Researcher Database

Takayoshi Nakamura
Research Institute for Electronic Science Green Nanotechnology Research Center
Professor

Researcher Profile and Settings

Affiliation

  • Research Institute for Electronic Science Green Nanotechnology Research Center

Job Title

  • Professor

URL

J-Global ID

Research Interests

  • 金属錯体化学   分子性物質   分子エレクトロニクス   Molecular Electronics   

Research Areas

  • Nanotechnology/Materials / Inorganic and coordination chemistry
  • Nanotechnology/Materials / Basic physical chemistry
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Electronic devices and equipment
  • Nanotechnology/Materials / Functional solid-state chemistry

Academic & Professional Experience

  • 1994 - 1997 北海道大学(電子科学研究所電子材料物性部門) 助教授
  • 1994 - 1997 Associate Professor
  • 1997 - 北海道大学(電子科学研究所電子材料物性部門) 教授
  • 1997 - Professor
  • 1993 - 1994 工業技術院物質工学工業技術研究所 主任研究官
  • 1991 - 1992 工業技術院化学技術研究所 主任研究官
  • 1984 - 1991 工業技術院化学技術研究所 研究官

Association Memberships

  • 日本化学会北海道支部   有機合成化学協会   日本物理学会   日本化学会   応用物理学会   

Research Activities

Published Papers

  • Yuyama Ken-ichi, Islam Md Jahidul, Takahashi Kiyonori, Nakamura Takayoshi, Biju Vasudevanpillai
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 57 (41) 13424 - 13428 1433-7851 2018/10/08 [Refereed][Not invited]
  • Kato Masaru, Ogura Kazuya, Nakagawa Shogo, Tokuda Shoichi, Takahashi Kiyonori, Nakamura Takayoshi, Yagi Ichizo
    ACS OMEGA 3 (8) 9052 - 9059 2470-1343 2018/08 [Refereed][Not invited]
  • Jun Xiong, Teng Luo, Jun Zhang, Xiao-Xia Li, Shao-Fang Lv, Jun-Jun Peng, Ming Li, Wei Li, Takayoshi Nakamura
    Crystals 8 (2) 2073-4352 2018/02/01 [Refereed][Not invited]
     
    New supramolecular structures were designed in this work using large-sized polyoxometalates (POMs) and crown-ether-based supramolecular cations selected as building blocks. Two novel supramolecular inorganic–organic hybrids [(3-F-4-MeAnis)([18]crown-6)]2 [SMo12 O40]•CH3 CN (1) and [(4-IAnis)([18]crown-6)]3 [PMo12 O40]•4CH3 CN (2) (3-F-4-MeAnis = 3-fluoro-4-methylanilinium and 4-IAnis = 4-iodoanilinium) were synthesized. Crystals 1 and 2 have been characterized by infrared spectroscopy (IR) and elemental analysis (EA). Based on X-ray diffraction analysis, Crystals 1 and 2 were constructed through noncovalent bonding interactions and belong to different space groups due to the difference of the building blocks used. Supramolecular cations formed due to strong N–H···O hydrogen bonding interactions between the six oxygen atoms of [18]crown-6 molecules and nitrogen atoms of anilinium derivatives. Crystal 1 has two different supramolecular cations with an anti-paralleled arrangement that forms a dimer through weak hydrogen bonding interactions between adjacent [18]crown-6 molecules. Crystal 2 has three independent supramolecular cations that fill large spaces between the [PMo12 O40] polyoxoanions forming a rhombus-shape packing arrangement in the ac plane. Crystals 1 and 2 are unstable at room temperature.
  • Hiroshi Nishiyama, Takashi Takeda, Norihisa Hoshino, Kiyonori Takahashi, Shin-Ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    Crystal Growth and Design 18 (1) 286 - 296 1528-7505 2018/01/03 [Refereed][Not invited]
     
    Diamino-4,4-bithiazole (1) formed host-guest binary molecular crystals with various types of organic guest molecules including pyridine (Py), benzonitrile (PhCN), piperidine (Pipe), DMF, THF, 1,4-dioxane (Diox), CH3OH, aniline (Ani), coumarin (Coum), nitrobenzene (PhNO2), hexamethylenetetramine (HMTA), and quinoline (Quino). Single crystal X-ray structural analyses at 100 K revealed the formation of 1·(guest) or 1·(guest)2 crystals. Reversible molecular adsorption-desorption responses were observed with Py, PhCN, Pipe, DMF, and Diox around room temperature as the crystalline powders were heated during the desorption process and exposed to guest vapor during the readsorption process. The adsorption-desorption isotherms of crystalline powders 1 with Diox at 298 K indicated a reversible gate-opening adsorption-desorption process. Although the host-guest molecular crystals 1·(THF)2 and 1·(CH3OH)2 were confirmed by X-ray crystal structural analyses at 100 K, the THF and CH3OH guests were already eliminated at room temperature. Guest desorption processes of crystalline powders 1·(guest)x were not observed in the host-guest molecular crystals with Ani, Coum, PhNO2, HMTA, and Quino after the crystalline powders were heated. A balance of both the dipole moment and vapor pressure of the guest molecules played an essential role to elicit reversible guest sorption. The crystal structures formed on account of double N-H⋯N hydrogen-bonded one-dimensional (1D) chains between the -NH2 group and the ring nitrogen atom of 1, which interacted to form two-dimensional (2D) sheet structures through π-stacking and/or S⋯S interactions. Alternating layers of N-H⋯N hydrogen-bonded herringbone packing of 1 and the guest molecules led to the formation of other types of crystal lattices. The hydrogen-bonding molecular assemblies of 1 demonstrated lattice flexibly via the configuration change in the molecular arrangements according to the boiling point of the guest molecules.
  • Misaki Shiga, Shogo Kawaguchi, Masaru Fujibayashi, Sadafumi Nishihara, Katsuya Inoue, Tomoyuki Akutagawa, Shin-Ichiro Noro, Takayoshi Nakamura, Ryo Tsunashima
    Dalton Transactions 47 (23) 7656 - 7662 1477-9234 2018 [Refereed][Not invited]
     
    Newly prepared single crystals of [Co(ii)(dabco)(NCS)2(MeOH)2]·dabco (1-pink dabco: 1,4-diazabicyclo[2.2.2]octane) showed chromotropic behaviour in the solid state, changing from pink to blue upon heating or grinding. The complex 1-pink exhibited a two-dimensional orthogonal network structure with the coordination chain of -dabco-Co- bridged by hydrogen bonds between coordinative methanol and a second dabco molecule, where the methanol molecule was trapped by coordinative and hydrogen bonds. Chromism was demonstrated to stem from the quantitative desorption of methanol from 1-pink to produce [Co(ii)(dabco)(NCS)2]·dabco (1-blue(c)) by thermogravimetric (TG) and temperature controlled gas chromatography-mass spectrometry (GC-MS) analyses, and powder X-ray diffraction (XRD) analysis suggests that the transformation between the crystalline phases of 1-pink and 1-blue(c) occurred with similar lattice parameters. Furthermore, the desolvated species showed chemo-chromic behaviour due to the selective size- and polarity-dependent adsorption of solvent molecules.
  • Takashi Takeda, Shin-Ichiro Noro, Takayoshi Nakamura, Yasutaka Suzuki, Jun Kawamata, Tomoyuki Akutagawa
    CrystEngComm 20 (1) 17 - 24 1466-8033 2018 [Refereed][Not invited]
     
    We report a series of crystal structures of arylsulfonamide-armed anthraquinones (AQs) (1-4). The arylsulfonamide-armed AQs formed orthogonal aromatic arrangements between the AQ unit and terminal aryl units due to well-defined intramolecular hydrogen bonding between the carbonyl units of AQs and the amino groups of sulfonamide units. Three disubstituted AQs 1-3 formed fundamental dimer structures, which were stabilized by intermolecular π-π interaction between AQs. Subtle differences in the dimer structures led to different packing structures. Among them, the 1,8-bis(arylsulfonamide) derivative (1) formed solvated crystals of 1·(MeCN), which exhibited reversible and selective MeCN and/or EtCN adsorption-desorption behavior. Tetra(arylsulfonamide) AQ (4) with four bulky substituents on its periphery formed various host-guest molecular crystals of 4·X2 (X = toluene, xylene, trimethylbenzenes, 1,2,3,5-tetramethylbenzene, anisole, and benzonitrile) with a rectangular zero-dimensional cage surrounded by the π-planes of 4.
  • Seigo Mori, Masatoshi Aketa, Takui Sakaguchi, Hirokazu Asahara, Takashi Nakamura, Tsunenobu Kimoto
    IEEE Journal of the Electron Devices Society 6 (1) 449 - 453 2168-6734 2018 [Refereed][Not invited]
     
    Low on-resistance 4H-SiC reverse-blocking (RB) metal-oxide-semiconductor field-effect transistors (MOSFETs) have been developed by adopting a non-punch-through (NPT) drift layer in order to suppress the punch-through (PT) current under the reverse-blocking condition. The n-type NPT drift layer was 40-μ m thick doped to 3.7×1015 cm-3. The forward and reverse breakdown voltages of the fabricated NPT RB MOSFET were 3.6 kV and -3.0 kV, respectively. The differential specific on-resistance was 13.5 mΩ · cm2 at room temperature, which was 33% lower than that of a 3 kV PT RB MOSFET, demonstrating superiority of the developed NPT RB MOSFET as a high-performance bidirectional switch.
  • Yuan-Yuan Tang, Peng-Fei Li, Ping-Ping Shi, Wan-Ying Zhang, Zhong-Xia Wang, Yu-Meng You, Heng-Yun Ye, Takayoshi Nakamura, Ren-Gen Xiong
    PHYSICAL REVIEW LETTERS 119 (20) 0031-9007 2017/11 [Refereed][Not invited]
     
    Recently, a plastic crystal of quinuclidinium perrhenate (HQReO(4)) was reported to have the feasibility of controlling the crystallographic orientation in the grown crystal, but the corresponding temperature window is only about 22 K (345-367 K). Such a narrow window and uncertain ferroelectricity at room temperature would extremely limit its application potential. In this report, we prepared a large area high-quality polycrystalline thin film of HQReO(4) and for the first time observed ferroelectricity in the temperature range from 298 to 367 K. Density functional theory calculations revealed the origin of room-temperature ferroelectricity is ascribed to the collaborative flipping of HQ (protonated quinuclidine) and ReO4-, which is dynamically preferred in the presence of a N-H center dot center dot center dot O hydrogen bond. A local piezoresponse force microscopy measurement was also employed to study the mechanisms of multiaxial polarization rotation and domain dynamics. By extending the ferroelectric temperature window to room temperature and the extraordinary thin-film processability, HQReO(4) would certainly become a suitable candidate for next generation ferroelectric materials.
  • Ryo Tsunashima, Ippei Nakamura, Rika Oue, Seiya Koga, Hirofumi Oki, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    DALTON TRANSACTIONS 46 (37) 12619 - 12624 1477-9226 2017/10 [Refereed][Not invited]
     
    The electrical conductivity of mixed-valence [(Mo2Mo16O54)-Mo-V-O-VI(SO3)(2)](6-) tetraalkylammonium salts was investigated through dependence on the inter-cluster distance that is controlled by tetraethylammonium, tetrapropylammonium, and tetrabutylammonium cations. The crystallographic analysis of single crystals revealed that the inter-cluster distances are dependent on the chain length of the alkyl groups on the counter cations. In addition, the electrical conductivities of the single crystals were found to be dependent on both temperature and chain length. Mixed-valence polyoxometalate (POM) clusters are considered to be a molecular particle of Mo bronze by which highly ordered networks will be developed using single crystals, where POMs are rather small and have a well-organized structure compared to colloidal nanostructures.
  • Rika Ochi, Shin-ichiro Noro, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY (34) 4013 - 4019 1434-1948 2017/09 [Refereed][Not invited]
     
    We attempted the synthesis and crystallographic characterization of light-metal coordination polymers (CPs) using a 4-(methylsulfonyl)benzoate (msbza(-)) ligand with a charge-polarized neutral methylsulfonyl coordination moiety, in order to diversify the limited structures of light-metal CPs, as compared with heavy-metal CPs. As expected from the results of DFT calculations, all of the obtained CPs {three-dimensional (3D) [Mg2Na2(msbza)(6)(H2O)(3)](n) (1), two-dimensional (2D) [KH(msbza)(2)](n) (2) and 2D [Na(msbza)](n) (3)} exhibited coordination of the methylsulfonyl moiety to light-metal cations, in addition to coordination of the carboxylate. These structural features suggest that the use of a neutral methylsulfonyl coordination site is a powerful tool for the structural diversification of light-metal CPs. In addition, the 3D CP 1, with the rare and unique tetranuclear Mg2Na2 secondary building unit, showed an unprecedented single-crystal-to-single-crystal transformation via the low-crystalline state.
  • Shin-ichiro Noro, Takayoshi Nakamura
    NPG ASIA MATERIALS 9 1884-4049 2017/09 [Refereed][Not invited]
     
    Fluorine, the element with the highest electronegativity and low electric polarizability, can produce a variety of characteristics, including specific adsorption sites for molecules as well as flexibility to the host materials. In this review, we will introduce fluorine-functionalized metal-organic frameworks/porous coordination polymers that show unique and unprecedented structures, structural transformations, and gas and vapor adsorption/separation properties derived from the fluorine characteristics.
  • Takashi Takeda, Yasutaka Suzuki, Jun Kawamata, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS 19 (35) 23905 - 23909 1463-9076 2017/09 [Refereed][Not invited]
     
    A new strategy for controlling the electron-accepting ability of an anthraquinone (AQ)-based pi-molecular system is proposed to take advantage of intramolecular hydrogen bonding interactions. The electron-accepting properties of AQ are enhanced by the introduction of bulky arylsulfonamide groups into AQ derivatives due to the formation of effective intramolecular N-H center dot center dot center dot O hydrogen bonding interaction and stabilization of the anion radical state even in solution.
  • Yu-Meng You, Yuan-Yuan Tang, Peng-Fei Li, Han-Yue Zhang, Wan-Ying Zhang, Yi Zhang, Heng-Yun Ye, Takayoshi Nakamura, Ren-Gen Xiong
    NATURE COMMUNICATIONS 8 2041-1723 2017/04 [Refereed][Not invited]
     
    Ferroelectric thin-films are highly desirable for their applications on energy conversion, data storage and so on. Molecular ferroelectrics had been expected to be a better candidate compared to conventional ferroelectric ceramics, due to its simple and low-cost film-processability. However, most molecular ferroelectrics are mono-polar-axial, and the polar axes of the entire thin-film must be well oriented to a specific direction to realize the macroscopic ferroelectricity. To align the polar axes, an orientation-controlled single-crystalline thin-film growth method must be employed, which is complicated, high-cost and is extremely substrate-dependent. In this work, we discover a new molecular ferroelectric of quinuclidinium periodate, which possesses six-fold rotational polar axes. The multi-axes nature allows the thin-film of quinuclidinium periodate to be simply prepared on various substrates including flexible polymer, transparent glasses and amorphous metal plates, without considering the crystallinity and crystal orientation. With those benefits and excellent ferroelectric properties, quinuclidinium periodate shows great potential in applications like wearable devices, flexible materials, bio-machines and so on.
  • Yoshimitsu Sagara, Kazuya Kubo, Takayoshi Nakamura, Nobuyuki Tamaoki, Christoph Weder
    CHEMISTRY OF MATERIALS 29 (3) 1273 - 1278 0897-4756 2017/02 [Refereed][Not invited]
     
    Mechanoresponsive luminescent (MRL) compounds change their emission color upon mechanical treatment. Hundreds of MRL compounds have been studied, but their mechanically triggered response at elevated temperature has remained virtually unexplored. Here, we demonstrate that the temperature can have a significant influence on the mechanically induced response of MRL compounds. The photoluminescence of a new cyano-substituted oligo(p-phenylenevinylene) derivative was shown to exhibit a significant red-shift when ground at ambient temperature, whereas the same treatment at 100 degrees C leads to a hypsochromic shift. The behavior at ambient is caused by a mechanically induced phase transition from a crystalline to an amorphous solid in which the dye molecules form excimers, whereas at elevated temperature the hypsochromic shift is ascribed to a crystalline-crystalline phase transition. Such temperature-dependent MRL behavior was not previously observed, but it appears to be a general effect that is useful for sophisticated mechano-sensing materials and devices.
  • Shin-ichiro Noro, Rika Ochi, Kazuya Kubo, Takayoshi Nakamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 89 (12) 1503 - 1509 0009-2673 2016/12 [Refereed][Not invited]
     
    Crystallization of neutral 3,5-pyridinedicarboxylic acid N-oxide (H-2-3,5-pydcao) molecules in the presence/absence of solvent molecules affords neutral hydrogen bond-supported one-dimensional, two-dimensional, and three-dimensional molecular networks of H-2-3,5-pydcao center dot DMF (1 center dot DMF), H-2-3,5-pydcao center dot H2O (1 center dot H2O), and H-2-3,5-pydcao (1), respectively, that have strong intermolecular hydrogen bonds of N delta+-O delta-center dot center dot center dot HOOC. These molecular networks were found to show reversible structural changes among 1, 1 center dot H2O, and 1 center dot DMF driven by solvent release/uptake.
  • Zhong-Sheng Cai, Shota Uchikawa, Norihisa Hoshino, Takashi Takeda, Li-Min Zheng, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    JOURNAL OF PHYSICAL CHEMISTRY B 120 (27) 6761 - 6770 1520-6106 2016/07 [Refereed][Not invited]
     
    Successive phase transitions of three kinds of simple 1:1 organic salts of laurylammonium (LA)-phenyl (3-pyridyl) phosphate derivative were examined in terms of thermal properties, single crystal Xray structural analyses, powder X-ray diffractions, and dielectric responses, where the phosphate anion was chemically modified from phenylphosphate (1) and 3-pyridylphosphate (2) to m-fluorophosphate (3). All 1:1 simple organic salts showed the successive solid-solid and solid-smectic A (SmA) phase transition with high thermal stability. Isostructural alternate cation-anion layer was observed in LA-1 and LA-2, and the packing structure of LA-3 was different from those of the former salts. The L-shaped cation-anion conformation in the molecular assemblies was transformed to the rod-like conformation through the phase transition to SmA phase, where both conformations coexisted in the intermediate solid phase of LA-2 and LA-3. The DSC, PXRD, and dielectric responses of LA-2 showed the antiferroelectric-paraelectric phase transition couple with the flip-flop motion of 3-pyridyl ring along the long axis of the molecule. On the contrary, such molecular motion of the phenyl ring did not show the dielectric phase transition due to no dipole change during molecular rotation of phenyl ring. The motional freedom of m-fluorophenyl ring in LA-3 was completely suppressed by the steric hindrance from the neighboring anions in the absence of dielectric ordering.
  • Rika Ochi, Shin-ichiro Noro, Yuichi Kamiya, Kazuya Kubo, Takayoshi Nakamura
    CHEMISTRY-A EUROPEAN JOURNAL 22 (31) 11042 - 11047 0947-6539 2016/07 [Refereed][Not invited]
     
    A two-dimensional (2D) layered Mg-II coordination polymer (CP) with a high tolerance for H2O was designed, synthesised, and crystallographically characterised. The synthesis was achieved by the introduction of a flexible 2D layered structure composed of MgII ions and isonicotinate N-oxide ligands. Owing to its high H2O tolerance, the obtained 2D layered structure has the flexibility to repeatedly adsorb a large amount of H2O associated with interlayer expansion and enable the removal of H2O from a H2O/2-propanol mixed vapour. These results indicate that the CP could be an excellent dehydrating agent.
  • Masashi Yoshitake, Kazuya Kubo, Toru Endo, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 89 (3) 354 - 360 0009-2673 2016/03 [Refereed][Not invited]
     
    Coordination polymers based on oxalate-bridged {[(MnCrIII)-Cr-II- (oxalate)(3)](-)}(infinity) complexes of (DAT-2H(2+))(DCH[18]crown-6)(2)[Mn-II(CH3OH)Cr-III(oxalate)(3)](-)(2)(CH3OH)(3) and (DABCO-H+)(2)(DABCO-2H(2+))[Mn-II(CH3OH)(Cl-)Cr-III(oxalate)(3)](2-)(2-) (CH3OH), where DAT, DABCO, and DCH[18]crown-6 denote 2,5-diaminotoluene, 1,4-diazabicyclo[2.2.2]octane, and cis-syncis-dicyclohexano[18]crown-6, respectively, were synthesized. The crystal structure of the former complex was composed of [Mn-II(Lambda)(CH3OH)Cr-III(Lambda)(oxalate)(3)](-) units, whereas that of the latter crystal was composed of [Mn-II(Lambda)(CH3OH)(Cl-)-Cr-III (Delta)(oxalate)(3)](2-) units. The large flexible supramolecular cation in the former provided the two-dimensional structure of [Mn-II(Lambda)(CH3OH)Cr-III(Lambda)(oxalate)(3)](-), although the two-dimensional honeycomb structure of the {[Mn-II(Delta)Cr-III(Lambda)-(oxalate)(3)](-)}infinity and {[Mn-II(Lambda)Cr-III(Delta)(oxalate)(3)](-)}(infinity) networks are often observed for the oxalate complexes. The round-shaped DABCO molecule in the latter induced a one-dimensional chain structure of [Mn-II(Lambda)(CH3OH)Cr-III(Delta)(oxalate)(3)](-). The former crystal showed a magnetic field dependence of magnetization typical for a spin-canting system.
  • Jun Xiong, Kazuya Kubo, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CRYSTAL GROWTH & DESIGN 16 (2) 800 - 807 1528-7483 2016/02 [Refereed][Not invited]
     
    To investigate the network structure of inorganic organic hybrid crystals, we synthesized a series of assemblies based on polyoxometallates (POMs) [SMo12O402-] and different supramolecular cations consisting of anilinium and crown ether derivatives. The compounds [(m-XAni(+))(B-[18]crown-6)](2)[SMo12O402-] (Ani(+) = anilinium; B [18] crown-6 = benzo[18]crown-6; X = F (1), Cl (2), Br (3), or I (4)), [ (4-MeAn(+)) (B [18] crown-6)](2)[SMo12O4020]center dot CH3CN (5), [(4-MeAni(+)) (DB [18] crown-6)](2)[SMo12O402-]center dot 2CH(3)CN (6), [(3-F-4-MeAni(+)) (DB [18] crown-6)](2)[SMo12O402-]center dot 2CH(3)CN (7), and [ (3-F-4-MeAni(+))(2)(DB [30]crown-10)] [SMo12O402-]center dot 2CH(3)CN (8) (4-MeAni(+) = 4-methylanilinium; DB [18] crown-6 = dibenzo[18]crown-6; 3-F-4-MeAni = 3-fluoro-4-methylanilinium; DB[30] crown-10 = dibenzo[30]crown-10) were synthesized. Their crystal architectures were characterized according to the size and charge of the supramolecular cations. In 1-4, two adjacent supramolecular cations ([(m-XAni(+))(B[18]crown-6)]) were connected through pi center dot center dot center dot pi interactions forming sandwich-type dimers with the cations that were stacked in an antiparallel manner. In 8, DB[30] crown-10 included two cations constructing a larger divalent supramolecular cation [(3-F-4-MeAni(+))(2)(DB[30]crown-10)]. In 1-4 and 8, the ratio between [SMo12O402-] and the supramolecular cations was 1:1, and the latter formed rectangular-assembled structures. In 5, the pi center dot center dot center dot pi stacking interaction was present in the adjacent B[18]crown-6. Monovalent supramolecular cations were present in 5-7 with a ratio of 1:2 between [SMo(12)O4(02)(-)] and the supramolecular cations. The supramolecular cations formed hexagonal-assembled structures.
  • Yu Ohshima, Kazuya Kubo, Takashi Matsumoto, Heng-Yun Ye, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CRYSTENGCOMM 18 (41) 7959 - 7964 1466-8033 2016 [Refereed][Not invited]
     
    Supramolecular crystals having one-dimensional (1d) columnar structures were constructed by using supramolecules based on tst-DCH[18]crown-6 (tst-DCH = trans-syn-trans-dicyclohexano). In the crystal of (Ani(+))(tst-DCH[18]crown-6)[Ni(dmit)(2)](-) (1) and (m-FAni(+))(tst-DCH[18]crown-6)[Ni(dmit)(2)](-) (2) (Ani(+) = anilinium(+), m-FAni(+) = m-fluoroanilinium(+), dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate), the tst-DCH[18]crown-6 formed supramolecular cations with Ani(+) and m-FAni(+), respectively, through N-H center dot center dot center dot O hydrogen bonds. The planar conformation of tst-DCH[18]crown-6 molecules in the crystals provided bidirectional hydrogen bonding from the upper and lower side of the molecule that were the driving forces for the construction of the 1d supramolecular architecture. The results provided a method to control arrangements of crown ether-based supramolecules in 1d columns that could be used for channels and/or molecular nanomachines such as molecular rotators.
  • Kiyonori Takahashi, Norihisa Hoshino, Takashi Takeda, Koichiro Satomi, Yasutaka Suzuki, Shin-ichiro Noro, Takayoshi Nakamura, Jun Kawamata, Tomoyuki Akutagawa
    DALTON TRANSACTIONS 45 (8) 3398 - 3406 1477-9226 2016 [Refereed][Not invited]
     
