。このような発光特性は、新規Sm錯体の配位数と非対称的な構造によるものと考えられる。このSm錯体の深赤色発光は、白色発光ダイオードの演色性を高める有力な材料となり得る。, 一般社団法人電子情報通信学会, 日本語 - 新規Sm(III)錯体の深赤色発光特性(ディスプレイに関する技術全般,LCD(バックライトを含む),PDP,有機/無機EL,CRT,FED,VFD,LEDなどのディスプレイに関するデバイス,部品・材料及び応用技術,発光型/非発光型ディスプレイ合同研究会)
川井 秀記, 趙 晨, 鶴岡 真一, 吉田 孝彦, 長谷川 靖哉, 河合 壯, 電子情報通信学会技術研究報告. EID, 電子ディスプレイ, 107, 453, 77, 80, 2008年01月17日
種々の新規なサマリウム錯体を合成し、その赤色発光特性について検討を行った。配位子を配位することにより、長波長域の644nmの発光が著しく増加した。磁気双極子遷移(598nm)に対する電気双極子遷移(644nm)の発光強度比は、ビピリジン(bpy),フェナントロリン(phen)を配位させたものに比べて、トリフェニルホスフィンオキシド(TPPO)を配位させたものが高い値を示した。このような発光特性は、新規Sm錯体の配位数と非対称的な構造によるものと考えられる。このSm錯体の深赤色発光は、白色発光ダイオードの演色性を高める有力な材料となり得る。, 一般社団法人電子情報通信学会, 日本語 - 「第20回配位化合物の光化学討論会」および「配位化合物の光化学20周年記念講演会」報告
末延 知義, 長谷川 靖哉, 光化学 = Photochemistry, 38, 3, 215, 215, 2008年01月15日
日本語 - 点不斉及び軸不斉配位子を組み合わせたEu(III)錯体の円偏光発光特性
原田聖, 河合壯, 中野陽子, 藤木道也, 内藤昌信, 長谷川靖哉, 光化学討論会講演要旨集, 2007, 134, 2007年09月21日
日本語 - C-13-3 新規サマリウム錯体を用いた有機EL素子の特性(C-13.有機エレクトロニクス,一般講演)
梶井 博武, 金 全健, 長谷川 靖哉, 河合 壮, 大森 裕, 電子情報通信学会ソサイエティ大会講演論文集, 2007, 2, 103, 103, 2007年08月29日
一般社団法人電子情報通信学会, 日本語 - 不斉配位子を有する非対称型Eu(III)錯体の円偏光発光特性
原田聖, 河合壯, 中野陽子, 藤木道也, 内藤昌信, 長谷川靖哉, 配位化合物の光化学討論会講演要旨集, 20th, 137, 138, 2007年08月07日
日本語 - 9配位構造を有する非対称型サマリウム錯体の深赤色発光
長谷川 靖哉, 鶴岡 真一, 吉田 孝彦, 川井 秀記, 河合 壯, 希土類 = Rare earths, 0, 50, 90, 91, 2007年05月10日
日本語 - Eu錯体の熱還元反応によるEuSeナノ粒子合成とその光磁気特性
長谷川 靖哉, 安達 隆明, AFZAAL Mohammad, O'BRIEN Paul, 和田 雄二, 河合 壯, 希土類 = Rare earths, 0, 48, 70, 71, 2006年05月23日
日本語 - 強発光希土類錯体の創成と発光素子への応用
川井 秀記, 中村 一希, 長谷川 靖哉, 保田 直紀, 和田 雄二, 柳田 祥三, 映像情報メディア学会技術報告, 30, 18, 19, 22, 2006年03月07日
映像情報メディア学会, 日本語 - 強発光希土類錯体の創成と発光素子への応用(表示記録用有機材料及びデバイス・一般)
川井 秀記, 中村 一希, 長谷川 靖哉, 保田 直紀, 和田 雄二, 柳田 祥三, 電子情報通信学会技術研究報告. OME, 有機エレクトロニクス, 105, 642, 19, 22, 2006年02月28日
配位子にホスフィンオキサイドを有する新規Eu(III)錯体を合成し、レーザー発振媒体としての評価・検討を行った。X線結晶構造解析により、Eu(III)錯体は、反転中心を持たない非対称構造を取っていることが示された。この非対称構造により生じる発光のスペクトルの半値幅は、2.1nmほどの非常に狭いものとなり、誘導放出断面積の値は、1.80×10^<-20>cm^<-2>と大きいものとなった。Eu(III)錯体を含んだポリマー薄膜を、パルスレーザー励起を行ったところ、基板端面からの発光は一次の指数関数に従い減衰した(τ=650μs)が、励起光強度を増加していくと、短い寿命成分(τ=83μs)が生じ、その割合が増加していた。この短い寿命成分は、増幅自然放出光によるものであり、しきい値は0.05mJ以下であった。, 一般社団法人電子情報通信学会, 日本語 - 強発光希土類錯体の創成と発光素子への応用(表示記録用有機材料及びデバイス・一般)
川井 秀記, 中村 一希, 長谷川 靖哉, 保田 直紀, 和田 雄二, 柳田 祥三, 電子情報通信学会技術研究報告. EID, 電子ディスプレイ, 105, 641, 19, 22, 2006年02月28日
配位子にホスフィンオキサイドを有する新規Eu(III)錯体を合成し、レーザー発振媒体としての評価・検討を行った。X線結晶構造解析により、Eu(III)錯体は、反転中心を持たない非対称構造を取っていることが示された。この非対称構造により生じる発光のスペクトルの半値幅は、2.1nmほどの非常に狭いものとなり、誘導放出断面積の値は、1.80×10^<-20>cm^<-2>と大きいものとなった。Eu(III)錯体を含んだポリマー薄膜を、パルスレーザー励起を行ったところ、基板端面からの発光は一次の指数関数に従い減衰した(τ=650μs)が、励起光強度を増加していくと、短い寿命成分(τ=83μs)が生じ、その割合が増加していた。この短い寿命成分は、増幅自然放出光によるものであり、しきい値は0.05mJ以下であった。, 一般社団法人電子情報通信学会, 日本語 - 強発光性Eu(III)錯体における吸収断面積が増幅自然放出光に及ぼす影響
中村一希, 長谷川靖哉, 川井秀記, 保田直紀, 塚原保徳, 和田雄二, 光化学討論会講演要旨集, 2006, 2006年 - 強発光性ユーロピウム(III)錯体における吸収断面積増加による増幅自然放出光の増大
中村一希, 長谷川靖哉, 川井秀記, 保田直紀, 塚原保徳, 和田雄二, 日本化学会講演予稿集, 86th, 1, 2006年 - Eu(III)錯体の光還元反応を用いたEuSナノ結晶合成
長谷川 靖哉, AFZAAL Mohammad, O'BRIEN Paul, 和田 雄二, 希土類 = Rare earths, 46, 0, 16, 17, 2005年05月18日
日本語 - マイクロ波加熱を用いたEuSナノ結晶合成
岡田 佳子, 中村 孝志, 片岡 朋治, 塚原 保徳, 長谷川 靖哉, 和田 雄二, 希土類 = Rare earths, 46, 0, 14, 15, 2005年05月18日
日本語 - EuSナノ粒子における新しい光磁気効果定数の提案
塚原 保徳, 片岡 朋治, 長谷川 靖哉, 和田 雄二, 希土類 = Rare earths, 46, 0, 18, 19, 2005年05月18日
日本語 - 構造制御された強発光Eu(III)錯体の光物性と増幅自然放出光の相関
中村 一希, 長谷川 靖哉, 川井 秀記, 保田 直紀, 和田 雄二, 希土類 = Rare earths, 46, 0, 102, 103, 2005年05月18日
日本語 - ゼオライト細孔内における非配位性分子からのエネルギー移動を経たTb(III)増感発光
佐藤 睦子, 塚原 保徳, 長谷川 靖哉, 和田 雄二, 希土類 = Rare earths, 46, 0, 104, 105, 2005年05月18日
日本語 - サリチル酸エステル配位子によって構成される九核Tb(III)錯体の合成および光増感発光
萬関 一広, 長谷川 靖哉, 和田 雄二, 希土類 = Rare earths, 46, 0, 106, 107, 2005年05月18日
日本語 - ナノサイズEuO/EuSを用いた光機能デバイス向けプラスチックの開発 (特集 近未来のプラスチック技術を探る--材料開発から廃プラ対策まで)
長谷川 靖哉, 工業材料, 53, 4, 76, 79, 2005年04月
日刊工業新聞社, 日本語 - Eu(III)錯体の光物性制御が増幅自然放出光に及ぼす影響
中村一希, 長谷川靖哉, 川井秀記, 保田直紀, 和田雄二, 光化学討論会講演要旨集, 2005, 2005年 - 強発光性ユウロピウム錯体の分子構造による増幅自然放出光の制御
中村一希, 長谷川靖哉, 川井秀記, 保田直紀, 柳田祥三, 和田雄二, 日本化学会講演予稿集, 85th, 1, 2005年 - 液体アンモニアを用いた量子サイズEuSナノ粒子の合成
片岡 朋治, トンチャン スピッチャー, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 44, 0, 78, 79, 2004年05月13日
日本語 - EuSナノ結晶粒子を含むポリマーのファラデー効果
長谷川 靖哉, トンチャン スピッチャー, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 44, 0, 80, 81, 2004年05月13日
日本語 - 先鋭化した発光スペクトルを示すEu(III)錯体のレーザー発振特性
中村 一希, 長谷川 靖哉, 川井 秀記, 保田 直紀, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 44, 0, 110, 111, 2004年05月13日
日本語 - 熱耐久性を有するEu(III)多核錯体の発光特性
萬関 一広, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 44, 0, 112, 113, 2004年05月13日
日本語 - ゼオライトを利用したアンテナ効果によるネオジム(III)増感発光
佐藤 睦子, 梁 宗範, 和田 雄二, 長谷川 靖哉, 柳田 祥三, 希土類 = Rare earths, 44, 0, 142, 143, 2004年05月13日
日本語 - フォージャサイト型ナノゼオライト細孔内ネオジムカチオンサイトと近赤外発光制御
和田 雄二, 梁 宗範, 大久保 達也, 長谷川 靖哉, 柳田 祥三, 希土類 = Rare earths, 44, 0, 144, 145, 2004年05月13日
日本語 - Eu(III)錯体の発光先鋭化と増幅自然放出光の増強
中村一希, 長谷川靖哉, 川井秀紀, 保田直紀, 長村利彦, 和田雄二, 柳田祥三, 日本化学会講演予稿集, 84th, 1, 2004年 - Eu(III)錯体を含むポリマー薄膜からの増幅自然放出光(ASE)
川井秀記, 長谷川靖哉, 中村一希, 和田雄二, 柳田祥三, 保田直紀, 長村利彦, 応用物理学関係連合講演会講演予稿集, 51st, 3, 2004年 - シリコーンラダーポリマーの光学素子への応用
保田直紀, 長谷川靖哉, 中村一希, 和田雄二, 柳田祥三, 川井秀記, 長村利彦, 高分子学会予稿集(CD-ROM), 53, 2 Disk1, 2004年 - 強発光Eu(III)錯体の構造制御によるASE発振特性の向上
中村一希, 長谷川靖哉, 川井秀紀, 保田直紀, 和田雄二, 柳田祥三, 光化学討論会講演要旨集, 2004, 2004年 - 大きな誘導放出断面積を有するEu(III)錯体におけるレーザー発振特性
中村一希, 長谷川靖哉, 川井秀紀, 保田直紀, 長村利彦, 和田雄二, 配位化合物の光化学討論会講演要旨集, 17th, 2004年 - Eu(hfa)_3(BINAPO)の全角運動量を考慮したCDスペクトル解析
長谷川 靖哉, 冨田 泰治, 和田 雄二, 和田 健彦, 井上 佳久, 柳田 祥三, 希土類 = Rare earths, 42, 0, 132, 133, 2003年05月20日
日本語 - 非対称型ユーロピウム錯体を用いた赤色発光バンドの先鋭化
中村 一希, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 42, 0, 134, 135, 2003年05月20日
日本語 - ゼオライト細孔内ネオジム錯体の発光特性とその応用
梁 宗範, 和田 雄二, 大久保 達也, 長谷川 靖哉, 柳田 祥三, 希土類 = Rare earths, 42, 0, 138, 139, 2003年05月20日
日本語 - 含フッ素ポリマー中におけるEu(III)錯体の低振動失活制御
安藤 善人, 田中 義人, 荒木 孝之, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 42, 0, 140, 141, 2003年05月20日
日本語 - レーザーパルスによるEuO発光体のナノ結晶成長
片岡 朋治, 長谷川 靖哉, すぴっちゃー とんちゃん, 和田 雄二, 中島 信昭, 柳田 祥三, 希土類 = Rare earths, 42, 0, 150, 151, 2003年05月20日
日本語 - 高い誘導放出断面積を示す強発光性Eu(III)錯体の創製
中村一希, 長谷川靖哉, 和田雄二, 柳田祥三, 光化学討論会講演要旨集, 2003, 2003年 - 赤色強発光を発するホスフィンオキシド二座配位ユウロピウム錯体の光物性
