基本情報

所属

• 理学研究院　化学部門　物理化学分野

職名

• 准教授

学位

• 博士(理学)（東京大学）

ORCID ID

•  https://orcid.org/0000-0001-7346-8446

J-Global ID

• 200901042831883068

研究キーワード

• 焦電体   強誘電体   圧電体   柔粘性結晶   分子運動   電荷移動錯体   結晶化学   

研究分野

• ナノテク・材料 / 有機機能材料
• ナノテク・材料 / 機能物性化学
• ナノテク・材料 / 構造有機化学、物理有機化学
• ナノテク・材料 / 基礎物理化学

担当教育組織

•  学士課程　理学部
•  修士課程　総合化学院
•  博士課程　総合化学院

学歴

• 1994年 - 1997年   東京大学   大学院理学系研究科   化学専攻博士課程
• 1992年 - 1994年   東京大学   大学院理学系研究科   化学専攻修士課程
• 1988年 - 1992年   東京大学   理学部   化学科

所属学協会

• 分子科学会   光化学協会   日本結晶学会   日本化学会   

研究活動情報

論文

• Intersecting multiaxial domain walls in plastic ferroelectric crystal films

  Yohei Uemura, Satoshi Matsuoka, Shunto Arai, Jun Harada, Tatsuo Hasegawa

  Physical Review Materials 7 3 2023年03月02日 [査読有り]
  
• Ferroelectric Ionic Molecular Crystals with Significant Plasticity and a Low Melting Point: High Performance in Hot‐Pressed Polycrystalline Plates and Melt‐Grown Crystalline Sheets

  Jun Harada, Haruka Takahashi, Rin Notsuka, Mika Takehisa, Yukihiro Takahashi, Tomoyasu Usui, Hiroki Taniguchi

  Angewandte Chemie International Edition 62 3 e202215286  2022年12月13日 [査読有り]
   

  Abstract Among ferroelectric crystals based on small molecules, plastic/ferroelectric crystals are currently receiving particular attention because they can be used as bulk polycrystals. Herein, we show that an ionic molecular ferroelectric crystal, guanidinium tetrafluoroborate, exhibits significant malleability and multiaxial ferroelectricity despite the absence of a plastic crystal phase. Powder samples of this crystal can be processed into transparent bulk crystalline plates either by press‐forming or by melt‐growing. The plates show high ferroelectric performance and related properties, demonstrating the largest hitherto reported spontaneous polarization for bulk polycrystals of small‐molecule‐based ferroelectrics. Owing to the ready availability of large‐scale materials and processability into various bulk crystalline forms, this ferroelectric crystal represents a highly promising functional material that will boost research on diverse applications as bulk crystals.
• Plastic/Ferroelectric Crystals with Distorted Molecular Arrangement: Ferroelectricity in Bulk Polycrystalline Films through Lattice Reorientation

  Jun Harada, Mika Takehisa, Yuto Kawamura, Haruka Takahashi, Yukihiro Takahashi

  Advanced Electronic Materials 8 2101415 - 2101415 2022年03月08日 [査読有り]
  
• Stabilization of Interfacial Polarization and Induction of Polarization Hysteresis in Organic MISIM Devices

  Seiya Yokokura, Akihiro Tomimatsu, Jun Ishiguro, Jun Harada, Haruka Takahashi, Yukihiro Takahashi, Yuto Nakamura, Hideo Kishida, Rie Suizu, Michio M. Matsushita, Kunio Awaga

  ACS Applied Materials & Interfaces 13 27 31928 - 31933 2021年07月01日 [査読有り]
  
• Charge injection phenomena at the contact interface between (5,10,15,20-tetramethylporphyrinato)cobalt(ii) and 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane single crystals

  Yukihiro Takahashi, Kenshiro Ishida, Sarasa Matsuno, Masashi Kurokawa, Takuro Shimada, Jun Harada, Tamotsu Inabe

  CrystEngComm 23 22 3975 - 3980 2021年04月24日 [査読有り][通常論文]
   

  Charge transfer phenomena occurring at the contact interface of heterogeneous organic crystals are investigated. About 10% more charge was injected into the crystal interface by the contact, which largely increased the surface conductivity.

• Plastic/ferroelectric molecular crystals: Ferroelectric performance in bulk polycrystalline forms

  Jun Harada

  APL Materials 9 2 020901 - 020901 2021年02月10日 [査読有り][招待有り]
  
• Electric and Thermosalient Properties of a Charge-Transfer Complex Exhibiting a Minor Valence Instability Transition

  Yukihiro Takahashi, Tsubasa Kondo, Seiya Yokokura, Mika Takehisa, Jun Harada, Tamotsu Inabe, Michio M. Matsushita, Kunio Awaga

  Crystal Growth & Design 20 7 4758 - 4763 2020年07月01日 [査読有り][通常論文]
   

  The charge-transfer (CT) complex 3,3 ',5,5 '-tetramethylbendizine-7,7,8,8-tetracyanoquinodimethane was found to display the thermosalient effect, in which crystals exhibit mechanical responses due to temperature changes. Such responses are rarely observed with CT complexes. Furthermore, while this crystalline complex was known to have an interesting phase transition in which the charge distribution changes at low temperatures, some of the physical properties of single crystals of the material were unknown, because the crystal is broken during the thermosalient event. In this study, we used a polymer-coating method to prevent cracking of the crystal, allowing us to observe drastic changes in resistivity and ferroelectric-like dielectric response accompanied by the phase transition at low temperature. This result suggests that organic solids with mechanical response and electric and magnetic functions can be produced, since CT complexes exhibit various electric and magnetic functions and physical properties.
• Incorporating Spacer Molecules into the Tetrathiafulvalene–p-Chloranil Charge-Transfer Framework: Modulating the Neutral–Ionic Phase Transition

  Yukihiro Takahashi, Mika Takehisa, Eri Tanaka, Jun Harada, Reiji Kumai, Tamotsu Inabe

  The Journal of Physical Chemistry Letters 11 4 1336 - 1342 2020年02月20日 [査読有り][通常論文]
  
• Molecular Dynamics Simulation Study of the Plastic/Ferroelectric Crystal Quinuclidinium Perrhenate

  Makoto Yoneya, Jun Harada

  The Journal of Physical Chemistry C 124 3 2171 - 2177 2020年01月23日 [査読有り][通常論文]
  
• Plastic/Ferroelectric Crystals with Easily Switchable Polarization: Low-Voltage Operation, Unprecedentedly High Pyroelectric Performance, and Large Piezoelectric Effect in Polycrystalline Forms

  Jun Harada, Yuto Kawamura, Yukihiro Takahashi, Yohei Uemura, Tatsuo Hasegawa, Hiroki Taniguchi, Koji Maruyama

  Journal of the American Chemical Society 141 23 9349 - 9357 2019年06月12日 [査読有り][通常論文]
   

  © 2019 American Chemical Society. Molecular ferroelectric crystals have attracted growing interest as potential alternatives to conventional lead-based ceramic ferroelectrics. We have recently discovered that a class of compounds known as plastic crystals can show multiaxial ferroelectricity, which allows ferroelectric performance even in polycrystalline forms. Here, we report new plastic/ferroelectric ionic molecular crystals that exhibit remarkably small coercive electric fields at room temperature. The easily switchable ferroelectric polarization enables low-voltage switching operations and high-frequency performance. Such ferroelectric crystals can be readily processed into bulk polycrystalline forms with desired shapes that are characterized by unprecedentedly high pyroelectric figures of merit and large piezoelectricity. These multifunctional molecular crystals represent highly attractive prospects for device elements with a diverse range of applications, which will significantly boost the development of molecular ferroelectric crystals.
• Crystals of Charge-Transfer Complexes with Reorienting Polar Molecules: Dielectric Properties and Order-Disorder Phase Transitions

  Harada Jun, Yoneyama Naho, Sato Shota, Takahashi Yukihiro, Inabe Tamotsu

  CRYSTAL GROWTH & DESIGN 19 1 291 - 299 2019年01月 [査読有り][通常論文]
  
• Electronic properties of tin iodide hybrid perovskites: effect of indium doping

  Kobayashi Keisuke, Hasegawa Hiroyuki, Takahashi Yukihiro, Harada Jun, Inabe Tamotsu

  MATERIALS CHEMISTRY FRONTIERS 2 7 1291 - 1295 2018年07月01日 [査読有り][通常論文]
   

  For solution-processable tin iodide cubic perovskites, a small amount of indium doping reduced the conductivity without changing the band gap or the carrier concentration. We demonstrated another possibility of foreign metal doping in tin iodide cubic perovskites and displayed a design strategy for electronic devices using hybrid perovskites.