    Polar crystals exhibiting second-order harmonic generation (SHG) were designed by adjusting the intermolecular interactions of mononuclear Cu(II) complexes in which one H2O, two pyridines (py), and two p-substituted benzoate (p-RBA) ligands (R = F, Cl, Br, I, CH3, and OCH3) were coordinated to a Cu(II) ion, forming a penta-coordinated asymmetric [Cu(II)(p-RBA)(2)(py)(2)(H2O)] mononuclear structure with a permanent dipole moment along the direction of the Cu-OH2 coordination axis. Each asymmetric [Cu(II) (p-RBA)(2)(py)(2)(H2O)] complex formed a polar one-dimensional hydrogen-bonded chain, [Cu(II) (p-RBA)(2)(py)(2)(H2O)](8), between the non-coordinated carboxylate oxygen atom of the p-RBA ligand and the hydrogen atom of the H2O molecule. The formation of a polar crystal depended on the arrangement of polar hydrogen-bonded chains; the parallel arrangement of each polar chain resulted in a polar crystal. The chemical design of the R group in the p-RBA ligand enabled tuning of the magnitude of the inter-chain interactions and crystal polarity; polar crystals were obtained using p-RBA ligands with R = Cl, Br, I, and OCH3. In contrast, apolar crystals were grown from complexes containing p-RBA ligands with R = F and CH3. In all crystals, a polar two-dimensional (2D) layer constructed from the parallel polar [Cu(II) (p-RBA)(2)(py)(2)(H2O)]8 chain arrangement was formed based on weak van der Waals C-H...O-- interactions between the hydrogen atom of py and the carboxylate oxygen atom of the p-RBA ligand. Weak interlayer halogen (X)center dot center dot center dot pi and multipoint C-H center dot center dot center dot pi interactions played important roles in forming parallel arrangements of polar 2D layers and polar crystals, but there were no effective intermolecular interactions between the polar 2D layers in apolar [Cu(II)(p-FBA)(2)(py)(2)(H2O)] and [Cu(II)(p-CH(3)BA)(2)(py)(2)(H2O)] crystals. The magnitudes of the interlayer interactions in the polar crystals were larger than those in the apolar ones because of the effective intermolecular interactions. The SHG intensities of the four polar crystals were approximately 0.7 times larger than that of sucrose.
  • T. Nakamura, S. Jayanty
    SOFT MATERIALS 14 (4) 309 - 315 1539-445X 2016 [Refereed][Not invited]
     
    Poly (4-styrenesulfonate) (PSS) templated polyaniline-carboxymethyl cellulose blend forming stable aqueous colloidal suspensions was prepared through simple synthesis. Morphology of the spin-coated films obtained from different concentrations of colloidal suspensions was studied through atomic force microscopy (AFM). The AFM images were found to be drastically altered at lower concentrations showing a regular network-like structure. Room-temperature surface resistivity for the network featured spin-coated film showed semiconducting behavior. This indicates the efficacy of dilution as a new design element for network structures, further exhibiting resistivity.
  • Qian-Chong Zhang, Takashi Takeda, Norihisa Hoshino, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    CRYSTAL GROWTH & DESIGN 15 (12) 5705 - 5711 1528-7483 2015/12 [Refereed][Not invited]
     
    The thermal properties, crystal structures, dielectric relaxations, and rotational potential energy curves were examined for new rod-like molecules 1 and 2 bearing three aromatic rings connected by two -CONH- linkage groups to clarify the dynamic molecular behavior and phase transition behavior of the molecular assemblies. The molecular structures of 1 and 2 differed in that the central aromatic ring was phenyl (-C6H4-) in 1 and pyridyl (-C5NH3-) in 2, which affected the phase transition behavior owing to the permanent dipole moment without the center of inversion in molecule 2. Although the crystal structures of 1 and 2 were isostructural, the melting point of crystal 2 was approximately 43 K lower than that of crystal 1, and a smectic A mesophase was reversibly observed in crystal 2. A broad endothermic thermal anomaly of crystal 2 was observed in the heating process on the differential scanning calorimetry chart because of thermally activated dipole fluctuation, which was consistent with the frequency- and temperature-dependent dielectric relaxations. Double- and single-minimum-type potential energy curves were observed in the rotations of -C6H4- and -C5NH3- rings, respectively, from density functional theory calculations. The difference in rotational symmetry affected the crystal lattice energy and appearance of the mesophase.
  • Shin-ichiro Noro, Rika Ochi, Yasutaka Inubushi, Kazuya Kubo, Takayoshi Nakamura
    MICROPOROUS AND MESOPOROUS MATERIALS 216 92 - 96 1387-1811 2015/11 [Refereed][Not invited]
     
    Porous coordination polymers (PCPs) that show a gate-type adsorption originating from structural flexibility represent a new concept for developing gas separation materials. Here, the gas adsorption and separation properties of a flexible one-dimensional (1D) copper(II) PCP, [Cu(BF4)(2)(1,3-bis(4-pyridyl) propane)(2)](n) were evaluated. The single-gas adsorption isotherms revealed different gate-opening pressures for CO2 and C1 similar to C4 linear alkanes, suggesting great possibility for the separation of mixtures of these gases. The gas separation properties were characterized by performing breakthrough experiments at ambient temperature using CH4/CO2 and CH4/C2H6 mixtures. The results demonstrated the practical utility of 1D PCPs in gas separation applications. Single-crystal X-ray diffraction analysis demonstrated high structural adjustability for the incorporation of a variety of guest molecules. (C) 2015 Elsevier Inc. All rights reserved.
  • Kiyonori Takahashi, Norihisa Hoshino, Takashi Takeda, Shin-ichiro Noro, Takayoshi Nakamura, Sadamu Takeda, Tomoyuki Akutagawa
    INORGANIC CHEMISTRY 54 (19) 9423 - 9431 0020-1669 2015/10 [Refereed][Not invited]
     
    CO2 and N-2 gas adsorption/desorption properties of one-dimensional copper(II) polymers with paddle-wheel units [Cu-2(II)(p-XBA)(4)(pyrazine)(infinity) were successfully controlled through the tuning of interchain interactions by modification of para-substituent X groups on the benzoate (BA) ligands (X = Cl, Br, I, and OCH3). Although none of the four crystals had sufficient void space to integrate the crystallization solvents, gate-opening gas adsorption and desorption behaviors coupled with structural phase transitions were observed for CO2 (T = 195 K) and N-2 (T = 77 K), with differences depending on the precise substituent. van der Waals interchain interactions, specifically pi center dot center dot center dot pi, halogen center dot center dot center dot pi, and C-H center dot center dot center dot pi contacts, were dominant in forming the crystal lattice; their magnitude was associated with gate-opening pressure and hysteresis behaviors. Both the type and magnitude of the interactions were evaluated by Hirshfeld surface analysis, which indicated that structural flexibility decreased as larger halogen atoms were included. Overall, weak interchain interaction and structural flexibility generated new void spaces to adsorb CO2 and N-2 gases.
  • Shin-ichiro Noro, Ryotaro Matsuda, Yuh Hijikata, Yasutaka Inubushi, Sadamu Takeda, Susumu Kitagawa, Yukiko Takahashi, Masashi Yoshitake, Kazuya Kubo, Takayoshi Nakamura
    CHEMPLUSCHEM 80 (10) 1517 - 1524 2192-6506 2015/10 [Refereed][Not invited]
     
    The development of highly efficient CO2 separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal-organic frameworks are one of a number of promising types of porous materials for CO2 separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO2 selectivity and inexpensive regeneration. However, this family of materials suffers from the coexistence of water that destroys the framework of PCPs and its adsorption in the pores is greater than that of CO2, which results in a deterioration in CO2-separation performance. Herein, a flexible and hydrophobic CuII PCP that is stable towards water has been designed and synthesised. This PCP has extremely high adsorption selectivity for CO2 over CH4, derived from its structural flexibility. Furthermore, the obtained water-tolerant flexible PCP, under CO2/CH4 mixed-gas conditions, exhibits highly selective CO2 adsorption over CH4, even in the presence of water.
  • Toru Endo, Kazuya Kubo, Masashi Yoshitake, Shin-ichiro Noro, Norihisa Hoshino, Tomoyuki Akutagawa, Takayoshi Nakamura
    CRYSTAL GROWTH & DESIGN 15 (3) 1186 - 1193 1528-7483 2015/03 [Refereed][Not invited]
     
    Metalorganic network structure based on oxalate bridges {[(MnCrIII)-Cr-II(oxalate)(3)]-}(infinity) and supramolecular cations (H2PPD2+)(benzo[18]crown-6)(2)[MnCr(oxalate)(3)](CH3OH)(CH3CN)(2) (1) and (o-FAni(+))(2)(DCH[18]crown-6)(2)[Mn(CH3OH)Cr(oxalate)(3)][MnCr(oxalate)(3)](CH3OH) (2), where H2PPD(2+), o-FAni(+), and DCH[18]crown-6 denote p-phenylenediammonium(2+), o-fluoroanilinium+, and cis-syn-cis-dicyclohexano[18]crown-6, respectively, were synthesized. The crystal structure of 1 was the combination of [Mn(boolean AND)Cr(boolean AND)(oxalate)(3)]- and [Mn(boolean AND)Cr(Delta)(oxalate)(3)]-, whereas that of crystal 2 was the combination of [Mn(boolean AND)(CH3OH)Cr(Delta)(oxalate)(3)] and [Mn(boolean AND)Cr(Delta)(oxalate)(3)]. Large flexible supramolecular cations provide the three-dimensional structure of {[(MnCrIII)-Cr-II(oxalate)(3)]-}(infinity), which is different from the two-dimensional honeycomb structure often observed for {[(MnCrIII)-Cr-II(oxalate)(3)]-}(infinity) complexes. Temperature-dependent magnetic susceptibilities of the complexes 1 and 2 exhibited ferromagnetic behaviors following the CurieWeiss law (C = 11.5 cm(3) K mol(-1), theta = 13.0 K for 1; C = 4.14 cm(-3) K mol(-1), theta = 12.3 K for 2).
  • Shin-ichiro Noro, Junya Mizutani, Yuh Hijikata, Ryotaro Matsuda, Hiroshi Sato, Susumu Kitagawa, Kunihisa Sugimoto, Yasutaka Inubushi, Kazuya Kubo, Takayoshi Nakamura
    NATURE COMMUNICATIONS 6 2041-1723 2015/01 [Refereed][Not invited]
     
    The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions. The three-dimensional magnesium(II) and calcium(II) PCPs synthesized using such a neutral ligand are stable and show selective adsorption and separation of carbon dioxide over methane at ambient temperature. This synthetic approach allows the structural diversification of Group II magnesium(II) and calcium(II) PCPs.
  • Manami Endo, Yuta Nakane, Kiyonori Takahashi, Norihisa Hoshino, Takashi Takeda, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    JOURNAL OF PHYSICAL CHEMISTRY B 119 (4) 1768 - 1777 1520-6106 2015/01 [Refereed][Not invited]
     
    Simple organic salts such as (Li+)(m-IBA) (1), (Na+)(m-IBA) (2), (K+)(m-IBA) (3), (Rb+)(m-IBA) (4), and (Cs+)(m-IBA) (5) (m-IBA = m-iodobenzoate) were shown to form a mesophase before crystal melting or decomposition. The crystals were obtained in the hydrated form, e.g., 1 center dot(H2O), 2 center dot(H2O), 3 center dot 0.5(H2O), 4 center dot(H2O), and 5 center dot(H2O); they were then converted into dehydrated forms by increasing the temperature to similar to 450 K. Optically anisotropic-layered mesophases were observed in unhydrated crystals 2, 3, 4, and 5, whereas an optically isotropic mesophase (e.g., rotator phase) was found for crystal 1. The single-crystal X-ray structural analysis of the hydrated crystals revealed an inorganic-organic alternate layer structure, which is consistent with the average molecular orientation in the layered mesophase. The m-IBA anions formed a p-stacking columnar structure in the hydrated crystals, while one- or two-dimensional M+similar to O networks were observed in the inorganic layers. Our results showed that the M+similar to O interactions and their connectivity are strongly influenced by the size of the cations. The reconstruction of the M+similar to O networks by removing H2O molecules was crucial for the formation of the mesophases. A strong response of both the real and imaginary parts of the dielectric constant was observed around the solid-mesophase phase-transition temperatures of crystals 1-5, with the ionic conductions playing a critical role.
  • Takashi Takeda, Jun'ya Tsutsumi, Tatsuo Hasegawa, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    JOURNAL OF MATERIALS CHEMISTRY C 3 (13) 3016 - 3022 2050-7526 2015 [Refereed][Not invited]
     
    Three electron-accepting dialkoxydicyanopyrazinoquinoxaline derivatives (1a, 1b, and 1c) showed properties of smectic (Sm) liquid crystals. Temperature-dependent X-ray diffraction studies were consistent with the formation of a bilayer structure through the pi-overlap and interdigitation of alkoxy chains in the Sm liquid crystalline state. Intermolecular dipole-dipole interactions between the cyano groups played an important role in stabilizing the bilayer structure and liquid crystalline properties. Elongation of the alkoxy chains from C6H13O- (1a) and/or C12H25O- (1b) to C18H37O- (1c) changed the molecular arrangements and the liquid crystal phase from SmA to SmC, suggesting the importance of the van der Waals interaction of CnH2n+1O-chains for stabilizing the liquid crystalline phase. A hole-mobility value of 5 x 10(-3) cm(2) V-1 s(-1) was observed for the SmA phase of 1b at 438 K based on transient photocurrent measurements.
  • Y. Yoshii, K. Sakai, N. Hoshino, T. Takeda, S. Noro, T. Nakamura, T. Akutagawa
    CRYSTENGCOMM 17 (31) 5962 - 5969 1466-8033 2015 [Refereed][Not invited]
     
    The Bronsted acid-base reaction between 3-hydroxy-2-quinoxalinecarboxylic acid (Hhqxc) and imidazole (Im) in acetone-H2O yielded two 1 : 1 salts: anhydrous (HIm(+))(hqxc(-)) (1) and hydrated (HIm(+))(hqxc(-))center dot(H2O) (2), where HIm(+) and hqxc(-) are imidazolium and 3-hydroxy-2-quinoxalinecarboxylate, respectively. Single-crystal X-ray structural analyses and vibrational spectra were consistent with the lactam tautomer of the hqxc(-) anion, which formed pi-dimers in both 1 and 2. Each pi-dimer in crystal 1 was connected by intermolecular N-H center dot center dot center dot O hydrogen-bonding interactions to form a linear hqxc(-) chain, whereas the pi-dimers in crystal 2 formed an intermolecular N-H center dot center dot center dot O hydrogen-bonding zigzag chain. The HIm(+) cations existed in the crystalline space between the hydrogen-bonding hqxc(-) anionic chains. A reversible crystal-to-crystal structural transformation between crystals 1 and 2 was observed following H2O adsorption-desorption, which was confirmed by powder X-ray diffraction measurements, single-crystal X-ray structural analyses, and H2O adsorption-desorption isotherms at 323 K. The structural rearrangement of the hqxc(-) anions was achieved through changes in the intermolecular hydrogen-bonding interactions. The temperature- and frequency-dependent dielectric constants of crystal 2 revealed a dielectric peak at similar to 330 K owing to thermal fluctuations of H2O molecules within the crystal.
  • J. Xiong, K. Kubo, S. Noro, T. Akutagawa, T. Nakamura
    CRYSTENGCOMM 17 (4) 856 - 861 1466-8033 2015 [Refereed][Not invited]
     
    Four supramolecular cations (m-XAni(+))(DB[18]crown-6) (X = F, Cl, Br or I; Ani(+) = anilinium ion; DB[18]crown-6 = dibenzo[18]crown-6) were introduced into crystals of a Keggin [SMo12O402-] polyanion to form [(m-XAni(+))(DB[18]crown-6)](2)[SMo12O402-]center dot 4CH(3)CN (1, 2, 3 or 4 for X = F, Cl, Br or I) through a hydrogen-bonding interaction. Crystals 1, 2, 3 and 4, which were isomorphous to each other, crystallized in the monoclinic space group P2(1)/(n). Supramolecular cations (m-XAni(+))(DB[18]crown-6) were constructed by a N-H+center dot center dot center dot O hydrogen-bonding interaction. [SMo12O402-] polyoxoanions were infinitely extended in three dimensions through a weak C-H center dot center dot center dot O hydrogen-bonding interaction with DB[18] crown-6. Disorder of the halogen atoms at the meta-position was observed in crystals 1, 2 and 3. The rotational freedom of the (m-XAni(+)) cations was suppressed because of weak interactions with surrounding molecules.
  • Yuya Yoshii, Norihisa Hoshino, Takashi Takeda, Hiroki Moritomo, Jun Kawamata, Takayoshi Nakamura, Tomoyuki Akutagawa
    CHEMISTRY-A EUROPEAN JOURNAL 20 (49) 16279 - 16285 0947-6539 2014/12 [Refereed][Not invited]
     
    Simple organic salts based on aniline-derived cations and D-tartrate anions formed organogels and helical nanofibers. The organic salt (p-fluoroanilinium)(D-tartrate) was found to generate an organogel despite the absence of a hydrophobic alkyl chain, whereas (p-iodoanilinium)(D-tartrate) formed helical nanofibers in braided ropelike structures through a rolling-up process. The helicity of these nanofibers could be reversed by changing the growth solvent. The driving forces responsible for the formation of the nanofibers were determined to be 1D OHO- hydrogen-bonding interactions between D-tartrate anions and stacking of anilinium cations, as well as steric hindrance between the hydrogen-bonded chains.
  • Yuta Shishido, Hayato Anetai, Takashi Takeda, Norihisa Hoshino, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    JOURNAL OF PHYSICAL CHEMISTRY C 118 (36) 21204 - 21214 1932-7447 2014/09 [Refereed][Not invited]
     
    Five simple benzenecarboxamide (BC) derivatives bearing multiple -CONHC14H29 chains-N,N'-bis(tetradecyl)-1,4-benzenedicarboxamide (2BC), N,N',N ''-tri-(tetradecyl)-1,3,5-benzenetricarboxamide (3BC), N,N',N '',N ''-tetra(tetradecyl)-1,2,4,5-benzenetetracarboxamide (4BC), N,N',N '',N''',N''''-penta(tetradecyl)benzenepentacarboxamide (5BC), and N,N',N '',N''',N'''',N'''''-hexa(tetradecyl)benzenehexacarboxamide (6BC)-were examined in terms of their molecular assemblies in solution, organogels, liquid crystals, and solids as well as their phase transition behavior and dielectric responses. The molecular assemblies of compounds 3BC-6BC were dominated by the intermolecular N-H similar to O= hydrogen-bonding interactions along the pi-stacking directions and formed one-dimensional pi-stacking nanofibers. The excellent organogelation characteristics of compound 3BC were observed in common organic solvents such as ethanol, acetonitrile, acetone, and N,N-dimethylformamide, whereas compounds 4BC and 6BC formed organogels in hexane and/or toluene. Mechanical fraying of the three-dimensional entangled nanofibers in the organogel state resulted in a two-dimensional cobweb-like nanofiber network, where the typical height and width of each nanofiber on the substrate surface were ca. 3.5 and 200 nm, respectively. A single nanofiber was constructed by a pi-stacking column through intermolecular N-H similar to O= hydrogen-bonding interactions, of which the hexagonal arrangement resulted in ordered hexagonal columnar (Col(ho)) discotic liquid crystalline phases for compounds 3BC-6BC. Both of the intercolumnar and intracolumnar distances in the Col(ho) phase were linearly increased according to the number of -CONHC14H29 chains. The temperature- and frequency-dependent dielectric constants of compounds 2BC-6BC in cast-films revealed dielectric anomalies around the solid to Col(ho) phase transition temperatures due to thermally activated molecular motion. Polarization-electric field (P-E) curves of compounds 2BC, 3BC, and 5BC in the mesophases showed hysteretic behavior with ferroelectric ground states, whereas paraelectric behavior with linear P-E dependence was observed for compounds 4BC and 6BC.
  • Kiyonori Takahashi, Norihisa Hoshino, Shin-Ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa
    SCIENCE OF ADVANCED MATERIALS 6 (7) 1417 - 1424 1947-2935 2014/07 [Refereed][Not invited]
     
    Cu(II) binuclear coordination polymers of [Cu(II)(ADCOO)(4)(pz)](infinity) (1), [Cu(II)(ADCOO)(4)(F-pz)](infinity) (2), and [Cu(II)(Cl-ADCOO)(4)(pz)](infinity) (3) were prepared, where ADCOO, Cl-ADCOO, pz, and F-pz are adamantane-1-carboxylate, 3-chloroadamantane-1-carboxylate, pyrazine, and 2-fluoropyrazine, respectively. The Cu(II) binuclear units of [Cu(II)(ADCOO)(4)] and [Cu(II)(Cl-ADCOO)(4)] were formed by the four bridging ligands of ADCOO and Cl-ADCOO to the two Cu(II) ions, respectively, which were further connected by the axial bidentate ligands of pz or F-pz, to form one-dimensional (1D) coordination polymers. Although the 1D coordination polymers were observed in the typical structures of crystals 1, 2, and 3, the packing structure of polymer 3 was different from those of crystals 1 and 2. Three-dimensional (3D) interdigitated polymer arrays were observed in 1 and 2 as cubic crystal systems with the I-43d space group, whereas the two-dimensional array of 1D polymers of 3 was the same as that of the [Cu(II)(C6H5COO)(4)(pz)](infinity) crystal. The crystal structure of 2 was not affected by the introduction of a polar F group into the axial pz ligand, whereas the introduction of the Cl-substituent into the ADCOO ligand significantly modified the packing structure of the coordination polymers. The polar ligands of F-pz in 2 and Cl-ADCOO in 3 were static at 110 K according to X-ray crystal structural analyses. The absolute magnitude of the dielectric constants was decreased in the order of 3, 2, and 1, which is consistent with the dipole moments of the ligands. No CO2 gas adsorption-desorption processes were observed in crystals 1, 2, and 3 at 195 K. The 3D interdigitated polymer arrangements in 1 and 2, and the strong dipole-dipole interaction between Cl-ADCOO ligands, were not responsible for the structural changes in the CO2 gas adsorption-desorption.
  • Shin-ichiro Noro, Kei Hasegawa, Kazuya Kubo, Takayoshi Nakamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 87 (5) 623 - 625 0009-2673 2014/05 [Refereed][Not invited]
     
    The one-dimensional Zn(II) coordination polymer, {[Zn-2(chdc)(2)(mepy)(4)]center dot 6H(2)O}(n) (1 superset of 6H(2)O, chdc: trans-1,4-cyclohexanedicarboxylate and mepy: 4-methylpyridine), stabilized unique water aggregate, finite winding (H2O)(12) chains.
  • Yin-Nan Yan, Kazuya Kubo, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 87 (3) 417 - 419 0009-2673 2014/03 [Refereed][Not invited]
     
    Supramolecular cation salt of adamantane rotator with a dithiolene complex, (fluoroadamantylammonium(+))([18]-crown-6)[Ni(dmit)(2)](-) (1) was synthesized. The fluorine atom of the adamantane unit showed a large thermal factor elongated latitudinally, suggesting molecular rotation in the solid state. Crystal 1 exhibited a large dielectric response by applying an AC field along the a axis.
  • Zun-qi Liu, Kazuya Kubo, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CRYSTAL GROWTH & DESIGN 14 (2) 537 - 543 1528-7483 2014/02 [Refereed][Not invited]
     
    4-Methylanilinium derivatives were used to introduce spaces for molecular rotation in crystals. The [Ni(dmit)(2)](-) (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) salts with supramolecular cations of dibenzo[18]crown-6 (DB[18]crown-6) and 4-methylanilinium derivatives, (4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (1), (2-fluoro-4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (2), and (3-fluoro-4-methylanilinium(+))(DB[18]crown-6)[Ni(dmit)(2)](-) (3) were synthesized. The potential energy curves for the molecular rotations of the cations in the crystals had double minimum shapes with maxima of 100, 210, and 230 kJ mol(-1) for crystals 1, 2, and 3, respectively. Introduction of a methyl substituent at the p-position was effective in reducing the potential energy maxima. For crystals 2 and 3, large dielectric responses originating from the flip-flop motions of the cationic molecules were observed upon applying an AC voltage. The temperature-dependent magnetic susceptibilities of complexes 1, 2, and 3 followed the Curie-Weiss law, showing weak antiferromagnetic interactions.
  • Yuki Noda, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    SCIENTIFIC REPORTS 4 3758  2045-2322 2014/01 [Refereed][Not invited]
     