中村一希, 長谷川靖哉, 富田泰治, 和田雄二, 柳田祥三, 日本化学会講演予稿集, 83rd, 1, 2003年 - 非対称型Eu(III)錯体を含むポリマーの強発光
長谷川 靖哉, 山室 正樹, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 40, 0, 134, 135, 2002年05月16日
日本語 - ナノサイズゼオライト細孔を利用した希土類の増感発光
内山 克博, 和田 雄二, 長谷川 靖哉, 柳田 祥三, 希土類 = Rare earths, 40, 0, 136, 137, 2002年05月16日
日本語 - 液体アンモニアを用いるEuOナノ結晶の合成と磁気特性
THONGCHANT Supitcha, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 40, 0, 208, 209, 2002年05月16日
日本語 - BINAPOを有するEu(III)錯体の配位子場に基づく特異的発光
冨田 泰治, 長谷川 靖哉, 山室 正樹, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 40, 0, 220, 221, 2002年05月16日
日本語 - フォトクロミック分子を用いた応用 : レーザー発振と出力コントロール
長谷川 靖哉, 化学と工業 = Chemistry and chemical industry, 55, 5, 581, 581, 2002年05月01日
日本語 - LEDの医療応用の可能性;ロボット手術での赤の演色性の改善の重要性
島田 順一, 天池 寿, 藤 信明, 稲葉 一樹, 谷口 弘毅, 内藤 和世, 川上 養一, 藤田 茂夫, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 日本外科学会雑誌, 103, 0, 644, 644, 2002年03月10日
一般社団法人日本外科学会, 日本語 - EuOナノ微結晶の強発光および光磁気特性
長谷川 靖哉, とんちゃん すぴっちゃー, 和田 雄二, 柳田 祥三, 希土類 = Rare earths, 0, 38, 164, 165, 2001年05月02日
日本語 - 希土類イオンの有機媒体発光:ネオジム錯体の配位子設計とその展開
柳田 祥三, 長谷川 靖哉, 岩室 光則, 河村 祐一郎, 和田 雄二, 有機合成化学協会誌, 58, 10, 945, 955, 2000年10月
The relatively low efficiency of Nd (III) emission in organic media has been improved by 1) suppression of the radiationless transition process via vibrational excitation of the surrounding medium, 2) prevention of dipole-dipole nonradiative energy transfer processes via energy migration, 3) suppression of radiationless transition of D<SUB>2</SUB>O molecules in the vicinity of Nd (III) complexes (formation of twelve-coordinate Nd (III) complex with DMSO-<I>d</I><SUB>6</SUB>), 4) allowance of electron transitions of Nd (III) by the introduction of asymmetric ligand field, 5) photosensitizati..., 社団法人 有機合成化学協会, 日本語, 書評論文,書評,文献紹介等 - ナノサイズゼオライト細孔内ネオジム錯体の強発光
和田 雄二, 大久保 達也, 梁 宗範, 中澤 徹, 長谷川 靖哉, 北村 隆之, 柳田 祥三, 希土類 = Rare earths, 0, 36, 192, 193, 2000年05月16日
日本語 - C-H結合を含む高振動媒体中でのスルホニルアミドNd(III)の強発光
長谷川 靖哉, 和田 雄二, 北村 隆之, 柳田 祥三, 希土類 = Rare earths, 0, 36, 266, 267, 2000年05月16日
日本語 - 有機媒体中で光らないネオジムを どのように光らせるか? -希土類の強発光体を作るための戦略-
長谷川 靖哉, 化学と工業 = Chemistry and chemical industry, 53, 2, 126, 130, 2000年02月01日
日本化学会, 日本語 - Electrode behavior of hydrogen reduction in LiCl-KCl melt - Voltammetric analysis
H Ito, Y Hasegawa, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 147, 1, 289, 295, 2000年01月
Hydrogen reduction in LiCl-KCl eutectic melt was studied by the potential-sweep method with Ni, Fz, Co, and Cu electrodes. A reaction model, which considers not only a surface redox process but also the behavior of absorbed hydrogen in the electrode, is proposed. Based on this model, I-E curves are numerically calculated and fitted with experimental voltammograms. A good agreement is obtained between calculated and experimental data in the reversible region, and the validity of this model is demonstrated for Ni, Fe, and Cu electrodes. The Henry's constant for hydrogen in the melt and the diffusion constant were determined from the calculations as follows: kappa(H) = 5.68 X 10(-12) mol cm(-3) Pa-1, D-H2 = 3.18 x 10(-5) cm(2) s(-1) at 723 K, (C) 2000 The Electrochemical Society. S0013-4651(99)05-071-5. All rights reserved., ELECTROCHEMICAL SOC INC, 英語 - 有機媒体中での特異的12配位構造形成によるNd(III)の強発光
長谷川 靖哉, 和田 雄二, 柳田 祥三, 山中 龍彦, 中島 信昭, 希土類 = Rare earths, 34, 20, 21, 1999年05月27日
日本語 - 振動励起失活過程の制御によるランタニド含有ポリマーの強発光
長谷川 靖哉, 曽我部 健作, 谷 昭二, 和田 雄二, 柳田 祥三, 中島 信昭, 山中 龍彦, レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 19, 0, 6, 6, 1999年01月01日
日本語 - 液体レーザーを目指したNd^<3+>およびYb^<3+>錯体の発光特性
金 正鎬, 中島 信昭, 長谷川 靖哉, 和田 雄二, 柳田 祥三, 山中 龍彦, レーザー研究, 26, 9, 691, 695, 1998年09月15日
Perdeuterated hexafluoroacetylacetonato-neodymium [Nd (HFA-D) 3] and -ytterbium [Yb (HFA-D) 3] complexes were synthesized by the keto-enol tautomerism reaction of Nd (HFA-H) 3 and Yb (HFA-H) 3 in methanol-d4 in order to reduce the radiationless transition to the ligands. The luminescence properties of the Nd (HFA-D) 3 complex in organic solvents were analyzed by the Judd-Ofeltheory. The luminescence quantum yield of the Yb (HFA-D) 3 complex increased with the increasing coordination ability of the solvent molecules. The luminescence lifetime of the Yb (HFA-D) 3 complex in dimethylstilfoxide (DMSO-d6) which had the highest coordination ability was 66 μs., レ-ザ-学会, 日本語 - Nd(III)の溶液中における発光 : 液体ネオジムレーザーの開発を目指して
柳田 祥三, 長谷川 靖哉, 岩室 光則, 和田 雄二, 光化学 = Photochemistry, 26, 0, 22, 29, 1997年11月30日
光化学協会, 日本語 - 新しいNd^<3+>・Yb^<3+>錯体溶液の有機溶媒中における光学特性
金 正鎬, 中島 信昭, 山中 龍彦, 長谷川 靖哉, 和田 雄二, 柳田 祥三, レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 17, 0, 89, 89, 1997年01月01日
日本語 - 新しいNd^<3+>錯体の有機溶媒中における発光特性
金 正鎬, 中島 信昭, 中塚 正大, 山中 龍彦, 長谷川 靖哉, 村越 敬, 柳田 祥三, レーザー学会学術講演会年次大会講演予稿集 = Annual meeting, of the Laser Society of Japan digest of technical papers, 16, 0, 31, 31, 1996年01月01日
日本語
書籍等出版物
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長谷川靖哉, 57, 86-89
セラミックス, 2022年, [分担執筆] - 発光色変化を示す希土類分子材料の開発
長谷川靖哉, 101-106
日本化学会編 化学同人, 2021年, [分担執筆] - 希土類元素ブロック高分子を用いた表示材料への展開
長谷川靖哉, 58, 138-146
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可視化情報, 2018年, [共著] - 希土類配位高分子の励起エネルギー移動
長谷川靖哉, ディビジョントピックス p.497
化学と工業, 2017年, [単著] - 新時代を切り開く希土類錯体ポリマー
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科学と工業, 2016年, [単著] - ナノ材料解析の実際
長谷川靖哉, 第26章 磁気光学効果
講談社, 2016年, [共著] - 元素ブロック材料の創出と応用展開
長谷川靖哉, 新型発光体創成を目指した希土類元素ブロックの三次元空間配列
シーエムシー出版, 2016年, [共著] - 発光の辞典 基礎からイメージングまで
長谷川靖哉, 5.5.4 希土類物質の発光
朝倉書店, 2015年, [共著] - 希土類物質のナノ構造制御と光機能
長谷川靖哉
化学工業, 2015年, 477 - 光を操る希土類高分子ブロック
中西貴之, 長谷川靖哉
高分子, 2015年, 64, 203 - カメレオン発光体の開発
長谷川靖哉
パリティ (丸善), 2015年, vol. 30, 25 - 希土類錯体を用いたルミネッセンス材料科学
長谷川靖哉
化学工業 (化学工業社), 2014年, vol.65, No.5, 348 - 温度変化を感知するカメレオン発光体
長谷川靖哉
パリティ (丸善), 2014年, vol.29, No.2, 44 - 温度センシングを可能にするカメレオン発光体
長谷川靖哉
工業材料 (日刊工業新聞社), 2014年, vol 62, No.1, 24-25 - 光化学の辞典
光化学協会, 光化学の辞典編集委員会
朝倉書店, 2014年, 24-25 - 錯体化学
長谷川靖哉, 伊藤肇
講談社, 2014年 - 授業:学生満足度ナンバー1の秘訣とは?