• X線結晶解析による分子ダイナミクスの解明と機能性結晶の開発

  原田 潤

  日本結晶学会誌 60 2-3 96 - 103 日本結晶学会 2018年05月31日 [査読無し]
  
• Band-Like Carrier Transport at the Single-Crystal Contact Interfaces between 2,5-Difluoro-7,7,8,8-tetracyanoquinodimethane and Electron Donors

  Takuro Shimada, Yukihiro Takahashi, Jun Harada, Hiroyuki Hasegawa, Tamotsu Inabe

  Journal of Physical Chemistry Letters 9 2 420 - 424 2018年01月18日 [査読有り][通常論文]
   

  Some heterojunction interfaces formed with molecular solids show metal-like transport behavior. In order to clarify the requirement, interfaces are fabricated by lamination of single-crystal electron-accepting 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F2TCNQ) and electron-donating molecules with a wide range of ionization potentials. Carrier injection between the acceptor and donor crystals leads to highly conducting interfaces, some of which exhibited band-like charge transport behaviors. Combinations with weak donors also resulted in interfaces with band-like transport properties. Accordingly, band-like conduction was achieved for interfaces where the donor and acceptor crystals do not have well-matched band energies. The results indicate that the wide range of candidates have great potential for modification of the electronic structure of organic crystals. The present method is expected to enable control of the electronic properties of the interface.
• Ferroelectricity and Piezoelectricity in Free-Standing Polycrystalline Films of Plastic Crystals

  Jun Harada, Naho Yoneyama, Seiya Yokokura, Yukihiro Takahashi, Atsushi Miura, Noboru Kitamura, Tamotsu Inabe

  Journal of the American Chemical Society 140 1 346 - 354 2018年01月10日 [査読有り][通常論文]
   

  Plastic crystals represent a unique compound class that is often encountered in molecules with globular structures. The highly symmetric cubic crystal structure of plastic crystals endows these materials with multiaxial ferroelectricity that allows a three-dimensional realignment of the polarization axes of the crystals, which cannot be achieved using conventional molecular ferroelectric crystals with low crystal symmetry. In this work, we focused our attention on malleability as another characteristic feature of plastic crystals. We have synthesized the new plastic/ferroelectric ionic crystals tetramethylammonium tetrachloroferrate(III) and tetramethylammonium bromotrichloroferrate(III), and discovered that free-standing translucent films can be easily prepared by pressing powdered samples of these compounds. The thus obtained polycrystalline films exhibit ferroelectric polarization switching and a relatively large piezoelectric response at room temperature. The ready availability of functional films demonstrates the practical utility of such plastic/ferroelectric crystals, and considering the vast variety of possible constituent cations and anions, a wide range of applications should be expected for these unique and attractive functional materials.
• Photochromism of Fulgide Crystals: From Lattice-Controlled Product Accumulation to Phase Separation

  Jun Harada, Masaya Taira, Keiichiro Ogawa

  CRYSTAL GROWTH & DESIGN 17 5 2682 - 2687 2017年05月 [査読有り][通常論文]
   

  Fulgides are photochromic in solution and lit the solid state. This study revealed that the photochromisin of fulgide crystals proceeds in two stages. On the basis,of a previously developed two-photon excitation method, a Singe, crystal X-ray diffraction study on (2E,3Z)-2[1-(2,5,-dimethyl-3-furyl)-,2-methylpropylidene]-3-sec-butylidenesuccinic anhydride (3) allowed, monitoring the structural changes in the 'solid state and confirmed that the photoeyclization proceeded in a conrotatory fashion. The lattice-controlled photoreaction was, however, limited to the early photoconversion stages, where only a small amount of photogenerated colored species was presentin the lattice of the reactant crystals. Upon further accumulation of the photoproduct, the reaction,proceeded to a second stage, where the crystals of the photoproduct separated from the reactant-like crystals to form-adifferent solid phase. The in situ observation of the solid-state photochromism was thus also limited to, the early stages,of the photochromic conversions, where the product yield is low and the irradiated crystals, retain the original crystal lattice.
• Structural and transport properties of neutral radical crystals of Co-III(tmp)(CN)(2) (tmp=5,10,15,20-tetramethylporphyrinato) and the CN-bridged polymer [Co-III( tmp)(CN)](n)

  Masashi Kurokawa, Judy Fe F. Jose-Larong, Hiroyuki Hasegawa, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe

  DALTON TRANSACTIONS 46 13 4422 - 4429 2017年04月 [査読有り][通常論文]
   

  An axially ligated Co(tmp) (tmp = 5,10,15,20-tetramethylporphyrinato) anion, [Co-III(tmp)(CN)(2)](-), has been prepared and subjected to electrochemical oxidation to obtain the open shell tmp pi-ligand. With acetone as the solvent, solvent-free neutral radical crystals of Co-III(tmp)(CN)(2) are obtained, whereas solvent-inclusive crystals of Co-III(tmp)(CN)(2)center dot 2CH(3)CN are obtained with CH3CN as the solvent. In both crystals, the open shell tmp ring deforms into a ruffled form, which makes the pi-pi interactions in the crystal weak. Thus, the electrical conductivity is low, and the crystals behave as semiconductors with a room temperature resistivity of 10(6) Omega cm and an activation energy of about 0.3 eV. When the solvent is acetone, non-oxidized crystals of the CN-bridged polymer {[Co-III(tmp)(CN)](acetone)}(n) are obtained as a byproduct. The closed shell tmp ring deforms into a ruffled form, and there pi-pi interactions in the crystal are negligible. The room temperature resistivity is rather high at about 10(8) Omega cm.
• Effective band gap tuning by foreign metal doping in hybrid tin iodide perovskites

  Hiroyuki Hasegawa, Keisuke Kobayashi, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe

  JOURNAL OF MATERIALS CHEMISTRY C 5 16 4048 - 4052 2017年04月 [査読有り][通常論文]
   

  Herein, we introduce a novel effective band tuning method in hybrid tin iodide perovskites using a different group element. With this method, band gap reduction down to 0.8 eV is observed in tin ( group 14) iodide-based hybrid perovskites as a result of bismuth ( group 15) doping. In this solution-processable material, the band gap is continuously controllable in the range from 1.3 to 0.8 eV even when the doping level was less than 10%. The effect of ``foreign metal'' doping on the band gap is larger than that of the mixed crystal with the same group elements. Bismuth doping reduces the conductivity of the materials depending on the doping levels though their behavior is still clearly metallic. From the results of the electronic structure and electronic properties of this material, it is clear that bismuth doping causes the narrowing of the band gap without changing the energy and DOS at the top of the valence band, and without increasing the number of carriers. The band tuning method will be useful for the design of solar cells.
• Directionally tunable and mechanically deformable ferroelectric crystals from rotating polar globular ionic molecules

  Jun Harada, Takafumi Shimojo, Hideaki Oyamaguchi, Hiroyuki Hasegawa, Yukihiro Takahashi, Koichiro Satomi, Yasutaka Suzuki, Jun Kawamata, Tamotsu Inabe

  NATURE CHEMISTRY 8 10 946 - 952 2016年10月 [査読有り][通常論文]
   

  Ferroelectrics are used in a wide range of applications, including memory elements, capacitors and sensors. Recently, molecular ferroelectric crystals have attracted interest as viable alternatives to conventional ceramic ferroelectrics because of their solution processability and lack of toxicity. Here we show that a class of molecular compounds-known as plastic crystals-can exhibit ferroelectricity if the constituents are judiciously chosen from polar ionic molecules. The intrinsic features of plastic crystals, for example, the rotational motion of molecules and phase transitions with lattice-symmetry changes, provide the crystals with unique ferroelectric properties relative to those of conventional molecular crystals. This allows a flexible alteration of the polarization axis direction in a grown crystal by applying an electric field. Owing to the tunable nature of the crystal orientation, together with mechanical deformability, this type of molecular crystal represents an attractive functional material that could find use in a diverse range of applications.
• Fabrication of Conducting Thin Films on the Surfaces of 7,7,8,8-Tetracyanoquinodimethane Single-Component and Charge-Transfer Complex Single Crystals: Nucleation, Crystal Growth, Morphology, and Charge Transport

  Yukihiro Takahashi, Tomohiro Mikasa, Kei Hayakawa, Seiya Yokokura, Hiroyuki Hasegawa, Jun Harada, Tamotsu Inabe

  JOURNAL OF PHYSICAL CHEMISTRY C 120 31 17537 - 17545 2016年08月 [査読有り][通常論文]
   

  Electrically conducting TTF-TCNQ thin films are fabricated on various molecular crystals containing 7,7,8,8-tetracyanoquinodimethane (TCNQ) by exposing a tetrathiafulvalene (TTF) vapor under ambient conditions. To systematically investigate the properties of the films, mixed stack TCNQ charge-transfer (CT) complex crystals with nine kinds of donors have been prepared as the substrates, and the morphology change of the films on the surfaces at the initial stage of the TTF vapor contact has been observed. When the substrate is a TCNQ single-component crystal, randomly oriented TTF TCNQ nanometer-size needle crystals are grown by the reaction with a TTF vapor. However, when the substrate is a TCNQ CT complex crystal, TTF TCNQ crystals are grown with alignment of their needle axis along the mixed-stack direction of the substrate. The surface roughness, the size of the needle crystals, and the degree of the dense packing of the needles have been found to systematically depend on the strength of the CT interactions in the substrate, and the sheet resistance also exhibits a systematic change. The resistance drop is rapid and remarkable when the donor of the substrate CT complex is weak. The difference in the morphology and the properties is considered to arise from the difference in the ease of nucleus formation and the rate of crystal growth of the TTF TCNQ nanocrystals.
• Charge Carrier Doping into the Peierls Insulator of the TCNQ Anion Radical Salt (TCNQ=7,7,8,8-Tetracyanoquinodimethane)

  Hiroyuki Kubota, Yukihiro Takahashi, Hiroyuki Hasegawa, Takuro Shimada, Jun Harada, Tamotsu Inabe

  JOURNAL OF PHYSICAL CHEMISTRY C 120 21 11545 - 11551 2016年06月 [査読有り][通常論文]
   

  Hole-doping into K-TCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane) crystals with segregated TCNQ, anion radical columns with dimeric deformation (Peierls state) has been performed by a contact doping method using F(4)TCNQ (F(4)TCNQ = 2,3,5;6-tetrafluoro-7,7;8,8-tetracyanoquinodimethane) crystals or powder. The sheet resistance of the K-TCNQ surface has been found to decrease by the F(4)TCNQ contact. Formation of K-F(4)TCNQ nanocrystals at the TCNQ contact interface has been observed, but conductive AFM images indicate that current paths form along the hole-doped K-TCNQ surface. Interestingly, hole-doping into K-TCNQ suppresses the phase transition to the high-temperature phase (Mott insulator). This is considered to result from the energy gain by the delocalization of the doped carriers.
• Transport Characteristics of the Organic Field-Effect Transistors Based on Charge Transfer Complex as Semiconductors

  Seiya Yokokura, Yukihiro Takahashi, Hiroyuki Hasegawa, Jun Harada, Tamotsu Inabe, Michio M. Matsushita, Kunio Awaga

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 16 4 3355 - 3359 2016年04月 [査読有り][通常論文]
   