    Gold nanoparticle assemblies possess diverse application potential, ranging from industrial nanotechnology to medical biotechnology. Because the structures and properties of assemblies are directly affected by the stabilization mechanism between the organic molecules serving as protecting ligands and the gold nanoparticle surface, it is crucial to find and investigate new stabilization mechanisms. Here, we report that pi-conjugated phthalocyanine rings can serve as stabilizing ligands for gold nanoparticles. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato) terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. AC magnetic measurements and the electron-transport properties of the assemblies give direct evidence that the phthalocyanines are isolated from each other. Each nanoparticle shows weak electronic coupling despite the short internanoparticle distance (similar to 1 nm), suggesting Efros-Shklovskii-type variable-range hopping and collective single-electron tunnelling behaviours.
  • Kiyonori Takahashi, Norihisa Hoshino, Takashi Takeda, Shin-ichiro Noro, Takayoshi Nakamura, Sadamu Takeda, Tomoyuki Akutagawa
    DALTON TRANSACTIONS 24 43 (24) 9081 - 9089 1477-9226 2014 [Refereed][Not invited]
     
    m-Fluorobenzoate (m-FBA), 2,3-difluorobenzoate (2,3-F(2)BA), m-methylbenzoate (m-MBA), and m-chlorobenzoate (m-ClBA) were introduced into the Cu(II) binuclear unit as bridging ligands between two Cu(II) sites, which were further connected by an axial pyrazine (pz) ligand to form one-dimensional coordination polymers of [Cu(II)(2)(m-FBA)(4)(pz)](infinity) (1), [Cu(II)(2)(2,3-F(2)BA)(4)(pz)](infinity) (2), [Cu(II)(2)(m-MBA)(4)(pz)](infinity) (3), and [Cu(II)(2)(m-ClBA)(4)(pz)](infinity) (4), respectively. The parallel arrangements of one-dimensional (1D) polymers result in 1D channels between the polymers that crystallization CH3CN molecules can occupy to form single crystals of 1 center dot 4CH(3)CN, 2 center dot 4CH(3)CN, 3 center dot 2CH(3)CN, and 4 center dot 2CH(3)CN. Both pi-dimer and dipole-dipole interactions were simultaneously observed in the interchain interactions of m-FBA and/or 2,3-F(2)BA ligands in crystals 1 and 2. The sizes of the one-dimensional channels between the polymers are thus modulated according to the interchain interactions between the polar BA ligands. CH3CN molecules within the channels were easily replaced by H2O under ambient conditions. CO2 adsorption-desorption isotherms of crystals 1, 2, and 3 at 195 K indicated gate-adsorption with a hysteresis, whereas two-step gate-adsorption behavior was observed for CO2 in crystal 4. Temperature- and frequency-dependent dielectric responses were not observed in crystals 1-4 under vacuum conditions, whereas dielectric anomalies were observed around 290 K for crystals 1 and 2 with adsorbed CO2. CO2 desorption from the channels in crystals 1 and 2 activated the molecular motions of polar BA ligands and dielectric responses around 290 K, which were confirmed from CO2 adsorption-desorption isotherms around 290 K and differential scanning calorimetries under CO2 conditions.
  • Sadafumi Nishihara, Xiao Zhang, Kazuhisa Kunishio, Katsuya Inoue, Xiao-Ming Ren, Tomoyuki Akutagawa, Jun-Ichiro Kishine, Masashi Fujisawa, Atsushi Asakura, Susumu Okubo, Hitoshi Ohta, Takayoshi Nakamura
    Dalton Transactions 42 (43) 15263 - 15266 1477-9226 2013/11/21 [Refereed][Not invited]
     
    Since carrier doping of two-leg spin ladders can theoretically induce a superconductive state, investigation of such systems is of great use in the study of superconductivity. In this paper, we report the successful creation of a non-magnetic impurity doped into a two-leg molecular spin ladder and the characterization of its magnetic properties. © 2013 The Royal Society of Chemistry.
  • T. Naito, H. Yamamoto, K. Okuda, K. Konishi, H. Mayama, D. Yamaguchi, S. Koizumi, K. Kubo, T. Nakamura
    EUROPEAN PHYSICAL JOURNAL B 86 (10) 1434-6028 2013/10 [Refereed][Not invited]
     
    It is well-known that cooperative properties such as magnetic ordering can depend on the samples' dimensions (Ds) in a qualitative way. However, there have been no samples with well-defined non-integer Ds. The dimension of a given sample has been always discussed on the anisotropy of the electronic/crystal/magnetic structures, which has no definition suitable for quantitative discussion on dimensions vs. properties. On the other hand a particular type of porous samples, i.e. fractal bodies, can have well-defined non-integer Ds dependent exclusively on the geometrical feature of structures, and physical properties of such materials remains unexplored. This paper reports on magnetic ordering in samples covering 2.5 <= D <= 3, in addition to a way of precise control of the fractal dimensions of given samples simply by wax (alkylketene dimer). The results show that the magnetic ordering temperatures, i.e. Neel temperatures (T(N)s), of CoO depend on D, and rapidly enhance immediately below D = 3. This means that one can control or enhance the critical temperature simply by tuning D with keeping the remaining magnetic properties unchanged.
  • Qiong Ye, Ping-Ping Shi, Xue-Qun Fu, Tomoyuki Akutagawa, Takayoshi Nakamura
    CrystEngComm 15 (26) 5307 - 5313 1466-8033 2013/07/14 [Refereed][Not invited]
     
    The hydrogen-bonding supramolecule with 4-ethoxyanilinium and [18]crown-6 is introduced to [Ni(dmit)2]- salt. The arrangement of supramolecular cations formed a three-dimensional structure with the one-dimensional channel filled with [Ni(dmit)2]- anions. The temperature-dependent structural analyses and DSC measurement disclose the first-order phase transition occurred around 285 K, where the lattice parameters show an abrupt change without a space group change. The title compound crystallizes in No. 1 space group P-1 and is piezoelectrically active with d33 value of 4.8 pC N-1. The frequency- and temperature-dependent dielectric constants and potential energy calculation are consistent with the forward-backward motion of the ethoxyl group in the cation. © 2013 The Royal Society of Chemistry.
  • Heng-Yun Ye, Yi Zhang, Shin-ichiro Noro, Kazuya Kubo, Masashi Yoshitake, Zun-Qi Liu, Hong-Ling Cai, Da-Wei Fu, Hirofumi Yoshikawa, Kunio Awaga, Ren-Gen Xiong, Takayoshi Nakamura
    SCIENTIFIC REPORTS 3 2249  2045-2322 2013/07 [Refereed][Not invited]
     
    Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10 kHz), and high performance in polarization switching up to 1 x 10(6) times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.
  • Mohammad Razaul Karim, Kazuto Hatakeyama, Takeshi Matsui, Hiroshi Takehira, Takaaki Taniguchi, Michio Koinuma, Yasumichi Matsumoto, Tomoyuki Akutagawa, Takayoshi Nakamura, Shin-ichiro Noro, Teppei Yamada, Hiroshi Kitagawa, Shinya Hayami
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 135 (22) 8097 - 8100 0002-7863 2013/06 [Refereed][Not invited]
     
    We measured the proton conductivity of bulk graphite oxide (GO'), a graphene oxide/proton hybrid (GO-H), and a graphene oxide (GO) nanosheet for the first time. GO is well-known electronic insulator, but for proton conduction we observed the reverse trend, as it exhibited superionic conductivity. The hydrophilic sites present in GO as -O-, -OH, and -COOH functional groups attract the protons, which propagate through hydrogen-bonding networks along the absorbed water film. The proton conductivities of GO' and GO-H at 100% humidity were similar to 10(-4) and similar to 10(-5) S cm(-1), respectively, whereas that for GO was amazingly high, nearly 10(-2) S cm(-1). This finding indicates the possibility of GO-based perfect two-dimensional proton-conductive materials for applications in fuel cells, sensors, and so on.
  • Shin-ichiro Noro, Katsuo Fukuhara, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    INORGANIC CHEMISTRY 52 (10) 5630 - 5632 0020-1669 2013/05 [Refereed][Not invited]
     
    The use of divalent Cu-II ions and an anion-mixing method led to the rational construction of a porous coordination polymer bridged by weak Lewis base inorganic CF3SO3- monoanions.
  • Katsuo Fukuhara, Shin-ichiro Noro, Kunihisa Sugimoto, Tomoyuki Akutagawa, Kazuya Kubo, Takayoshi Nakamura
    INORGANIC CHEMISTRY 52 (8) 4229 - 4237 0020-1669 2013/04 [Refereed][Not invited]
     
    Porous coordination polymer (PCP) polymorphs with the formula [Cu(CF3SO3)(2)(bpp)(2)](n) [1 and 2, where bpp = 1,3-bis(4-pyridyl)propane] have been synthesized and crystallographically characterized, and their distinguishable porous properties have been investigated. 1 was obtained by the removal of guest acetone molecules from one-dimensional PCP {[Cu(CF3SO3)(bpp)(2)]center dot CF3SO3 center dot 2acetone}(n) (1 superset of 2acetone), while 2 was derived from two-dimensional PCP {[Cu(CF3SO3)(2)(bpp)(2)]center dot H2O} (2 superset of H2O) by the loss of guest H2O molecules. The desolvated PCPs 1 and 2 with the same formula [Cu(CF3SO3)(2)(bpp)(2)] showed distinguishable structures, suggesting PCP polymorphs. In addition, their adsorption behaviors were completely different: 1 showed adsorption with the structural transformation from closed to open forms, while 2 appeared to expand its framework for only as long as was required for the passage of guest molecules. To the best of our knowledge, PCP polymorphs showing either of two different types of flexible pores are very rare.
  • Toru Endo, Kazuya Kubo, Masashi Yoshitake, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CHEMISTRY LETTERS 42 (2) 137 - 139 0366-7022 2013/02 [Refereed][Not invited]
     
    A single crystal of (3-fluoro-4-methoxyanilinium)(+)([18]crown-6)[(MnCrIII)-Cr-II(oxalate)(3)](-)(CH3OH)(2) had the space group C-c owing to the arrangement of the 3-fluoro-4-methoxyanilinium(+) cation with C-1 symmetry and, therefore, was pyroelectric. A ferromagnetic transition at 5.5K was observed, which originated from the two-dimensional honeycomb structure of the [(MnCrIII)-Cr-II(oxalate)(3)](-) anion.
  • Zun-qi Liu, Kazuya Kubo, Li Lin, Norihisa Hoshino, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    DALTON TRANSACTIONS 42 (8) 2930 - 2939 1477-9226 2013 [Refereed][Not invited]
     
    Supramolecular cations formed by monoprotonated pyridazinium cations and cis-anti-cis-dicyclohexano-[18]-crown-6 (DCH[18]-crown-6) or dibenzo[18]-crown-6 (DB[18]-crown-6) were introduced into [Ni(dmit)(2)](-) salts (where dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate). X-ray crystal structure analysis of (pyridazinium(+))(DCH[18]-crown-6)[Ni(dmit)(2)](-) (1) revealed a chair-type conformation of the DCH[18]-crown-6 moiety. A V-shaped conformation of the DB[18]-crown-6 moiety was observed in (pyridazinium(+))(DB[18]-crown-6)(2)[Ni(dmit)(2)](-)(H2O)(2) (2). Nitrogen atoms in the pyridazinium cations interacted with the oxygen atoms of the DCH[18]-crown-6 and DB[18]-crown-6 through N-H+similar to O hydrogen bonds, forming 1 : 1 and 1 : 2 supramolecular structures, respectively. Sufficient space for molecular motions of the pyridazinium cations, namely flip-flop and in-plane rotations, exists in salt 1. Disorder in nitrogen atoms was observed by X-ray analysis, indicating dynamic motion of the pyridazinium cation, namely flip-flop motion and in-plane motion. A potential energy calculation further supported the possibility of dynamic motion of cations in the crystal. By contrast, the flip-flop motion of the pyridazinium group in salt 2 is restricted by the two nearest-neighbouring DB[18]-crown-6 molecules. Weak antiferromagnetic intermolecular interactions between the [Ni(dmit)(2)](-) anions in the two-dimensional layers of salt 1 were observed, resulting in alternating antiferromagnetic Heisenberg chain-type magnetic susceptibility. Quasi-one-dimensional intermolecular interactions between the [Ni(dmit)(2)](-) anions were observed in salt 2, whose magnetic behaviour followed the Bonner-Fisher model.
  • Shin-ichiro Noro, Yuh Hijikata, Munehiro Inukai, Tomohiro Fukushima, Satoshi Horike, Masakazu Higuchi, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    INORGANIC CHEMISTRY 52 (1) 280 - 285 0020-1669 2013/01 [Refereed][Not invited]
     
    High selectivity and low-energy regeneration for adsorption of CO2 gas were achieved concurrently in a two-dimensional Cu(II) porous coordination polymer, [Cu-(PF6)(2)(4,4'-bpy)(2)] (4,4'-bpy = 4,4'-bipyridine), containing inorganic fluorinated PF6- anions that can act as moderate interaction sites for CO2 molecules.
  • Shin-ichiro Noro, Katsuo Fukuhara, Kunihisa Sugimoto, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    DALTON TRANSACTIONS 31 42 (31) 11100 - 11110 1477-9226 2013 [Refereed][Not invited]
     
    We report the syntheses and crystal structures of novel porous assemblies of coordination complexes (PACs) with/without guest molecules, alpha-[Cu(A)(2)(py)(4)] (alpha-PAC-2-A (A = PF6, BF4, CF3SO3, and CH3SO3); py = pyridine), gamma-{[Cu(PF6)(2)(py)(4)]center dot 2guest} (gamma-PAC-2-PF6 superset of 2guest (guest = acetone and py)), gamma-{[Cu(BF4)(2)-(py)(4)]center dot 2acetone} (gamma-PAC-2-BF4 superset of 2acetone), and beta-{[Cu(CH3SO3)(2)(py)(4)]center dot 2.67H(2)O} (beta-PAC-2-CH3SO3 superset of 2.67H(2)O). The single-crystal X-ray diffraction analyses of alpha-PAC-2-A show that alpha-PAC-2-A have dense packing structures, in which anions of the discrete coordination complexes form weak hydrogen-bonding and anion-pi interactions. In contrast, gamma-PAC-2-PF6 superset of 2guest, gamma-PAC-2-BF4 superset of 2acetone, and beta-PAC-2-CH3SO3 superset of 2.67H(2)O form guest-including structures with coordination environments around the Cu-II atoms similar to the a-forms. The vapour adsorption measurements for MeCN and acetone in alpha-PAC-2-A suggest that the adsorption associated with structural transformations is induced by weak Lewis-base PF6- and BF4- anions covered only with fluorine atoms, which weaken the host-host interactions.
  • Kazuya Kubo, Yin-Nan Yan, Shin-Ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    Inorganica Chimica Acta 404 206 - 209 0020-1693 2013 [Refereed][Not invited]
     
    Single crystal of supramolecuar cation salt (adamantylammonium +)2(benzo[18]crown-6)2[Pd(dmit) 2]2-(- acetone)2 were synthesized by an electrochemical crystallization. In the crystal, two supramolecular cations and two acetones and one [Pd(dmit)2]2- dianion were crystallographically asymmetric. Molecular rotation of adamantyl groups was suggested from anisotropic thermal factors in the X-ray analysis at 173 K. © 2013 Elsevier B.V.
  • Norihisa Hoshino, Yuuya Yoshii, Masaki Aonuma, Kazuya Kubo, Takayoshi Nakamura, Tomoyuki Akutagawa
    INORGANIC CHEMISTRY 51 (23) 12968 - 12975 0020-1669 2012/12 [Refereed][Not invited]
     
    Supramolecular assemblies of anilinium (Ani(+)) and fluoroanilinium derivatives (FAni(+)) with [18]crown-6 were introduced into electrically conducting [Ni(dmit)(2)] crystals (dmit(2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The crystal structures, electrical conductivities, and magnetic susceptibilities of four new crystals of (Ani(+))([18]crown-6)[Ni(dmit)(2)](3) (1), (o-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (2), (m-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (3), and (p-FAni(+))([18]crown-6)[Ni(dmit)(2)](3) (4) were examined from the viewpoint of dynamic supramolecular rotator structures within the crystals. The crystal structures, electrical conduction, and magnetic properties were classified into group-I (crystals 1 and 4) and group-II (crystals 2 and 3). The hydrogen-bonding interaction between -NH3+ and the oxygen atoms of [18]crown-6 formed the stand-up configuration of rotator-stator structures of (Ani(+))([18]crown-6) and (FAni(+))([18]crown-6) supramolecules. The potential energy barriers for the 2-fold flip-flop motion of phenyl- and p-fluorophenyl-rings in crystals 1 and 4 had a relatively small magnitude of similar to 150 kJmol(-1), suggesting that rotations of Ani(+) and p-FAni(+) cations around the C-NH3+ axis occurred in the crystals. In contrast, a large magnitude of the potential energy barriers for the rotations of o-FAni(+) and m-FAni(+) cations in crystals 2 and 3 (>600 kJmol(-1)) resulted in static supramolecular cationic structures. The cation:anion ratio of 1:3 in these crystals yielded a trimer pi-stack of [Ni(dmit)(2)] with a semiconductor-like temperature dependence. The magnetic susceptibilities of the static crystals 2 and 3 were reproduced by the one-dimensional antiferromagnetic linear Heisenberg chain through the one-dimensional linear trimer arrangement. The magnetic susceptibilities of dynamic crystals 1 and 4 enhanced electron delocalization through the intratrimer and intertrimer interactions within the trimer stack, where the molecular rotations of Ani(+) and p-FAni(+) cations played an important role.
  • Shin-ichiro Noro, Katsuo Fukuhara, Kazuya Kubo, Takayoshi Nakamura
    CHEMISTRY LETTERS 41 (10) 1314 - 1316 0366-7022 2012/10 [Refereed][Not invited]
     
    A Werner-type Cu(II) complex, alpha-[Cu(CF3SO3)(2)(4-mepy)(4)] (alpha-PAC-1-CF3SO3, PAC: porous assembly of coordination complex and 4-mepy: 4-methylpyridine), was synthesized, crystallographically characterized, and its adsorption properties were compared with those of the derivative alpha-[Cu(PF6)(2)(4-mepy)(4)] (alpha-PAC-1-PF6).
  • Shin-ichiro Noro, Kazuya Kubo, Takayoshi Nakamura
    CHEMISTRY LETTERS 41 (8) 772 - 773 0366-7022 2012/08 [Refereed][Not invited]
     
    The reaction of [Cu(PF6)(2)(py)(4)] (py: pyridine) with [Cu(CH3SO3)(2)(py)(4)], both of which are Werner-type Cu(II) complexes, in a MeOH solution led to the formation of a one-dimensional framework composed of [-{Cu(1)(2)(MeO)(2)}-Cu(2)-Cu(3)-Cu(3)-Cu(2)-] repeating units bridged by inorganic CH3SO3- anions.
  • Qiong Ye, Ping-Ping Shi, Zi-Qi Chen, Tomoyuki Akutagawa, Shin-ichiro Noro, Takayoshi Nakamura
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY (23) 3732 - 3739 1434-1948 2012/08 [Refereed][Not invited]
     
    Reactions exchanging the cation in (nBu4N)[Ni(dmit)2] to cis-cyclohexane-1,4-diammonium (cis-CHDA) in the presence of [18]crown-6, benzo[18]crown-6 (B[18]crown-6) and dibenzo[18]crown-6 (DB[18]crown-6) yielded crystals of the monovalent [Ni(dmit)2] complex, namely (cis-CHDA)([18]crown-6)2[Ni(dmit)2]2 (1), (cis-CHDA)(B[18]crown-6)2[Ni(dmit)2]2 (2) and (cis-CHDA)(DB[18]crown-6)2[Ni(dmit)2]2 (3). The two ammonium groups (NH3+) of the cis-CHDA dication at axial and equatorial positions interact with oxygen atoms of the corresponding upper and lower crown ethers to form sandwich-type supramolecular cationic structures. The lateral [Ni(dmit)2]- anion arrangements through SS contacts along the short and long axis of [Ni(dmit)2] anions were realised in crystals of 1, 2, and 3 by the asymmetrical cis-CHDA dication. The temperature- and frequency-dependent anisotropic dielectric constants of a crystal of 1 were evaluated along the a, b and c axes, where the thermally activated motion of the structurally flexible cis-CHDA dication was consistent with the dielectric responses.
  • Qiong Ye, Ping-Ping Shi, Zi-Qi Chen, Tomoyuki Akutagawa, Shin-ichiro Noro, Takayoshi Nakamura
    INORGANIC CHEMISTRY COMMUNICATIONS 20 219 - 224 1387-7003 2012/06 [Refereed][Not invited]
     
    [Ni(dmit)(2)](-) salt (dmit(2)(-)2-thioxo-1,3-dithiole-4,5-dithiolate) with flexible supramolecular cation (4-cyanomethylanilinium)(dibenzo[18]crown-6) has been synthesized and investigated its structure, magnetism and rotation. The comparable large steric hindrances limit the rotation of cyanomethyl group to result in no phase transition occurred. Magnetic and potential energy calculations by OFT method were consistent with the magnetic and structure measurements. (C) 2012 Elsevier B.V. All rights reserved.
  • Daigoro Endo, Tomoyuki Akutagawa, Kazuya Kubo, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 85 (3) 305 - 315 0009-2673 2012/03 [Refereed][Not invited]
     
    Single crystals formed from hydrogen-bonding supramolecular cations of o-aminoanilinium (HOPD+) crown ethers, (HOPD+)([12]crown-4), (HOPD+)([15]crown-5), and (HOPD+)([18]crown-6), and one-electron-reduced [PMo12O40](4-) Keggin-type clusters were synthesized. The crystal structures and dielectric responses of the three new compounds (HOPD+)(4)([12]crown-4)(4)[PMo12O40](4-)center dot 4CH(3)CN (1), (HOPD+)(4)([15]crown-5)(4)[PMo12O40](4-)or (2), and (HOPD+)(4)([18]crown-6)(4)[PMo12O40](4-)center dot 8CH(3)CN (3) were examined. The CH3CN molecules in salts 1 and 3 were included in zero-dimensional pores and one-dimensional channels, respectively; higher thermal stability was observed in the former lattice because of its extended hydrogen-bonding network. Large frequency- and temperature-dependent dielectric responses were confirmed in salts 2 and 3, whereas the dielectric response of salt 1 was quite small. The fixed orientation of HOPD+ because of the hydrogen-bonding network was consistent with the dielectric property of salt I. In contrast, large magnitudes of dielectric responses in the temperature range above 280K were observed for salt 3. Thermal motions of CH3CN molecules in the channel were the origin of such dielectric responses. In salt 2, the thermally activated coupled motion of the orthogonally arranged HOPD+ pair along the C-NH3+-axis with the potential energy barrier of ca. 80 kJ mol(-1) resulted in large dielectric responses.
  • Ryo Tsunashima, Takumi Matsumoto, Norihisa Hoshino, Wataru Niiho, Mizuki Kimura, Kei Kondo, Yoshihiko Suyama, Yukihiro Nishioka, Jun Kawamata, Shin-ichiro Noro, Takayoshi Nakamura, Tomoyuki Akutagawa, Katsuya Ishiguro
    DALTON TRANSACTIONS 41 (33) 10060 - 10064 1477-9226 2012 [Refereed][Not invited]
     
    A new salt-[NiII(DMSO)(5)(TTFPy)](2)[alpha-SiW12O40] (1)-based on polyoxometalates was prepared by coordinating a cationic electron donor of pyridyltetrathiafulvalene (TTFPy) with Ni-II. Although the TTFPy molecule did not form a salt with the anionic alpha-[SiWVI O-12(40)](4-)because of the weak charge-transfer (CT) interaction, the coordination of Ni with the pyridyl moiety permitted salt formation driven by electrostatic interaction, giving a single crystal of 1. Crystallographic analysis, UV-vis and IR spectroscopy and electrochemical characterization revealed that the fully oxidized alpha-[SiWVI O-12(40)](4-)was crystallized with the neutral TTFPy moiety from the acetonitrile solution because of the low electronwithdrawing ability of alpha-[(SiW12O40)-O-VI](4-), forming a brown-orange crystal. The crystal colour quickly turned to black by immersing in methanol, due to CT from TTF moiety to alpha-[(SiW12O40)-O-VI](4-), which was caused by the solvent effect. Increase in the solvent acceptor number from 18.9 for acetonitrile to 41.3 for methanol resulted in the enhancement of the electron withdrawing ability of alpha-[(SiW12O40)-O-VI](4-)by 0.317 V in methanol.
  • Norihisa Hoshino, Kazuya Kubo, Takayoshi Nakamura, Tomoyuki Akutagawa
    DALTON TRANSACTIONS 41 (31) 9297 - 9303 1477-9226 2012 [Refereed][Not invited]
     
    Sandwich-type hydrogen-bonded supramolecular dications (DAAz(2+))([18]crown-6)(2) and (DAAz(2+)) (dicyclohexane[18]crown-6)(2) (DAAz(2+) = 4,4'-(phenylazophenyl)diammonium) were introduced into [Ni(dmit)(2)](-) anions via a diffusion method to form novel single crystals (DAAz(2+))([18]crown-6)(2)-[Ni(dmit)(2)](2) (1) and (DAAz(2+))(dicyclohexane[18]crown-6)(2)[Ni(dmit)(2)](2) (2), respectively, which were characterized based on their crystal structures and magnetic susceptibilities. The molecular assembly structures and its physical properties were expanded in the use of a three component molecular network system. The two ammonium groups (-NH3+) of the DAAz(2+) dication formed N-H+-O hydrogen-bonding interactions with the oxygen atoms of [18]crown-6 and dicyclohexane[18]crown-6. In the case of crystal 1, an alternating pi-stacking interaction was observed for the [Ni(dmit)(2)](-) anions, whereas orthogonal linear pi-S interactions were detected for crystal 2. Temperature-dependent magnetic susceptibilities of crystals 1 and 2 followed the alternate Heisenberg antiferromagnetic chain (J = -15.8 K) and linear Heisenberg antiferromagnetic chain (J = -13.7 K) models, respectively.
  • Kiyonori Takahashi, Norihisa Hoshino, Kazuya Kubo, Takayoshi Nakamura, Tomoyuki Akutagawa
    CRYSTENGCOMM 14 (16) 5235 - 5241 1466-8033 2012 [Refereed][Not invited]
     