長谷川靖哉
化学 (化学同人), 2013年, vol.68, No.4, 17-19 - 金属ナノ・マイクロ粒子の最新技術と応用
米澤徹監修, 3−4光磁気材料
シーエムシー出版, 2013年, 209-217 - 希土類が拓く次世代光機能材料の創成
長谷川靖哉
希土類, 2012年, 61, 11-22 - 世界を底から変える力 「化学」を自由に使いこなす方法
長谷川靖哉
化学工業日報, 2012年 - 属および半導体ナノ粒子の科学
日本化学会編, 15章ランタニド系半導体の光物性
化学同人, 2012年 - 磁性半導体EuXナノ結晶の合成と光磁気機能
長谷川靖哉, 河合壯
日本結晶成長学会誌, 2010年, 37, 273 - 次世代の光情報通信用を指向した新型希土類ナノ結晶の開発
長谷川靖哉
化学工業, 2010年, 61, 744-751 - 希土類ナノ結晶を用いた次世代光情報通信用の機能材料
長谷川靖哉
未来材料, 2010年, 10, 12, 61 - 強発光を示すEu錯体の分子設計
長谷川靖哉
マテリアルインテグレーション(ティーアイシー), 2010年, 23, 20 - 光ナノ科学への招待
長谷川靖哉, 細川陽一郎, 中嶋琢也
化学同人, 2010年, 4759803882 - 配位化合物の電子状態と光物理
山内, 野崎編, 2章
三共出版, 2010年 - 希土類錯体を用いた蛍光体
長谷川靖哉
光アライアンス(日本工業出版), 2009年, 20, 17-20 - 京都・花灯路を希土類錯体で照らす
長谷川靖哉
Electronics Communications, 2009年, 25, 2 - 光機能を有する希土類錯体
長谷川靖哉, 中川哲也
化学工業, 2009年, 60, 590 - 希土類錯体を用いた発光材料および顔料
長谷川靖哉
顔料, 2008年, 52, 2, 2 - 新しい機能材料創成を目指したフォトクロミック希土類錯体の開発
長谷川靖哉, 中川哲也, 河合壯
化学工業, 2008年, 59, 879 - 光磁気特性を有する希土類ナノ結晶
長谷川靖哉
光化学, 2008年, 39, 11 - 希土類錯体が拓いた光の色彩画
長谷川靖哉
現代化学, 2008年, 4, 25 - 蛍光材料の基礎と新展開−固体照明・ディスプレイ材料−
金光義彦, 岡本伸治編, 3章 局在発光中心:希土類・遷移金属
オーム社, 2008年, 79-130 - 希土類の材料技術ハンドブック: 第2章14節 非対称配位子錯体の蛍光体 合成法, 構造, 評価法
足立吟也編, 第2章14節 非対称配位子錯体の蛍光体 合成法, 構造, 評価法
エヌティーエス, 2008年, 120-127 - 紫外線で発光する透明インク
長谷川靖哉
化学, 2007年, vol. 62, No. 11, p.73 - 光機能性高分子材料の新たな潮流:第I編
市村國宏編, 第3章 希土類を基盤とした光情報機能物質
シーエムシー出版, 2007年, 37-58 - 錯体化学会選書2 金属錯体の光化学
佐々木陽一, 石谷治編著, 9章 希土類の金属錯体の発光
三共出版, 2007年 - 強発光を示す希土類錯体の設計戦略
長谷川靖哉
Bull. Jpn. Soc. Coord. Chem., 2006年, 48, 2 - 光る分子の底力 ―発光体デザインの魅力―
長谷川靖哉, 柳田祥三
化学同人, 2006年, 4873266165 - 希土類の機能と応用
足立吟也編, 2.8章 希土類錯体を用いた発光材料
シーエムシー出版, 2006年, 138-144 - 希土類錯体の発光過程制御とレーザー発振に関する研究
長谷川靖哉
光化学, 2005年, 36, 41 - ナノサイズEuO/EuSを用いた光機能デバイス向けプラスティックの開発
長谷川靖哉
工業材料, 2005年, 53, 76 - 光機能を有する希土類錯体および希土類ナノ結晶の創成
長谷川靖哉
希土類, 2004年, 45, 1 - 海外レポート・マンチェスター大学留学記
長谷川靖哉
Electronics Communications, 2004年, 20, 32 - 光子ブロックって何?
高原淳一, 川畑弘, 長谷川靖哉, 長山智男, 小西毅, 細川陽一郎, 兼松泰男, 小林哲郎
OPTRONICS, 2003年, 2, 150 - 錯体化学−基礎と最新の話題−
基礎錯体工学研究会編, 6.4.2章 有機強発光体としての希土類錯体
講談社, 2003年 - フォトクロミック分子の応用:レーザー発振と出力コントロール
長谷川靖哉
化学と工業, 2002年, 55, 581 - 光らないネオジムをどのように光らせるか
長谷川靖哉
化学と工業, 2000年, 53, 126 - フッ素化合物を用いた光機能の創製
柳田祥三, 北村隆之, 和田雄二, 長谷川靖哉
科学と工業, 1998年, 72, 333 - Nd(III)の溶液中における発光:液体ネオジムレーザーの開発を目指して
柳田祥三, 長谷川靖哉, 岩室光則, 和田雄二
光化学, 1997年, 26, 22
担当経験のある科目_授業
共同研究・競争的資金等の研究課題
- ミセル反応場で合成する希土類配位ナノ粒子の構造制御と光機能材料化
科学研究費助成事業 基盤研究(B)
2022年04月 - 2026年03月
長谷川 靖哉
日本学術振興会, 基盤研究(B), 北海道大学, 研究代表者, 22H02152 - 水圏環境で生体分子と会合体を形成する発光性希土類錯体の開発
科学研究費助成事業 新学術領域研究(研究領域提案型)
2022年04月 - 2024年03月
長谷川 靖哉
日本学術振興会, 新学術領域研究(研究領域提案型), 北海道大学, 研究代表者, 22H04516 - 情報科学を基盤としたキラル型希土類錯体の機械学習および探索
科学研究費助成事業 挑戦的研究(萌芽)
2020年07月 - 2023年03月
長谷川 靖哉
本研究では情報科学と機械学習を基盤としたキラルEu(III)錯体の配位空間研究を検討した。具体的には、機械学習を行うために必要な基礎データとして、数種類のキラルEu(III)錯体[Eu(+hfc)4]-M+ (M = Na, K, Rb, Cs, NEt4+,NEt3Me+, hfc: へプラフルオロブチリルカンファー)の合成および光物性評価を行った。
[Eu(+hfc)4]- Cs+の三分子に関しては四つの+hfc配位子のフルオロアルキル基が全て対カチオンを取り囲む向きに配置しており、複数のCH-F相互作用およびCs-F間の結合があることが分かった。一方で、[La(+hfc)4]- Na+は三つの+hfc配位子がNaイオンを取り囲む向きに配位しているのに対して、残り一つのhfc配位子はフルオロアルキル基がLa-Naの結合に対して垂直な方向に延びていた。このことより、[La(+hfc)4]- Na+は他の三つの錯体と比較して配位幾何学構造が大きく異なることが分かった。
[Eu(+hfc)4]- Cs+のgCPLは本測定と既報でほぼ等しい値が得られた。 [Eu(+hfc)4]-NEt4+および[Eu(+hfc)4]- NEt3Me+では1.4を超える大きいgCPLが観測され、対カチオンの構造を最適化することでさらなるgCPL増大の可能性が示唆された。一方、MeOH溶液中での[Eu(+hfc)4]- NEt4+のgCPLは-0.08であった。Square antiprism構造を取らない[Eu(+hfc)4]- Na+もgCPLが+0.15と低いことから、Eu(+hfc)4錯体ではSquare antiprism構造によって+hfc配位子のフルオロアルキル基がEu(III)イオンに対し一方向に局在する配位環境がCPL強度を増大させると考えられる。
日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 20K21201 - 形状制御された酸化チタン微結晶上での結晶面選択的光不斉水素化反応の解明
科学研究費助成事業
2019年04月01日 - 2022年03月31日
甲谷 繁, 宮部 豪人, 川島 祥, 長谷川 靖哉, 北川 裕一
本研究では、2-アセトナフトン(2-NP)などのアキラルな芳香族ケトンから不斉炭素を有するキラルな2級アルコール(2-NPOH)への光不斉水素化反応において、TiO2に共吸着するキラルな低分子有機化合物によるエナンチオ選択的な不斉誘起機構を検討した。
成果(1):新しく見出したキラル共吸着剤2-アミノ-1-フェニルエタノール(PhEA)は、安定に2-NPの水素化反応へ関与し、高い収率と比較的強いエナンチオ選択性を示すことが明らかとなった。成果(2):本反応のエナンチオ選択性は、結晶面の割合のみに依存するわけではなく、フッ化物イオンの吸着によっても立体化学的に強く影響を受けることが明らかとなった。
日本学術振興会, 基盤研究(C), 兵庫医療大学, 19K05681 - 水圏環境における発光性希土類分子会合体の形成と光機能
科学研究費助成事業 新学術領域研究(研究領域提案型)
2020年04月 - 2022年03月
長谷川 靖哉
水圏環境における生体環境計測のための検出分子として、水溶性の発光性希土類錯体が現在注目されている。この希土類錯体は極めて長い発光寿命(数百マイクロ秒)を示すことから、時間分解蛍光解析による水溶液中および生体系の状態観察が可能になる。本研究課題では、発光性の希土類錯体にポリエーテル鎖を導入し、水圏環境における分子集合体の形成と新しい生体環境モニター開発を目指した。具体的には、昨年合成されたポリエーテル鎖導入ユウロピウム錯体(水溶性ユウロピウム錯体)の水溶液中における会合体形成と光物性(発光量子効率、発光寿命、光増感エネルギー移動効率)との関係を明らかにし、得られた水溶性ユウロピウム錯体を癌細胞の生体観察へと展開した。具体的には、生理培養液(DMEM+FBS: アミノ酸、グルコース、牛血清などを含む水溶液)での水溶性ユウロピウム錯体の発光挙動を計測し、この生理培養液の中にがん細胞を導入することによる水溶性ユウロピウム錯体の発光挙動変化を計測した。
水溶性のポリエーテルを導入したユウロピウム錯体Eu-ntfa-TEGPOを合成した。Eu-ntfa-TEGPOは水圏環境で巨大な分子集合体を形成し、発光量子効率が増大することがわかった。この発光機能増大は、分子集合体形成による振動失活への抑制が行われたためと考えられる。さらに、水溶性のユウロピウム錯体をがん細胞へ導入する試験(生体環境への導入)も行ったところ、がん細胞へユウロピウム錯体が取り込まれる様子が観察された。
水溶性ポリエーテルを導入した新しいユウロピウム錯体を導入し、水圏環境で分子集合体を形成することによる強発光化に成功した。さらに アミド結合によって分子集積する希土類配位高分子や希土類錯体のナノ集積体合成にも成功した。分子集合体は希土類錯体の光機能化に重要であることが明らかになった。
日本学術振興会, 新学術領域研究(研究領域提案型), 北海道大学, 20H05197 - 希土類錯体から配位高分子へのソフトクリスタル変形と光機能評価
科学研究費助成事業 新学術領域研究(研究領域提案型)
2020年04月 - 2022年03月
長谷川 靖哉