  The n-type organic field-effect transistors are fabricated with using four kinds of charge transfer (CT) complexes with PXX (peri -xanthenoxanthene) as a donor component. The CT complexes with four kinds of acceptors form mixed-stack type one-dimentional columns with different PXX-acceptor overlaps. Comparison of the field-effect properties reveals the correlation between the device performance and intermolecular interaction in the semiconducting CT complexes.
• Switching of Transfer Characteristics of an Organic Field-Effect Transistor by Phase Transitions: Sensitive Response to Molecular Dynamics and Charge Fluctuation

  Seiya Yokokura, Yukihiro Takahashi, Hiroki Nonaka, Hiroyuki Hasegawa, Jun Harada, Tamotsu Inabe, Reiji Kumai, Hiroshi Okamoto, Michio M. Matsushita, Kunio Awaga

  Chemistry of Materials 27 12 4441 - 4449 2015年06月23日 [査読有り]
  
• Molecular Motion, Dielectric Response, and Phase Transition of Charge-Transfer Crystals: Acquired Dynamic and Dielectric Properties of Polar Molecules in Crystals

  Jun Harada, Masaki Ohtani, Yukihiro Takahashi, Tamotsu Inabe

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 13 4477 - 4486 2015年04月 [査読有り][通常論文]
   

  Molecules in crystals often suffer from severe limitations on their dynamic processes, especially on those involving large structural changes. Crystalline compounds, therefore, usually fail to realize their potential as dielectric materials even when they have large dipole moments. To enable polar molecules to undergo dynamic processes and to provide their crystals with dielectric properties, weakly bound charge-transfer (CT) complex crystals have been exploited as a molecular architecture where the constituent polar molecules have some freedom of dynamic processes, which contribute to the dielectric properties of the crystals. Several CT crystals of polar tetrabromophthalic anhydride (TBPA) molecules were prepared using TBPA as an electron acceptor and aromatic hydrocarbons, such as coronene and perylene, as electron donors. The crystal structures and dielectric properties of the CT crystals as well as the single-component crystal of TBPA were investigated at various temperatures. Molecular reorientation of TBPA molecules did not occur in the single-component crystal, and the crystal did not show a dielectric response due to orientational polarization. We have found that the CT crystal formation provides a simple and versatile method to develop molecular dielectrics, revealing that the molecular dynamics of the TBPA molecules and the dielectric property of their crystals were greatly changed in CT crystals. The TBPA molecules underwent rapid in-plane reorientations in their CT crystals, which exhibited marked dielectric responses arising from the molecular motion. An order-disorder phase transition was observed for one of the CT crystals, which resulted in an abrupt change in the dielectric constant at the transition temperature.
• Highly ordered alignment of conducting nano-crystallites on organic semiconductor single crystal surfaces

  Tomohiro Mikasa, Yukihiro Takahashi, Kei Hayakawa, Seiya Yokokura, Hiroyuki Hasegawa, Jun Harada, Tamotsu Inabe

  THIN SOLID FILMS 579 38 - 43 2015年03月 [査読有り][通常論文]
   

  A conducting thin layer of aligned fibrous nano-crystallites of tetrathiafulvalene-7,7,8,8,-tetracyanoquinodimethane (TTF-TCNQ) is fabricated directly on semiconducting organic crystals under ambient conditions. The widths of the crystallites are 50-100 nm. Their growth direction is governed by the direction of the intermolecular charge transfer interactions in the substrate crystal. The carrier transport in the film is metallic between 150 K and 300 K, reflecting the uniform alignment of the TTF-TCNQ nano- crystallites on the substrate crystal. (C) 2015 Elsevier B.V. All rights reserved.
• Structural and Physical Properties of a Series of 7,7,8,8-Tetracyanoquinodimethane Salts with Dications Bearing Two Terminal Pyridinium Rings

  Hiroyuki Kubota, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe

  CRYSTAL GROWTH & DESIGN 14 11 5575 - 5584 2014年11月 [査読有り][通常論文]
   

  A series of radical anion salts composed of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and dications with -CnH2n- (n = 16) chains between two pyridinium rings are synthesized. The dication and TCNQ formed either 1:4 or 1:3 stoichiometries with no correlation between the composition and n. The 1:4 stoichiometry salts were obtained when n = 1, 3, 4, 5, 6, where TCNQ formed a one-dimensional column with either dimerization or tetramerization. In these salts, the individual dication length varied considerably, but the effective dication length (the distance between two adjacent dications in the lattice) was independent of n. For n = 1, solvent molecules were involved. However, the 1:4 stoichiometry could not be formed for n = 2 since an appropriate effective dication length could not be attained. The 1:3 stoichiometry salts were obtained when n = 2 and 6. In both crystals, TCNQ assembled into a trimer. For both stoichiometries, the crystals were moderately conducting (resistivity at room temperature: 10(-1)10(4) Omega cm) and had a semiconducting temperature dependence, demonstrating nonuniform TCNQ stacking. The charge-localized feature was revealed by the magnetic properties. All of the salts showed antiferromagnetic interactions between the localized spins with varying exchange interaction parameters, reflecting the structural features.
• Hole Doping of Tin Bromide and Lead Bromide Organic Inorganic Hybrid Semiconductors

  Giancarlo S. Lorena, Hiroyuki Hasegawa, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe

  CHEMISTRY LETTERS 43 10 1535 - 1537 2014年10月 [査読有り][通常論文]
   

  Isomorphous layered A(2)MBr(4) perovskite (A = C6H5C2-H4NH3+ and C6H9C2H4NH3+; M = Sn and Pb) semiconductors with energy gaps of 2.5-2.9 eV were prepared. Though the as-grown A(2)MBr(4) perovskites displayed lower conductivities than the iodide analogs, they were found to be spontaneously doped. Furthermore, we demonstrated that hole doping is effective in wide-ranging A(2)MX(4) materials that have sizable valence and conduction bands with tunable band gaps, showing potential as soluble semiconductors.
• What Molecules Are Likely or Unlikely To Undergo Pedal Motions in Crystals?

  Jun Harada, Keiichiro Ogawa

  CRYSTAL GROWTH & DESIGN 14 10 5182 - 5188 2014年10月 [査読有り][通常論文]
   

  The crystal structures of several (E)-stilbenes and 1,2-diarylethane that have methyl or chloro substituents were examined by variable-temperature X-ray diffraction analysis. All the compounds showed disorders in their crystal structures at least at room temperature. In the crystal structures of the molecules with ortho-methyl groups, the disorder observed at room temperature disappeared at 90 K. The dynamic disorders in these crystals were explained in terms of the conformational changes induced by pedal motions, which were not obstructed by the ortho-methyl groups. In the crystals of the stilbenes with alpha-substituents, however, the populations of the two disordered conformers did not change with temperature, which indicates that the disorders were static and these molecules did not undergo the pedal motions in their crystals. Theoretical calculations on the energy barriers for the pedal motions indicated that the observed restriction of the pedal motion in crystals was originated not only in the intramolecular steric repulsions involving the alpha-substituents but mainly in the steric repulsions between the alpha-substituents and the surrounding molecules in the crystals. The pedal motion can proceed only when the shapes of the molecules do not largely change during the process.
• One-dimensional phthalocyanine-based conductor with S=3/2 isotropic magnetic centers

  Yusuke Takita, Hiroyuki Hasegawa, Yukihiro Takahashi, Jun Harada, Akinori Kanda, Noriaki Hanasaki, Tamotsu Inabe

  JOURNAL OF PORPHYRINS AND PHTHALOCYANINES 18 8-9 814 - 823 2014年08月 [査読有り][通常論文]
   

  The axially ligated phthalocyanine conductor of TPP[Cr(Pc)(CN)(2)](2) (TPP = tetraphenylphosphonium and Pc = phthalocyaninato) with d(3) (S = 3/2) metal Cr-III has been successfully prepared. The crystal is completely isomorphous with those of the Co and Fe analogs, and the degree of pi-pi interaction is almost the same in these three salts. The electrical conductivity at room temperature of the Cr system is almost the same with that of the Fe system in which S = 1/2 magnetic centers embedded in the conduction path, and the temperature dependence reveals the development of the charge disproportionation reflecting the existence of magnetic moments. Magnetic susceptibility of the Cr system shows Curie-like behavior with isotropic local moments of S = 3/2. In contrast with the Fe system, only weak antiferromagnetic interaction operates between the localized d-spins. The resistance decreases when magnetic fields are applied, but the magnetoresistance effect is not so large compared with the Fe system, indicating that the pi-d interaction in the Cr system is somewhat different from that in the Fe system.
• A tricky water molecule coordinated to a verdazyl radical-iron(II) complex: a multitechnique approach

  Hajime Kamebuchi, Masashi Okubo, Atsushi Okazawa, Masaya Enomoto, Jun Harada, Keiichiro Ogawa, Goro Maruta, Sadamu Takeda, Norimichi Kojima, Cyrille Train, Michel Verdaguer

  PHYSICAL CHEMISTRY CHEMICAL PHYSICS 16 19 9086 - 9095 2014年 [査読有り][通常論文]
   