    The hydrogen-bonding (m-fluoroanilinium)(dibenzo[18]crown-6) supramolecule was complexed with the monovalent [Ni(mnt)(2)](-) (mnt(-2) = maleonitriledithiolate) anion and the crystal structure, thermal stability, and dielectric properties were investigated with respect to the motional freedom of m-fluoroanilinium (m-FAni(+)) in (m-FAni(+))(dibenzo[18]crown-6)[Ni(mnt)(2)](-)center dot(CH3CN)(0.25) (1). The pi-planar [Ni(mnt)(2)](-) anions were stacked along the a-axis and the orientational disorder of fluorine atoms in the m-FAni(+) cation was observed by X-ray crystal structural analysis at 100 K. Thermogravimetry and differential scanning calorimetry analyses and dielectric constant measurements showed an anomaly at 360 K during the first heating process, where the CH3CN molecule was released from the crystal while maintaining the block-shape of the single crystal. The cation-anion packing was compared with that of ferroelectric (m-FAni(+))(dibenzo[18]crown-6)[Ni(dmit)(2)](-) (2) and ferromagnetic (m-FAni(+))(dibenzo[18]crown-6)[CrMn(oxalate)(3)]center dot(CH3CN)(CH3OH) (3). The orientational disorder of the F-sites of m-FAni(+) in crystal 1 was associated with the presence of the CH3CN molecule, which was different from the twofold flip-flop motion of m-FAni(+) in ferroelectric crystal 2. Potential energy calculations revealed asymmetric double minimum-type potential energy with energy barriers of 180 and 900 kJ mol(-1). The cation-anion packing of crystal 1 was loose compared with that of crystals 2 and 3; therefore, the thermal stability of crystal 1 was lower than that of crystals 2 and 3. The two-dimensional anionic layer in crystals 2 and 3 enhanced the thermal stability of the crystals, whereas the one-dimensional pi-stacking structure of anions in 1 decreased its thermal stability.
  • Yuuya Yoshii, Norihisa Hoshino, Takayoshi Nakamura, Tomoyuki Akutagawa
    CRYSTENGCOMM 14 (21) 7458 - 7465 1466-8033 2012 [Refereed][Not invited]
     
    Ionic molecular crystals of (anilinium(+))(L-tartrate(-)) were prepared in C2H5OH-H2O via Bronsted acid-base reaction between aniline and L-tartaric acid. Strong intermolecular O-H center dot center dot center dot O- hydrogen-bonding interactions between the terminal -COOH and -COO- groups of the L-tartrate(-) monoanion (L-HTart(-)) are essential in forming the one-dimensional hydrogen-bonding (L-HTart(-))(infinity) chains. Furthermore, N-H+center dot center dot center dot O- hydrogen-bonding interactions between L-HTart(-) and the ammonium moiety of anilinium (Ani(+)) form a pi-stacking arrangement of the Ani(+) cations that are orthogonal to the (L-HTart(-))(infinity) chains. DSC analysis revealed a two-step behavior with reversible phase transitions at similar to 220 and similar to 270 K, in which three types of crystal phases (I, T < 220 K; II, 220 < T < 270 K; III, 270 K < T) were identified. Phase I possesses the same acentric space group (P1), while its unit cell volume is half of that of phases II and III, in which the p-stacking periodicity of the Ani(+) cations of phases II and III are double that of phase I. Although the conformation of the hydroxy (-OH) groups of L-HTart(-) of phase II (T = 250 K) was identical to that of phase I (T = 100 K), the rotation of the C-OH bond (activation energy of similar to 70 kJ mol(-1)) was observed for phase III. The thermal fluctuation of the polar -OH group in phase III was dominated by a single minimum-type potential energy curve, as evaluated from the calculations. The temperature-and frequency-dependent dielectric constants suggested a low-frequency thermal fluctuation at temperatures above similar to 250 K.
  • Subbalakshmi Jayanty, Tomoyuki Akutagawa, Takayoshi Nakamura
    CRYSTENGCOMM 14 (11) 3875 - 3881 1466-8033 2012 [Refereed][Not invited]
     
    Intramolecular and/or intermolecular hydrogen-bonded maleate (HMA(-)) monoanions were introduced into cation radical salts of tetrathiafulvalene (TTF), forming three kinds of crystals: (TTF+)(H2MA)(HMA(-)) (1), (TTF+)(3)(HMA(-))(3)(CH3OH)(H2O)(0.5) (2), and (TTF+)(3)(TTF0)(5)(HMA(-))(3) (3). In crystals 1 and 2, the monovalent TTF+ cation formed a strong pi-dimer of (TTF+)(2) and a pi-trimer of (TTF+)(3), respectively. In crystal 3, a non-uniform pi-stack of TTF0 and TTF+ was formed, which was further surrounded by neutral TTF through S center dot center dot center dot S and S center dot center dot center dot pi interactions, forming a cylindrical TTF0 array around the pi-stack. A charge-separated electronic state of (TTF+)(3)(TTF0)(5)(HMA(-))(3) in crystal 3 was observed in the Raman spectra. Crystal 3 showed a semiconducting temperature dependent behavior with a room temperature conductivity of 3 x 10(-3) S cm(-1), which was six orders of magnitude higher than those of crystals 1 and 2. The protonated state of the (H2MA)(HMA(-)) anion in crystal 1 was representative of an (HMA(-)center dot center dot center dot H+center dot center dot center dot HMA(-)) dimer, where the bridging proton between the two HMA(-) anions was located at the midpoint between the two oxygen sites. A very strong intramolecular symmetrical O-H center dot center dot center dot O- hydrogen-bonding interaction was observed in crystals 1-3 according to potential energy calculations of proton coordination in the O-H center dot center dot center dot O- hydrogen bonding.
  • Qiong Ye, Kiyonori Takahashi, Norihisa Hoshino, Takemitsu Kikuchi, Tomoyuki Akutagawa, Shin-ichiro Noro, Sadamu Takeda, Takayoshi Nakamura
    CHEMISTRY-A EUROPEAN JOURNAL 51 17 (51) 14442 - 14449 0947-6539 2011/12 [Refereed][Not invited]
     
    The temperature-dependent dynamic properties of [Cu-2(II)(ADCOO)(4)(DMF)(2)]center dot(DMF)(2) (1) and [Cu-2(II)(ADCOO)(4)(AcOEt)(2)] (2) crystals were examined by X-ray crystallography, H-1 NMR spectroscopy, and measurements of the dielectric constants and magnetic susceptibilities (ADCOO = adamantane carboxylate, DMF = N,N-dimethylformamide, and AcOEt = ethyl acetate). In both crystals, four ADCOO groups bridged a binuclear Cu-II-Cu-II bond, forming a paddle-wheel [Cu-2(II)(ADCOO)(4)] structure. The oxygen atoms of two DMF molecules in crystal 1 and two AcOEt molecules in crystal 2 were coordinated at axial positions of the [Cu-2(II)(ADCOO)(4)] moiety, forming [Cu-2(II)-(ADCOO)(4)(DMF)(2)] and [Cu-2(II)(ADCOO)(4)(AcOEt)(2)], respectively. Two additional DMF molecules were included in the unit cell of crystal 1, whereas AcOEt was not included in the unit cell of crystal 2. The structural analyses of crystal 1 at 300 K showed three-fold rotation of the adamantyl groups, whereas rotation of the adamantyl groups of crystal 2 at 300 K was not observed. Thermogravimetric measurements of crystal 1 indicated a gradual elimination of DMF upon in-creasing the temperature above 300 K. The dynamic behavior of the crystallized DMF yielded significant temperature-dependent dielectric responses in crystal 1, which showed a huge dielectric peak at 358 K in the heating process. In contrast, only small frequency-dependent dielectric responses were observed in crystal 2 because of the freezing of the molecular rotation of the adamantyl groups. The magnetic behavior was dominated by the strong antiferromagnetic coupling between the two S = 1/2 spins of the Cu-II-Cu-II site, with magnetic exchange energies (J) of -265 K (crystal 1) and -277 K (crystal 2).
  • Hong-Ling Cai, Wen Zhang, Jia-Zhen Ge, Yi Zhang, Kunio Awaga, Takayoshi Nakamura, Ren-Gen Xiong
    PHYSICAL REVIEW LETTERS 107 (14) 147601  0031-9007 2011/09 [Refereed][Not invited]
     
    A new organic ferroelectric compound, 4-(cyanomethyl) anilinium perchlorate, proceeds a second-order phase transition from a paraelectric phase (P2(1)/m) to a ferroelectric phase (P2(1)) at 184 K. A perfect ferroelectric hysteresis loop was observed even at 10 KHz. It is the first example of a molecule-based organic ferroelectric whose polarization can be switched at such a high frequency. The temperature dependent second harmonic generation effect shows that the second-order nonlinear coefficient is nearly zero above T-c and proportional to the spontaneous polarization below T-c, suggesting the occurrence of symmetry breaking, in good agreement with crystal structural determination. The origin of ferroelectricity was ascribed to the displacements of -NH3+ cations and ClO4- anions from the symmetric positions including a small part of the order-disorder behaviors of the ClO4- anions.
  • Qiong Ye, Tomoyuki Akutagawa, Norihisa Hoshino, Takemitsu Kikuchi, Shin-ichiro Noro, Ren-Gen Xiong, Takayoshi Nakamura
    CRYSTAL GROWTH & DESIGN 11 (9) 4175 - 4182 1528-7483 2011/09 [Refereed][Not invited]
     
    Structurally flexible trans-cyclohexane-1,4-diammonium (CHDA(2+)) forms a hydrogen-bonded sandwich-type supramolecule with benzo[18]crown-6 in (CHDA(2+))(benzo[18]crown-6)(2)[Ni(dmit)(2)](2) (1) (dmit(2-) : 2-thioxo-1,3-dithiole-4,5-dithiolate). During the crystallization, the three crystal polymorphs 1a, 1b, and 1c were obtained in the space groups P2(1)/c, P (1) over bar, and P (1) over bar, in which the orientation of the benzene rings of benzo[18]crown-6 in the sandwich-type supramolecular cations and the [Ni(dmit)(2)](-) arrangements were different. Crystal 1c had a structural phase transition at similar to 200 K, at which the unit cell volume of the low-temperature phase (1d) became twice that of the high-temperature phase (1c). The [Ni(dmit)(2)] pi-dimer was observed in crystals 1a, 1b, 1c, and Id. A double-minimum-type potential energy profile was observed for the rigid rotation of CHDA(2+) around the N-N axis. Among four new crystals, the relatively low potential energy barrier of similar to 120 kJ mol(-1) for crystal 1b was consistent with the temperature- and frequency-dependent dielectric constants. The crystal polymorph and structural phase transition were coupled in (CHDA(2+))(benzo[18]crown-6)(2)[Ni(dmit)(2)](2)(-).
  • Tomoyuki Akutagawa, Fumito Kudo, Ryo Tsunashima, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    INORGANIC CHEMISTRY 50 (14) 6711 - 6718 0020-1669 2011/07 [Refereed][Not invited]
     
    Hydrogen-bonded assemblies of the two-electron reduced mixed-valence Keggin clusters [PMo12O40](5-) and [SiMo12O40](6-) were obtained by the one-pot electron-transfer reactions between p-phenylenediamine (PPD) or 2,3,5,6-tetramethyl-PPD (TMPPD) (donors) and H-3(+)[PMo12O40](3-) or H-4(+)[SiMo12O40](4-) (acceptors) in CH3CN. The redox states of the [PMo12O40](5-) and [SiMo12O40](6-) clusters were confirmed by the redox titrations and electronic absorption measurements. In (HPPD+)(3)(H+)(2)[PMo12O40](5-)(CH3CN)(3-6) (1), the N-H similar to O hydrogen-bonded interactions between the monoprotonated HPPD+ (or diprotonated H2PPD(2+)) and the [PMo12O40](5-) resulted in a windmill like assembly and hydrophilic one-dimensional channels are formed with a cross-sectional area of 0.065 nm(2), and these are filled by the CH3CN molecules. Also, the CH3CN molecules in salt 1 were removed by immersing the single crystals of 1 into H2O, CH3OH, and C2H5OH solvents. In the compound, (HTMPPD+)(6)[SiMo12O40](6-) (CH3CN)(6) (2), the N-H similar to O hydrogen bonded interactions between the monoprotonated HTMPPD+ molecules and the [SiMo12O40](6-) formed a "Saturn-ring"-like assembly. Each Saturn-ring was arranged into an hexagonally packed array via hydrogen-bonded and pi-stacking interactions of HTMPPD+, while the CH3CN solvent present in salt 2 are only found in the zero-dimensional isolated cavities.
  • Shin-ichiro Noro, Katsuo Fukuhara, Kazuya Kubo, Takayoshi Nakamura
    CRYSTAL GROWTH & DESIGN 11 (6) 2379 - 2385 1528-7483 2011/06 [Refereed][Not invited]
     
    A one-dimensional Cu(II) coordination polymer {[Cu(bpetha)(2,2'-bPY)(MeOH)]center dot 2PF(6)}(n) (bPetha =1,2-bis(4-pyridyl)ethane; 2,2'-bpy =2,2'-bipyridine) with wide coordination space at the axial site was rationally synthesized and crystallographically characterized, in which [Cu(2,2'-bpy)] units are bridged by bpetha ligands, forming a one-dimensional zigzag chain that shows smooth adsorption for EtOH, MeOH, and H2O vapors.
  • Toru Endo, Tomoyuki Akutagawa, Shin-ichiro Noro, Takayoshi Nakamura
    DALTON TRANSACTIONS 40 (7) 1491 - 1496 1477-9226 2011 [Refereed][Not invited]
     
    A supramolecular cation of (m-FAni(+))(DB[18]crown-6), where m-FAni(+) and DB[18]crown-6 denote m-fluoroanilinium(+) and dibenzo[18]crown-6, respectively, which is the polar unit rotating in the ferroelectric crystal of (m-FAni(+))(DB[18]crown-6)[Ni(dmit)(2)](-), was introduced into a ferromagnetic [MnCr(oxalate)(3)](-) salt as the counter cation. The crystal structure of (m-FAni(+))(DB[18]crown-6)[MnCr(oxalate)(3)](-)(CH3OH)(CH3CN) (1) is constructed from alternating layers of a two-dimensional honeycomb layer of [MnCr(oxalate)(3)](-) and (m-FAni(+))(DB[18]crown-6) supramolecular cations. The anionic layer is composed of Mn-II and Cr-III ions with S = 5/2 and S = 3/2 spins, respectively, bridged by the oxalate anions, which show ferromagnetic ordering at 5.5 K. The supramolecular structure is formed through the formation of hydrogen bonds between the ammonium hydrogen atoms of the m-FAni(+) cations and the oxygen atoms of the DB[18]crown-6 cavity. No orientational disorder of the fluorine atoms was observed in our X-ray structural analysis, suggesting that a two-fold flip-flop motion of the m-FAni(+) cations does not occur in the salt. The rotational freedom of the m-FAni(+) cations in the salt is restricted by the steric hindrance from neighbouring DB[18]crown-6 molecules. A design strategy for the rotation in a salt is discussed, based on the volume that the supramolecular cations occupy in the unit cell.
  • Shin-ichiro Noro, Tomonori Ohba, Katsuo Fukuhara, Yukiko Takahashi, Tomoyuki Akutagawa, Takayoshi Nakamura
    DALTON TRANSACTIONS 40 (10) 2268 - 2274 1477-9226 2011 [Refereed][Not invited]
     
    The quasi-Werner-type copper(II) complex, [Cu(PF(6))(2)(4-mepy)(4)] (1), in which 4-mepy is the 4-methylpyridine ligand, has flexible and polar axial bonds of Cu-PF(6). Flexibility of the Cu-PF(6) bonds induces diverse and unprecedented guest-inclusion structures, such as {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(acetone)]center dot PF(6)center dot 4acetone} (gamma-1 superset of 2.5acetone), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(2-butanone)]center dot PF(6)center dot 3.5(2-butanone)} (gamma-1 superset of 2.25(2-butanone)), {[Cu(PF(6))(2)(4-mepy)(4)][Cu(PF(6))(4-mepy)(4)(H(2)O)]center dot PF(6)center dot 4benzene} (gamma-1 superset of 0.5H(2)O center dot 2benzene), and {[Cu(PF(6))(2)(4-mepy)(4)]center dot 2benzene} (gamma-1 superset of 2benzene). Exposure of the dense form, alpha-1, to benzene vapor affords the benzene-inclusion complex {[Cu(PF(6))(2)(4-mepy)(4)]center dot 2benzene} (gamma-1 superset of 2benzene), all benzene guests of which are easily removed by vacuum drying, reforming guest-free, dense alpha-1' with smaller sized crystals than alpha-1. In contrast to alpha-1, which shows almost no CO(2) adsorption, alpha-1' adsorbs CO(2) gas with structural transformations, this being the first example that exhibits adsorption of gas in a dense Werner-type complex and a drastic change in adsorption properties depending on the size of the crystals.
  • Ryo Tsunashima, De-Liang Long, Toru Endo, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura, Raul Quesada Cabrera, Paul F. McMillan, Paul Koegerler, Leroy Cronin
    PHYSICAL CHEMISTRY CHEMICAL PHYSICS 13 (16) 7295 - 7297 1463-9076 2011 [Refereed][Not invited]
     
    The Dawson-type polyanion [alpha-Mo18O54(SO3)(2)](4-), with two SO32- templates embedded inside a polyoxomolybdate(VI) cage, exhibits thermochromism over an exceptionally wide temperature range (similar to 500 K). The temperature dependence of the cluster structure, established from X-ray crystallography, IR and Raman spectroscopy and DFT calculations, is related to a decreasing HOMO-LUMO gap in the near UV with increasing temperature. We postulate this is due to geometrical changes that affect both the occupied and unoccupied frontier molecular orbitals of this cluster anion.
  • Da-Wei Fu, Wen Zhang, Hong-Ling Cai, Yi Zhang, Jia-Zhen Ge, Ren-Gen Xiong, Songping D. Huang, Takayoshi Nakamura
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50 (50) 11947 - 11951 1433-7851 2011 [Refereed][Not invited]
  • Qiong Ye, Tomoyuki Akutagawa, Heng-Yun Ye, Tian Hang, Jia-Zhen Ge, Ren-Gen Xiong, Shin-ichiro Noro, Takayoshi Nakamura
    CRYSTENGCOMM 13 (20) 6185 - 6191 1466-8033 2011 [Refereed][Not invited]
     
    A flexible hydrogen-bonding supramolecular cation of 4-cyanomethylanilinium (CMAni(+))-[18]crown-6 was introduced into the [Ni(dmit)(2)](-) salt (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) as a counter cation to form (CMAni(+))([18]crown-6)[Ni(dmit)(2)](-). The rotation of the cyanomethyl group of the CMAni(+) cation is associated with the structural phase transition at 153 K, at which temperature the space group was changed from Pbcn (high-temperature phase) to P2(1)2(1)2(1) (low-temperature phase). The temperature dependent dielectric constants and potential energy calculations were consistent with the rotation of the cyanomethyl group of CMAni(+).
  • Gunzi Saito, Hideo Ikegami, Yukihiro Yoshida, Olga O. Drozdova, Kazukuni Nishimura, Sachio Horiuchi, Hideki Yamochi, Akihiro Otsuka, Takaaki Hiramatsu, Mitsuhiko Maesato, Takayoshi Nakamura, Tomoyuki Akutagawa, Toru Yumoto
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 83 (12) 1462 - 1480 0009-2673 2010/12 [Refereed][Not invited]
     
    A series of charge-transfer (CT) solids of trifluoromethyl-7,7,8,8-tetracyanoquinodimethane (CF(3)TCNQ) with various electron donor molecules were prepared and their IR and UV-vis-near-IR spectra and electrical conductivity were measured. The information was applied to produce an ionicity phase diagram of CF(3)TCNQ CT solids. A boundary for ionicity of CF3TCNQ was found in combination with donor molecules of dibenzo[c,d]phenothiazine, diaminodurene, or dibenzotetrathiafulvalene (DBTTF). With stronger donors than DBTTF, the CF(3)TCNQ molecules were fully ionized and acted as a counter anion. No conductors with partially charged CF(3)TCNQ species were obtained. Besides the conventional 1:1 fully ionic insulators with segregated stacks, tetramethyl-TTF center dot CF(3)TCNQ center dot CH3CN and bis(methylthio)ethylenedithio-TTF center dot CF(3)TCNQ had fully ionic alternating stacks of DDAA units and showed Frenkel triplet excitons. (BEDO-TTF)(2)(CF(3)TCNQ) [BEDO-TTF: bis(ethylenedioxy)-TTF] consisted of a mixed-valence segregated stack of donor molecules and completely ionized acceptor molecules, and showed metallic behavior down to 1.8K even in a compressed pellet sample. Langmuir-Blodgett films composed of (BEDO-TTF)(2)(CF(3)TCNQ) and matrix (arachidic acid) showed a conductivity of 3-6 S cm(-1) at room temperature and a nearly temperature-independent conductivity down to 80 K. Semiconducting (TMTSF)(2)(CF(3)TCNQ) (TMTSF: tetramethyltetraselenafulvalene) had one-dimensional segregated stacks of dimerized TMTSF molecules separated by completely ionized CF(3)TCNQ, the molecular plane of which was arranged parallel to the TMTSF column. The ionicity phase diagram of the CF(3)TCNQ CT solids, i.e., a plot of the first CT transition energy vs. donor strength, clearly discriminated these different kinds of CT solids and will be utilized for the prediction and design of the functional CT solids.
  • Qiong Ye, Tomoyuki Akutagawa, Shin-ichiro Noro, Takayoshi Nakamura, Ren-Gen Xiong
    CRYSTAL GROWTH & DESIGN 10 (11) 4856 - 4860 1528-7483 2010/11 [Refereed][Not invited]
     
    Supramolecular cationic structures of (CHDA(2+))(DCH[18]crown-6)(2) were introduced into [Ni(dmit)(2)](-) salts (where CHDA(2+), DCH[18]crown-6, and dmit(2-) represent cis-cyclohexane-1,4-diammonium, meso-dicyclohexanol[18]crown-6. and 2-thioxo-1,3-dithiole-4,5-dithiolate, respectively). The crystal polymorphs of (CHDA(2+))(DCH[18]crown-6)(2)[Ni(dmit)(2)](2) (crystals 1 and 2) within the same crystallization batch were classified in the space groups P2(1)/n (1) and PT (2). The N-11(+)similar to O hydrogen-bonding interactions between the axial- and equatorial-ammonium moieties of the CHDA(2+) cation and the oxygen atoms of DCH[18]crown-6 yielded a sandwich-type 1:2 adduct of the supramolecular cation in 1 and 2. Although the overall cationic structures in 1 and 2 resembled one another, the [Ni(dmit)(2)](-) anion arrangements were distinctively different from each other. The lateral [Ni(dmit)(2)](-) dimer along the short axis of the anion was observed in 1. whereas two types of [Ni(dmit)(2)](-) pi-dimer existed independently in 2. The weak intermolecular interactions between the [Ni(dmit)(2)](-) anions in 1 was reflected by the temperature dependent magnetic susceptibility, which followed the Curie-Weiss model. For 2, two different magnetic exchange energies arising from the different strengths of the pi-dimer units dominated the magnetic properties.
  • Qiong Ye, Tomoyuki Akutagawa, Toru Endo, Shin-ichiro Noro, Takayoshi Nakamura, Ren-Gen Xiong
    INORGANIC CHEMISTRY 49 (18) 8591 - 8600 0020-1669 2010/09 [Refereed][Not invited]
     
    Structurally flexible (1R,2R)-cyclohexanediammonium (CHDA(2+)) dication formed hydrogen-bonding supramolecules with [18]crown-6, benzo[18]crown-6 (B[18]crown-6), dibenzo[18]crown-6 (DB[18]crown-6), and dicyclohexano-[18]crown-6 (DCH[18]crown-6) in [Ni(dmit)(2)](-) salts (dmit(2-)=2-thioxo-1,3-dithiole-4,5-dithiolate). The two ammonium moieties of CHDA2+ interacted with the crown ethers to form open-mouth-shaped sandwich-type cationic structures of (CHDA(2+))(crown ethers)(2), that is, (CHDA(2+))([18]crown-6)(2)[Ni(dmit)(2)](2)(-) (1), (CHDA(2+))(B[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (2), (CHDA(2+))(DB[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (3), and (CHDA(2+))(DCH[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (4). The chiral structure of CHDA(2+) induced asymmetrical [Ni(dmit)(2)](-) arrangements in the crystals. A large frequency and temperature dependence of the dielectric response was observed in (CHDA(2+)) B[18]crown-6)(2), due to the pendulum motion of the cyclohexane ring along the nitrogen-nitrogen direction of CHDA(2+). Since the inversion center of the [Ni(dmit)(2)](-) arrangements was lost in the unit cell due to the chiral space group, the salts 1-4 showed rather complicated magnetic behaviors. The temperature-dependent magnetic properties of salts 3 and 4 were explained by the sum of the Cube Weiss and singlet-triplet thermal excitation models, with positive (ferromagnetic) and negative (antiferromagnetic) magnetic exchange energies, respectively.
  • Yoko Tatewaki, Shuji Okada, Ryosuke Itagaki, Takayoshi Nakamura, Atsuhiro Fujimori
    JOURNAL OF COLLOID AND INTERFACE SCIENCE 343 (1) 281 - 290 0021-9797 2010/03 [Refereed][Not invited]
     