本研究では、外部刺激によって希土類の配位数と幾何学構造が変化する新しいソフトクリスタル変形の創成および光機能評価を検討した。七配位Tb(III) 錯体から八配位のTb(III)配位高分子へのソフトクリスタル転移の結晶連結の詳細を検討した。また、加熱による結晶相転移が起こるキラル型Eu(III)配位高分子の円偏光機能解析についても検討を行った。
七配位から八配位へのソフトクリスタル変形の結晶連結では、七配位型の二核Tb(III)錯体(図1)から八配位のTb(III) 配位高分子への変形は2つの異なる結晶を連結することができる。この結晶連結に関して、接合結晶面の方位依存性があることが明らかになった。さらに、レーザー光によってDy(III) 結晶からTb(III)結晶へ光エネルギーが確実に伝達していることを明らかにした。
キラルEu(III) 配位高分子の相転移計算では、相転移が可能なキラル型Eu(III)配位高分子の円偏光発光特性は配位高分子の配列構造に大きく依存していることを明らかにした。今回はその配列構造を段階的に変化させたモデルを設定し、それらのモデルの遷移双極子モーメント(ED)を計算した。この計算の結果、Eu(III)配位高分子のL M C TにおけるEDの大きさは配列距離に大きく依存することがわかった。 このED変化が円偏光発光特性に強く影響を与えていると推測される。
以上、希土類配位高分子の配位構造および結晶の構造転移に基づく光機能の発現および機能解明に成功した。これらの研究成果は本領域の研究推進に大きく貢献したと言える。
日本学術振興会, 新学術領域研究(研究領域提案型), 北海道大学, 20H04653 - ソフトクリスタル挙動を示すキラル希土類配位高分子の合成と光機能評価
科学研究費助成事業 新学術領域研究(研究領域提案型)
2018年04月 - 2020年03月
長谷川 靖哉
キラル配位子を導入した希土類錯体は異方性の高い円偏光発光を示す。この集合状態におけるキラル希土類錯体の光機能解明は学術的に重要である。本研究では、結晶相転移(ソフトクリスタル挙動)を誘起するキラル希土類配位高分子の合成および光機能評価を行う。具体的には、相転移挙動を誘起するエチニル含有ホスフィンオキシドとキラル型Eu(III)錯体との反応によりキラル希土類配位高分子の合成を行う。そのキラル希土類配位高分子の様々な固体状態(結晶系α、結晶系β、ガラス状態など)における基礎光物性とキラル光機能(CDおよびCPL特性)の評価を行い、相転移挙動におけるキラル機能を明らかにする。さらに、Eu(III)とTb(III)の混合系配位高分子を合成し、温度変化による光誘起エネルギー移動過程をアレニウス解析によって評価する。
初年度では、本研究に先立ち、キラル配位子を導入したユウロピウム配位高分子の合成に成功した。この配位高分子は螺旋構造を形成していることがX線構造解析により明らかになった。その螺旋構造の形成により希土類配位高分子の発光特性と円偏光特性が大きく向上することを明らかにした。また、テルビウム配位高分子の光誘起エネルギー移動過程が錯体をつなぐリンカー配位子の分子構造によって大きく影響を受けることも本研究により明らかになった。さらに、エチニル基を導入したキラル型ユウロピウム配位高分子の合成にも初めて成功した。
以上のことから、本研究は研究の目的および実施計画どおりに研究が進行し、優れた研究成果をいくつもあげることに成功した。さらに、本研究を進めるにあたり、領域内のエキスパート研究者との共同研究も大きく進展し、本領域の活性化に大きく貢献できた。
日本学術振興会, 新学術領域研究(研究領域提案型), 北海道大学, 研究代表者, 18H04497 - 積層構造を有する発光性希土類配位ナノ粒子の合成と光機能
科学研究費補助金(基盤研究(B) )
2018年04月 - 2020年03月
長谷川靖哉
文部科学省, 研究代表者, 競争的資金 - 元素ブロック高分子材料の創出
科学研究費助成事業
2012年06月28日 - 2017年03月31日
中條 善樹, 菅原 義之, 中 建介, 渡辺 明, 大下 浄治, 國武 雅司, 冨田 育義, 郡司 天博, 西野 孝, 松川 公洋, 内藤 裕義, 長谷川 靖哉, 田中 一義
無機元素を含む機能の最小ユニットを「元素ブロック」と呼ぶ。これらを連結、集積することで「元素ブロック材料」と呼べる無機成分の特性を活かした高機能性材料の創出が期待できる。新奇の元素ブロックとそれらの連結・集積・複合化から、様々な高機能性材料が得られてくると期待できる。特に、それらの新素材から従来の高分子では達成できない機能や、一般的な無機材料では乏しいとされる製膜性や機能設計の適用性などを兼ね備えた物性が得られる可能性が多分にある。我々は、この考えの元、様々な元素ブロックを開発し、学理を構築することができた。さらに、多様な高機能性材料を元素ブロックを組み合わせることで生み出すことができた。
日本学術振興会, 新学術領域研究(研究領域提案型), 京都大学, 24102001 - 希土類半導体へのナノ磁気格子導入による光磁気特性増大
科学研究費補助金(基盤研究(B)
2014年04月 - 2017年03月
長谷川靖哉
文部科学省, 研究代表者, 競争的資金 - 磁性金属元素ブロックの三次元空間制御による新機能性高分子の創成
科学研究費補助金(新学術領域研究(研究領域提案型))
2012年10月 - 2017年03月
長谷川 靖哉
金属元素ブロックを三次元的に空間制御および分子レベルで機能化することで、従来の無機材料や高分子材料を超えた新領域の機能物質を構築できる。我々はこの金属元素ブロックとして希土類を選択し、希土類元素が三次元的に配列することによる光磁気機能の発現について研究を行った。希土類錯体が三次元配列した希土類元素ブロック高分子の開発に成功し、熱耐久特性および発光効率が向上することを明らかにした。さらに、希土類ナノ結晶を鰓裂させることによる光磁気効果増大にも成功した。
文部科学省, 新学術領域研究(研究領域提案型), 北海道大学, 研究代表者, 競争的資金, 24102012 - テルビウムクラスターの協奏的ファラデー効果発現および光磁気機能解明
科学研究費補助金(挑戦的萌芽研究)
2012年04月 - 2015年03月
長谷川 靖哉
常磁性のテルビウムイオンを9つ含むテルビウムクラスターの光磁気特性が検討された。このテルビウムクラスターの幾何学構造はX線構造解析により明らかになった。テルビウムクラスターを含むPMMA薄膜の光磁気特性はファラデー効果により評価を行った。得られたファラデー効果は単核のテルビウム錯体よりも大きく、市販されているテルビウムガラスよりも150倍に相当することがわかった。本研究では、テルビウムクラスターの配位構造と光磁気特性との相関を初めて明らかにした。
文部科学省, 挑戦的萌芽研究, 北海道大学, 研究代表者, 競争的資金, 24655109 - 磁性半導体ナノ結晶の磁気光学効果増強のための内部・表面磁気構造制御
科学研究費補助金(基盤研究(B))
2011年04月 - 2013年03月
長谷川 靖哉
文部科学省, 基盤研究(B), 北海道大学, 研究代表者, 競争的資金, 23350057 - 希土類ナノ結晶と金粒子の超格子形成と機能創発
科学研究費補助金(新学術領域研究(研究領域提案型))
2011年 - 2012年
長谷川 靖哉
金ナノ粒子は光エネルギーを吸収することにより、表面プラズモン電場増強が発生する。この電場増強が配列したEuXのスピン偏極に影響を与え、特異的な光磁気物性が期待できる。本研究「希土類ナノ結晶と金粒子の超格子形成と機能創発」を行うために、23年度はEuSナノ結晶とAuナノ粒子の複合体形成(EuS-金ナノ複合体)を行い、電場増強下における光磁気機能評価を行った。
具体的には、Au錯体を新規に合成し、オレイルアミン中で300℃にて反応をおこなうことににより、Auナノ粒子を合成した。同時にユーロピウム錯体を原料としたEuSナノ結晶を合成し、EuSナノ結晶とAuナノ粒子をヘキサンジチオールで連結した(EuS-金ナノ複合体)。その複合形状は透過型電子顕微鏡により観察した。
得られたEuS-金ナノ複合体は、金ナノ粒子のプラズモンバンドに起因する吸収帯のレッドシフトが観測された。このレッドシフトは誘電率が高いEuSが金ナノ結晶の近傍に存在することを意味している。
このEuS-金ナノ複合体をポリメタクリル酸メチルのTHF溶液に分散し、キャスト法にてEuS-金ナノ複合体を含むポリメタクリル酸メチル薄膜を調整した。得られたEuS-金ナノ複合体含有ポリマー薄膜に印可磁場150000eにおけるファラデー回転(磁場印加中の物質に偏光をあてると、その偏光面が回転する現象:ファラデー回転)がプラズモン吸収バンド領域において増大することが明らかとなった。
本研究により、EuSナノ結晶の光磁気特性(ファラデー効果)におけるプラズモン電場増強効果が初めて明らかになった。
文部科学省, 新学術領域研究(研究領域提案型), 北海道大学, 研究代表者, 競争的資金, 23111701 - 半導体ナノ結晶の自己会合体における秩序の構造構築と光磁性材料への展開
科学研究費助成事業
2010年 - 2012年
河合 壯, 中嶋 琢也, 湯浅 順平, 長谷川 靖哉
半導体ナノ結晶の自己組織化による高機能化を目指してPb(II), Eu(III), Cd(II)のカルコゲナイド半導体のナノ結晶の精密合成とその複合材料化による自己組織構造形成に取り組んだ。EuSナノ結晶については、PbSナノ結晶との複合化に成功し、コアシェル構造を創出することに成功した。さらにこれにより光磁気特性の高感度化に成功した。
日本学術振興会, 基盤研究(B), 奈良先端科学技術大学院大学, 22350062 - 走査型電気化学ナノ顕微鏡の開発と局部界面反応発現機構・速度論の解明
科学研究費補助金(基盤研究(B))
2009年 - 2011年
伏見 公志, 金野 英隆, 長谷川 靖哉
本研究の目的は、実用材料界面構造ゆらぎのin situ解析を目指した超高分解能走査型電気化学ナノ顕微鏡(SECN)を開発と「材料下地金属組織および組成の不均一性を要因とする金属溶解反応および不働態皮膜形成反応の不均一性発現機構および局部反応速度分布の定量」への適用である。今年度、以下の事項について検討、研究成果を得た。1)前年度に引き続き、LIGA技術による電極代表長さ1μm以下のプローブ微小電極の作製と走査型レーザー変位計への組み込みによるSECNシステムの構築を試みた。電極代表長さ0.2μm程度のSECN用白金プローブ作製に成功したものの、電気化学測定への再現性ある取り付けに難航しており、SECNシステムの完成には至っていない。2)炭化水素熱分解法により同軸二重構造微小炭素化物電極を新規に開発した。本電極と多チャンネルポテンショスタットの動作により走査型電気化学顕微鏡(SECM)プローブに新しくシールド機能を付加した。白金/エポキシ樹脂境界モデル試料上のレドックスメディエータを用いたSG/TCモード測定において、検出感度と面分解能をそれぞれ45%ならびに5%程度、向上させることができた。3)2)にて開発したSECMを用いて、硫酸系水溶液中、多結晶鉄電極の鉄溶解反応速度に関する金属組織依存性を調査した。低指数面のうち001面の溶解速度が多結晶面に比べて低く、これが昨年度の調...