  The first iron complexes of high-spin iron(II) species directly coordinated to verdazyl radicals, [Fe-11(vdCOO)(2)(H2O)(2)].2H(2)O (1; vdCOO(-) = 1,5-dimethyl-6-oxo-verdazyl-3-carboxylate) and [Fe-11(vdCOO)(2)(D2O)(2)].2D(2)O (2), were synthesized. The crystal structure of 1 was investigated by single-crystal X-ray diffraction at room temperature and at 90 K. The compound crystallizes in the P1 space group with no phase transition between 300 and 90 K. The crystals are composed of discrete [Fe-11(vdCOO)(2)(H2O)(2)] complexes and crystallization water molecules. In the complex, two vdCOO(-) ligands coordinate to the iron(II) ion in a head-to-tail arrangement and two water molecules complete the coordination sphere. The Fe-X (X = O, N) distances vary in the 2.069-2.213 A range at 300 K and in the 2.0679-2.2111 A range at 90 K, indicating that the iron(II) ion is in its high-spin (HS) state at both temperatures. At 300 K, one of the coordinated water molecules is H-bonded to two crystallization water molecules whereas the second one appears as loosely H-bonded to the two oxygen atoms of the carboxylate group of two neighboring complexes. At 90 K, the former H-bonds remain essentially the same whereas the second coordinated water molecule reveals a complicated behavior appearing simultaneously as tightly H- bonded to two oxygen atoms and non-H-bonded. The Fe-57 Mossbauer spectra, recorded between 300 K and 10 K, give a clue to this situation. They show two sets of doublets typical of HS iron(II) species whose intensity ratio varies smoothly with temperature. It demonstrates the existence of an equilibrium between the high temperature and low temperature forms of the compounds. The solid-state magic angle spinning H-2 NMR spectra of 2 were recorded between 310 K and 193 K. The spectra suggest the existence of a strongly temperature- dependent motion of one of the coordinated water molecules in the whole temperature range. Variable- temperature magnetic susceptibility measurements indicate an antiferromagnetic interaction (J(Fe-vd) = -27.1 cm(-1); H = -J(ij)S(i)S(j)) of the HS iron(II) ion and the radical spins with high g(Fe) and D-Fe values (g(Fe) = 2.25, D-Fe = +3.37 cm(-1)) for the HS iron(II) ion. Moreover, the radicals are strongly antiferromagnetically coupled through the iron(II) center (J(vd-vd) = -42.8 cm(-1)). These last results are analysed based on the framework of the magnetic orbitals formalism.
• Charge Conduction Properties at the Contact Interface between (Phthalocyaninato)nickel(II) and Electron Acceptor Single Crystals

  Yukihiro Takahashi, Kei Hayakawa, Katsuya Takayama, Seiya Yokokura, Jun Harada, Hiroyuki Hasegawa, Tamotsu Inabe

  CHEMISTRY OF MATERIALS 26 2 993 - 998 2014年01月 [査読有り][通常論文]
   

  Single-component crystals of both (phthalocyaninato)nickel(II) (Ni(Pc)) and 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F(2)TCNQ) are typical band insulators. However, the contact interface between them demonstrates metal-like transport properties. Although Ni(Pc) and F2TCNQ are an electron donor and an acceptor, respectively, the combination of these two components does not yield any charge transfer (CT) complex crystals. Infrared spectra show that the highly conductive feature originates from charge injection at the contact interface. The thermoelectric power of the mixed powder reveals that the transport at the contact interface is dominated by the holes in the Ni(Pc) crystal.
• Alternating Ferro- and Antiferromagnetic Couplings in One-Dimensional Chain Hexachlorodicuprate(II), (MV)[CuCl₃]₂ (MV = Methyl Viologen)

  Yasushi Seki, Atsushi Okazawa, Masaya Enomoto, Jun Harada, Keiichiro Ogawa, Norimichi Kojima

  CIC 3 2 94 - 100 Bentham Science Publishers Ltd. 2013年08月 [査読有り][通常論文]
  
• The bis(ethylenedithio)tetrathiafulvalene-based ionic charge-transfer complex with 2,3-dichloro-5,6-dicyano-p-benzoquinone

  Yuki Nakagawa, Yukihiro Takahashi, Jun Harada, Tamotsu Inabe

  ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 69 400 - + 2013年04月 [査読有り][通常論文]
   

  In the ionic charge-transfer (CT) complex composed of bis(ethylenedithio)tetrathiafulvalene (ET) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), C10H8S8 center dot C8Cl2N2O2, the donor and acceptor molecules both form centrosymmetric dimers associated by strong face-to-face interactions. The disordered DDQ molecules form a one-dimensional pi-stacked column, while the ET molecules form a two-leg ladder through additional short S...S contacts between adjacent pi-pi-bonded dimers. The crystal structure of ETDDQ revealed in this study will provide a valuable example of the two-leg spin ladder system, which has rarely been reported for ET-based CT complexes.
• 結晶中における分子のペダル運動

  原田 潤

  日本結晶学会誌 55 1 19 - 23 日本結晶学会 2013年 [査読無し]
  
• Solid-State Photochromism of Chromenes: Enhanced Photocoloration and Observation of Unstable Colored Species at Low Temperatures

  Jun Harada, Keigo Ueki, Masahide Anada, Yuta Kawazoe, Keiichiro Ogawa

  CHEMISTRY-A EUROPEAN JOURNAL 17 50 14111 - 14119 2011年12月 [査読有り][通常論文]
   

  Solid-state photochromism of benzopyrans and naphthopyrans (chromenes) was investigated in the temperature range between 300 and 80 K. Variable-temperature diffuse reflectance spectroscopy of microcrystalline powders showed that the extent of photocoloration was greatly enhanced at low temperatures. All the chromenes examined exhibited solid-state photochromism at low temperatures, even when they showed little or no photocoloration at room temperature. The solid-state photochromic properties of the chromenes were quite similar to those reported for analogous photochromic compounds of spiropyrans and spirooxazines, which indicates that these classes of compounds are generally photochromic even in the solid state. Photobleaching reactions of the colored merocyanine forms proceeded at low temperatures through the formation of a colorless intermediate, instead of directly resuming the original closed form. In addition to two stable planar merocyanine forms, which are usually observed in the photochromic reactions in solution, photoreactions at low temperatures allowed us to observe unstable colored species, which were tentatively assigned as nonplanar cisoid forms, and were stabilized in the solid state at low temperatures.
• Photochromism of spiropyrans and spirooxazines in the solid state: low temperature enhances photocoloration

  Jun Harada, Yuta Kawazoe, Keiichiro Ogawa

  CHEMICAL COMMUNICATIONS 46 15 2593 - 2595 2010年 [査読有り][通常論文]
   

  In this study we have revealed that spiropyrans and spirooxazines, which have long been believed to be non-photochromic in the solid state, are generally photochromic in the solid state at least at low temperatures and that their photoreactivity increases greatly as the temperature is lowered.
• ChemInform Abstract: Pedal Motion in Crystals

  Jun Harada, Keiichiro Ogawa

  ChemInform 40 47 2009年11月
• Hydrogen-Bonded Cyclic Dimer Formation in Temperature-Induced Reversal of Tautomerism of Salicylideneanilines

  Toshikatsu Fujiwara, Jun Harada, Keiichiro Ogawa

  JOURNAL OF PHYSICAL CHEMISTRY A 113 9 1822 - 1826 2009年03月 [査読有り][通常論文]
   

  Tautomeric equilibrium of salicylideneanilines is in favor of the enol form in most organic solvents at room temperature. We have previously reported that the equilibrium in saturated hydrocarbon solvents is reversed at low temperature, being totally in favor of the cis-keto form, which is unfavorable at room temperature. Although this stabilization of the cis-keto form has been explained in terms of aggregation of molecules at low temperature, the structure of the aggregate has remained uncharacterized. In this study, we measured UV-vis absorption spectra of salicylideneanilines including those which have tert-butyl groups at various positions of the benzene rings. The cis-keto form did not appear at low temperature, when salicylideneanilines have a tert-butyl group at a specific position or is restrained to a planar conformation. From these results we propose here that the temperature-induced reversal of the tautomeric equilibrium proceeds through the formation of intermolecular hydrogen-bonded cyclic dimers and the subsequent formation of the higher-order aggregates.
• MS17

  Hidehiro UEKUSA, Masako KATO, Jun HARADA, Keiichiro OGAWA

  Nihon Kessho Gakkaishi 51 1 47 - 50 2009年
• Single crystal cis-trans photoisomerizations of 2-(9-anthrylmethylene)-1-indanones

  Jun Harada, Mayuko Harakawa, Shingo Sugiyama, Keiichiro Ogawa

  CRYSTENGCOMM 11 7 1235 - 1239 2009年 [査読有り][通常論文]
   

  cis-trans Photoisomerizations of 2-(9-anthrylmethylene)-1-indanones were carried out in the solid state. The photoisomerizations proceeded without destruction of the crystal lattices. The crystal structural changes accompanying the photoisomerizations were observed by X-ray diffraction analysis. From the structural correlation between the reactants and products, the single-crystal isomerizations were proved to proceed through one bond flip (OBF), where the indanonyl moiety of the molecule rotates around the isomerizing double bond.
• Pedal motion in crystals

  Jun Harada, Keiichiro Ogawa

  CHEMICAL SOCIETY REVIEWS 38 8 2244 - 2252 2009年 [査読有り][通常論文]
   

  This tutorial review introduces pedal motion in crystals, where a pair of benzene rings in a molecule move like the pedals of a bicycle. The pedal motion triggers conformational interconversions, which result in disordered crystal structures. The pedal motion also plays important roles in solid-state reactions. This type of molecular motion occurs in a wide range of compounds, although the detection of the process is difficult in most cases. This review also describes how powerful X-ray diffraction analysis is in investigating dynamic processes in crystals, especially focusing on disorder analysis as a function of temperature.
• Crystalline-state conformational change of beta-nitrostyrenes and its freezing at low temperature

  Jun Harada, Mayuko Harakawa, Keiichiro Ogawa

  CRYSTENGCOMM 11 4 638 - 642 2009年 [査読有り][通常論文]
   

  The crystal structures of three beta-nitrostyrenes were examined by X-ray diffraction analysis at various temperatures. At room temperature, disordered structures were observed in all the crystals, where the molecules took two conformations with different orientations. The disorders were found to be dynamic and the populations of the minor conformers decreased as the temperature was decreased. The observed dynamic disorders were accounted for in terms of a conformational change through a pedal motion in crystals. The detailed analysis of temperature dependence of the populations revealed that the solid-state pedal motions of beta-nitrostyrenes were frozen in at low temperature.
• Crucial Role of N center dot center dot center dot Si Interactions in the Solid-State Coloration of Disilylazobenzenes