    We investigated the molecular arrangement and Surface morphology of organized molecular films Of alkylammonium-M bis(1,3-dithiole-2-thione-4,5-dithiolate) ((dmit)(2), M = Ni, Au, and Pd) charge-transfer complexes using the Surface pressure-area (pi-A) isotherm, polarized visible spectroscopy, in-plane and out-of-plane X-ray diffractions (XRD), and atomic force microscopy (AFM). Since Langmuir-Blodgett films of alkylammonium-M(dmit)(2) generally exhibit superconductivity, it may be possible to develop novel electronic molecular devices on the subnanometer scale. In the bulk state, several alkylammonium-M(dmit)(2) molecules Could not form a highly ordered layered Structure along the c-axis and a subcell structure of the alkyl chain in the ab-plane; however, almost all molecules formed a layered structure in the film multilayers. Monolayers of alkylammonium-M(dmit)(2) molecules on the water Surface were extremely condensed. Out-of-plane and in-plane XRD measurements revealed that over a long period, systematic changes occurred in the two-dimensional lattice structure of alkylammonium-M(dmit)(2) molecules and not in their bulk state. These structural changes appear to be Caused by enhancement of the van der Waals interaction among long hydrocarbons and the pi-pi interaction among (dmit)(2) units arranged two dimensionally. In addition, both the molecular arrangement and the Structural morphology of the films showed dependence on the hydrocarbon chain length, number of long alkyl chains, and kind of central metal. In particular, the molecular arrangement of materials having didecyl chains changed drastically and (dmit)(2) units were highly oriented in the ab-plane. Such Structural formations are suggested to significantly influence the stacking Of functional dmit units presiding over the conductive properties. (c) 2010 Published by Elsevier Inc.
  • Tomoyuki Akutagawa, Hiroyuki Koshinaka, Qiong Ye, Shin-ichiro Noro, Jun Kawamata, Hiroshi Yamaki, Takayoshi Nakamura
    CHEMISTRY-AN ASIAN JOURNAL 5 (3) 520 - 529 1861-4728 2010 [Refereed][Not invited]
     
    The supramolecular (HOPD+)(DB[18]crown-6) cation, in which HOPD+ and DB[18]crown-6 are o-aminoanilinium and dibenzo[18]crown-6, respectively, was introduced into [Ni(dmit)(2)](-) salts (dmit(2-) = 2-thioxo-1,3-dithiole-4,5 - dithiolate). Conformational polymorphs were observed as tetragonal (HOPD+)(DB[18]crown-6)[Ni(dmit)(2)](-) (1) and monoclinic (HOPD+)(DB[18]crown-6)[Ni(dmit)(2)](-) (2). The ammonium group of HOPD+ in salts 1 and 2 formed the N-H+center dot center dot center dot O hydrogen bonds at the bottom and upper positions of V-shaped DB[1.8]crown-6, respectively, thereby producing a different supramolecular conformation. The [Ni(dmit)(2)](-) anion arrangements in salts 1 and 2 were 4(1)-helical pi stacking and a two-dimensional layer, respectively, depending on the conformation of the supramolecular cations. The magnetic behavior of salts 1 and 2 obeyed the Curie-Weiss law at room temperature with S = 1/2 spin on the [Ni(dmit)(2)](-) anion. However, the g value and line width in the electron resonance spectra of salt 1 showed a magnetic anomaly at 28 K, which was owing to antiferromagnetic ordering in the 4(1)-helical [Ni(dmit)(2)](-) a stack. Large temperature- and frequency-dependent dielectric responses were observed for salt 2 at temperatures above 200 K, whereas no particular dielectric responses were observed in salt 1. The molecular motion of HOPD+ within the cationic layer of salt 2 contributed to the dielectric response, and this was supported by ab initio calculations showing the potential-energy curve for pendulum motion and by the large thermal parameters in the X-ray crystal structure analysis. The fixed (HOPD+)(DB[18]crown-6) arrangement in the crystal of salt 1 was consistent with the small dielectric response. The steric hindrance of the o-amino group of HOPD+ in the supramolecular cation structure yielded the conformational polymorph with different dielectric and magnetic properties.
  • Ken-ichi Sakai, Sami Takahashi, Ataru Kobayashi, Tomoyuki Akutagawa, Takayoshi Nakamura, Masaaki Dosen, Masako Kato, Umpei Nagashima
    DALTON TRANSACTIONS 39 (8) 1989 - 1995 1477-9226 2010 [Refereed][Not invited]
     
    Zinc(II)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties. The pyridine complex is strongly fluorescent (fluorescence quantum yield Phi = 0.22), giving rise to a significantly Stokes-shifted spectrum. From its thin film photopumped by a nitrogen gas laser, amplified spontaneous emission was observed. These results suggest that the fluorescence occurs by way of excited-state intramolecular proton-transfer (ESIPT) in the hydrogen bond of hqxc. On the other hand, the DMSO complex shows fluorescent intensity (Phi = 0.08) lower than that of the pyridine complex, and shows normal emission in addition to ESIPT emission. From IR measurements for these complexes, it is concluded that axial ligands influence the hydrogen bond strength of the equatorial hqxc ligand via zinc and thus the ESIPT efficiency.
  • Tomoyuki Akutagawa, Daisuke Sato, Qiong Ye, Shin-ichiro Noro, Takayoshi Nakamura
    DALTON TRANSACTIONS 39 (9) 2191 - 2193 1477-9226 2010 [Refereed][Not invited]
     
    Ferromagnetic coupling of the [Ni(dmit)(2)](-) anion layer through lateral sulfur -sulfur interactions along the short-axis of the anion was achieved using the flexible supramolecular cation of (m-fluoroanilinium(+))(meso-dicyclohexano[18]crown-6).
  • Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CHEMICAL COMMUNICATIONS 46 (18) 3134 - 3136 1359-7345 2010 [Refereed][Not invited]
     
    A flexible one-dimensional Cu(II) coordination polymer with shape-recognizing space shows selective adsorption of larger 2-butanone guests from Lewis-base mixtures containing 2-butanone-EtOH or 2-butanone-MeOH.
  • Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura
    CHEMICAL COMMUNICATIONS 46 (25) 4619 - 4621 1359-7345 2010 [Refereed][Not invited]
     
    The dinuclear Cu(II) complex bridged by a single F- anion has orthogonal Jahn-Teller axes, which induce a ferromagnetic interaction between the intramolecular Cu(II) ions.
  • Tomoyuki Akutagawa, Daisuke Sato, Qiong Ye, Toru Endo, Shin-Ichiro Noro, Sadamu Takeda, Takayoshi Nakamura
    DALTON TRANSACTIONS 39 (35) 8219 - 8227 1477-9226 2010 [Refereed][Not invited]
     
    Supramolecular cations of HOPD+([18]crown-6) and HMPD+([18] crown-6) were introduced into [Ni(dmit)(2)](-) salts (HOPD+: o-aminoanilinium, HMPD+: m-aminoanilinium, and dmit(2-): 2-thioxo-1,3-dithiole-4,5-dithiolate). Alternate layers of cations and anions were observed in the two new salts of (HOPD+)([18]crown-6)[Ni(dmit)(2)](-) (1) and (HMPD+)([18] crown-6)[Ni(dmit)(2)](-) (2). From X-ray crystal structural analyses, solid state H-1 nuclear magnetic resonance (NMR) spectra, and dielectric constants, the thermal rotations of [18]crown-6 in both of the (HOPD+)([18]crown-6) and (HMPD+)([18]crown-6) supramolecules occurred at temperatures above similar to 200 K based on the orientational disorder in the crystal structures. The two-fold flip-flop motions of HOPD+ and HMPD+ cations in salts 1 and 2 were suppressed, due to the relatively large potential energy barriers. The [Ni(dmit)(2)](-) anion formed pi-dimer arrangements in both salts, with a layer structure by lateral sulfur-sulfur interatomic contacts. Although the simple dimer model reproduced the magnetic properties of salt 1, the ladder arrangement of the p-dimer in salt 2 yielded the magnetic behavior of a spin-ladder with a spin-gap of 92.5 K. The temperature dependent magnetic susceptibility of salt 2 was well reproduced by the magnetic anisotropy of J(1)/J(2) approximate to 8 between the ladder-leg (J(1): intra-dimer interaction) and ladder-rung (J(2): inter-dimer interaction). The [18] crown-6 supramolecular rotator of (HMPD+)([18] crown-6) was coexistent with the spin-ladder chain of [Ni(dmit)(2)]- anions in salt 2.
  • Atsushi Kobayashi, Yuki Fukuzawa, Shin-ichiro Noro, Takayoshi Nakamura, Masako Kato
    CHEMISTRY LETTERS 38 (10) 998 - 999 0366-7022 2009/10 [Refereed][Not invited]
     
    A simple Pt-II-terpyridine complex [Pt(NCS)(tpy)](SCN) (tpy = 2,2': 6', 2 ''-terpyridine) shows distinct two-step vapochromism from red to yellow through dark red in response to methanol vapor. The adsorption isotherm for methanol vapor reveals that the two-step vapochromic behavior originates from breathing-like structural transformations.
  • Manabu Ishikawa, Satoshi Yamashita, Toshio Naito, Masaki Matsuda, Hiroyuki Tajima, Noriaki Hanasaki, Tomoyuki Akutagawa, Takayoshi Nakamura, Tamotsu Inabe
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 78 (10) 0031-9015 2009/10 [Refereed][Not invited]
     
    The charge transport properties of a partially oxidized salt composed of Co(Pc)(CN)(2) units with a typical one-dimensional electronic system have been suggested to be determined by charge disproportionation. The current-voltage (I-V) characteristics show nonlinear behavior at low temperature, which is suppressed by applying pressure. The observed nonlinearity is considered to result from the electric-field-induced delocalization of carriers in the charge disproportionation state. In the isomorphous magnetic Fe(Pc)(CN)(2) system, the nonlinear behavior is observed at higher temperatures, suggesting that charge disproportionation is more developed in a system with local moments. The threshold voltage of negative differential resistance decreases when an external magnetic field is applied, confirming that the localization of charge carriers is released by magnetic field application.
  • Wen Zhang, Li-Zhuang Chen, Ren-Gen Xiong, Takayoshi Nakamura, Songping D. Huang
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 (35) 12544 - + 0002-7863 2009/09 [Refereed][Not invited]
     
    A detailed study of two alum-type complexes containing the SeO(4)(2-) anion, 1,4-diazoniabicyclo[2.2.2]octane hexaaquacopper(II) bis(selenate) [(H(2)dbco)Cu(H(2)O)(6)(SeO(4))(2), 1] and its deuterated analogue (D(2)dbco)Cu(D(2)O)(6)(SeO(4))(2) (2), has revealed that 1 and 2 are new ferroelectrics that undergo a paraelectric-ferroelectric phase transition at ca. -140 to -138 degrees C as a result of order-disorder features of the cation ([H(2)dbco](2+) or [D(2)dbco](2+)) and anion (selenate). These are the first examples of ferroelectrics based on divalent metal anion alum analogues since the discovery of ferroelectrics based on trivalent metal anion alum in similar to 1960.
  • Hiroyuki Imai, Tomoyuki Akutagawa, Fumito Kudo, Mitsuhiro Ito, Kazuhiro Toyoda, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 (38) 13578 - + 0002-7863 2009/09 [Refereed][Not invited]
     
    Single crystals of the nanoscale polyoxomolybdate wheel, Na15Fe3Co16[Mo176O528(H2O)(80)]Cl-27 center dot 450H(2)O, was synthesized by the condensation reaction of Na0.4Co0.8[MoO4]center dot 1.5H(2)O at low pH and in the presence of an iron-based reducing agent, and these crystals were characterized by the synchrotron-based X-ray single crystal analysis, magnetic susceptibility, and ionic conductivity measurements.
  • Keiji Takeda, Hiroko Tokoro, Fumiyoshi Hakoe, Akira Yamaguchi, Hatsumi Mori, Hidehiko Ishimoto, Takayoshi Nakamura, Shinya Kuriki, Shin-ichi Ohkoshi
    POLYHEDRON 28 (9-10) 1746 - 1749 0277-5387 2009/06 [Refereed][Not invited]
     
    We have developed a high temperature superconductor (HTS) micro SQUID magnetometer for molecular-based magnets. By employing the dipole approximation, we verified the flux value of 40 Phi(0) from the saturation magnetic moment of the ferrimagnetic microcrystal of [Mn(2)(H(2)O)(2)(CH(3)COO)][W(CN)(8)]center dot 2H(2)O (15 x 15 x 13 mu m). Considering the relative arrangement of the sample and the SQUID loop, including the influence of the film and grease, the calculated the flux values were Phi = 71 Phi(0) and 31 Phi(0) at distances of 20 and 30 mu m between the sample bottom face and the SQUID plane, respectively. Thus, the experimentally obtained flux value is reasonable. (C) 2008 Elsevier Ltd. All rights reserved.
  • Xiao-Ming Ren, Guang-Xiang Liu, Heng Xu, Tomoyuki Akutagawa, Takayoshi Nakamura
    POLYHEDRON 28 (9-10) 2075 - 2079 0277-5387 2009/06 [Refereed][Not invited]
     
    A nonmagnetic compound, [NO(2)BzPy][Cu(mnt)(2)] (mnt(2-) = maleonitriledithiolate; NO(2)BzPy(+)=1-(4'-nitrobenzyl)pyridinium), is isostructural with [NO(2)BzPy][Ni(mnt)(2)], which is a quasi-1D spin system and exhibits a spin-Peierls-like transition with J = 192 K in the gapless state and spin energy gap = 738 K in the dimerization state, respectively. Further, five nonmagnetic impurity doped compounds [NO(2)BzPy][Cu(x)Ni(1-x)(mnt)(2)] (x = 0.04-0.74) were prepared, and their crystal structures as well as magnetic properties were investigated. The nonmagnetic doping causes the suppression of the spin transition with an average rate of 139(13) K/percentage of dopant concentration, and the transition collapse is estimated at around x > 0.5. (c) 2009 Elsevier Ltd. All rights reserved.
  • Tomoyuki Akutagawa, Kozo Shitagami, Masaki Aonuma, Shin-ichiro Noro, Takayoshi Nakamura
    INORGANIC CHEMISTRY 48 (10) 4454 - 4461 0020-1669 2009/05 [Refereed][Not invited]
     
    Sandwich-type (Cs+)(2)(benzo[18]crown-6)(3) and (Cs+)(dibenzo[18]crown-6)(2) supramolecular cations were introduced as counterions of [Ni(dMit)(2)](-) (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate) anions to induce unique [Ni(dmit)(2)](-) anion (S = 1/2) arrangements and magnetic properties. The magnetic exchange energy ( between the [Ni(dmit)(2)](-) anions was dependent on the mode of the intermolecular interactions. In the case of (Cs+)(2)(benzo[18]crown-6)(3)[Ni(dmit)(2)](-)(2) (1), the asymmetric arrangement of the [Ni(dMit)(2)](-) anions involved the coexistence of a pi-dimer chain along with a two-dimensional layer via lateral S center dot center dot center dot S contacts, in which the magnetic properties of the T-dimer chain and the two-dimensional layer were characterized by antiferromagnetic (J = -5.2 K) and ferromagnetic coupling (Weiss temperature = +1.1 K), respectively. The unique [Ni(dMit)(2)](-) arrangements and magnetic behaviors for crystal 1 can be attributed to the asymmetrical benzo[18]crown-6. In the case of Cs+(dibenzo[18]crown6)(2)[Ni(dmit)(2)](-) (2), however, the formation of the lateral [Ni(dmit)(2)](-) dimer via S center dot center dot center dot S contacts yielded antiferromagnetic coupling corresponding to the dimer model (J = -25.5 K).
  • Tomoyuki Akutagawa, Hiroyuki Koshinaka, Daisuke Sato, Sadamu Takeda, Shin-Ichiro Noro, Hiroyuki Takahashi, Reiji Kumai, Yoshinori Tokura, Takayoshi Nakamura
    NATURE MATERIALS 8 (4) 342 - 347 1476-1122 2009/04 [Refereed][Not invited]
     
    Molecular rotation has attracted much attention with respect to the development of artificial molecular motors, in an attempt to mimic the intelligent and useful functions of biological molecular motors. Random motion of molecular rotators-for example the 180 degrees flip-flop motion of a rotatory unit-causes a rotation of the local structure. Here, we show that such motion is controllable using an external electric field and demonstrate how such molecular rotators can be used as polarization rotation units in ferroelectric molecules. In particular, m-fluoroanilinium forms a hydrogen-bonding assembly with dibenzo[18]crown-6, which was introduced as the counter cation of [Ni(dmit)(2)](-) anions (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate). The supramolecular rotator of m-fluoroanilinium exhibited dipole rotation by the application of an electric field, and the crystal showed a ferroelectric transition at 348 K. These findings will open up new strategies for ferroelectric molecules where a chemically designed dipole unit enables control of the nature of the ferroelectric transition temperature.
  • Tomoyuki Akutagawa, Hiroyuki Koshinaka, Daisuke Sato, Sadamu Takeda, Shin-Ichiro Noro, Hiroyuki Takahashi, Reiji Kumai, Yoshinori Tokura, Takayoshi Nakamura
    NATURE MATERIALS 8 (4) 342 - 347 1476-1122 2009/04 [Refereed][Not invited]
     
    Molecular rotation has attracted much attention with respect to the development of artificial molecular motors, in an attempt to mimic the intelligent and useful functions of biological molecular motors. Random motion of molecular rotators-for example the 180 degrees flip-flop motion of a rotatory unit-causes a rotation of the local structure. Here, we show that such motion is controllable using an external electric field and demonstrate how such molecular rotators can be used as polarization rotation units in ferroelectric molecules. In particular, m-fluoroanilinium forms a hydrogen-bonding assembly with dibenzo[18]crown-6, which was introduced as the counter cation of [Ni(dmit)(2)](-) anions (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate). The supramolecular rotator of m-fluoroanilinium exhibited dipole rotation by the application of an electric field, and the crystal showed a ferroelectric transition at 348 K. These findings will open up new strategies for ferroelectric molecules where a chemically designed dipole unit enables control of the nature of the ferroelectric transition temperature.
  • Shin-ichiro Noro, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    PROGRESS IN POLYMER SCIENCE 34 (3) 240 - 279 0079-6700 2009/03 [Refereed][Not invited]
     
    The chemistry of coordination polymers has been extensively advanced in recent decades, producing various architectures that are rationally constructed from a variety of molecular building blocks and interactions between them. Researchers have worked to create a diverse range of coordination frameworks and have raised the structural chemistry to a mature level. The next challenge is to explore their chemical and physical functionalities, which are associated with the microporous properties of frameworks. This review focuses on crystal structures and microporous properties of coordination polymers containing organic N-containing heterocyclic molecules as bridging ligands. (C) 2008 Elsevier Ltd. All rights reserved.
  • Yoko Tatewaki, Tatsuya Hatanaka, Ryo Tsunashima, Takayoshi Nakamura, Mutsumi Kimura, Hirofusa Shirai
    CHEMISTRY-AN ASIAN JOURNAL 4 (9) 1474 - 1479 1861-4728 2009 [Refereed][Not invited]
     
    Tetrathiafulvalenes (TTF) S-T-IT and R-TTF having four chiral amide end groups self-organize into helical nanofibers in the presence of 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyano-p-quinodimethane (F(4)TCNQ). The intermolecular hydrogen bonding among chiral amide end groups and the formation of charge-transfer complexes results in a long one-dimensional supramolecular stacking, and the chirality of the end groups affects the molecular orientation of TTF cores within the stacks. Electronic conductivity of a single helical nanoscopic fiber made of S-TTF and F(4)TCNQ is determined to be (7.0 +/- 3.0) x 10(-4) S cm(-1) by point-contact current-imaging (PCI) AFM measurement. Nonwoven fabric composed of helical nanofibers shows a semiconducting temperature dependence with an activation energy of 0.18 eV.
  • Carsten Streb, Ryo Tsunashima, Donald A. MacLaren, Thomas McGlone, Tomoyuki Akutagawa, Takayoshi Nakamura, Antonino Scandurra, Bruno Pignataro, Nikolaj Gadegaard, Leroy Cronin
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 48 (35) 6490 - 6493 1433-7851 2009 [Refereed][Not invited]
  • Shin-ichiro Noro, Ryo Tsunashima, Yuichi Kamiya, Kazuhiro Uemura, Hidetoshi Kita, Leroy Cronin, Tomoyuki Akutagawa, Takayoshi Nakamura
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 48 (46) 8703 - 8706 1433-7851 2009 [Refereed][Not invited]
  • Shin-ichiro Noro, Nobuhiro Yanai, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    INORGANIC CHEMISTRY 47 (16) 7360 - 7365 0020-1669 2008/08 [Refereed][Not invited]
     
    The solvatochromic indicator [Cu(acac)(tmen)(H2O)] center dot PF6 (1 center dot H2O) has been synthesized and crystallographically characterized. 1 center dot H2O binds an H2O molecule at the Cu(II) axial site, while the PF6- anion is coordination free. The binding properties of [Cu(PF6)(acac)(tmen)] (1) and [Cu(BF4)(acac)(tmen)] (2) have been investigated in solution and the solid state. The donor number of the PF6- anion (DNPF6) was determined from the UV-vis spectra of 1 in 1,2-dichloroethane. The value of DNPF6 of the PF6- anion is slightly larger than that of the tetraphenylborate anion (BPh4-), which is known as a noncoordinating anion. In the solid state, 1 and 2 reversibly bind and release H2O molecules at the Cu(II) axial sites. The coordinated H2O molecules in 2 are more easily removed than those in 1 because of the strong Lewis basicity of the BF4- anion compared to the PF6- ion. The lower melting point of 1 versus 2 is attributed to the loose binding of the PF6- anions to the Cu(II) centers, which induces the dynamic nature of the crystal.
  • Tomoyuki Akutagawa, Daisuke Sato, Hiroyuki Koshinaka, Masaaki Aonuma, Shin-ichiro Noro, Sadamu Takeda, Takayoshi Nakamura
    INORGANIC CHEMISTRY 47 (13) 5951 - 5962 0020-1669 2008/07 [Refereed][Not invited]
     
    Supramolecular rotators of hydrogen-bonding Assemblies between anilinium (Ph-NH3+) or adamantylammonium (AD-NH3+) and dibenzo[18]crown-6 (DB[18]crown-6) or meso-dicyclohexano[18]crown-6 (DCH[18]crown-6) were introduced into [Ni(dMit)(2)] salts (dmit(2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The ammonium moieties of Ph-NH3+ and AD-NH3+ cations were interacted through N-H+similar to O hydrogen bonding with the six oxygen atoms of crown ethers, forming 1:1 supramolecular rotator-stator. structures. X-ray crystal-structure analyses revealed a jackknife-shaped conformation of DB[18]crown-6, in which two benzene rings were twisted along the same direction, in (Ph-NH3+)(DB[18]crown-6)[Ni(dmit)(2)](-) (1) and (AD-NH3+)(DB[18]crown-6)[Ni(dmit)(2)](-) (3), whereas the conformational flexibility of two dicyclohexyl rings was observed in (Ph-NH3+)(DCH[18]crown-6)[Ni(dmit)(2)](-) (2) and (AD-NH3+)(DCH[18]crown-6)[Ni(dMit)(2)](-) (4). Sufficient space for the molecular rotation of the adamantyl group was achieved in the crystals of salts 3 and 4, whereas the rotation of the phenyl group in salts 1 and 2 was rather restricted by the nearest neighboring molecules. The rotation of the adamantyl group in salts 3 and 4 was evidenced from the temperature-dependent wide-line H-1 NMR spectra, dielectric properties, and X-ray crystal structure analysis. ab initio calculations showed that the potential energy barriers for the rotations of adamantyl groups in salts 3 (Delta E approximate to 18 kJmol(-1)) and 4 (Delta E approximate to 15 kJmol(-1)) were similar to those of ethane (similar to 12 kJmol(-1)) and butane (17-25 kJmol-1) around the C-C single bond, which were 1 order of magnitude smaller than those of phenyl groups in salts 1 (Delta E approximate to 180 kJmol(-1)) and 2 (Delta E approximate to 340 kJmol(-1)). 1D or 2D [Ni(dmit)(2)](-) anion arrangements were observed in the crystals according to the shape of crown ether derivatives. The 2D weak intermolecular interactions between [Ni(dMit)21- anions in salts 1 and 3 led to Curie-Weiss behavior with weak antiferromagnetic interaction, whereas 1 D interactions through lateral sulfur-sulfur atomic contacts between [Ni(dMit)(2)](-) anions were observed in salts 2 and 4, whose magnetic behaviors were dictated by ferromagnetic (salt 2) and singlet-triplet (salt 4) intermolecular magnetic interactions, respectively.
  • Keiji Takeda, Hatsumi Mori, Akira Yamaguchi, Hidehiko Ishimoto, Takayoshi Nakamura, Shinya Kuriki, Toshiya Hozumi, Shin-ichi Ohkoshi
    JOURNAL OF APPLIED PHYSICS 103 (7) 0021-8979 2008/04 [Refereed][Not invited]
     