文部科学省, 基盤研究(B), 北海道大学, 連携研究者, 競争的資金, 21360350 - プラズモン増強電場による希土類ナノ結晶の光磁気効果の影響に関する研究
科学研究費補助金(特定領域研究)
2009年 - 2010年
長谷川 靖哉, 河合 壯, 中嶋 琢也, 湯浅 順平
これまで、ファラデー効果に理想的な物質として希土類ナノ結晶EuX(ユーロピウムカルコゲナイド:X=O,S,Se)の合成およびファラデー効果に関する研究を世界に先駆けて行ってきた。希土類ナノ結晶EuXのファラデー効果(光磁気効果)における表面プラズモンの電場増強効果を検討し、大きなファラデー効果増大および学術的機構解明を目的として、AuとEuSが結合した複合系ナノ粒子の合成を行った。複合型ナノ粒子の合成は、平均粒子サイズ15nmの立方体型EuS結晶と平均粒子サイズ10nmの球状型Au粒子をトルエン中に入れ、ヘキサンジチオールを添加して撹拌することで得た。得られた複合ナノ粒子は透過型電子顕微鏡にて状態観察を行った。さらに、吸収スペクトル測定により、複合型ナノ粒子におけるAuのプラズモン吸収バンドが長波長側へのおおきくシフトしていることが明らかとなった。これは、金ナノ粒子近傍に存在するEuSナノ粒子の影響と考えられる。得られたEuS-Au複合ナノ粒子をポリマー(ポリメタクリル酸メチル)が溶解した有機溶媒中に分散し、キャスト法にて「EuS-Au複合ナノ粒子含有ポリマー薄膜」を作製した。得られたポリマー薄膜に1.5Tの磁場を印可し、偏光の回転角度変化(ファラデー効果)に関する測定を行った。この測定の結果、プラズモン吸収バンド領域の波長において、おおきく偏光回転角が変化することが分かった...
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学->北海道大学, 研究代表者, 競争的資金, 21020023 - 希土類ナノ物質/有機ハイブリッド化による巨大組織体形成と機能創発
科学研究費補助金(新学術領域研究(研究領域提案型))
2009年 - 2010年
長谷川 靖哉
これまで、ファラデー効果に理想的な物質として希土類ナノ結晶EuX(ユーロピウムカルコゲナイド:X=0,S,Se)の合成およびファラデー効果に関する研究を世界に先駆けて行ってきた。このEuXナノ結晶から構成される巨大な自己組織体はEuXナノ結晶間の磁気的相互作用を増大させると考えられ、新しい機能材料への展開が期待される。本年度は溶液中におけるEuSナノ結晶から構成される巨大組織体の構造制御および機能発現に関する検討を行った。平均粒子サイズ15nmのEuSナノ結晶をアルコール中に分散し、その溶液中における自己会合体形成を光散乱測定(DLS測定)により観察した。観察の結果、アルコール分子の分子サイズが小さいもにほど、大きなEuSナノ結晶会合体を形成することがわかった。さらに、その会合体の大きさは使用するアルコール分子の種類によって制御できることも明らかにした。この溶液中における自己会合体の構造については小角X線散乱測定により同定をした。EuSナノ結晶会合体を含むアルコール溶液に磁場を印可し、偏光回転角測定を行った。測定の結果、偏光回転が見られる波長領域はEuSナノ結晶分散溶液にくらべて大きく超波長シフトしていることがあきらかとなった。これは、EuSナノ結晶会合体においてEuS結晶同士のエキシトン・カップリングが発生したためと現在考えている。本研究により、EuSナノ結晶会合体を形成す...
文部科学省, 新学術領域研究(研究領域提案型), 奈良先端科学技術大学院大学->北海道大学, 研究代表者, 競争的資金, 21111516 - 発光性イオン液体複合材料の開発とセンサーへの応用
科学研究費補助金(特定領域研究)
2008年 - 2009年
中嶋 琢也, 長谷川 靖哉, 湯浅 順平, 河合 壯
通常、高分子電解質の交互積層(Layer-by-Layer)法による薄膜の作成には水媒体が用いられるが、水分の存在は薄膜の応用を大幅に制限している。特に、水素貯蔵材料などの禁水系材料や電子デバイスのコーティングには無水条件が望まれ、非水系へのLayer-by-Layer法の展開が必要とされる。我々は、イオン液体がそのイオン組成により種々の物質、特に、ポリマーに対する溶解性を制御できることから交互積層膜作製の媒体として利用できると考えた。さらに、いくつかのイオン液体はセルロースやシルクならびにカーボンナノチューブなど難溶性の物質を容易に溶解できることから、分子性溶媒では達成できない薄膜が作製できると期待される。また、ナノメートルスケールで垂直方向に設計が可能な交互積層薄膜作製法の開発により、イオン液体含有高性能センサー作製のための基礎技術が確立できる。以上より、本研究では、典型的な高分子電解質、カーボンナノチューブならびにセルロースを材料とした交互積層薄膜の作製を行った。いずれの材料においても、規則的な膜厚成長が確認され、特にセルロースにおいては高透明、高強度の薄膜を与えた。
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 20031018 - 形態制御された希土類ナノキューブの会合体形成および光機能材料への展開
科学研究費補助金(基盤研究(C))
2007年 - 2009年
長谷川 靖哉, 杉浦 忠男
EuSナノ結晶は光情報通信用の光アイソレーターや磁気メモリへの応用が期待される重要な物質である。本研究では、キュービック形状を有するEuSナノ結晶の合成を行い、その自己会合体(三次元超格子:SLS)形成に初めて成功した。さらに、その自己会合体の磁気特性向上が観測された。
文部科学省, 基盤研究(C), 奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 19510104 - コアシェル構造を有する希土類ナノ結晶の光磁気特性
科学研究費補助金
2008年 - 2008年
長谷川 靖哉, 河合 壯, 中嶋 琢也, 湯浅 順平
EuXナノ結晶は希土類元素から構成される磁性半導体である。磁場印加下では、この物質を通過する直線偏光は回転(ファラデー効果)することから、次世代の光情報通信用アイソレーター素子として、現在注目されている。このEuXナノ結晶を光機能材料へ展開するために、まずEuSおよびEuSeナノ結晶を含むポリマー薄膜を作製した。具体的には、EuSおよびEuSeナノ結晶をPMMA含有エチルメチルケトンに溶解し、ガラス基板状にスピンコートすることにより薄膜を調製した。得られた薄膜に1.5Tの磁場(B)を印加し、薄膜中を透過する直線偏光の回転角を測定したところ、この回転角はEuSナノ結晶の形状に依存することが明らかとなり、キューブ状のEuSおよびEuSeナノ結晶は大きな回転角(ファラデー効果)を示すことがわかった。この大きなファラデー効果の原因を明らかにするために、EuSおよびEuSeナノ結晶の磁気測定を行った。キューブ形状を有するEuSおよびEuSeナノ結晶は保持力を有することがこの測定から明らかとなり、この保持力が大きなファラデー効果発現の原因となっていることがわかった。
文部科学省, 奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 20900127 - イミダゾリウム基を含むフォトクロミック分子材料の開発
科学研究費補助金(特定領域研究)
2008年 - 2008年
中嶋 琢也, 長谷川 靖哉, 湯浅 順平, 河合 壯
電荷の局在状態の光制御を実現するシステムを目指し、ジアリールエテン、ターアリーレン(ジアリールアリーレン)へのイミダゾリウム環の導入を行った。光化学反応に伴い、導入されたイミダゾリウム環は正電荷が非局在化したイミダゾリウム型と局在化したイミダゾリニウム型に相互変換する。本年度は、この正電荷の局在構造変化によるソルバト、イオノクロミズムや反応性の発現など興味深い特徴を見出した。(1)イミダゾリウム置換ジアリールエテンはトルエンからピリジンまで幅広い極性の溶媒中においてフォトクロミック反応を示すことを見出した。閉環体における局在正電荷はルイス塩基結合サイトとして働き、高ドナー数を有する分子やアニオンと特異的に相互作用する。その結果、π共役構造を変化させ、マルチクロミック特性(光、溶媒、イオン応答)を示すことを見出した。(2)ジチアゾリルイミダゾリウムは種々の溶媒中で可逆的にフォトクロミック反応を示し、(1)と同様に、ソルバトクロミズムを示した。この場合、溶媒のドナー数ではなく誘電率に応答した吸収ピークシフトを示した。低極性溶媒中において局在カチオンはヨードアニオンと強く相互作用し、イミダゾリニウムのN(1)-C(2)-N(3)の二重結合性を低下させ、π共役系の縮小により低波長シフトを与えた。さらに、局在カチオンの高い反応性は、強い求核剤であるメトキシドとの求核付加反応によりpho...