  Masaki Yamamura, Naokazu Kano, Takayuki Kawashima, Tomonari Matsumoto, Jun Harada, Keiichiro Ogawa

  JOURNAL OF ORGANIC CHEMISTRY 73 21 8244 - 8249 2008年11月 [査読有り][通常論文]
   

  2.2'-Bis(fluorodiphensylsilyl)azobenzenes bearing two methyl and butyl groups at the 4- and 4'-positions were synthesized, and their X-ray crystallographic analyses revealed that they have tetracoordinated and pentacoordinated silicon atoms, respectively. Although the two compounds showed almost the same spectra in solution, the reflectance spectra of the solid revealed that the pentacoordinated state had a weaker absorbance in the long-wavelength region compared with that of the tetracoordinated state, which is ascribed to the shift of the n-pi* transition. This difference in the absorptions due to the n-pi* transition drastically affects the color of the azobenzenes: the color of the pentacoordinated state becomes apparently paler than that of the tetracoordinated state.
• X-ray diffraction analysis of photochromic reaction of fulgides: Crystalline state reaction induced by two-photon excitation

  Jun Harada, Ryo Nakajima, Keiichiro Ogawa

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 130 22 7085 - 7091 2008年06月 [査読有り][通常論文]
   

  Although most fulgides show their photochromism in the solid state, crystal structure changes accompanying the photochromism have not been previously observed. The photochromic reactions have been so far considered to take place on surfaces or at defects of the crystals or to proceed with destruction of the crystals. In this study we have succeeded in observing crystal structure changes accompanying the photochromism of fulgides using X-ray diffraction analysis. Detection of the photoproducts in the crystal structures was not possible when the single crystals of the fulgides were irradiated with steady UV light. Two-photon excitation by pulsed laser light was essential to produce a sufficient amount of the photoproducts without significant deterioration in the quality of the crystals.
• Conformational change of all-trans-1,6-diphenyl-1,3,5-hexatriene in two crystalline forms

  Jun Harada, Mayuko Harakawa, Keiichiro Ogawa

  CRYSTENGCOMM 10 12 1777 - 1781 2008年 [査読有り][通常論文]
   

  The crystal structures of all-trans-1,6-diphenyl-1,3,5-hexatriene in two polymorphic forms were examined by X-ray diffraction analysis at various temperatures. In both crystal forms, a misoriented minor conformer was observed at higher temperatures, and it disappeared at lower temperatures. The temperature dependence of the crystal structures was accounted for in terms of a conformational change through pedal motions in crystals.
• Crucial role of fluorescence in the solid-state thermochromism of salicylideneanilines

  Jun Harada, Toshikatsu Fujiwara, Keiichiro Ogawa

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 129 51 16216 - 16221 2007年12月 [査読有り][通常論文]
   

  The thermochromism of salicylideneanilines in the solid state has been so far explained only in terms of the temperature-induced change of light absorption, which is caused by the shift of the tautomeric equilibrium between the enol and cis-keto forms. In this study, we measured variable temperature diffuse reflectance and fluorescence spectra of the crystalline powders of salicylideneanilines. We also determined their fluorescence quantum yields. The chromaticity coordinates at each temperature were calculated from these data and compared to the perceived colors of the powders. We found that the temperature-induced shift of the tautomeric equilibrium is not the main cause of the thermochromic color change of the thermochromic crystals and that the thermochromism can be explained only by taking account of the temperature-induced change of fluorescence.
• Temperature-induced reversal of proton tautomerism: Role of hydrogen bonding and aggregation in 7-hydroxyquinolines

  Masatoshi Miura, Jun Harada, Keiichiro Ogawa

  JOURNAL OF PHYSICAL CHEMISTRY A 111 39 9854 - 9858 2007年10月 [査読有り][通常論文]
   

  UV-vis absorption spectra of 7-hydroxyquinolines in saturated hydrocarbon solvents were measured at various temperatures between 293 and 77 K. The tautomeric equilibrium was found to reverse when the temperature was lowered. At 293 K, the enol form was exclusively present. As the temperature was lowered, the enol form decreased substantially, and the keto form became predominant. A close examination of the spectral changes suggests that the reversal of the tautomeric equilibrium at lower temperatures proceeds in two steps: aggregation of the enol forms by intermolecular hydrogen bonding and further aggregation of the hydrogen-bonded aggregates.
• 最近のX線結晶解析

  原田 潤

  化学と教育 55 5 224 - 225 公益社団法人 日本化学会 2007年 [査読無し]
  
• Torsional motion of stilbene-type molecules in crystals

  Jun Harada, Keiichiro Ogawa

  Topics in Stereochemistry 25 31 - 47 2006年 [査読有り][通常論文]
  
• UV-vis absorption spectra of powdered materials: Direct measurements by optical waveguide spectroscopy

  K Ogawa, J Harada, T Fujiwara, H Takahashi

  CHEMISTRY LETTERS 33 11 1446 - 1447 2004年11月 [査読有り][通常論文]
   

  UV-vis absorption spectra of powders of naphthalene and salicylideneaniline were obtained using optical waveguide spectroscopy. It is demonstrated that the optical waveguide spectroscopy is an excellent method for the measurement of UV-vis absorption spectra of powdered materials as they are, without any treatment.
• Torsional vibration and central bond length of N-benzylideneanilines

  J Harada, M Harakawa, K Ogawa

  ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60 578 - 588 2004年10月 [査読有り][通常論文]
   

  The crystal structures of N-benzylideneaniline (1), N-benzylidene-4-carboxyaniline (2), N-(4-methylbenzylidene)-4-nitroaniline (3), N-(4-nitrobenzylidene)-4-methoxyaniline (4), N-(4-nitrobenzylidene)-4-methylaniline (5), N-(4-methoxybenzylidene) aniline (6) and N-(4-methoxybenzylidene)-4-methylaniline (7) were determined by X-ray diffraction analyses at various temperatures. In the crystal structures of all the compounds, an apparent shortening of the central C=N bond was observed at room temperature. As the temperature was lowered, the observed bond lengths increased to approximately 1.28 Angstrom at 90 K, irrespective of substituents in the molecules. The shortening and the temperature dependence of the C=N bond length are interpreted in terms of an artifact caused by the torsional vibration of the C-Ph and N-Ph bonds in the crystals. In the crystal structures of (1) and (7), a static disorder around the C=N bond was observed, which is also responsible for the apparent shortening of the C=N bond.
• Conformational change of N-benzylideneanilines in crystals

  J Harada, M Harakawa, K Ogawa

  ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60 589 - 597 2004年10月 [査読有り][通常論文]
   

  The crystal structures of N-(4-nitrobenzylidene)aniline (1), N-(4-chlorobenzylidene)-4-methylaniline (2) and N-(4-methylbenzylidene)-4-methylaniline (3) were determined by X-ray diffraction analyses at various temperatures. A dynamic disorder was observed in the crystal structures of all compounds. The dynamic disorder is accounted for in terms of a conformational change involving a pedal motion in the crystals.
• Solid-state thermochromism studied by variable-temperature diffuse reflectance spectroscopy. A new perspective on the chromism of salicylideneanilines

  T Fujiwara, J Harada, K Ogawa

  JOURNAL OF PHYSICAL CHEMISTRY B 108 13 4035 - 4038 2004年04月 [査読有り][通常論文]
   

  This paper reports a successful application of variable-temperature diffuse reflectance spectroscopy for the study of the solid-state thermo- and photochromism of salicylideneanilines, which belong to a class of the most well-known chromic organic compounds. This study disproves fundamental aspects that have been widely accepted for as long as 40 years and provides a new perspective on the chromism. The enol form of salicylideneaniline, which has been wrongly regarded as pale yellow, is in fact colorless, and the pale yellow is due to a trace of the cis-keto form, which is in equilibrium with the enol form. The phototransformation from the cis-keto to the trans-keto form was observed for the first time. Although it has been accepted that a given modification of salicylideneanilines is either photochromic or thermochromic but not both, this study reveals that such an exclusive property on the chromism does not exist and that salicylideneanilines are generally thermochromic in the solid state, whether they are photochromic or not. This study demonstrates that the color of materials is controlled by a trace of colored species and that the variable-temperature diffuse reflectance spectroscopy is quite an effective tool for its detection and therefore for the study of the chromism in the solid state.
• X-ray diffraction analysis of nonequilibrium states in crystals: Observation of an unstable conformer in flash-cooled crystals

  J Harada, K Ogawa

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126 11 3539 - 3544 2004年03月 [査読有り][通常論文]
   

  Some molecules with a molecular skeleton similar to that of stilbenes and azobenzenes show orientational disorder in the crystals. If the disorder is dynamic, a conformational interconversion takes place through a pedal motion. In this study X-ray diffraction analyses of (E)-stilbene (1) and azobenzene (2) were carried out at various temperatures. We succeeded in observing thermodynamic nonequilibrium states that were generated by fast freezing of the conformational interconversion at low temperatures. The populations of the two conformers in crystals of 1 at 90 K varied with the cooling rate. Flash cooling of a crystal of 2 from room temperature to 90 K made it possible to observe the minor unstable conformer that does not exist in the equilibrium state at the same temperature.
• Photochromism of aza-aromatics with hydroxy group. Intermolecular proton transfer in glassy solution

  K Ogawa, M Miura, T Nakayama, J Harada

  CHEMISTRY LETTERS 32 9 840 - 841 2003年09月 [査読有り][通常論文]
   

  When solutions of 2-hydroxyphenazine (1), 3-hydroxyacridine (2), and 7-hydroxyquinoline (3) were irradiated with UV light at 77 K, they became deeply colored. The color of the solutions reverted to the original one, when they were left in the dark at 77 K or at a higher temperature. We ascribe the photochromism to proton tautomerization, which is most likely induced by an intermolecular proton transfer in the excited state.
• Aggregation controlled proton tautomerization in salicylideneanilines

  K Ogawa, J Harada

  JOURNAL OF MOLECULAR STRUCTURE 647 1-3 211 - 216 2003年02月 [査読有り][通常論文]
   