    A high-temperature-superconductor-type micrometer-sized dc-SQUID (SQUID denotes superconducting quantum interference divice) magnetometer with much higher sensitivity than a commercial system has been developed. Several kinds of YBa(2)Cu(3)O(7-delta) micro-SQUIDs were fabricated with photolithography techniques to have a hole of 4x9 mu m(2) and 2-mu m-wide grain boundary Josephson junctions. Combined with a three dimensional magnetic field coil system, the voltage modulation was observed for three different field directions. (c) 2008 American Institute of Physics.
  • Keiji Takeda, Hatsumi Mori, Akira Yamaguchi, Hidehiko Ishimoto, Takayoshi Nakamura, Shinya Kuriki, Toshiya Hozumi, Shin-ichi Ohkoshi
    REVIEW OF SCIENTIFIC INSTRUMENTS 79 (3) 033909  0034-6748 2008/03 [Refereed][Not invited]
     
    We have developed a high temperature superconductor (HTS) micrometer-sized dc superconducting quantum interference device (SQUID) magnetometer for high field and high temperature operation. It was fabricated from YBa(2)Cu(3)O(7-delta) of 92 nm in thickness with photolithography techniques to have a hole of 4 x 9 mu m(2) and 2 mu m wide grain boundary Josephson junctions. Combined with a three dimensional magnetic field coil system, the modulation patterns of critical current I(c) were observed for three different field directions. They were successfully used to measure the magnetic properties of a molecular ferrimagnetic microcrystal (23 x 17 x 13 mu m(3)), [Mn(2)(H(2)O)(2)(CH(3)COO)][W(CN)(8)]center dot 2H(2)O. The magnetization curve was obtained in magnetic field up to 0.12 T between 30 and 70 K. This is the first to measure the anisotropy of hysteresis curve in the field above 0.1 T with an accuracy of 10(-12) J T(-1) (10(-9) emu) with a HTS micro-SQUID magnetometer. (C) 2008 American Institute of Physics.
  • Tomoyuki Akutagawa, Reina Jin, Ryo Tunashima, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    LANGMUIR 24 (1) 231 - 238 0743-7463 2008/01 [Refereed][Not invited]
     
    Clusters based on the mixed-valence gigantic inorganic ring [Mo154O462H14(H2O)(70)](14-) ({Mo-154}-ring) and dimethyldioctadecylammonium (DODA) were combined to form novel molecular assemblies of an inorganic-organic hybrid molecular system as Langmuir-Blodgett (LB) and cast films. (DODA)(20)[MO154O462H8(H2O)(70)] (2) was prepared by cation exchange and was characterized by a combination of thermogravimetry, IR, UV-vis-NIR, H-1 NMR, and XRD measurements. The salt 2 was soluble in common organic solvents, and the chemical stability Of {Mo-154}-ring encapsulated by DODA cationic surfactants in CHCl3 was found to be higher than that of the "native" sodium salt of the {Mo-154}-ring in H2O. Uniform spherical vesicle-like molecular assemblies of (DODA)(20)[Mo154O462H8(H2O)(70)] were observed in dilute THF, whose average diameter of 95 nm and a normalized variance of 5.7% were confirmed by a X-ray small-angle scattering. Deposition of 2 as a cast film showed circular domains with a typical diameter of similar to 100 nm, indicating possible similarities between solution and surface-deposited structures. The resulting LB films of salt 2 were transferred from an acidic buffer subphase with pH = 1.5 onto mica, giving a two-dimensional film surface with a unity transfer ratio. Further, the electronic absorption spectra of the LB multilayer were consistent with the classic type II mixed-valence Mo-V/Mo-VI electronic state well know for molybdenum blue {Mo-154}-ring systems, and it appears that on the surface the plane of the {Mo-154}-ring is approximately parallel to the substrate surface, as indicated by polarized electronic spectra, while the alkyl chains of DODA were relatively normal to the substrate surface. Therefore, the layer between the {Mo-154}-rings and DODA cations was alternately stacked along the direction of film propagation. Finally, it was found that the surface morphology of the cast and LB films was determined by the molecular assembly of (DODA)(20)[Mo154O462H8(H2O)70] in solution and the air-water interface, respectively.
  • Zhi-Rong Qu, Qiong Ye, Hong Zhao, Da-Wei Fu, Heng-Yun Ye, Ren-Gen Xiong, Tomoyuki Akutagawa, Takayoshi Nakamura
    CHEMISTRY-A EUROPEAN JOURNAL 14 (11) 3452 - 3456 0947-6539 2008 [Refereed][Not invited]
     
    Hydrothermal (deuterato-thermal) reaction Of L-ethyl lactate (Lig-Et) with Eu(ClO4)(3)center dot 6H(2)O gives colorless block crystals of [Eu(Lig)(2)(X2O)(2)][ClO4] (1, X=H; 2, X=D) both of which possess a two-dimensional laminar homochiral framework. Single-crystal dielectric measurements reveal that 1 and 2 display a giant dielectric anisotropy approximately exceeding 100 and large isotopic effect with about 54% enhancement along the a axis. Their ferroelectric features further confirm this respect. Crystal parameters: 1, C6H14ClO12Eu, M-r= 465.58, monoclinic, C-2, a=8.6786(6), b = 8.3965(6), c = 10.2153(7) angstrom, beta = 92.040(1)degrees, V=743.92(9) angstrom(3), Z=2, rho(calcd) = 2.079 Mg m(-3), R, = 0.0508, wR(2) = 0.1239, mu = 4.448 mm(-1), S = 1.043; Flack=0.04(5). 2: C6H10D4ClO12Eu, M-r=469.61, monoclinic, C-2, a = 8.689(2), b = 8.410(2), c = 10.224(3)A, beta = 92.057(4)degrees, V = 746.7(3) angstrom(3), Z=2, rho(calcd) = 2.089 Mg m(-3), R-1=0.0465, wR(2)=0.1150, mu = 4.432 mm(-1), S = 1.058; Flack = 0.02(5).
  • Guo-Xi Wang, Guang-Fan Han, Qiong Ye, Ren-Gen Xiong, Tomoyuki Akutagawa, Takayoshi Nakamura, Philip Wai Hong Chan, Songping D. Huang
    DALTON TRANSACTIONS (19) 2527 - 2530 1477-9226 2008 [Refereed][Not invited]
     
    A homochiral rare-earth metal Tb complex that exhibited a very large dielectric anisotropic property with a temperature-independent feature is obtained. Our findings on high-dielectric anisotropy will provide a new impetus in this field of materials science.
  • Ryo Tsunashima, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura, Hiroko Kawakami, Kazunori Toma
    CHEMISTRY-A EUROPEAN JOURNAL 14 (27) 8169 - 8176 0947-6539 2008 [Refereed][Not invited]
     
    Fullerene derivative C60TT, which is substituted with the low-molecular-weight organogelator tris(dodecyloxy)benzamide, formed nanowire structures on application of the Langmuir-Blodgett (LB) method. The surface morphology of the C60TT LB film was dependent on the holding time before deposition at a surface pressure of 5 mN m(-1); it changed from a homogeneous monolayer to a bilayer fibrous structure via a fibrous monolayer structure, which was estimated to have dimensions of 1.2 nm in height, 8 nm in width, and 5-10 mu m in length. From the structural and spectroscopic data, it is inferred that close packing of the fullerene moiety occurs along with intermolecular hydrogen bonding within the monolayer fibrous structure. The morphological changes in the LB film are explained kinetically by the Avrami theory, based on the decrease in the surface area of the monolayer at the air/water interface. The growth of the quasi-one-dimensional fibrous monolayer structures at holding times from 0 to 0.2 h is considered to be an interface-controlled process, whereas the growth of the quasi-one-dimensional bilayer fibrous structures from 0.2 to 18 h is thought to be a diffusion-controlled process.
  • Tomoyuki Akutagawaa, Takayoshi Nakamura
    DALTON TRANSACTIONS (45) 6335 - 6345 1477-9226 2008 [Refereed][Not invited]
     
    Artificial molecular rotators were designed in an attempt to achieve unidirectional molecular rotation. Supramolecular assemblies of cations and crown ethers in the solid state were shown to form rotator structures, diverse in their rotational symmetry and frequency. The counter cation of [Ni(dmit)(2)](-) anion, bearing one S = 1/2 spin, was used to couple molecular rotation to magnetic properties. Random rotation of [18]crown-6 molecules was first observed in the Cs(2)(+)([18]crown-6)(3) supramolecule, where the rotational freedom of [18]crown-6 rotators was evidently coupled to the magnetic properties of [Ni(dmit)(2)](-) pi-dimer. In other cases, dual rotary motions of anilinium([18] crown-6) and rotator-stator assemblies of (adamantylammonium)(dibenzo[18]crown-6) were investigated as a means to control rotational symmetries and frequencies in the solid state. The supramolecular approach for construction of molecular rotator-stator assemblies in the solid state is a convenient approach to the design of molecular rotary functionality in [Ni(dmit)(2)](-) salts.
  • Tomoyuki Akutagawa, Daigoro Endo, Shin-Ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    COORDINATION CHEMISTRY REVIEWS 251 (21-24) 2547 - 2561 0010-8545 2007/11 [Refereed][Not invited]
     
    The design of new materials by directing the self-assembly of organic-inorganic hybrid molecular assemblies of polyoxometalate crown-ether complexes with supramolecular cations is reviewed with a particular focus on mixed-valence [PMo12O40](4-) building blocks. Structurally configurable supramolecular cations of organic ammonium and crown ethers, i.e. protonated aromatic amines complexed by crown ethers are also outlined. The design principles for the one-electron reduced mixed-valence polyoxomolybdate cluster of [PMo12O40](4-) are also deduced. The construction principles behind these assemblies and also the concept of using cluster-based "crowns" to complex the cations to extend the design concept further is discussed, especially in the development of inorganic crowns that could combine the properties of the electronically interesting building block along with the receptor building blocks. (C) 2007 Elsevier B. V. All rights reserved.
  • Da-Wei Fu, Yu-Mei Song, Guo-Xi Wang, Qiong Ye, Ren-Gen Xiong, Tomoyuki Akutagawa, Takayoshi Nakamura, Philip Wai Hong Chan, Songping D. Huang
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 129 (17) 5346 - + 0002-7863 2007/05 [Refereed][Not invited]
     
    Hydrothermal reaction of (S)-1,1'1' '-2,4,6-trimethylbenzene-1,3,5-triyl-tris(methylene)-tris-pyrrolidine-2-carboxylic acid (TBPLA) with Ni(ClO4)(2)center dot 6H(2)O gave pale green block crystals of 1. X-ray crystal structure analysis showed the complex to be a trinuclear descrete homochiral molecule with each Ni center sitting in distorted octahedron geometries. Anisotropic permittivity measurements reveal that 1 exhibits huge dielectric anisotropy along its three different crystal axes that is ca. 3.5 times of epsilon(r) (E//c)/epsilon(r) (E//b) with temperature and frequency independence.
  • Daisuke Sato, Tomoyuki Akutagawa, Sadamu Takeda, Shin-ichiro Noro, Takayoshi Nakamura
    INORGANIC CHEMISTRY 46 (2) 363 - 365 0020-1669 2007/01 [Refereed][Not invited]
     
    Adamantylammonium (ADNH(3)(+)) was complexed with [18]crown-6, forming a supramolecular cation of (ADNH(3)(+))([18]crown6), which was introduced into a [Ni(dmit)(2)](-) salt as a supramolecular rotor. The cation layers were alternately arranged with [Ni(dmit)(2)](-) layers in the crystal, in which the molecular rotation of (ADNH(3)(+))([18]crown-6) was confirmed from the temperature-dependent solid-state H-1 NMR.
  • Qiong Ye, Hong Zhao, Zhi-Rong Qu, Da-Wei Fu, Ren-Gen Xiong, Yi-Ping Cui, Tomoyuki Akutagawa, Philip Wai Hong Chan, Takayoshi Nakamura
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 46 (36) 6852 - 6856 1433-7851 2007 [Refereed][Not invited]
  • Sadafumi Nishihara, Tomoyuki Akutagawa, Daisuke Sato, Sadamu Takeda, Shin-ichiro Noro, Takayoshi Nakamura
    CHEMISTRY-AN ASIAN JOURNAL 2 (9) 1083 - 1090 1861-4728 2007 [Refereed][Not invited]
     
    A solid-state dynamic supramolecular structure consisting of (anilinium)([18]crown-6) was arranged as the cation in a salt of [Ni(dmit)2](-)(dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate). With the ammonium moiety of anilinium located within the cavity of [18]crown-6, a hydrogen-bonded supramolecular. structure is formed, with an orthogonal arrangement between the a plane of anilinium and the mean 06 plane of [18]crown-6. In this supramolecular cation, both anilinium and [18]crown-6 act as dynamic units with different rotational modes in the solid state. The uniform stacks of cations form an antiparallel arrangement, thus producing a layer structure. Sufficient space for the 180 degrees flip-flop motion of the phenyl ring and the rotation of [18]crown-6 was observed in the cation layer. Thermally activated 180 degrees flip-flop motions, with a frequency of 6 MHz at room temperature and an activation energy of 31 kJmol(-1), were confirmed by temperature-dependent H-2 NMR spectra of ([D-5]anilinium)([18]crown-6)[Ni(dmit)(2)]. A double-minimum potential for the molecular rotation of anilinium, with a barrier of approximately 40 kJmol(-1), was indicated by ab initio calculations. The wideline H-1 NMR spectra indicated a thermally activated rotation of [18]crown-6 at temperatures above 250 K. Therefore, multiple molecular motions of the 180 degrees flip-flop motion of the phenyl ring and the rotation of [18]crown-6 occur simultaneously in the solid state. The temperature-dependent dielectric constants revealed that the molecular motion of [1,8]crown-6, other than the flip-flop motion, dominates the dielectric response in the measured temperature and frequency range.
  • Shin-ichiro Noro, Satoshi Horike, Daisuke Tanaka, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    INORGANIC CHEMISTRY 45 (23) 9290 - 9300 0020-1669 2006/11 [Refereed][Not invited]
     
    A series of guest-binding Cu-parallel to coordination polymers, {[Cu(bpetha)(2)(acetone)(2)]center dot 2PF(6)}(n) (bpetha = 1,2-bis(4-pyridyl)ethane) (1), {[Cu(bpetha)(2)(DMF)(2)]center dot 2PF(6)}(n) (2), {[Cu(bpetha)(2)(MeCN)(2)]center dot 2PF(6)center dot 2MeCN}(n) (3), {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 3THF center dot 2H(2)O}(n) (4), {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 3dioxane}(n) (5), and {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 2-PrOH center dot 2H(2)O}(n) ( 6), have been synthesized and crystallographically characterized. Their framework stabilities and guest-exchange properties have also been investigated. All compounds form a similar framework motif, a "double chain", in which the bpetha ligands bridge Cu-parallel to centers to form 1-D [Cu(bpetha)(2)](n) double chains. A variety of Lewis base guest molecules, such as H2O, acetone, DMF, MeCN, THF, dioxane, and 2-PrOH, are incorporated into the assembly of the 1-D double chains. These chains flexibly change their forms of assembly in a guest-dependent manner. Interestingly, acetone, DMF, and MeCN guests with a carbonyl or cyanide group coordinate directly to the axial sites of the Cu-parallel to centers; in contrast, THF, dioxane, and 2-PrOH guests with an ether or alcohol group are incorporated into the frameworks not via coordination bonds but via weak interactions (hydrogen bonds and van der Waals forces). This selectivity is probably due to steric effects at coordinated oxygen or nitrogen atoms of the guests. Crystal-to-crystal transformations triggered by guests are observed, during which guests coordinated to the Cu-parallel to axial sites are readily removed and replaced by other guests.
  • Tomoyuki Akutagawa, Daigoro Endo, Hiroyuki Imai, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura
    INORGANIC CHEMISTRY 45 (21) 8628 - 8637 0020-1669 2006/10 [Refereed][Not invited]
     
    Electron transfer from the electron donor of p-phenylenediamine (PPD) to the electron acceptor of (H+)(3)[PMo12O40](3-) forms a one-electron-reduced Keggin cluster of [PMo12O40](4-), bearing a S) (1)/(2) spin, while proton transfer from the proton donor of (H+)(3)[PMo12O40](3-) to the proton acceptor of PPD yielded mono- and diprotonated cations of 4- aminoanilinium (HPPD+) and p- phenylenediammonium (H2PPD(2+)). By introduction of crown ether receptors during the crystallization process, supramolecular cations of (HPPD+)(crown ethers) and/or (H2PPD(2+))(crown ethers) were successfully introduced into three new alpha-[PMo12O40](4-) salts of (H2PPD2+)(2)([12] crown-4)(4)[PMo12O40](4-) (1), (HPPD+)(4)-[ 15] crown-5)(4)[PMo12O40](4-) (2), and (HPPD+)(2)(H2PPD2+)([18]crown-6)(4)[PMo12O40](4-) (3) as the countercation. The protonated states of PPD and molecular-assembly structures of the supramolecular cations depended on the size of the crown ethers. In salt 3, a novel mixed- protonated state of HPPD+ and H2PPD2+ was confirmed to be complexed in the cation structure. According to the changes in the cation structures, the anion arrangements were modulated from those of the two-dimensional layer for salt 1 to the isolated cluster for salts 2 and 3. The temperature-dependent magnetic susceptibilities of salts 1-3 were consistent with the isolated spin arrangements of [PMo12O40](4-). The electronic spectra of salts 1-3 indicated the intervalence optical transition from pentavalent MoV to hexavalent Mo-VI ions within the [PMo12O40](4-)cluster. Temperature-dependent electron spin resonance spectra of salt 2 revealed the delocalization-localization transition of the S = (1)/(2) spin at 60 K. The spin on the [PMo12O40](4-) cluster was localized on a specific MoV site below 60 K, which was thermally activated with an activation energy of 0.015 eV.
  • Shin-ichiro Noro, Ryo Kitaura, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    INORGANIC CHEMISTRY 45 (22) 8990 - 8997 0020-1669 2006/10 [Refereed][Not invited]
     
    Ni(II) coordination polymers with a 4,4 '-azobis(pyridine) (azpy) ligand, {[Ni(2)(NCX)(4)(azpy)(4)]center dot G}(n) (X = S, G (guest molecule) = MeOH (1 center dot MeOH); X = S, G = EtOH (1 center dot EtOH); X = S, G = H(2)O (1 center dot H(2)O); X = S, G = no guest (1); X = Se, G = MeOH (2 center dot MeOH); X = Se, G = H(2)O (2 center dot H(2)O); X = Se, G = no guest ( 2)), have been synthesized and structurally characterized with their porosity. These compounds have one-dimensional periodic ultramicropores that contain the small guest molecules, H(2)O, MeOH, or EtOH, whose hydroxy groups interact with the S or Se atoms of isothiocyanate or isoselenocyanate, respectively, via-S(Se)center dot center dot center dot HO-hydrogen bonds. Although the molecular dimensions of the MeOH guest are considerably larger than the window size of the ultramicropore, 1, MeOH and 2, MeOH easily release their guest molecules without decomposition of the framework to form 1 and 2 without any guest molecules. This shows that 1 and 2 have dynamic ultramicropores constructed from the interpenetrating framework. The guest desorption experiments using 1 center dot MeOH and 1 center dot EtOH reveal that the difference in the desorption behavior is due to van der Waals interactions that depend on the molecular shape of the guest molecule in the ultramicropores and/or an entrance blocking effect that depends on the minimum dimensions of the guest molecule for the pore windows. A marked difference in the N(2) and CH(4) adsorption isotherms was observed and is associated with the strength of the host-guest interaction.
  • Takayoshi Nakamura, Hideto Miyata, Keisuke Wakahara, Tomoyuki Akutagawa, Tatsuo Hasegawa, Hiroyuki Hasegawa, Shinro Mashiko, Christian A. Christensen, Jan Becher
    JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 6 (6) 1833 - 1837 1533-4880 2006/06 [Refereed][Not invited]
     
    Structures and electronic states of a 1:1 mixture of bis-tetrathiafulvalene annulated macrocycle (1) and C-60. in Langmuir films at the air-water interface and Langmuir-Blodgett (LB) films on solid substrates were examined. Compression of the Langmuir films induced for the first time a phase transition from a weakly interacting state without charge transfer (CT) to a neutral CT state. The scanning force microscope images of LB films transferred onto mica by a single withdrawal showed quite different spatial patterns depending on the CT states. When deposited at around 1 mNm(-1), a domain structure with 3 nm height was obtained, which corresponded to the state without CT interaction. Contrastingly, once the CT interaction was induced by applying surface pressure, a network structure was observed with a height of 6 nm. The CT band, whose transition moment was almost parallel to the substrate surface, was observed at 11.5 x 10(3) cm(-1) in the polarized UV-VIS-NIR spectra of the films deposited at 9 mNm-1. The phase transition was irreversible, although the surface pressure-area isotherm showed a reversible behavior below 9 mNm-1. The morphology and electronic state of the film was controllable merely by changing the surface pressure at the air-water interface.
  • T Akutagawa, T Motokizawa, K Matsuura, S Nishihara, SI Noro, T Nakamura
    JOURNAL OF PHYSICAL CHEMISTRY B 110 (12) 5897 - 5904 1520-6106 2006/03 [Refereed][Not invited]
     
    Sandwich-type supramolecular cation structures of (M+)([12]crown-4)(2) complexes (M+ = Li+, Na+, K+, and Rb+) were introduced as countercations to the [Ni(dmit)(2)](-) anion, which bears an S = 1/2 spin, to form novel magnetic crystals (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate). The zigzag arrangement of Li+([12]crown-4)(2) cations in Li+([12]crown-4)(2)[Ni(dmit)(2)](-) salt induced weak intermolecular interactions of [Ni(dmit)(2)](-) dimers, whose magnetic spins were isolated from each other. The molecular arrangements of cations and anions in M+([12]crown-4)(2)[Ni(dmit)(2)](-) salts (M+ = Na+, K+, and Rb+) were isostructural to each other. In the case of Na+([12]crown-4)(2)[Ni(dmit)(2)](-), the space group C2/m changed to C2/c with a lowering in temperature from 298 to 100 K. This structural change occurred at 222.5 K as a first-order phase transition. The space group C2/m (T = 298 K) in the salt K+([12]crown-4)(2)[Ni(dmit)(2)](-) also changed to C2/c (T = 100 K), which transition occurred at 270 K. Crystal structural analyses at 298 and 100 K revealed changes in both supramolecular cation conformation and [Ni(dmit)(2)](-) anion arrangements. The transition from C2/m to C2/c crystals generated a dipole mornent in the Na+([12]crown-4)(2) and K+([12]crown-4)(2) structures, which were reconstructed to cancel the net dipole moment of the C2/c crystals. These cation transformations led to changes in intermolecular interactions between the [Ni(dmit)(2)](-) anions via structural rearrangements. The crystal structure of C2/c was stabilized in Rb+([12]crown-4)(2)[Ni(dmit)(2)](-) at 298 K. The [Ni(dmit)(2)](-) configuration in these salts with the C2/c space group was a one-dimensional uniform chain, which showed the temperature-dependent magnetic susceptibility of a one-dimensional linear Heisenberg anti ferromagnetic chain.
  • S Kitagawa, S Noro, T Nakamura
    CHEMICAL COMMUNICATIONS (7) 701 - 707 1359-7345 2006/02 [Refereed][Not invited]
     
    Pore surface control of microporous coordination polymers is of great interest due to the potentially exciting functionalities it presents, such as highly selective separation, chemisorption, and novel catalysts and sensors. A discussion of our unique strategy aimed at surface engineering using metalloligands, i.e., introduction of coordinatively unsaturated metal centers, is presented.
  • XM Ren, S Nishihara, T Akutagawa, S Noro, T Nakamura, W Fujita, K Awaga
    CHEMICAL PHYSICS LETTERS 418 (4-6) 423 - 427 0009-2614 2006/02 [Refereed][Not invited]
     
    Two new molecular magnets, based on [M(mnt)2](-) [M = Pt (1) or Ni (2)), were prepared and characterized structurally and magnetically. The [M(mnt)2]- anions form the columnar stack in 1 and 2. Both compounds are expected to be ideal quasi-ID magnets. For 1, the Zm value passes a maximum at - 150 K and increase again below 120 K, a spin transition then occurs at similar to 80 K with 4 K hysteresis. For 2, chi(m) the chi(m) value decreases, exponentially upon cooling and drops rapidly below similar to 90 K. At this temperature a spin transition occurs, with no sizable hysteresis detected upon heating. (c) 2005 Elsevier B.V. All rights reserved.
  • K Katoh, T Akutagawa, T Nakamura
    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 63 (10) 960 - 969 0037-9980 2005/10 [Refereed][Not invited]
     
    We have synthesized series of amphiphilic bis-TTF annulated macrocycles 1-6 by using complementary routes involving deprotection-alkylation methods of monothiolate. These amphiphilic bis-TTF annulated macrocycles were designed from the viewpoints of (i) electrically active TTF 14 units for realizing electrically conducting one-dimensional pi-pi stacks, (ii) ion recognition at the macrocyclic moiety, and (iii) two-hydrophobic alkyl chains to fabricate nanoscale thin films. Nanostructures such as molecular nanowires, nanodots of the charge transfer (CT) complexes of amphiphilic bis-(TTF)-annulated macrocycle 1 and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quin-odimethane (F-4-TCNQ) were constructed. The nanowires are oriented to specific directions, by recognizing the potassium array on mica surface. The open-shell electronic structure of nanostructures was determined by electronic spectra. Other nanostructures such as nanodomains and nanodots in addition to molecular thin films were fabricated from CT complexes of 1-6 and organic or inorganic acceptor molecules.
  • XM Ren, T Akutagawa, S Nishihara, T Nakamura, W Fujita, K Awaga
    JOURNAL OF PHYSICAL CHEMISTRY B 109 (35) 16610 - 16615 1520-6106 2005/09 [Refereed][Not invited]
     