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 20044019 - フォトクロミックスイッチングユニットによるπ共役分子鎖の光機能化
科学研究費補助金(特定領域研究)
2005年 - 2008年
河合 壯, 中嶋 琢也, 田中 仙君, 松井 龍之介, 長谷川 靖哉, 湯浅 順平, 田中 仙君
フォトクロミック分子によるπ共役系スイッチングを目指して、さまざまなπ共役系を有するフォトクロミック分子の開発とその評価を行った。フォトクロミックターアリーレンの中央のアリール部に対してπ共役ユニットを導入したところ、π共役系の拡張に伴って吸収の長波長シフトが見出された。さらにフォトクロミック反応前後の吸収波長はそれぞれの構造におけるπ共役系の広がりに対応して変化することが見出され、ターアリーレン系フォトクロミック分子においてπ共役系の方向切り替えが可能であること明らかになった。一方、光によりπ共役分子ワイヤーの形成を目指して、光照射に伴って安定な芳香族ユニットが形成する新しい光化学反応の開発に成功した。この分子では光反応後に形成する中間体から、自発的にメタノールが脱離し、安定な芳香族分子を形成し、さらにπスタックによる超分子集合体を形成することが見出された。類似の反応は従来は酸素などの酸化剤の存在が必要であったらが、脱離ユニットを安定なアルコールとすることで、自発的な光脱離反応が可能となった。
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 17067011 - コアシェル構造を有する希土類ナノ結晶の光磁気特性
科学研究費補助金(特定領域研究)
2007年 - 2007年
長谷川 靖哉, 河合 壯, 中嶋 琢也
二価のユーロピウムEu(II)から構成されるカルコゲナイド(EuX;X=O,S,Se,Te)は強磁性を示す化合物半導体でる。これまでEuXナノ結晶の合成および特異的な光磁気特性が報告されているが、そのナノ結晶の会合状態や配列を制御した例はない1)。大きな磁気光学効果を示すEuXナノ結晶を任意に会合および配列できれば、会合状態に基づく新たな光磁気特性が期待できる。本研究ではEuSのナノサイズ化及びEuSナノ会合体の形状制御を行い、光の放射圧によってナノ粒子を補足して操作するレーザートラッピング法を用いてEuSナノ会合体の形態制御を行った。EuSナノ結晶の原料となるEu(III)錯体は、塩化ユウロピウムと硫黄を含む有機配位子との錯形成により合成した。この錯体を6時間加熱還元し、反応終了後にクロロホルム・ヘキサン混合溶液を用いて精製することにより紫色粉末を得た。得られた紫色粉末のXRD測定の結果より、バルクのEuSのピークと一致することが明らかとなり、Scherer式から算出される平均サイズは11nmとなった。さらに、この立方体型EuSナノ結晶はメタノール中において平均サイズ330nm程度の会合体を形成していることがDLS測定から明らかになった。次にレーザートラッピング法を用いて、ガラス基板上におけるEuS会合体の二次元配列を試みた。レーザートラッピング実験における散乱光強度の経時...
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 19018017 - フォトクロミック・ターアリレン誘導体による革新光スイッチ分子の構築
科学研究費補助金(基盤研究(B))
2005年 - 2007年
河合 壯, 池田 篤志, 長谷川 靖哉, 中嶋 琢也
π共役ポリマーや分子の性質は、π共役系とその広がりに強く支配されている。π共 役系の広がりを光や外部摂動で制御できれば、従来にない分子レベルの光スイッチングや光メモリが可能となる。特に、光照射に伴い可逆に分子構造が変化するフォトクロミック分子は本質的にπ共役系の構造が可逆に変化することから、光スイッチングユニットとして有力な候補と考えられる。本研究では、光スイッチングユニットの中でも、とくにπ共役系の方向切り替え特性を有するターアリーレン系フォトクロミック分子を中心にπ共役スイッチングユニットの開発を進めた。ターアリーレン系フォトクロミックユニットとして、立体障害の抑制の観点から、チアゾールやイミダゾールをアリールユニットとして導入したリアリールイミダゾールおよびジアリールチアゾール誘導体を合成した。ジチエニルチアゾール構造の場合には比較的高い反応量子収率を示すことや単結晶状態での高い反応性を観測するなど、比較的優れたフォトクロミック反応性を見出した。単結晶構造解析の結果、チアゾールユニットの窒素原子とメチルチオフェンユニットのメチル水素原子との間で水素結合が形成しており、これが比較的高い反応性の起源となっていることが明らかになった。また、アリールユニットの芳香族性を制御することにより、着色状態の熱安定性が大きく変化する現象を見出した。この現象を利用すると、光照射後に着色状態...
文部科学省, 基盤研究(B), 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 17350069 - ビナフチル・ペリレンダイマーの単一分子円偏光蛍光計測と光スイッチング
科学研究費補助金(萌芽研究)
2005年 - 2007年
河合 壯, 内藤 昌信, 長谷川 靖哉, 中嶋 琢也
光学活性分子から発せられる蛍光は右円偏光成分と左円偏光成分の強度が異なり、この現象は円偏光性発光(CPL)と呼ばれる。近年、CPLを基盤にした高輝度液晶ディスプレイ用の偏光光源をはじめとして、3次元ディスプレイ、記憶材料、光通信など高度な光情報プロセッシングが提案されており、幅広い応用が期待されている。本研究では、光学活性なフルオロフォアからなる高特性の円偏光性発光材料の開発を行った。前年度開発されたビナフチルペリレンダイマーは高い蛍光量子収率、高い円二色性をしめし有望である。今年度はビナフチルペリレンダイマーの会合状態におけるCPL非対称性を評価し、さらに光照射に伴うスイッチングを検討した。従来、散乱性媒質におけるCPL非対称性の精密計測は成功例がなく、今回はこのため顕微CPL計測システムの検討を行った。その結果、顕微蛍光計測においても安定で高精度なCPL計測が可能であることを初めて見出した。また、ビナフチルペリレンダイマーの会合状態における発光スペクトルとCPLスペクトルの計測に初めて成功した。会合状態においては特徴的なCPLの増強が観測された。また会合状態においてはCPLの非対称性には特徴的な分散を有することを初めて見出した。これは非結晶性の分子会合状態における局所構造の不均質性を直接観測したものと考えている。分子会合状態をレーザー光により制御することで、CPL特性の光...
文部科学省, 萌芽研究, 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 17655019 - 希土類ナノ粒子の光磁気ポーラロン発生に伴うf軌道のスピン制御
科学研究費補助金(特定領域研究)
2005年 - 2006年
長谷川 靖哉, 河合 壯, 中嶋 琢也
本研究では、EuOやEuSよりも高い光磁気効果が期待されるEuSeナノ粒子の検討を行なった。EuSeナノ粒子の原料となるEu(III)錯体は、セレンを含む有機配位子Se_2P(Ph)_2の誘導体とEu(III)イオンとの錯化反応により合成した。このEu(III)錯体に関して、構造が異なる2種類の錯体を原料としてそれぞれEuSeナノ結晶の合成検討を行った。具体的には、各Eu錯体をHDA(Hexadecylamine)中300℃で24時間熱還元反応を行い、反応終了後に粒子を遠沈させることで紫色の固体粉末を得た。紫色粉末固体の同定は、透過型電子顕微鏡測定(TEM)およびX線粉体解析(XRD)を用いて行った。得られた紫色粉体を含むPMMA薄膜をガラス基板上に作製し、ファラデー測定により光磁気特性の評価を行なった。比較サンプルとして、従来の合成法によって得られたEuSナノ粒子を含むPMMAも同時に調製を行なった。紫色粉体のXRD測定から2θ=25.1^0,28.6^0,41.0^0,48.8^0,59.8^0および67.6^0に回折ピークが観測され、これらのピークはEuSeの(111),(200),(220),(311),(400)および(420)に相当することがわかった。さらに、TEM測定を行ったところ、原料であるEu(III)錯体の化学構造に違いにより、異なった形状(球状および立方...
文部科学省, 特定領域研究, 大阪大学->奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 17042015 - イオン性液体-蛍光性半導体ナノ結晶界面構造反応の単一粒子・単一分子蛍光計測
科学研究費補助金(特定領域研究)
2005年 - 2006年
河合 壯, 長谷川 靖哉, 中嶋 琢也
II-VI族半導体は発光性材料として広く研究されてきた。特に近年、ナノメートルサイズの半導体結晶においてその発光現象が広く検討されている。ナノ結晶の構造上の特徴として、表面に有機分子を保護層として有していることが挙げられ、さまざまな有機配位子に関する工夫や提案も進められている。このように半導体ナノ結晶は有機化学からの工夫の余地が広く、また界面におけるダイナミックな反応の解析と制御を目指す本特定領域の趣旨からも興味深い研究対象のひとつであると考えられる。本研究ではこれまでに見出されたイオン性液体中におけるCdTeナノ結晶からの蛍光の増強現象の解明とイオン液体中におけるCdTeナノ結晶の単一分子レベルの蛍光計測を進めた。イオン液体中においてはCdTeナノ結晶の蛍光は冷却に伴ってさらに増強されることが見出された。このような低温での蛍光増強は水溶液中で蛍光が低下することとまったく逆の傾向となった。さらに100K以下ではほぼ100%の蛍光量子収率を示すことが明らかになった。また、その発光波長は低温では格子定数の低下に伴い、次第に短波長シフトすることが見出された。20K以下の低温では、逆に発光波長が長波長シフトする現象が見出された。この傾向はCdSeなど関連するナノ結晶で見出されており、励起子の電子準位が電子間の交換相互作用により分裂していることに対応している。ナノ結晶の粒径が小さくなる...
文部科学省, 特定領域研究, 奈良先端科学技術大学院大学, 連携研究者, 競争的資金, 17034042 - 非対称型ユーロピウム(III)錯体の分子設計と光物理特性
科学研究費補助金(若手研究(B))
2003年 - 2005年
長谷川 靖哉
非対称型ユーロピウム錯体、Eu(hfa)3(TPPO)2をポリフェニルシルシスキ,オキサン(polyphenylsilsesqioxane : PPSQ)中にドープすることにより、錯体の非対称構造に基づくレーザー発振特性の向上を明らかにした。さらに、配位子場を非対称化させることにより、Eu(hfa)3(TPPO)2よりも優れたレーザー発振特性を導くことに成功した。これらのユーロピウム錯体の非対称構造はX線構造解析により明らかにし、その非解消構造に基づく電子遷移許容化の程度は量子化学計算(Judd-Ofelt解析)により見積を行なった。これらの解析結果から、ユーロピウム錯体の発光特性向上には非対称構造が極めて重要と結論した。さらに、非対称配位子場を有するユーロピウム4核錯体(クラスター)の合成も行なった。このユーロピウム多核錯体は強発光特性とともに「熱耐久性」にも優れ、300℃以上の加熱においても発光特性を維持できることが明らかとなった。この特異的な「熱耐久性」は4つのユーロピウムイオンからなるネットワーク構造が重要と考えられる。さらに、配位子による「配位部位の非対称構造」が優れた発光特性を可能にしていると結論づけた。本研究は、強発光特性を示す希土類錯体を材料へ展開する上で興味深い成果である。また、以上の考え方を応用することにより、強発光テルビウム錯体の合成にも成功した。このテ...