  Proton tautomerization of salicylideneanilines in the solid state and in solution is reviewed, mainly focusing on the zwitterionic character of the NH form and its stabilization in the solid state and in solution at low temperature. The essential role of aggregation of molecules in proton tautomerization is emphasized. (C) 2003 Elsevier Science B.V. All rights reserved.
• Heavy-row atom effects on the strength of the weak nonbonded interactions between divalent selenium and halogen atoms

  M Iwaoka, T Katsuda, S Tomoda, J Harada, K Ogawa

  CHEMISTRY LETTERS 5 518 - 519 2002年05月 [査読有り][通常論文]
   

  The Se-77 NMR chemical shifts observed for 2-selenobenzyl halide derivatives and the density functional theoretical calculation revealed that the strength of intramolecular nonbonded interactions between a divalent selenium and halogen atoms decreases in the order, Se...F > Se...C1 greater than or equal to Se...Br.
• Clathrate formation of gossypol: The structure of the complex of gossypol with tropolone

  SA Talipov, BT Ibragimov, Y Ohashi, J Harada, MI Saleh

  CRYSTALLOGRAPHY REPORTS 47 3 443 - 448 2002年05月 [査読有り][通常論文]
   

  The clathrate of gossypol with tropolone is prepared for the first time and studied by X-ray diffraction. The structure is determined and refined using 7307 reflections (Siemens SMART/CCD diffractometer). The crystals are monoclinic, C30H30O8 . 2C(7)H(6)O(2), a = 35.5892(1) Angstrom, b = 12.8893(2) Angstrom, c = 18.5910(2) Angstrom, beta = 118.54(3)degrees, Z = 8, space group C2/c, and R = 0.058. Each gossypol molecule is linked to two tropolone molecules through hydrogen bonds. The host (gossypol) and guest (tropolone) molecules form separate bilayers that are parallel to the be plane and alternate along the a-axis. (C) 2002 MAN "Nauka/lnterperiodica".
• Invisible but common motion in organic crystals: A pedal motion in stilbenes and azobenzenes

  J Harada, K Ogawa

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 123 44 10884 - 10888 2001年11月 [査読有り][通常論文]
   

  Some molecules that have a molecular skeleton similar to stilbenes and azobenzenes are known to show an orientational disorder in the crystals. Some of the disorders are known to be dynamic and mediated by a pedal motion in crystals. Dynamic processes of (E)-stilbene (1) and (E)-3,3',4,4'-tetramethylazobenzene (2) in the crystals were investigated by X-ray diffraction analyses. The dynamic disorder and the pedal motion were detected at higher temperature, even in the molecules that showed no traces of the disorder at room temperature. The results demonstrated that the pedal motion should always be taken into account, even if no disorder is detected. The reasons for the nonoccurrence of the disorder and for the prevalence of the pedal motion are also discussed.
• Ethane bond length in 1,2-diphenylethanes

  J Harada, K Ogawa

  STRUCTURAL CHEMISTRY 12 3-4 243 - 250 2001年08月 [査読有り][通常論文]
   

  Crystal structures of 1,2-diphenylethane (1), 1,2-bis(4-dimethoxyphenyl)ethane (3), 1,2-bis(2,3-dimethylphenyl)ethane (4), 1,2-bis(2,4-dimethylphenyl)ethane (5) and 1,2-bis(2,4,6-trimethylphenyl)ethane (6) were determined by X-ray diffraction analysis at various temperatures. An apparent shortening of the ethane bond and its temperature dependence were observed and it was interpreted as an artifact caused by the torsional vibration of the C-Ph bonds in crystals. The extent of the shortening was dependent on the compounds and was explained in terms of the difference in the amplitude of the torsional vibration controlled by ortho methyl groups. In the crystal structures of 1, a so far unrecognized orientational disorder was observed at room temperature and 315 K. The disorder, which disappeared at lower temperatures, proved to be dynamic and was ascribed to a conformational interconversion through a very large amplitude torsional vibration. The disorder might be another reason for the exceptionally short ethane bond in 1.
• Thermochromism of salicylideneanilines in solution: Aggregation-controlled proton tautomerization

  K Ogawa, J Harada, T Fujiwara, S Yoshida

  JOURNAL OF PHYSICAL CHEMISTRY A 105 13 3425 - 3427 2001年04月 [査読有り][通常論文]
   

  Many salicylideneanilines have been known to exhibit thermochromism in the solid state. In contrast, in the solution, the thermochromism has rarely been observed. This paper reveals that salicylideneanilines are generally thermochromic in the solution of hydrocarbon solvents and that the proton tautomerization, which is the origin of the thermochromism, is controlled by the aggregation of molecules. This is evidenced by the electronic absorption spectra of salicylideneaniline (1), N-(5-chloro-2-hydroxybenzylidene)aniline (2), N-(2-hydroxy 4-methoxybenzylidene)aniline (3), N-(2-hydroxy-5-nitrobenzylidene)aniline (4), N-(2-hydroxy-5-nitrobenzylidene)-2,6- dimethylaniline (5), and N-(3,5-di-tert-butyl-2-hydroxybenzylidene)aniline (6) in isopentane or the mixture of isopentane and methylcyclohexane (volume ratio = 3:1) at different temperatures between 297 and 77 K. They exhibited a remarkable spectral change with lowering temperature, except for 6. At 297 K the OH form is exclusively populated. When the temperature is lowered, the absorption bands of the OH form decrease in intensity and new bands that are assigned to the NH form emerge. At 77 K, the OH form disappears and the NH form is exclusively populated. The spectra of 6 do not change with lowering of the temperature.
• ２１世紀に向けた結晶学の新たな挑戦 ２． 分子の変化をみる 有機結晶のサーモクロミズム

  小川 桂一郎, 原田 潤

  日本結晶学会誌 43 1 27 - 37 日本結晶学会 2001年 [査読無し][通常論文]
  
• X-ray crystallographic analysis of the NH form of a salicylideneaniline at 15 K

  K Ogawa, J Harada, Tamura, I, Y Noda

  CHEMISTRY LETTERS 5 528 - 529 2000年05月 [査読有り][通常論文]
   

  The structure of the NH form of a salicylideneaniline was determined by X-ray crystallographic analysis of N-(5-chloro-2-hydroxybenzylidene)-4-hydroxyaniline at 15 K. Comparison of the X-ray structure with the structure obtained from quantum mechanical calculations using density functional theory revealed that the NH form is predominantly zwitterionic in crystals and predominantly quinoidal in gas phase.
• Direct observation of deuterium migration in crystalline-state reaction by single-crystal neutron diffraction. II. 3-1 Photoisomerization of a cobaloxime complex

  T Ohhara, J Harada, Y Ohashi, Tanaka, I, S Kumazawa, N Niimura

  ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 56 245 - 253 2000年04月 [査読有り][通常論文]
   

  Single crystal neutron diffraction analysis of photo-exposed (3-cyanopropyl-d(2)(alpha,alpha))-[(R)-1-phenylethylamine-d(11)]bis(dimethylglyoximato-d(14))cobalt(III) was carried out in order to clarify the mechanism of the crystalline-state photoisomerization of the 3-cyanopropyl group bonded to the Co atom in some cobaloxime complexes. Before irradiation the two H atoms bonded to the C-1 atom of the 3-cyanopropyl group were exchanged with the D atoms such as -CH2CH2CD2CN. On exposure to a xenon lamp, the cell dimensions of the crystal were gradually changed. After 7 d exposure the change became insignificantly small. The structure was analyzed by neutron diffraction. The 3-cyanopropyl group was transformed to the l-cyanopropyl group such as -CD(CN)C-(H-1/2,D-1/2)(2)CH3 with retention of the single-crystal form. This indicates that one of the D atoms bonded to C-1 migrates to either position bonded to C-2. The other atoms of the complex remained unchanged. These results indicate that photoisomerization proceeded in two steps: the 3-cyanopropyl group was isomerized to the 2-cyanopropyl group in the first place and then the 2-cyanopropyl group was transformed to the 1-cyanopropyl group. Moreover, it was made clear that the second-step isomerization was irreversible, since one of the D atoms was retained. The disordered structure at C-2 is estimated to be caused by the interconversion between the 1-cyanopropyl group produced and its dehydrogenated olefin after the photoisomerization.
• A crystallographic study on the thermochromism of salicylideneanilines

  K Ogawa, T Fujiwara, J Harada

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS 344 169 - 178 2000年 [査読有り][通常論文]
   

  A variable temperature X-ray crystallographic analysis of N-(5-chroro-2-hydroxybenzylidene)-4-hydroxyaniline showed the crystal structure change associated with the thermochromism.
• Mechanism of deuterium-hydrogen exchange in the photoisomerization of cobalt complex

  Y Ohashi, T Ohhara, J Harada, Tanaka, I, S Kumazawa, N Niimura

  JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 60 8-9 1515 - 1517 1999年08月 [査読有り][通常論文]
   

  The 3-cyanopropyl(-CH2CH2CH2CN) group bonded to the cobalt atom in cobaloxime complexes is isomerized to the 1-cyanopropyl{-CH(CN)CH2CH3} group with retention of the single crystal form by photo irradiation. When the dideuterated 3-cyanopropyl group (-CH2CH2CD2CN) was used, the crystal structure analysis by neutron diffraction revealed that the produced 1-cyanopropyl group was not {-CD(CN)CHDCH3} but the disordered {-CD(CN)C(H1/2D1/2)(2)CH3} group. This indicates that the reaction proceeds through the 1-cyanopropyl group and that the olefinic molecule and the cobalthydride may exist in the intermediate stages of the reaction. (C) 1999 Elsevier Science Ltd. All rights reserved.
• X-ray analysis of structural changes in photochromic salicylideneaniline crystals. Solid-state reaction induced by two-photon excitation

  J Harada, H Uekusa, Y Ohashi

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 121 24 5809 - 5810 1999年06月 [査読有り][通常論文]
  