    Crystal structures and magnetic properties were determined for two novel compounds, [1-(4'-iodobenzyl)Zn pyridinium][M(mnt)(2)] (mnt(2)- = maleonitriledithiolate; M = Ni (1) or Cu (2)). At room temperature, single crystals of 1 and 2 were isostructural, featuring the formation of segregated columnar structures with regular stacks of cations and anions. For crystal 1, a magnetic transition was observed at similar to 120 K; furthermore, its magnetic behavior was consistent with that of a regular Heisenberg antiferromagnetic (AFM) chain of S 1/2 in the high-temperature phase (HT phase) and that of a spin-gap system in the low-temperature phase (LT phase). Such a phenomenon is similar to the spin-Peierls transition. However, the crystal structure of I in the LT phase at 100 K revealed that its structural transition is associated with the magnetic transition. Because crystal 2 (S = 0) did not exhibit a structural transition, the structural transition of 1 is driven by spin-lattice interaction.
  • MS Chandra, MG Krishna, H Mimata, J Kawamata, T Nakamura, TP Radhakrishnan
    ADVANCED MATERIALS 17 (16) 1937 - + 0935-9648 2005/08 [Refereed][Not invited]
     
    Laser irradiation accelerates pi dimerization of hemicyanine nonlinear optical chromophores in monolayer LB films and causes degradation of their second harmonic generation capability. The metastability of the film is overcome effectively by polyelectrolyte templating. Nanoscopic characterization (see Figure) of the ultrathin films reveals the impact of the polyelectrolyte.
  • S Noro, HC Chang, T Takenobu, Y Murayama, T Kanbara, T Aoyama, T Sassa, T Wada, D Tanaka, S Kitagawa, Y Iwasa, T Akutagawa, T Nakamura
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127 (28) 10012 - 10013 0002-7863 2005/07 [Refereed][Not invited]
  • S Ikeuchi, Y Miyazaki, S Takeda, T Akutagawa, S Nishihara, T Nakamura, K Saito
    JOURNAL OF CHEMICAL PHYSICS 123 (4) 044514  0021-9606 2005/07 [Refereed][Not invited]
     
    Heat capacity of Cs-2(18-crown-6)(3)[Ni(dmit)(2)](2) was measured by adiabatic calorimetry. A broad thermal anomaly was observed around 225 K. The entropy gain (about 52 J K-1 mol(-1)) is much larger than that expected for twofold disordering of 18-crown-6 assumed in the previous structure analysis. The shape of thermal anomaly was qualitatively explained by a linear Ising model developed for cooperative disordering in polymers. The 18-crown-6 molecules forming a one-dimensional chain in the crystal are orientationally disordered with moderate cooperativity. (C) 2005 American Institute of Physics.
  • T Akutagawa, K Matsuura, A Hashimoto, T Nakamura
    INORGANIC CHEMISTRY 44 (13) 4454 - 4456 0020-1669 2005/06 [Refereed][Not invited]
     
    Meso- and (1S, 2S)-diphenyl-1,2-ethanediammonium (DPEDA(2+)) complexed with [8]crown-6 were introduced into [Ni(dmit)2]-based magnetic salts as countercations. The configurational difference of DPEDA(2+) modulated the crystal structure and magnetic behavior of the salts. A two-dimensional (2D) Heisenberg antiferromagnetic square lattice was observed in (meso-diphenyl-1,2-ethane diammonium(2+)) ([18]crown-6)2[Ni(dmit)2](-)(2), which was the first example of a 2D magnetic lattice in [Ni(dmit)2](-) salts.
  • S Noro, S Kitagawa, T Nakamura, T Wada
    INORGANIC CHEMISTRY 44 (11) 3960 - 3971 0020-1669 2005/05 [Refereed][Not invited]
     
    Coordination compounds with a 4,4'-azobis(pyridine) (azpy) ligand, {[M(2)(azpy)(6)(H(2)O)(5)](.)4PF(6)(.)azpy-H(2)O}(n) (M = Ni(II), (1) or Co(II) (2)) (0-dimensional (0-D) dimer), {[Zn(azpy)(3)(H(2)O)(2)](.)2PF(6)(.)2azpy-4H(2)O}(n) (3) (1-dimensional (1-D) fishbone-type chain), {[Ag(azpy)](.)PF(6)}(4) (1-D linear chain), {[Mn(NCS)(2)(azpy)(2)](.)azpy}, (5) (2-dimensional (2-D) grid sheet), and {[Ni(NCS)(2)(azpy)(2)](.)3toluene}, (6) (2-D grid sheet), were synthesized and structurally characterized. Compounds 1 and 2 have a 0-D dimer motif, in which one M(II) (M(II) = N(II) or Co(II)) coordination site is shared by unidentate azpy and H(2)O ligands, each with half-occupancy, i.e., exhibiting static disorder. Compounds 3 and 4 afford 1-D fishbone-type and 1-D linear chain motifs, respectively. Azpy mediates pi-pi and pi-p interactions between these low-dimensional structures. Compounds 5 and 6 possess a 2-D grid sheet motif. These sheets assemble to form microporous frameworks that incorporate aromatic guests, such as coordination-free azpy (5) and toluene (6), There exist not only pi-pi and pi-p interactions but also CH-pi interactions between the framework azpy ligands and guests. It should be noted that the azpy ligand is a good candidate for the construction of new assembling systems of coordination compounds through its aromatic interactions.
  • T Akutagawa, K Shitagami, S Nishihara, S Takeda, T Hasegawa, T Nakamura, Y Hosokoshi, K Inoue, S Ikeuchi, Y Miyazaki, K Saito
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127 (12) 4397 - 4402 0002-7863 2005/03 [Refereed][Not invited]
     
    Nanoscale molecular rotors that can be driven in the solid state have been realized in Cs-2([18]crown-6)(3)[Ni(dmit)(2)](2) crystals. To provide interactions between the molecular motion of the rotor and the electronic system, [Ni(dmit)(2)](-) ions, which bear one S = (1)/(2) spin on each molecule, were introduced into the crystal. Rotation of the [18]crown-6 molecules within a Cs-2([18]crown-6)(3) supramolecule above 220 K was confirmed using X-ray diffraction, NMR, and specific heat measurements. Strong correlations were observed between the magnetic behavior of the [Ni(dmit)(2)](-) ions and molecular rotation. Furthermore, braking of the molecular rotation within the crystal was achieved by the application of hydrostatic pressure.
  • T Nakamura, Y Tatewaki, T Ohta, K Wakahara, T Akutagawa, T Hasegawa, H Tachibana, R Azumi, M Matsumoto, CA Christensen, J Becher
    BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 78 (2) 247 - 254 0009-2673 2005/02 [Refereed][Not invited]
     
    The Langmuir layers of amphiphilic bis(tetrathiafulvalene) [bis(TTF)] annelated macrocycle (1) and those of the (1)[2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (F-4-TCNQ)](2) charge-transfer (CT) complex were evaluated. The neutral molecule of 1 recognized Cs+ ion at the air-water interface forming a domain structure. Contrastingly, (1)(F-4-TCNQ)(2) did not recognize Cs+ ion at the air-water interface. The Langmuir layers of 1 were deposited on a mica surface, resulting in the formation of fibrils. The highly oriented structure of the fibrils at the molecular level was confirmed by a large dicroism in the IR spectra. The (1)(F-4-TCNQ)(2) layer deposited on the mica surface consisted of nanowires oriented in specific directions. The UV-vis-NIR spectra revealed an intramolecular dimer structure of the donor 1 cation radical in the CT complex. An extended nanowire network structure was obtained when the K+ cation was introduced into the subphase. The stacking of intramolecular TTF dimers and intermolecular F-4-TCNQ dimers directed the formation of nanowires, which are oriented on mica by recognizing fully occupied hexagonal K+ sites at the surface. The nanowire orientation was readily disturbed by varying film deposition conditions such as subphase temperature, deposition speed, or surface pressure, indicating that the fluidity of Langmuir layer was important for obtaining nanowire structure.
  • A Akutsu-Sato, H Akutsu, SS Turner, P Day, MR Probert, JAK Howard, T Akutagawa, S Takeda, T Nakamura, T Mori
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 44 (2) 292 - 295 1433-7851 2005 [Refereed][Not invited]
  • T Akutagawa, K Kakiuchi, T Hasegawa, S Noro, T Nakamura, H Hasegawa, S Mashiko, J Becher
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 44 (44) 7283 - 7287 1433-7851 2005 [Refereed][Not invited]
  • T Akutagawa, K Kakiuchi, T Hasegawa, T Nakamura, CA Christensen, J Becher
    LANGMUIR 20 (10) 4187 - 4195 0743-7463 2004/05 [Refereed][Not invited]
     
    Amphiphilic bis(tetrathiafulvalene) [bis(TTF)] macrocycles with four alkyl chains were fabricated as novel electrically active Langmuir-Blodgett (LB) films. Two TTF units were linked via [24]crown-8, [21]crown-7, and [18]crown-6 macrocycles, forming charge-transfer (CT) salts with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (F(4)-TCNQ) at the air-water interface and on solid substrates. The CT salt of the amphiphilic bis(TTF)-macrocycle having a [24]crown-8 ring system formed a uniform surface morphology on mica. Using single-crystal X-ray structural analysis, the layer structure between the hydrophobic chains and the one-dimensional pi-pi stack of the CT salt was confirmed. Our results show that the bis(TTF)-macrocycle was folded at the flexible [24]crown-8 moiety, forming intramolecular pi-pi dimer structures and one-dimensional intermolecular pi-pi stacks with F(4)-TCNQ dimers. The open-shell electronic structure of the LB films was determined by electronic spectra, electrical conductivity, and electron spin resonance analyses. Asymmetry was introduced into the bis(TTF)-macrocycle by changing the ring size from [24]crown-8 to [21]crown-7. The surface morphology of the CT salts with F(4)-TCNQ was established as two-dimensional round-shape domains on mica. Further reduction of the macrocyclic ring from [21]crown-7 to [18]crown-6 resulted in a CT salt of the bis(TTF)-macrocycle with F(4)-TCNQ with a leaf-shape domain morphology and a typical dimension of similar to1 mum(2) on mica. In general, decreasing the macrocyclic ring size from [24]crown-8 to [21]crown-7 or [18]crown-6 affected the inter- and intramolecular interactions and the surface morphologies of LB films.
  • T Sato, T Hasegawa, T Akutagawa, T Nakamura, R Kondo
    PHYSICAL REVIEW B 69 (7) 1098-0121 2004/02 [Refereed][Not invited]
     
    Structural and magnetic properties were investigated in a series of isomorphous 2:1 donor-acceptor-type organic charge-transfer (CT) complexes of (DMET)(2)(X(1)X(2)TCNQ) [DMET denotes dimethyl(ethylenedithio)diselenadithiafulvalene, TCNQ denotes tetracyanoquinodimethane, X(1),X(2)=Br,Cl,F,CH(3),H]. In these complexes, donors (D's) formed quasi-one-dimensional (Q1D) molecular stacks (D=+1/2), which were bridged with each other, by acceptor molecules whose molecular planes were parallel to the stacking axes. By the magnetic measurements, we found that the compounds could be classified into two groups in terms of the 2k(F) transitions of the donor stacks: two complexes exhibited the transitions at around room temperature, while the other two at lower temperature below 10 K. We discuss the origin of the difference in the observed 2k(F) transitions in terms of the subsidiary lattice effect by the acceptor molecules on the Q1D donor stacks.
  • T Akutagawa, S Takeda, T Hasegawa, T Nakamura
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126 (1) 291 - 294 0002-7863 2004/01 [Refereed][Not invited]
     
    One-dimensional dielectric (N...H...N)(infinity) hydrogen-bonding chains of monoprotonated 1,4-diazabicyclo[2.2.2] octane (HDABCOdagger) were Introduced Into an electrically conducting 7,7,8,8-tetracyano-P-quinodimethane (TCNQ) salt as the countercation structure. Room-temperature electrical conductivity Was similar to10(-3) S cm(-1), with a semiconductive behavior. The temperature-dependent dielectric constants of (HDABCO(+))(2)(TCNQ)(3) indicated a dielectric transition at 306 K. A large deuterium Isotope effect for the dielectric transition (DeltaT = 70 K) was observed for the deuterated salt, (DDABCO(+))(2)(TCNQ)(3), Thermally activated order/disorder of the protons or deuteriums within the one-dimensional hydrogen-bonding chains of (HDABCO(+))(infinity) and (DDABCO(+))(infinity) affected the dielectric responses in the TCNQ-based semiconductors.
  • Y Tatewaki, T Akutagawa, T Hasegawa, T Nakamura, CA Christensen, J Becher
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 424 17 - + 1542-1406 2004 [Refereed][Not invited]
     
    We have already reported a nanowire structure of bis-tetrathiafulvalenb (bisTTF) annelated macrocycle - tetrafluorotetracyanoquinodimethane (F(4)TCNQ) charge transfer complex, formed by Langmuir-Blodgett (LB) technique. Nanowires oriented on the mica substrates forming an angle of 60 degree to each other recognizing hexagonal potassium array of mica surface. In the present study, we examined the conditions for obtaining well oriented nanowires and found that the nanowire orientation was quite sensitive to the temperature and potassium-ion concentration of subphase as well as the deposition speeds. By a slight change in. conditions a variety of nanowire morphology was observed on mica surface.
  • T Akutagawa, M Uchigata, T Hasegawa, T Nakamura, KA Nielsen, JO Jeppesen, T Brimert, J Becher
    JOURNAL OF PHYSICAL CHEMISTRY B 107 (50) 13929 - 13938 1520-6106 2003/12 [Refereed][Not invited]
     
    Electrically active Langmuir-Blodgett (LB) films based on charge-transfer (CT) complexes between an amphiphilic monopyrrolo-tetrathiafulvalene (MP-TTF) electron donor and different derivatives of the electron acceptor 7,7,8,8-tetracyano-p-quinodimethane (TCNQ), namely, 2,5-difluoro-TCNQ, fluoro-TCNQ, TCNQ, decyl-TCNQ, 2,5-dimethyl-TCNQ, and 2-methoxy-5-ethoxy-TCNQ, have been fabricated and investigated systematically. The electronic ground state of the CT complex, (MP-TTF+delta)(TCNQs(-delta)), in the LB films varied from ionic (delta = 1) to neutral (delta similar to 0) depending on the electron affinity of the TCNQ derivative used. CT excitation energies of the LB films were correlated against the difference between the redox potentials of the MP-TTF and TCNQ derivatives, exhibiting agreement with a neutral-ionic (N-I) phase diagram proposed for mixed-stack CT complexes. Of the six kinds of LB films, the (MP-TTF+0.3)(decyl-TCNQ(-0.3)) and (MP-TTF (+0.6))(TCNQ(-0.6)) complexes were located closest to the N-I phase boundary. In all of the LB films, the CT transition moment was found to be parallel to the substrate surface based on information from polarized UV-vis-NIR, IR transmission, and reflection-absorption spectra. After being transferred onto a mica surface by a single withdrawal, the surface morphologies of the films were found to be uniform or exhibited spongelike domain structures of thickness about 1.8 nm.
  • H Miyata, Y Tatewaki, T Akutagawa, T Hasegawa, T Nakamura, CA Christensen, J Becher
    THIN SOLID FILMS 438 1 - 6 0040-6090 2003/08 [Refereed][Not invited]
     
    Tetracyanoquinodimethane (TCNQ) derivatives, 2-fluoroTCNQ (F(1)TCNQ), 2,5-difluoroTCNQ (F(2)TCNQ) and 2,5-dichloroTCNQ (Cl(2)TCNQ) were applied to form molecular nanowire structures of charge transfer complex with dialkyl derivative of bistetrathiafulvalene substituted macrocycle (1). When we used Cl(2)TCNQ, nanowire network structure was obtained as in the case of tetrafluoroTCNQ (F(4)TCNQ) previously reported. Although the nanowires were shorter compared with those of F(2)TCNQ complex and formed bundles, they oriented in specific directions recognizing the ionic array on mica surface. In the case of F(2)TCNQ and F(2)TCNQ, we obtained nanowire structures almost identical with those of pure 1. The Cl(2)TCNQ formed an ionic complex with 1, in which donor units and Cl(2)TCNQ were in fully charge-transferred state. Reflecting the electronic structure, the conductivity of nanowires was estimated to be 2 X 10(-4) S cm(-1). (C) 2003 Elsevier Science B.V. All rights reserved.
  • S Nishihara, T Akutagawa, T Hasegawa, T Nakamura
    INORGANIC CHEMISTRY 42 (8) 2480 - 2482 0020-1669 2003/04 [Refereed][Not invited]
     
    Crystal structure and magnetic properties of Gd-2([18]crown-6)(2)-(OH)(2)(CH3CN)(2)[Ni(dmit)(2)](2) (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate) are reported. Gd3+ ions (S = 7/2) were introduced into the pi-spin network of [Ni(dMit)(2)](-) (S = 1/2) complex as a binuclear supramolecular cation, Gd-2([18]crown-6)(2)(OH)(2)(CH3CN)(2), in which two Gd([18]crown-6) units are bridged with two hydroxide ions. The weak antiferromagnetic interactions between Gd...Gd through hydroxide ions were observed, and [Ni(dMit)(2)](-) formed isolated monomers and dimers in the crystal.
  • S Nishihara, T Akutagawa, T Hasegawa, T Nakamura, S Fujiyama, T Nakamura
    SYNTHETIC METALS 137 (1-3) 1279 - 1280 0379-6779 2003/04 [Refereed][Not invited]
     
    H-1-NMR measurements of [Ph(NH3)](18-crown-6)[Ni(dmit)(2)] having two-leg spin ladder structure were performed. The nuclear spinlattice relaxation rate (T-l(-1)) showed a sharp drop at 50 K. The temperature dependence was fitted by activation-type formula, whose gap was in good arrangement with the spin gap estimated by magnetic susceptibility measurements.
  • A Akutsu-Sato, H Akutsu, SS Turner, D Le Pevelen, P Day, ME Light, MB Hursthouse, T Akutagawa, T Nakamura
    SYNTHETIC METALS 135 (1-3) 597 - 598 0379-6779 2003/04 [Refereed][Not invited]
     
    Charge transfer salts with stoichiometry beta"-(BEDT-TTF)(4)[M(C(2)O(4))(3)](18-crown-6 ether)(9H(x)O), where M = Cr, Ga or Fe and x = 2 or 3 are reported. Their structures suggest that proton migration is possible. Variable temperature resistivity measurements on the Cr salt show metallic behaviour down to 180K. Magnetic susceptibility of the Cr salt is paramagnetic down to 1.8 K. Preliminary impedance measurements suggest that the proton conductivities of the Cr and Ga salts are the order of 10(-3) S cm(-1) at 300 K.
  • S Takeda, G Maruta, T Akutagawa, T Hasegawa, T Nakamura
    SYNTHETIC METALS 133 427 - 429 0379-6779 2003/03 [Refereed][Not invited]
     
    In the integrated molecular systems of the crown ether-based ionic channel and the electronic conducting column of Ni(dmit)(2), an interaction is expected between the dynamic motion of ions in the crown ether channel and the electronic state of the conducting column. To investigate an ability of the crown ether molecule for providing the environment suitable for the ionic motion, the dynamic behavior of the ammonium ion of semiconducting [(NH4+)(18-crown-6)][Ni(dmit)(2)](3) was studied by the solid state D NMR and N-15 CP NMR. The D NMR spectrum of deuterated analogue of [(ND4+)(18-crown-6)][Ni(dmit)(2)](3) indicated that the ND4+ ion rotated rapidly with jumping rate more than the order of 10(6) Hz above room temperature. The quadrupole coupling of e 2 Qq/h = 6.5 kHz remained even at 360 K for deuterium atom of ND4+ ion. The anisotropic tensor of N-15 chemical shift, the principal values of which were sigma(11) = -356.0 ppm, sigma(22) = -353.2 ppm and sigma(33) = -342.6 ppm, was found. These results suggest that the rotating ammonium ion is slightly deformed in the cavity of 18-crown-6. (C) 2002 Elsevier Science B.V. All rights reserved.
  • T Hasegawa, T Akutagawa, T Nakamura
    SYNTHETIC METALS 133 623 - 625 0379-6779 2003/03 [Refereed][Not invited]
     
    We report on a novel spin-lattice phase transition in an ionic mixed-stack charge-transfer (CT) compound of (BEDO-TTF)(Cl(2)TCNQ)- We found that the rotational modes for rigid-body displacements of molecules afforded an appreciable quantitative variation in the exchange interactions along the mixed stacks, which resulted in the symmetry-invariant first-order magneto-lattice phase transition at around 110 K. It was found in the electron paramagnetic resonance (EPR) spectra that the low-temperature strongly interacting spin phase was followed by a magnetic order at 16 K. We discuss the origin of the transition at 110 K in terms of the competition of free energy between the respective spin states. We also present neutral-ionic (NI) phase transition in the isomorphous compound of (BEDT-TTF)(ClMeTCNQ) under pressure. (C) 2002 Published by Elsevier Science B.V.
  • T Akutagawa, A Hashimoto, S Nishihara, T Hasegawa, T Nakamura
    JOURNAL OF PHYSICAL CHEMISTRY B 107 (1) 66 - 74 1520-6106 2003/01 [Refereed][Not invited]
     
    Flexible supramolecular cation structures, [(XyDA)(0.5)(crown ethers)](+) complexes, were introduced as countercations to [Ni(dmit)(2)](-) anions, which bear an S = 1/2 spin, to form novel magnetic crystals (XyDA = p-xylylenediammonium, dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate, and crown ethers = [12]crown-4, [15]crown-5, or [18]crown-6). Sandwich-type [(XyDA)(0.5)(crown ethers)](+) structures were formed through hydrogen-bonding interactions in the crystals between the ammonium moieties of XyDA and the oxygen atoms of the crown ethers. [12]Crown-4 yielded three types of [(XyDA)(0.5)([12]crown-4)](+)[Ni(dmit)(2)] polymorphs, whereas two types of [(XyDA)(0.5)([15]crown-5)](+)[Ni(dmit)(2)] polymorphs were obtained using [15]crown-5. Three types of [(XyDA)(0.5)(crownethers)](+) structures were identified for these polymorphs. Since the flexible -CH-)-NH3+ moieties connected to benzene plane have rotational freedom, the [(XyDA)(0.5)(crown ethers)](+) structures varied according to the conformations of the XyDA cation in the crystals. The larger ring size of [18]crown-6 than that of [12]crown-4 and [15]crown-5 reduced the flexibility of the XyDA cation, and provided only one type of crystal. The [Ni(dMit)(2)](-) anion existed as dimer structures, which are in the singlet ground state. The arrangement of the [Ni(dmit)(2)](-) anion in the crystals were depended on the structure of [(XyDA)(0.5)(crown ethers)](+). Correlation of the absolute values of magnetic exchange energy J to the square of the intradimer transfer integral t(2) were confirmed.
  • Akutagawa T, Hasegawa T, Nakamura T, Inabe T, Saito G
    Chemistry (Weinheim an der Bergstrasse, Germany) 19 8 4402 - 4411 0947-6539 2002/10 [Refereed][Not invited]
  • T Akutagawa, T Hasegawa, T Nakamura, T Inabe
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 124 (30) 8903 - 8911 0002-7863 2002/07 [Refereed][Not invited]
     
    Hydrogen-bonded supramolecular cation assemblies of (NH4+/NH2-NH3+)(crown ether), where the crown ether is [12]crown-4, [15]crown-5, or [18]crown-6, were incorporated into electrically conducting [Ni(dmit)(2)] salts (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate). (NH4+)([12]crown-4)[Ni(dmit)(2)](3)(CH3CN)(2) had a pyramidal shape, while ionic channels were observed in (NH4+)0.88([15]crown-5)[Ni(dmit)(2)](2) and (NH4+)(0.70)- ([18]crown-6)[Ni(dmit)(2)](2). Both (NH4+)(0.88)([15]crown-5) and (NH4+)(0.70)([18]crown-6) contained regularly spaced [Ni(dMit)(2)] stacks formed by N-(HO)-O-... hydrogen bonding between the oxygen atoms in crown ethers and the NH4+ ion. NH4+ occurred nonstoichiometrically; there were vacant ionic sites in the ionic channels. The ionic radius of NH4+ is larger than the cavity radius of [15]crown-5 and [18]crown-6. Therefore, NH4+ ions could not pass through the cavity and were distributed randomly in the ionic channels. The static disorder caused the conduction electrons to be randomly localized to the [Ni(dMit)(2)] stacks. Hydrazinium (NH2NH3+) formed the supramolecular cations in (NH2-NH3+)([12]crown-4)(2)[Ni(dmit)(2)](4) and (NH2-NH3+)(2)([15]crown-5)(3)[Ni(dmit)(2)](6), possessing a sandwich and club-sandwich structure, respectively. To the best of our knowledge, these represent the first hydrazinium-crown ether assemblies to be identified in the solid. In the supramolecular cations, hydrogen bonding was detected between the ammonium or the amino protons of NH2-NH3+ and the oxygen atoms of crown ethers. The sandwich-type cations coexisted with the [Ni(dmit)(2)] dimer stacks. Although the assemblies were typically semiconducting, ferromagnetic interaction (Weiss temperature = +1 K) was detected in the case of (NH2-NH3+)(2)([15]crown-5)(3)[Ni(dmit)(2)](6). The (NH2- NH3+)(0.8)([18]crown-6)[Ni(dmit)(2)](2) and (NH4+)(0.76)([18]crown-6)[Ni(dmit)(2)](2) crystals were isomorphous. The large and flexible [18]crown-6 allowed for maintaining the same ionic channel structure through replacement of the NH4+ cation by NH2-NH3+.
  • T Akutagawa, T Ohta, T Hasegawa, T Nakamura, CA Christensen, J Becher
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 99 (8) 5028 - 5033 0027-8424 2002/04 [Refereed][Not invited]
     