文部科学省, 若手研究(B), 大阪大学->奈良先端科学技術大学院大学, 研究代表者, 競争的資金, 15750155 - ナノサイズ酸化ユーロピウム(II)の合成および光磁気特性
科学研究費補助金(奨励研究(A), 若手研究(B))
2001年 - 2002年
長谷川 靖哉
概要高強度エキシマーレーザー照射によるEuOナノ結晶の合成に成功した。本系においては繰り返し周波数1Hz、レーザー強度130mJに設定し、レーザー光を1000回サンプル(硝酸ユーロピウム(III)、尿素、メタノール)に照射することにより、結晶性の高い、平均粒径4.7nmのナノサイズEuOが得られた。得られたEuOナノ結晶は青色領域に強発光を示すことが発光スペクトル測定より明らかとなった。合成時間は約15分であり、これまでの水銀ランプによる光還元法(72時間光照射)に較べて極めて速い時間でEuOの合成が可能になった。さらに、レーザー照射回数毎の発光スペクトルおよび吸収スペクトルを測定したところ、EuOナノ結晶の結晶成長に重要なEu(II)の前駆体の存在が明らかとなった。本研究はEuOナノ結晶の結晶成長のメカニズム解明に重要な知見を与えた。一方、前年度報告した液体アンモニア法によるEuOナノ結晶合成を応用して、EuS(硫化ユーロピウム(II))ナノ結晶の合成に成功した。本合成法は液体アンモニアに硫化水素を吹き込むことにより合成ができ、平均粒径20nmのEuSが得られた。このEuSナノ結晶は磁化率測定(SQUID)により強磁性を示すことが明らかとなった。世界初のEuSナノ結晶の合成および磁気特性を本研究により明らかとした。
文部科学省, 奨励研究(A), 若手研究(B), 大阪大学, 研究代表者, 競争的資金, 13740397 - ゼオライトナノ結晶発光性分子複合素子
科学研究費補助金(基盤研究(B))
2000年 - 2002年
和田 雄二, 長谷川 靖哉, 北村 隆之, 柳田 祥三
Nd^<3+>の光吸収能力は、f-f電子遷移に由来するため、本質的に低い。光吸収能力の高い配位子の励起3重項状態からのエネルギー移動を経た発光を示すNd^<3+>錯体が報告されている。Nd^<3+>の発光の良好な増感剤と知られる8-quinolinolを、ゼオライト細孔内のNd^<3+>にPMSと共配位さたことによる、初のゼオライト細孔内でのエネルギー移動を経たNd^<3+>発光に成功した。細孔内のNd^<3+>に対して低振動な環境を与えることのできるPMSを導入した後、8-quinolinolに導入した。その結果、8-quinolinolからのエネルギー移動を経たNd^<3+>の発光を観測することができた。Ru[bpy_3]^<2+>は、系間交差率がほぼ100%で、^3MLCT発光を示す。この準位はNd(III)の吸収準位と良く一致することから、Nd(III)の良好な増感剤候補である。Gd(III)の導入されたサンプルに比べてNd(III)の導入されたサンプルの^3MLCT発光強度は減少した。また、^3MLCTの発光寿命が減少したことから、[Ru(bpy)_3]^<2+>の^3MLCTからNd(III)へエネルギー移動が確認された。寿命測定からエネルギー移動効率は、Φ_=0.63と、高い値を示すことがわかった。Nd(III)の発光波長を検知した励起スペクトルにおいて...
文部科学省, 基盤研究(B), 大阪大学, 連携研究者, 競争的資金, 12450345 - 色素増感型酸化チタン太陽電池の実用化研究
科学研究費補助金(基盤研究(A))
1999年 - 2001年
柳田 祥三, 村澤 貞夫, 北村 隆之, 和田 雄二, 長谷川 靖哉
(1)低分子ゲル化剤を用いた擬固体化色素増感太陽電池の電解質溶液中のヨウ素酸化還元対の電子伝達機構について検討し、イオンの拡散だけではなく、要素間の結合の相互変換を伴う電子ホッピング(Grotthuss型)によることを明らかにした。また、常温で液体で蒸気圧がなく、不燃性の溶融塩を用いた太陽電池を構築し、かつ、溶融塩とゲル化剤を組み合わせた擬固体太陽電池を構築し、80℃の高温下でも安定な色素増感太陽電池の構築に成功した。(2)色素増感太陽電池の作用電極である多孔質酸化チタン中の、電子伝達挙動について理論的な解析を試み、電解質中のイオンの種類、濃度の影響から、電子の移動がアンバイポーラー拡散によること、またイオンの酸化チタン表面への強い吸着が電子移動速度を加速させることを明らかにした。(3)酸化チタン微結晶の結晶系を精密に制御し、同じ原料から純粋なアナタースおよびルチル結晶を作り分けることに成功した。また結晶系の違いによる電子伝達挙動に違いを明らかにした。(4)水溶性のセルロース増粘剤を用いた酸化チタンゾルを調製し、有機溶媒を用いないスクリーンプリント法による多孔質酸化チタン電極作製法を開発した。(5)導電性高分子(ポリピロール)を用いた固体型色素増感太陽電池の改善を行った。対極にカーボンブラック粒子からなる導電性炭素材料を用いることで、性能は従来の6倍まで向上した。ポリ(3,4...
文部科学省, 基盤研究(A), 大阪大学, 連携研究者, 競争的資金, 11358006 - 無機ナノゼオライトホストによる導電性高分子の高秩序配列化と新物性
科学研究費補助金(特定領域研究(A))
2000年 - 2000年
和田 雄二, 長谷川 靖哉, 北村 隆之, 柳田 祥三
概要1)ナノサイズホージャサイト型ゼオライトの合成を文献に基づきその手法を確立した。そのナノゼオライトをネオジム交換し、さらにフッ素アルキル基を含むスルホニルアミド(PMS)を配位子として、ネオジム錯体をゼオライト細孔内に合成した。このゼオライトは、(Nd(PMS)-n-FAU)は、ジメチルスルホキシド中に安定に分散することが、DLS測定ならびに吸収スペクトルから明らかとなった。吸収スペクトルには、ネオジムに起因のf-f遷移がみられた。未処理のものはほとんど分散しないことことから、PMSはn-FAU粒子の外表面を化学的に修飾することにより、分散を促進していることがわかった。吸収スペクトルから、均一に溶解したと仮定したジメチルスルホキシド中のネオジム濃度は8.7mMと計算された。発光スペクトルには、ネオジムの遷移に帰属される近赤外領域の発光が観測された。寿命は22msで一次減衰であった。吸収スペクトルの形状からネオジムは、対称性の高い環境に存在しすることがわかった。重水素化ジメチルスルホキシド中の発光量子収率は有機媒体中における最高値9.5%と、錯体溶液の値、3.3%の3倍にも向上したことから、ゼオライトは低振動ホストとして優れていると結論できる。この値は、有機溶媒中におけるネオジムからの発光として最高値である。2)ナノサイズホージャサイト型ゼオライトをユーロピウムで交換し、か...
文部科学省, 特定領域研究(A), 大阪大学, 連携研究者, 競争的資金, 12020232 - 超高圧下での有機光化学反応
科学研究費補助金(萌芽的研究)
1999年 - 2000年
柳田 祥三, 北村 隆之, 和田 雄二, 長谷川 靖哉
基底状態のオリゴパラフェニレンは,気相中や溶液中では隣り合う芳香環同士が互いにおよそ20度程度捻れた構造を取り,光励起状態では共平面状態になるという構造変化を引き起こす。さまざまなオリゴフェニレン誘導体の光物性を高圧条件下に測定し,吸収,蛍光スペクトルの長波長シフトと,吸光度の増加,蛍光量子収率の減少が観測された。これらの変化は,圧力の増加に伴う溶媒の誘電率が上昇したために起こる基底状態分子への作用と,溶媒の粘度が上昇したことに伴う,励起状態での構造緩和過程への作用とによることが明らかとなった。一方部分フッ素化パラフェニレン類は,基底状態で会合体を形成するが,圧力の上昇に伴い会合体の形成が促進されることが明らかとなった。また励起状態では,構造の緩和過程が促進されるため,発光量子収率の増加が観測された。パラフェニレン類のこれらの光物性の変化は,圧力の印可に伴う溶質分子,あるいは溶媒分子との間の分子間相互作用の増強によることを明らかにした。アゾベンゼンとソのぺルフルオロ体の光異性化反応を希薄溶液中高圧条件下に測定し,異性化の速度,および定常状態でのcis-trans比を求めた。圧力が高い場合にはtrans体の生成比が増大し,励起中間体から基底状態のtrans体への失活過程の活性化体積が小さいことが判明した。一方,これら両化合物の1:1混合溶液の場合,逆に圧力の印可に伴いcis体の...