• Structure and natural bond orbital analysis of oxiranes substituted with a group 14 element. A comment of SN2 regioselectivity

  T Ikeno, J Harada, S Tomoda

  CHEMISTRY LETTERS 5 409 - 410 1999年05月 [査読有り][通常論文]
   

  Crystal structure analysis of oxiranes substituted with a group 14 element revealed that silyl and stannyl groups lengthened their alpha C-O bonds. Natural bond orbital analysis showed that silyl group raised the energy level of alpha C-O a orbital and lowered that of alpha C-O sigma* orbital. It was suggested that the former might lengthen the a C-O bond and that the latter should affect the regioselectivity in ring-opening reactions.
• Synthesis and structure of tris[(2-alkoxymethyl)phenyl]germanes and tris[(2-methylthiomethyl)phenyl]germane

  Y Takeuchi, H Yamamoto, K Tanaka, K Ogawa, J Harada, T Iwamoto, H Yuge

  TETRAHEDRON 54 33 9811 - 9822 1998年08月 [査読有り][通常論文]
   

  Tris[(2-alkoxymethyl)phenyl]germanes and tris[(2-methylthiomethyl)phenyl]germane were prepared and their structures were investigated by means of X-ray crystallographic: analysis and Ge-73 NMR spectra, which indicated incipient dative bonding between germanium and sulfur or oxygen atoms to make the germanium atom hexavalent and heptavalent, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.
• Crystal structure change for the thermochromy of N-salicylideneanilines. The first observation by x-ray diffraction

  K Ogawa, Y Kasahara, Y Ohtani, J Harada

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 120 28 7107 - 7108 1998年07月 [査読有り][通常論文]
  
• Interpretation of Bond Length Anomaly: Molecular Motion and Reactions in Crystals

  Keiichiro Ogawa, Jun Harada

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 313 167 - 172 1998年 [査読有り][通常論文]
   

  Origins of the bond length anomalies observed for the X-ray structures of a series of organic compounds are discussed in terms of molecular motion and reactions in crystals.
• Molecular motion and conformational interconversion of azobenzenes in crystals as studied by X-ray diffraction

  J Harada, K Ogawa, S Tomoda

  ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 53 662 - 672 1997年08月 [査読有り][通常論文]
   

  Crystal structures of (E)-azobenzene (1), (E)-2,2'-dimethylazobenzene (2), (E)-3,3'-dimethylazobenzene (3) and (E)-4,4'-dimethylazobenzene (4) were determined by X-ray diffraction at various temperatures. An apparent shrinkage of the N=N bond and its temperature dependence were observed and are interpreted in terms of an artifact caused by the torsional vibration of the N-Ph bonds in crystals. In the crystal structures of (1), (3) and (4) the dynamic disorder was observed. The disorder is accounted for by the torsional vibration whose amplitude is large enough to give rise to the conformational interconversion. No disorder was observed for a crystal of (2). This is ascribed to the large difference in energy of the two conformers as free molecules. The true length of the N=N bond in azobenzenes was estimated to be 1.26-1.27 Angstrom.
• N-arylpiperidine with axial N-aryl bond. Conformational variation in crystals.

  K Ogawa, J Harada, M Endo, Y Takeuchi, H Kagawa

  TETRAHEDRON LETTERS 38 32 5663 - 5666 1997年08月 [査読有り][通常論文]
   

  Single crystal X-ray diffraction and C-13 NMR spectroscopic study of two new N-arylpiperidines 4 and 6 reveals that 4 adopts the conformation with the axial N-aryl bond in crystals in contrast to the general tendency of N-arylpiperidines to assume the conformation with an equatorial N-aryl bond. It is shown that the degree of pyramidalization of the nitrogen atom and the orientation of the N-aryl bond are strongly affected by intermolecular interactions in crystals. (C) 1997 Elsevier Science Ltd.
• The central C-C bond length in the bi(anthracene-9,10-dimethylene) photoisomer: Unusual elongation and crystalline state reaction

  J Harada, K Ogawa, S Tomoda

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 276 A119 - A123 1996年 [査読有り][通常論文]
   

  Crystal structure analysis of bi(anthracene-9,10-dimethylene) photoisomer (1) revealed that the anomalous elongation of the central C-C bond in the previously reported X-ray structure is an artifact caused by partial cycloreversion of 1 to no-bonded isomer in crystalline state.
• SYNTHESES AND CRYSTAL-STRUCTURES OF NOVEL ANTIMONY-CONTAINING CYCLIC POLYSULFIDES

  N TOKITOH, Y ARAI, J HARADA, R OKAZAKI

  CHEMISTRY LETTERS 10 959 - 960 1995年10月 [査読有り][通常論文]
   

  reaction of a dihydrostibine bearing a 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt) group, TbtSbH(2), with elemental sulfur resulted in the formation of two kinds of novel Sb-containing cyclic polysulfides, TbtSbS(5) and TbtSbS(7), together with another type of two cyclic polysulfides having two TbtSb units, 1,3,4,5,2,6-tetrathiadistibane and 1,3,5,2,4-trithiadistibolane derivatives.
• STIFF CIS-STILBENES - (Z)-6,6'-DIMETHYL-1,1'-BIINDANYLIDENE AND (Z)-4,4',7,7'-TETRAMETHYL-1,1-BIINDANYLIDENE

  J HARADA, K OGAWA, S TOMODA

  ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 51 2125 - 2127 1995年10月 [査読有り][通常論文]
   

  The X-ray crystal structures of (Z)-6,6'-dimethyl-1,1'-biindanylidene, C20H20 (1), and (Z)-4,4',7,7'-tetramethyl-1,1'-biindanylidene, C22H24 (2), were determined at 90 K. The structure around the ethylene bond in (2) is distorted by steric congestion due to the methyl groups at C7 and C7'.
• THE CENTRAL C-C BOND-LENGTH IN THE BI(ANTHRACENE-9,10-DIMETHYLENE) PHOTOISOMER - UNUSUAL ELONGATION AND CRYSTALLINE STATE REACTION

  J HARADA, K OGAWA, S TOMODA

  CHEMISTRY LETTERS 8 751 - 752 1995年08月 [査読有り][通常論文]
   

  Crystal structure analysis of bi(anthracene-9,10-dimethylene) photoisomer (1) revealed that the anomalous elongation of the central C-C bond in the previously reported X-ray structure is an artifact caused by partial cycloreversion of 1 to no-bonded isomer in crystalline state.
• UNUSUALLY SHORT ETHYLENE BOND AND LARGE-AMPLITUDE TORSIONAL MOTION OF (E)-STILBENES IN CRYSTALS - X-RAY CRYSTALLOGRAPHIC STUDY OF STIFF STILBENES

  K OGAWA, J HARADA, S TOMODA

  ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 51 240 - 248 1995年04月 [査読有り][通常論文]
   

  Crystal structures of (E)-4,4'-dimethyl-1,1'-biindanylidene, (E)-5,5'-dimethyl-1,1'-biindanylidene, (E)-6,6'-dimethyl-1,1'-biindanylidene, (E)-7,7'-dimethyl-1,1'-biindanylidene and (E)-2,2,2',2'-tetramethyl-1,1'-biindanylidene were determined by X-ray diffraction at 296 and 120 K. The observed ethylene bond length is 1.35-1.36 angstrom, independent of the temperature and the compound, which agrees well with the length estimated from the molecular mechanics calculations. The results make a sharp contrast with those for ordinary (E)-stilbenes and strongly support the interpretation that the unusual short ethylene bond in the X-ray structures of (E)-stilbenes is an artifact which originates from the large-amplitude torsional motion of the C-Ph bonds in crystals. The true length of the ethylene bond in (E)-stilbenes is safely estimated to be 1.35-1.36 angstrom.
• THE CENTRAL BOND-LENGTH IN 1,2-DIPHENYLETHANES

  J HARADA, K OGAWA, S TOMODA

  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 117 16 4476 - 4478 1995年04月 [査読有り][通常論文]
   

  Crystal structures of 1,2-diphenylethane (1) and 1,2-bis(2-methylphenyl)ethane (3) were determined at different temperatures by X-ray diffraction. The observed length of the central C-C bond in 1 at 240 K (1.506(5) Angstrom) appears to be considerably shorter than the standard value of a C(sp(3))-C(sp(3)) bond (1.541(3) Angstrom). The observed length, however, substantially increases with lowering of the temperature. On the contrary, the ethane bond length in 3 (1.534(5) Angstrom and 240 K) is normal and remains constant at different temperatures. It is concluded that the anomaly in the ethane bond length of 1,2-diphenylethanes, which has been attempted to be explained in terms of various electronic effects, is an artifact caused by the torsional vibration of the C-Ph bonds in crystals.
• SYNTHESIS AND STRUCTURES OF EXTREMELY HINDERED AND STABLE DISILENES

  H SUZUKI, N TOKITOH, R OKAZAKI, J HARADA, K OGAWA, S TOMODA, M GOTO

  ORGANOMETALLICS 14 2 1016 - 1022 1995年02月 [査読有り][通常論文]
   

  Extremely hindered and stable disilenes Tbt(Mes)Si=Si(Mes)Tbt, ((Z)- and (E)-6; Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phnyl, Mes = 2,4,6-trimethylphenyl) were synthesized by a reductive coupling reaction of the corresponding overcrowded dibromosilane Tbt(Mes)SiBr2 (4) with lithium naphthalenide in THF. The molecular structures of (Z)- and (E)-6 were determined by X-ray crystallographic analysis at 120 K. Compound (Z)-6 crystallizes in the monoclinic space group P2(1)/n with a = 22.212(3) Angstrom, b = 13.368(2) Angstrom, c = 29.725(3) Angstrom, beta = 91.344(9)degrees, V = 8824(2) Angstrom(3), and Z = 4. Compound (E)-6 C10H8 crystallizes in the monoclinic space group P2(1)/c with a = 18.130(3) Angstrom, b = 18.466(3) Angstrom, c = 28.522(2) Angstrom, beta = 95.976(9)degrees, V = 9497(2) Angstrom(3), and Z = 4. The X-ray structures show remarkable pyramidalization around silicon atoms and elongation of the Si-Si double bond (2.195(4) Angstrom for (Z)-6 and 2.228(2) Angstrom for (E)-6), the values of which are the longest ones reported so far for disilenes having carbon substituents on the silicon atoms. Both disilenes were found to be stable for weeks in the open air even in a microcrystalline form, and they were gradually oxidized to afford stereospecifically the (Z)- and (E)-1,3,2,4-dioxadisiletane compounds 10. Compound (Z)-10 crystallizes in the monoclinic space group P2(1)/n with a = 22.420(5) Angstrom, b = 13.458(6) Angstrom, c = 30.417(4) Angstrom, beta = 90.96(1)degrees, V = 9176(4) Angstrom(3), and Z = 4. Reaction of Tbt(t-Bu)SiBr2 (5) with lithium naphthalenide proceeded in a different way to afford the benzosilacyclobutene 11, which was most likely an intramolecular C-H insertion product of the intermediary silylene Tbt(t-Bu)Si: (12).
• アゾベンゼン類の結晶中における分子内運動と相転移

  原田 潤, 小川 桂一郎, 友田 修司

  日本結晶学会誌 37 31 - 31 The Crystallographic Society of Japan 1995年
• (Z)-1,2-DI(1-ADAMANTYL)ETHENE AND (E)-1,2-DI(1-ADAMANTYL)ETHENE

  AP MARCHAND, DX XING, SG BOTT, K OGAWA, J HARADA

  TETRAHEDRON LETTERS 35 48 8935 - 8938 1994年11月 [査読有り][通常論文]
   

  A highly;stereoselective four-step synthesis of (Z)-1,2-di(1-adamantyl)ethene (1a, overall yield 64%) which employs methyl 1-adamantanecarboxylate (2) as starting material is described. Compound 1a is isomerized quantitatively to the corresponding E- isomer (1b) by reaction with molecular iodine. Some features of the X-ray crystal structures of 1a and 1b are described.

書籍

• 化学

  (担当:分担執筆)
  東京書籍 2023年02月 (ISBN: 9784487166688) 224p, 図版 [5] p
• 新編化学基礎

  (担当:分担執筆)
  東京書籍 2022年02月 (ISBN: 9784487166268) 224, 6p
• 化学基礎

  (担当:分担執筆)
  東京書籍 2022年02月 (ISBN: 9784487166251) 231, 7p
• 化学便覧 基礎編 改訂6版

  編集:日本化学会 (担当:分担執筆)
  丸善出版 2021年01月 (ISBN: 9784621305218) xviii, 1509p
• 日本の結晶学(II)ーその輝かしい発展ー

  原田 潤 (担当:分担執筆範囲:サリチリデンアニリン類のサーモクロミズムとフォトクロミズム)
  日本結晶学会 2014年
• 化学辞典 第2版

  編集代表:吉村壽次 (担当:分担執筆)
  森北出版 2009年
• 基礎化学実験 第2版

  編集:東大教養学部化学部会 (担当:分担執筆)
  東京化学同人 2008年
• Topics in Stereochemistry Vol. 25

  Jun Harada, Keiichiro Ogawa (担当:共著範囲:Chapter 2: Torsional Motion of Stilbene-type Molecules in Crystals)
  Wiley 2006年04月 (ISBN: 9780471682448)
• 基礎化学実験

  編集:東大教養学部化学部会 (担当:分担執筆)
  東京化学同人 2006年

講演・口頭発表等

• Development of Plastic/Ferroelectric Ionic Molecular Crystals  [招待講演]

  原田 潤

  9IDMRCS 9th International Discussion Meeting on Relaxations in Complex Systemes 2023年08月 口頭発表（招待・特別）
• 柔粘性/強誘電性結晶の開発  [招待講演]

  原田 潤

  第2回柔粘性結晶研究会 2023年07月 口頭発表（招待・特別）
• デバイス応用可能な新規分子性強誘電結晶の開発  [招待講演]

  原田 潤

  電気学会有機バイオSDGs調査専門委員会2022年第2回会合 2022年05月 口頭発表（招待・特別）
• Development of Plastic/Ferroelectric Ionic Molecular Crystals  [招待講演]

  原田 潤

  ISOME2022 12th International Symposium on Organic Molecular Electronics 2022年05月 口頭発表（招待・特別）
• Development of Plastic/Ferroelectric Molecular Crystals  [招待講演]

  原田 潤

  MRM2021 Materials Research Meeting 2021 2021年12月 口頭発表（招待・特別）
• 柔粘性/強誘電性分子結晶の開発  [招待講演]

  原田 潤

  日本セラミックス協会第34回秋季シンポジウム 2021年09月 口頭発表（招待・特別） オンライン
• Development of Plastic/Ferroelectric Ionic Molecular Crystals  [招待講演]

  原田 潤

  CEMS Topical Meeting on Modern Ferroelectrics 2018 (Wako) 2018年10月 口頭発表（招待・特別）
• Development of Plastic/Ferroelectric Crystals  [招待講演]

  原田 潤

  ICCC2018 (Sendai) 2018年08月 口頭発表（招待・特別）
• 分子性強誘電体の開発と構造物性  [招待講演]

  原田 潤

  有機固体若手の学校2018 (新潟県) 2018年03月 口頭発表（招待・特別）
• X線結晶解析による分子ダイナミクスの解明と機能性結晶の開発  [招待講演]

  原田 潤

  日本結晶学会平成29年度学術賞受賞講演 (広島) 2017年11月 口頭発表（招待・特別）
• Unique Properties Found in Plastic/Ferroelectric Molecular Crystal  [招待講演]

  原田 潤

  ISCOM2017 (Zao) 2017年09月 口頭発表（招待・特別）
• 柔粘性/強誘電性分子結晶の開発  [招待講演]

  原田 潤

  日本物理学会2017年秋季大会 (盛岡) 2017年09月 口頭発表（招待・特別）
• Unique ferroelectric properties found in organic ionic plastic crystals  [招待講演]

  原田 潤

  AsCA2016 (Hanoi) 2016年12月 口頭発表（招待・特別）
• 柔粘性イオン結晶の示す特異な強誘電性  [招待講演]

  原田 潤

  平成28年度物性研究所短期研究会「パイ電子系物性科学の最前線」(柏) 2016年08月 口頭発表（招待・特別）
• Unique Ferroelectricity Found in Organic Ionic Plastic Crystals  [招待講演]

  原田 潤

  The 12th Hokkaido University-Nanjing University-NIMS/MANA Joint Symposium (Sapporo) 2016年07月 口頭発表（招待・特別）
• Pedal motion of molecules in crystals  [招待講演]

  原田 潤

  ICMAT 2013 (Singapore) 2013年07月 口頭発表（招待・特別）
• Molecular motions in organic crystals and their application to design of ferroelectrics  [招待講演]

  原田 潤

  HU-AGH Joint Symposium (Sapporo) 2013年07月 口頭発表（招待・特別）
• Solid-state photochromic reactions of spiropyrans and spirooxazines  [招待講演]

  原田 潤

  Challenges in Advanced Chemistry of Asia (Sapporo) 2012年12月 口頭発表（招待・特別）
• 結晶学による分子ダイナミックスへのアプローチ  [招待講演]

  原田 潤

  日本結晶学会平成24年度年会 (仙台) 2012年10月 口頭発表（招待・特別）
• 有機固相光反応の追跡  [招待講演]

  原田 潤

  日本結晶学会平成22年度年会 (吹田) 2010年12月 口頭発表（招待・特別）
• 結晶中における有機分子のペダル運動  [招待講演]

  原田 潤

  日本化学会第90春季年会 第24回若い世代の特別講演会 (東大阪) 2010年03月 口頭発表（招待・特別）
• Photochromism and Thermochromism of Crystalline Salicylideneanilines  [招待講演]

  原田 潤

  IUCr2008 (Osaka) 2008年08月 口頭発表（招待・特別）

その他活動・業績

• 柔粘性/強誘電性結晶：分子の回転運動にもとづく機能材料

  原田 潤 日本応用物理学会 有機分子・バイオエレクトロニクス分科会誌 32 (4) 205 -210 2021年 [査読無し]
  
• 柔粘性/強誘電性結晶の開発

  原田 潤 機能材料 39 (2) 46 -54 2019年 [査読無し]
  
• ベルダジルラジカルが配位した新奇鉄(II)錯体[Fe^II(vdco)₂(H₂O)₂]・2H₂Oの結晶構造と物性:水分子の配向挙動に起因する⁵⁷Feメスバウアースペクトルの異常な振舞いの解明

  亀渕萌, 岡澤厚, 榎本真哉, 原田潤, 小川桂一郎, 大久保將史, 丸田悟朗, 武田定, 小島憲道 KURRI KR (168) 51 -56 2012年02月 [査読無し][通常論文]
  
• サリチリデンアニリン類結晶のサーモクロミズム．50年ぶりの新解釈

  原田 潤, 小川 桂一郎 光化学 42 64 -68 2011年 [査読無し]
  
• 結晶中の分子の動きを見る

  原田 潤 化学と工業 = Chemistry and chemical industry 63 (12) 980 2010年12月01日
• 有機結晶の色変化を理解する－サリチリデンアニリン類のサーモクロミズムの真相－

  原田 潤, 小川 桂一郎 現代化学 (1) 25 -30 2009年 [査読無し]
  

受賞

• 2017年11月 日本結晶学会 平成29年度日本結晶学会賞・学術賞
   

  受賞者: 原田 潤
• 2010年03月 日本化学会 第24回若い世代の特別講演会
   

  受賞者: 原田 潤

共同研究・競争的資金等の研究課題

• 柔粘性イオン結晶固溶体による分子性強誘電材料開発の多次元的展開

  日本学術振興会：科学研究費助成事業

  研究期間 : 2023年04月 -2026年03月 

  代表者 : 原田 潤
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