文部科学省, 萌芽的研究, 大阪大学, 連携研究者, 競争的資金, 11875188 - 希土類錯体から配位高分子へのソフトクリスタル変形と光機能評価
産業財産権
- 発光材料、酸素センサー、及び塗料
特許権, 北川裕一, 中井拓真, 島かおり, 庄司淳, 長谷川靖哉, 伏見公志
特願2022-03353, 2022年03月04日 - 希土類錯体、発光材料、発光体、及び、ホスフィンオキシド基を有する化合物
特許権, 長谷川靖哉, 林嬢, 北川裕一, 伏見公志
特願2021-074135, 2021年04月26日 - 発光材料;発光インク;発光体及び発光デバイス
特許権, 長谷川靖哉, ツァンテン, 北川裕一
特願2020-119391, 2020年07月10日 - ビスホスフィンオキシド希土類錯体及び光学機能性材料
特許権, 長谷川靖哉、北川裕一、鶴井真、田村健、佐野夏博
特願2019-132858, 2019年07月18日 - 希土類錯体, 希土類錯体溶液、発光性成形体、発光性物品を製造する方法
特許権, 北川裕一、島かおり、和田智志、長谷川靖哉、伏見公志
特願2019-085626, 2019年04月26日 - 希土類化合物、ホスフィンオキシド化合物及び発光体
特許権, 北川裕一, 鈴江郁哉, 長谷川靖哉, 伏見公志
特願2018-241307, 2018年12月25日 - 希土類錯体、発光体及び発光デバイス
特許権, 長谷川靖哉, フェレイラダダローサペドロパウロ, 北川裕一, 伏見公志
特願2018-158240, 2018年08月27日 - 希土類錯体、放射線治療用光学イメージング剤、中性子線検出用シンチレーター及びカルボラン誘導体
特許権, 長谷川靖哉、齋藤康樹、北川裕一、中西貴之、伏見公志
特願特願2019-30678, 2018年06月28日 - 希土類錯体ポリマー及び発光体
特許権, 中西貴之, 松田賢司, 沢登拓矢, 北川裕一, 伏見公志, 長谷川靖哉
特願2018-011508, 2018年 - 希土類錯体及び発光材料
特許権, 北川裕一, 鈴江郁哉, 中西貴之, 伏見公志, 長谷川靖哉
特願2017-035043, 2017年02月27日 - ホスフィンオキシド化合物、希土類錯体及び発光材料
特許権, 長谷川靖哉, フェレイラ ダ, ローサ, ペドロ パウロ, 中西貴之, 北川裕一, 伏見公志
特願2017-035041, 2017年02月27日 - 希土類化合物、発光体、発光デバイス、波長変換材料及びセキュリティ材料
特許権, 中西貴之, 袴田翔, 北川裕一, 伏見公志, 長谷川靖
特願2017-221678, 2017年 - Eu錯体及び有機EL素子
特許権, 長谷川靖哉, 名取詩織, 中西貴之, 北川裕一, 伏見公志, 赤木努, 内藤裕義, 福留淳
特願2016-170553, 2016年09月01日 - 近赤外線発光を示すポルフィリンガラス
特許権, 森末光彦, 佐々木園, 中西貴之, 長谷川靖哉
特願2016-161750, 2016年08月22日 - キラル型希土類錯体ポリマーおよびそれを用いた光学機能材料
特許権, 長谷川靖哉, 北川裕一, 中西貴之, 伏見公志, 小礒尚之
特願2016-135217, 2016年07月07日 - 希土類錯体ポリマー
特許権, 中西貴之, 平井悠一, 北川裕一, 伏見公志, 長谷川靖哉
特願2016-092667, 2016年 - 蛍光材料、蛍光材料の発光スペクトルを制御する方法及び蛍光システム
特許権, 中西貴之, 松井貴文, 北川裕一, 伏見公志, 長谷川靖哉
特願2016-122896, 2016年 - 発光材料、インク、及び発光デバイス
特許権, 中西貴之, 岡井翼, 北川裕一, 伏見公志, 長谷川靖哉, 田中一生, 権正行, 中條善樹
特願2016-176913, 2016年 - キラル型希土類錯体ポリマーおよびそれを用いた光学機能材料
特許権, 長谷川靖哉, 三浦由衣, 北川裕一, 中西貴之, 伏見公志, 小礒尚之
特願2016-019164, 2016年 - 高分子錯体及びその製造方法,長谷川靖哉
特許権, 中島綾子, 中西貴之, 北川裕一, 伏見公志
特願2015-45416, 2015年
特許第6666009号 - 希土類錯体及びその製造方法、並びにプラスチック成形体
特許権, 長谷川靖哉, 小野寺宏光
特願2015-046001, 2015年 - 希土類錯体および発光素子
特許権, 北川裕一, 大野良輔, 長谷川靖哉, 伏見公志, 中西貴之
特願2015-045930, 2015年 - 希土類錯体、発光材料及びその製造方法、並びに発光シート
特許権, 中西貴之, 岡井翼, 長谷川靖哉, 北川裕一, 伏見公志
特願2015-046202, 2015年 - 希土類金属錯体及びそれを用いる発光装置
特許権, 長谷川靖哉, 柳澤慧, 中西貴之, 北川裕一, 伏見公志, 小飯塚徹
特願2015-003282, 2015年
特許第6643804号 - 三光子励起により発光する発光性組成物
特許権, 川俣純, 鈴木康孝, 守友博紀, 藤井旺成, 長谷川靖哉, 山本昌紀
特願2014-205115, 2014年 - 配位子、高分子錯体及びその製造方法
特許権, 長谷川靖哉, 山本昌紀, 中西貴之, 伏見公志
特願2014- 023813, 2014年 - 有機ELデバイス用薄膜及びその製造方法
特許権, 長谷川靖哉, 菅原猛司, 赤木努, 砂糖正典, 上野一彦
特願2013-183620, 2013年 - 希土類錯体ポリマーとその製造方法、及びプラスチック成形体
特許権, 小野寺宏光, 長谷川靖哉
特願2013-183142, 2013年 - 配位子および希土類錯体
特許権, 長谷川靖哉, 平井悠一, 中西貴之, 伏見公志
特願2013-141994, 2013年 - シート集積型希土類錯体及びその用途
特許権, 長谷川靖哉, 立野栞, 中西貴之, 伏見公志
特願2013-141995, 2013年 - 発光性複合材料および発光体ナノ結晶
特許権, 小野寺宏光, 長谷川靖哉
特願2012-245490, 2012年 - 機能性材料の構造体及び機能性材料の構造体の製造方法
特許権, 中西貴之, 長谷川靖哉, 前田将司, 川島祥, 伏見公志
特願2011-264892, 2011年 - 希土類錯体ポリマー
特許権, 長谷川靖哉, 宮田康平, 伏見公志, 加藤昌子, 小林厚志
特願2011-103136, 2011年 - 金属イオンドープEu(II)化合物のナノ結晶及び薄膜
特許権, 長谷川靖哉, 前田将司, 熊谷美那, 伏見公志
特願2011-047623, 2011年 - Eu(II)化合物及び金属を含有する複合ナノ結晶及び複合薄膜
特許権, 長谷川靖哉, 川島祥, 熊谷美那, 伏見公志
特願2011-047595, 2011年 - 円偏光発光性希土類錯体
特許権, 湯浅順平, 宮田康平, 妻鳥紘之, 原田聖, 長谷川靖哉, 河合壯
特願2012-504424, 2011年
特許第5713360号 - 希土類錯体及びその利用
特許権, 長谷川靖哉, 河合壯, 中嶋琢也, 中川哲也, 宮田康平
特願2009-176558, 2009年
US 8,975,385 B2 - 金属錯体およびその利用
特許権, 河合壯, 長谷川靖哉, 中川哲也
特願2009-120950, 2009年 - 希土類錯体およびその利用
特許権, 長谷川靖哉, 河合壯, 原田聖
特願2009-503899, 2009年
特許第5371009号 - 希土類錯体ナノ結晶およびその応用
特許権, 長谷川靖哉, 中川哲也, 河合壯
特願2008-241703, 2008年 - 構造解析装置及び構造解析方法
特許権, 長谷川靖哉, 河合壯, 湯浅順平, 片岡幹雄, 山田晃平
特願2008-232489, 2008年
特許第5414073号 - 希土類金属錯体並びにそれを用いた波長変換材料
特許権, 長谷川靖哉, 河合壯, 倉持悠輔, 横尾敏明
特願2008-320608, 2008年 - 近赤外強発光性希土類錯体
特許権, 長谷川靖哉, 河合壯, 川井秀記
特願2008-052779, 2008年
特許第5207492号 - 希土類錯体およびその利用
特許権, 長谷川靖哉, 河合壯, 原田聖
特願2007-059484, 2007年 - 発光性希土類九核錯体
特許権, 柳田祥三, 長谷川靖哉, 萬関一広
特願2006-029509, 2006年
特許第4702887号 - 希土類錯体およびその利用
特許権, 長谷川靖哉, 河合壯, 中川哲也
特願2006-208684, 2006年
特開2008-031120
特許第5110484号 - ナノサイズEuSe結晶及びナノサイズEuSe結晶の製造方法
特許権, 長谷川靖哉, 河合壯, 安達隆明
特願2006-64890, 2006年 - 情報識別装置、情報識別方法、情報識別システム、及び発光部材
特許権, 長谷川靖哉, 河合壯
特願2005-239452, 2005年 - 発光性希土類多核錯体
特許権, 萬関一広, 長谷川靖哉, 柳田 祥三
特願2005-033363, 2005年 - 耐酸性希土類錯体
特許権, 堀木エリ子, 長谷川靖哉, 兼松泰男, 松本雅治, 猪谷太栄, 八伏俊彰
特願2005-067240, 2005年 - 円偏光発光性を有する新規希土類錯体
特許権, 永田美彰, 長谷川靖哉, 柳田祥三
特願2004-72487, 2004年
特開2005-97240
特許第3687791号 - 有機ラジカル配位子を有する希土類錯体を含有する発光材料
特許権, 塚原保徳, 長谷川靖哉, 柳田祥三
特願2003-428217, 2003年
特開2005-187546
特許第4009587号 - 識別マーク
特許権, 矢野大輔, 永田美彰, 長谷川靖哉, 柳田祥三
特願2003-346988, 2003年
特開2005-114909 - 印刷インキおよび印刷物
特許権, 矢野大輔, 永田美彰, 長谷川靖哉, 柳田祥三
特願2003-346987, 2003年
特開2005-112947 - 熱耐久性を有する希土類錯体
特許権, 萬関一広, 長谷川靖哉, 柳田祥三
特願2003-348491, 2003年 - 強発光性希土類錯体
特許権, 長谷川靖哉, 柳田祥三, 和田雄二
特願2003-315948, 2003年
特許第4378139号 - ナノサイズのEuO結晶又はEuS結晶を含有する光磁気応答性プラスティック
特許権, 柳田祥三, スピッチャー・トンチャン, 長谷川靖哉, 和田雄二
特願2003-155534, 2003年 - 強発光希土類錯体
特許権, 長谷川靖哉, 柳田祥三, 和田雄二
特願2003-102237, 2003年
特開2004-262909 - 発光強度の増強された無機蛍光体、該無機蛍光体を含む分散液
特許権, 萬関一広, 兼松 泰男, 柳田 祥三, 長谷川靖哉, 前田和紀
特願2003-070161, 2003年 - 発光ブロック
特許権, 長谷川靖哉, 兼松泰男, 川畑弘, 長山智男, 小西毅, 小林哲郎
特願2003-020635, 2003年 - 希土類錯体含有薄膜を用いたレーザー発振装置
特許権, 長谷川靖哉, 柳田祥三, 保田直紀, 川井秀記, 長村利彦
特願2002-342126, 2002年
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特許権, 長谷川靖哉, 柳田祥三, 和田雄二
特願2002-064542, 2002年
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特許権, 長谷川靖哉, 柳田祥三, 和田雄二, 島田順一, 川上養一, 藤田茂夫
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特許権, 長谷川靖哉, 柳田祥三, 和田雄二, 島田順一, 川上養一, 藤田茂夫
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特許権, 島田順一, 川上養一, 藤田茂夫, 長谷川靖哉, 柳田祥三, 和田雄二
特願2001-135116, 2001年
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特許権, 曽我部健作, 長谷川靖哉, 柳田祥三
特願平2000-278207, 2000年 - ナノサイズの希土類酸化物又は硫化物及びそれらの光化学反応を用いた製法
特許権, 柳田祥三, 和田雄二, 長谷川靖哉
特願2000-175299, 2000年
特開2001-354417
特許第4148635号 - 希土類金属担持ナノサイズ(ホスト-ゲスト)複合体
特許権, 柳田祥三, 和田雄二, 長谷川靖哉
特願平11-62298, 1999年
特開2000-256251 - 発光性インク組成物
特許権, 長谷川靖哉, 柳田祥三, 藤田淳
特願平10-257777, 1998年
特開2000-086952 - 希土類錯体を含む樹脂組成物及び成形体
特許権, 長谷川靖哉, 曽我部健作, 和田雄二, 柳田祥三
特願平10-238973, 1998年
特開2000-063682 - 有機EL素子
特許権, 長谷川靖哉, 河村祐一郎, 和田雄二, 柳田祥三
特願平810-063512, 1998年
特開平11-260552 - 希土類錯体
特許権, 長谷川靖哉, 曽我部健作
特願平10-071361, 1998年
特開平11-246510 - 希土類錯体
特許権, 岩室光則, 柳田祥三, 長谷川靖哉
特願平9-238568, 1997年
特開平11-080165 - スルホンイミド及びその製造方法
特許権, 長谷川靖哉, 曽我部健作
特開平11-92446, 1997年
特願平09-273668 - 希土類錯体
特許権, 柳田祥三, 長谷川靖哉, 和田雄二, 山中龍彦, 大久保崇, 藤田淳
特願平9-56718, 1997年
特願平10-539429 - 結晶化ガラス複合体の製造方法および結晶ガラス複合体
特許権, 中西貴之, 渡邊和音, 伏見公志, 長谷川靖哉
特願2012-060575
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