    Molecular "nanowire" structures composed of the charge transfer complex of a bis-tetrathiafulvalene substituted macrocycle and tetrafluorotetracyanoquinodimethane were constructed on mica substrates by employing the Langmuir-Blodgett technique. The nanowires transferred from a dilute aqueous potassium chloride subphase had typical dimensions of 2.5 nm X 50 nm X 1 mum. The nanowires are oriented to specific directions, corresponding to the directions of the potassium-ion array on the mica surface having sixfold symmetry. Such correlation between the nanowires and the substrate surface was also observed when a dilute aqueous rubidium chloride subphase was used. On the other hand, the correlation completely disappeared when the subphase contained divalent cations, indicating that the molecular nanowires orient by recognizing the monocation array on the mica surface. The nanowires formed by the vertical dipping method coexist with the monolayers. Only nanowire structures are, however, observed when we apply the horizontal lifting method. Based on the crystal structure of a related complex, a possible structure of the nanowires is presented. The conductivity of the nanowires was estimated to be of the order of 10(-3) S(.)cm(-1). The nanowires formed specific (regular) structures such as T-shape junctions, suggesting their use in construction of future molecular nanoscale devices.
  • T Akutagawa, T Nakamura
    COORDINATION CHEMISTRY REVIEWS 226 (1-2) 3 - 9 0010-8545 2002/03 [Refereed][Not invited]
     
    The assembly of monovalent species of [Ni(dmit)(2)] (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate), which bear S = 1/2 spin on each molecule, was controlled by using crown-ether based supramolecular cations. We could regulate the shape and valence of the supramolecular cations by changing the ring size of the crown ethers as well. as the metal cations included. Since the structure of the ionic crystals is mainly determined by the Madelung energy and the Leanard-Jones potential (shape of molecules), a large diversity in crystal structure was observed. A relationship between the overlap of [Ni(dmit)(2)] frontier orbitals and the magnetism is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
  • S Nishihara, T Akutagawa, T Hasegawa, T Nakamura
    CHEMICAL COMMUNICATIONS (5) 408 - 409 1359-7345 2002 [Refereed][Not invited]
     
    A novel molecular spin ladder structure of a nickel dithiolate complex has been constructed using a supramolecular cation composed of anilinium and 18-crown-6.
  • T Akutagawa, N Takamatsu, T Hasegawa, T Nakamura, T Inabe
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 376 39 - 46 1058-725X 2002 [Refereed][Not invited]
     
    The crystals of M+(15-crown-5)(2)[Ni(dmit)(2)] (M+ = K+ (1), Rb+ (2) and NH4+ (3)) were prepared, In the crystal, M+ and 15-crown-5 formed a barrel-shape supramolecular cation structure, which filled the space between the [Ni(dmit)(2)](-) layers. The [Ni(dmit)(2)](-) formed the pi - pi dimers which were connected through the side-by-side S similar to S contacts. The interactions between [Ni(dmit)(2)](-) within the dimer were not strong enough and the crystals showed Curie-Weiss magnetic susceptibility with the Weiss temperature theta of -3.8, -2.8 and -3.2 K for the salts 1, 2 and 3, respectively.
  • K Shitagami, T Akutagawa, T Hasegawa, T Nakamura, N Robertson
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 57 1271 - 1273 0108-2701 2001/11 [Refereed][Not invited]
     
    In the title compound, K[Ni(C3S5)(2)]C20H24O6 .C3H6O, K+ is incorporated in the cavity of the 1,4,7,10,13,16-hexaoxa-2,3:11,12-dibenzocyclooctadeca-2,11-diene (DB18c6) molecule and is coordinated by the six DB18c6 O atoms and the propanone O atom. Two {K+ (DB18c6)[(CH3)(2) CO]} units form a dimer which is aligned in a one-dimensional manner along the a axis through a face-to-face interaction between the benzene rings of neighboring DB18c6 molecules. [Ni(dmit)(2)](-) anions are also aligned along the a axis through side-by-side S . . .S interactions.
  • T Akutagawa, T Hasegawa, T Nakamura, S Takeda, T Inabe, K Sugiura, Y Sakata, AE Underhill
    CHEMISTRY-A EUROPEAN JOURNAL 7 (22) 4902 - 4912 0947-6539 2001/11 [Refereed][Not invited]
     
    The [(M+),([18]crown-6)] supramolecular cations (SC), in which M+ and [18]crown-6 are alkali metal ions (M+ = Li+, Na+, and Cs+), and 1,4,7,10,13, 16-hexaoxacyclooctadecane, respectively, form ionic channel structures through the regular stacks of [18]crown-6 in [Ni(dmit)(2)]-based molecular conductors (dmit(2) =2-thioxo-1,3-dithiole-4,5-dithiolate). In addition to the [Ni(dmit)(2)] salts that have the ionic channel structures (these salts are abbreviated as type I salts), Li+ and Na+ form dimerized [(M+)(2)([18]crown-6)(2)] units in the crystals (type II salts). The K+ and Rb+ are coordinated tightly into the [18]crown-6 cavity to form typical diskshape SC+ units in the corresponding [Ni(dmit)(2)] salts (type III salts). The type I, II, and III salts have typical stoichiometries of [(M+),([18]crown-6)]-[Ni(dmit)(2)](2), [(M+)([18]crown-6)(H2O)(x),(CH3CN)(1.5-x)][Ni(dmit)(2)](3) (x = 1 for Li+ or 0.5 for Na+). and [M+([18]crown-6)][Ni(dmit)(2)](3), respectively; the salts of the same type are isostructural. In agreement with the trimer structures of [Ni(dmit)(2)] in the type II and III salts, they exhibit semiconducting behavior with electrical conductivities at 300 K (sigma (300K) of 0.01 - 0.1 S cm(-1). Type I salts contain a regular stack of partially oxidized [Ni(dmit)(2)] units, which form a quasi one-dimensional metallic band within the tight-binding approximation regime. The electrical conductivities at 300 K are 10 - 30 S cm(-1), and an almost temperature-independent conductivity was observed at higher temperatures, However, the one-dimensional electronic structures in these salts are strongly influenced by the static and dynamic structures of the coexisting ionic channel. The Na+ salt is a semiconductor, whose magnetic behavior is described by the disordered one-dimensional antiferromagnetic chain. On the other hand, the Cs+ salt is a exhibits metallic properties with 2k(P) instability at room temperature. The Li+ salt shows a gradual transition from the high-temperature metallic phase to the low-temperature one-dimensional antiferromagnetic semiconductor phase, which was associated with the freezing of Li+ motion at lower temperatures. The preferential crystallization of type I salts was possible by controlling the equilibrium constant (K-c) of the complex formation between M+ ions and the [18]crown-6 molecule. The ionic channel structures were obtained when the K-c was low in the electrocrystallization solution, while type II or III salts were formed in the high K-c region.
  • T Takahashi, K Sakai, T Yumoto, T Akutagawa, T Hasegawa, T Nakamura
    THIN SOLID FILMS 393 (1-2) 7 - 11 0040-6090 2001/08 [Refereed][Not invited]
     
    Langmuir-Blodaett films of [Au(tmdt)(2)] [tmdt(2-) = bis(methylthio)tetrathiafulvalenedithiolate] without alkyl chains are described. We synthesized tridecylmethylammonium salt of complex 1 as a film forming material so that the alkyl chains of the salt make the complex soluble in solution and help the formation of monolayers. The complex I formed stable monolayers at the air-water interface, which were successfully transferred to solid substrates by the horizontal lifting method. The oxidation of the complex to the neutral form occurred during the film forming process, which was indicated by the IR measurements. The alkylammonium part was removed by methanol and the single component LB films of neutral [Au(tmdt)(2)] were obtained. The LB films showed semiconducting behavior after electrochemical doping. (C) 2001 Elsevier Science B.V. All rights reserved.
  • K Sakai, T Akutagawa, T Hasegawa, T Nakamura
    SYNTHETIC METALS 120 (1-3) 805 - 806 0379-6779 2001/03 [Refereed][Not invited]
     
    The d-pi hybrid charge-transfer system, Cu-0.39[Ni(dmit)(2)] was prepared, and the crystal and electronic band structures were investigated. In the crystal, a unique layered structure is constructed, which results from the stacks of dimerized Ni(dmit)(2) being largely slipped along the long molecular axis. The copper ions are located at the interlayer spaces with large thermal factors. From the tight-binding band calculation, a quasi-one-dimensional Fermi surface was obtained.
  • T Naito, T Inabe, K Takeda, K Awaga, T Akutagawa, T Hasegawa, T Nakamura, T Kakiuchi, H Sawa, T Yamamoto, H Tajima
    JOURNAL OF MATERIALS CHEMISTRY 11 (9) 2221 - 2227 0959-9428 2001 [Refereed][Not invited]
     
    An electrolysis of bis(ethylenedithio)tetrathiafulvalene (ET) and a Mn-cluster in a 1,1,2-trichloroethane solution containing 10% (vol/vol) of ethanol yields black lustrous single crystals, beta"-(ET)(3)(MnCl4)(1,1,2-C2H3Cl3) based on the X-ray structural study. The crystal structure can be characterized as alternating two-dimensional donor sheets and insulating sheets made of isolated [MnCl4](2-) ions and the 1,1,2-C2H3Cl3 molecules. Every pair of the neighbouring donor molecules has a large displacement along both short and long molecular axes. A tight-binding band calculation suggests that this arrangement should lead to a weak but isotropic intermolecular interaction in the donor sheets, and this in turn should lead to a marginally metallic or semiconducting electronic structure. Although the polarized reflectance spectra and the temperature-dependent spin susceptibility derived from the EPR spectra on the single crystal indicate metallic nature, the electrical behaviour under atmospheric pressure is semiconductive with room temperature conductivity of 35 S cm(-1) and apparent activation energy of 0.023 eV. It exhibits a resistive hump with hysteresis at around 60 K, which could be associated with a structural transition demonstrated by a series of low temperature X-ray oscillation photographs. The magnetic susceptibility at 4.5-300 K does not exhibit any anomaly and is well reproduced by the Curie-Weiss model with Curie constant C/emu K mol(-1) = 3.89 and Weiss temperature theta /K = -0.10. This magnetic behaviour can be quantitatively understood as the sum of Pauli paramagnetism of the pi -electrons and the contribution from the local spins on the Mn(II) ions with d(5)-configuration S = 5/2). High pressure easily suppresses the increase in resistivity at low temperature, and the electrical behaviour is particularly sensitive to the first 3-5 kbar.
  • S Mikami, K Sugiura, T Maruta, Y Maeda, M Ohba, N Usuki, H Okawa, T Akutagawa, S Nishihara, T Nakamura, K Iwasaki, N Miyazaki, S Hino, E Asato, JS Miller, Y Sakata
    JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS (4) 448 - 455 1472-7773 2001 [Refereed][Not invited]
     
    The direct redox reaction between tetracyanoethylene (TCNE) and meso-tetraphenylporphyrinatoiron(II), [Fe-II(TPP)], formed the electron transfer salt (ETS) [Fe-III(TPP)][TCNE], which has been structurally, spectroscopically, and magnetically characterized. It has an extended one-dimensional linear chain with coordination polymer motif comprised of [Fe-III(TPP)](+) and bridging mu-[TCNE](-) with Fe-N-TCNE distance 1.889(2) Angstrom. This coordination geometry is consistent with a low-spin iron(III) ion, i.e., one electron transfer from Fe-II to TCNE produces S=1/2 [Fe-III(TPP)](+) having a (d(xy))(2)(d(yz),d(zx))(3) configuration and S=1/2 [TCNE](-). Fe-57 Mossbauer data, delta =0.28 mm s(-1) and DeltaE epsilon=epsilon2.19 mm s(-1) at 77 K, also support the low-spin state. The room temperature magnetic moment of the ETS, 1.20 mu (B), arises from two S=1/2 systems having antiferromagnetic coupling, -190 cm(-1) (H=-2 Sigma J(ij)S(i)S(j)).
  • T Akutagawa, N Takamatsu, K Shitagami, T Hasegawa, T Nakamura, T Inabe, W Fujita, K Awaga
    JOURNAL OF MATERIALS CHEMISTRY 11 (9) 2118 - 2124 0959-9428 2001 [Refereed][Not invited]
     
    Calcium ion (Ca2+) and crown ethers, 12-crown-4, 15-crown-5, 1-aza-18-crown-6 (A18-crown-6) and 1,10-diaza-18-crown-6 (DA18-crown-6), were assembled into divalent supramolecular cation (SC2+) structures in the monovalent [Ni(dmit)(2)](-) salts (dmit(2-) =2-thioxo-1,3-dithiole-4,5-dithiolate), which regulate the arrangement of the [Ni(dmit)(2)](-) anions in the crystal. The divalent SC2+-[Ni(dmit)(2)](-) system showed a larger diversity of crystal structures compared with the monovalent SC+ system. Peculiar magnetic behavior was observed depending on the arrangement of the S = 1/2 spins on the [Ni(dmit)(2)](-) anions. Single crystals of Ca2+ (12-crown-4)(2)[Ni(dmit)(2)](2) (1) and Ca2+ (15-crown-5)(2)[Ni(dmit)(2)](2)(CH3CN)(0.7) (2) had a typical sandwich-type Ca2+ (crown ether), structure, which included the formation of pi-pi dimers and monomers of [Ni(dmit)(2)](-) anions in the crystal. The temperature-dependent magnetic susceptibility (chi (m)) of salt 1 showed a magnetic transition at 190 K, at which temperature the spins on each [Ni(dmit)(2)](-) dimer formed a singlet pair. On the other hand. the magnetic behavior of salt 2 obeyed the Curie-Weiss law. The Ca2+ ions in the isostructural single crystals of Ca2+ (A18-crown-6)[Ni(dmit)(2)](2)(CH3CN)(2) (3) and Ca2+ (DA18-crown-6)[Ni(dmit)(2)](2)(CH3CN)(2) (4) were completely included into the 18-crown-6 cavity, and further interacted with two CH3CN molecules from the axial posit ion. The resultant Ca2+(18-crown-6)(CH3CN)(2) cations induced the formation of uniform zig-zag chains of the [Ni(dmit)(2)](-) anions, the magnetic susceptibility of which were explained by a one-dimensional Heisenberg antiferromagnetic linear chain. The magnetism of these salts was discussed in terms of the intermolecular transfer integral t.
  • An infinite supramolecular array structure in metal dithiolate complexes: crystal structure of K (dibenzo-18-crown-6)[M(dmit)(2)](CH3CN)(2) (M = Ni, Au)
    K Shitagami, T Akutagawa, T Hasegawa, T Nakamura, N Robertson
    CRYSTENGCOMM (52) art. no. - 52 1466-8033 2001 [Refereed][Not invited]
     
    K( dibenzo- 18- crown- 6)[M(dmit) (2)](CH3CN)(2) (M = Ni, Au), which have a one- dimensional supramolecular array, have been prepared. These salts are isomorphous and each K+ (dibenzo- 18- crown- 6) suparamolecular cation unit is connected through the interaction of two CH3CN molecules. The [Ni(dmit)(2)] - molecules exist as isolated monomers, and the magnetic susceptibility of the salt exhibits Curie- type behavior.
  • T Hasegawa, T Mochida, R Kondo, S Kagoshima, Y Iwasa, T Akutagawa, T Nakamura, G Saito
    PHYSICAL REVIEW B 62 (15) 10059 - 10066 1098-0121 2000/10 [Refereed][Not invited]
     
    We report synthesis and examination of the electronic properties of an isomorphous series of mixed-stack organic charge-transfer complexes, composed of [bis(ethylenedithio) tetrathiafulvalene] (BEDT-TTF)-based electron donors and electron accepters of halogen-substituted tetracyanoquinodimethanes (TCNQ's). Single crystals of (BEDT-TTF)(Me,TCNQ), (BEDT-TTF)(CIMeTCNQ), and (BEDO-TTF)(Cl(2)TCNQ) were investigated as to their crystal structures, and optical and magnetic properties. The intermolecular overlaps between the stacked columns were comparable to the face-to-face overlap between the donor and the acceptor molecules inside the stacks. As seen from the optical and magnetic measurements, the (BEDT-TTF)(Me,TCNQ) and (BEDT-TTF)(ClMeTCNQ) complexes were neutral, while the (BEDO-TTF)(Cl(2)TCNQ), complex was found to be ionic. Among these complexes, anomalous magnetic properties were observed in the ionic complex of (BEDO-TTF)(Cl(2)TCNQ). (BEDO-TTF)(CI,TCNQ) is a magnetic insulator with Curie-Weiss behavior in magnetic susceptibility followed by a sharp drop at around 120 K, which is in sharp contrast to conventional "spin-Peierls-type'' nonmagnetic mixed-stack ionic compounds.
  • T Akutagawa, S Nishihara, N Takamatsu, T Hasegawa, T Nakamura, T Inabe
    JOURNAL OF PHYSICAL CHEMISTRY B 104 (25) 5871 - 5873 1089-5647 2000/06 [Refereed][Not invited]
     
    Magnetic cation of Co2+ was incorporated in a monovalent [Ni(dmit)(2)](-) (2-thioxo-1,3-dithiole-4,5-dithiolate) salt by using the supramolecular framework of 15-crown-5. The pi-spins of [Ni(dmit)(2)](-) formed a one-dimensional Heisenberg antiferromagnetic linear chain, while the d-spin of Co2+ behaved as a free S = 3/2 spin within the crystal.
  • T Akutagawa, T Hasegawa, T Nakamura, S Takeda, T Inabe, K Sugiura, Y Sakata, AE Underhill
    INORGANIC CHEMISTRY 39 (12) 2645 - 2651 0020-1669 2000/06 [Refereed][Not invited]
     
    Monovalent cations (M+ = Na+, K+, Rb+, and NH4+) and 12-crown-4 were assembled to new supramolecular cation (SC+) structures of the M+(12-crown-3)(n) (n = 1 and 2), which were incorporated into the electrically conducting Ni(dmit)(2) salts (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate), The Na+, K+, and Rb+ salts are isostructural with a stoichiometry of the M+(12-crown-3)(2)[Ni(dmit)(2)](4), while the NH4+ salt has a stoichiometry of NH4+(12-crown-4) [Ni(dmit)(2)](3)(CH3CN)(2). The electrical conductivities of the Na+, K+, Rb+, and NH4+ salts at room temperature are 7.87, 4.46, 0.78, and 0.14 S cm(-1), respectively, with a semiconducting temperature dependence. The SC+ structures of the Na+, K+, and Rb+ salts have an ion-capturing sandwich-type cavity of M+(12-crown-4)(2), in which the M+ ion is coordinated by eight oxygen atoms of the two 12-crown-3 molecules. On the other hand, the NH4+ ion is coordinated by four oxygen atoms of the 12-crown-4 molecule. Judging from the M+-O distances, thermal parameters of oxygen atoms, and vibration spectra, the thermal fluctuation of the Na+(12-crown-4)(2) structure is larger than those of K+(12-crown-4)2 and Rb+(12-crown-4)2. The SC+ unit with the larger alkali metal cation gave a stress to the Ni(dmit)(2) column, and the SC+ structure changed the pi-pi overlap mode and electrically conducting behavior.
  • K Uesugi, Suemune, I, T Hasegawa, T Akutagawa, T Nakamura
    APPLIED PHYSICS LETTERS 76 (10) 1285 - 1287 0003-6951 2000/03 [Refereed][Not invited]
     
    The temperature dependence of band gap energies of GaAsN alloys was studied with absorption measurements. As the N concentration in GaAsN increased, the temperature dependence of the band gap energy was clearly reduced in comparison with that of GaAs. The redshift of the absorption edge in GaAsN for the temperature increase from 25 to 297 K was reduced to 60% of that of GaAs for the N concentration larger than similar to 1%. The differential temperature coefficient of the energy gap at room temperature was also reduced to 70% of that of GaAs. The main factor for this reduced temperature dependence in GaAsN was attributed to the transition from band-like states to nitrogen-related localized states with detailed studies of the temperature-induced shift of the absorption edge. (C) 2000 American Institute of Physics. [S0003-6951(00)04110-3].
  • T Akutagawa, T Nakamura
    COORDINATION CHEMISTRY REVIEWS 198 297 - 311 0010-8545 2000/03 [Refereed][Not invited]
     
    The dithio late complex, [Ni(dmit)(2)] (dmit = 2-thioxo-1,3-dithiol-4,5-dithiolate) is an organic pi-molecule which gives highly conducting salts with closed shell cations or organic donors, We have found that crown ether macrocycles can be incorporated into the salts in which the crown ethers include alkali metal cations forming supramolecular cation (SC) structures, The SC structural diversity was observed to depend on the size of the crown ether and cation. Three kinds of crown ethers, 12-crown-4, 15-crown-5 and 18-crown-6 in addition to an acyclic polyether analog of pentaetyleneglycol were incorporated in the conducting [Ni(dmit)(2)] crystals. The structure of these crystals will be described with emphasis on both the structures of SC and Ni(dmit)(2) conducting layers. In one example, the crown ether forms a channel in which the cation has a translational freedom. The cation, otherwise merely forms a periodic Coulomb potential in the crystal, can influence the electrical conduction through the motion in the channel. The monovalent [Ni(dmit)(2)] salts, which are possible candidates for molecular magnets will be described on a salt having SC structure. (C) 2000 Elsevier Science S.A. All rights reserved.
  • Tuning of intramolecular pi-pi overlap mode of tetrathiafulvalene bisannulated macrocycles in the open-shell electronic state
    T Akutagawa, Y Abe, T Hasegawa, T Nakamura, T Inabe, CA Christensen, J Becher
    CHEMISTRY LETTERS (2) 132 - 133 0366-7022 2000/02 [Refereed][Not invited]
     
    Charge-transfer complexes of bis(methylthio)tetrathiafulvalene (DMT-TTF) bisannulated macrocycles with 2,3,5,6-tetrafluoro-7,7,8,S-tetracyanoquinodimethane (F-4-TCNQ) were prepared. The crystal structural analysis revealed an intramolecular dimer structure with the pi-pi overlap of DMT-TTF units. The magnitude of intramolecular pi-pi overlap depends on the ring size of macrocycles.
  • M+(crown ether) supramolecular cations (M+= K+, Rb+, NH4+) for controlling magnetic properties of monovalent [Ni(dmit)(2)](-) salts
    N Takamatsu, T Akutagawa, T Hasegawa, T Nakamura, T Inabe, W Fujita, K Awaga
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 343 481 - 486 1058-725X 2000 [Refereed][Not invited]
     
    Supramolecular cations (SC+) of K+, Rb+, or NH4+(crown ether) were incorporated into the monovalent [Ni(dmit)(2)](-) salts. The K+ and Rb+(DA18-crown-6) units had a planar disk-shaped SC+ structure, while the [NH4+(15-crown-5)(2)](2) was the barrel type SC+ structure. The [Ni(dmit)(2)](-) arrangement and magnetic properties of these salts depended on the coordination properties in the cation structures.
  • T Akutagawa, Y Abe, T Ohta, T Hasegawa, T Nakamura, C Christensen, J Lau, J Becher
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 349 379 - 382 1058-725X 2000 [Refereed][Not invited]
     
    Crystal structures of dimethylthio-tetrathiafulvalene (DMT-TTF) multiannulated macrocycles, bis(DMT-TTF) and tris(DMT-TTF), were examined. The intramolecular dimerization was a common structural feature for these multi-TTF macrocycles in open-shell electronic state.
  • T Akutagawa, Y Abe, T Hasegawa, T Nakamura, T Inabe, K Sugiura, Y Sakata, CA Christensen, J Lau, J Becher
    JOURNAL OF MATERIALS CHEMISTRY 9 (11) 2737 - 2742 0959-9428 1999/11 [Refereed][Not invited]
     
    Cation radical salts of the bis(methylthio)tetrathiafulvalene (DMT-TTF) trisannulated macrocycles, [tris(DMT-TTF)]I-3(-) (1) and [tris(DMT-TTF)]IBr2- (2), were prepared and the crystal structures and polarized reflectance spectra of the salts 1 and 2 were investigated. An isostructural character is observed for the two salts. The C-3 symmetry of tris(DMT-TTF) bearing three equivalent DMT-TTF units (A, B, and C) within a molecule is broken through the formation of cation radical salts. Two DMT-TTF units (B and C) of three equivalent units form an intramolecular dimer structure through the face-to-face pi-pi overlap, whereas the plane of the A unit is orthogonal to the dimer plane and isolated from the other units. The intramolecular dimers are further dimerized through the intermolecular B-B' interaction, resulting in a DMT-TTF tetramer unit (C-B-B'-C') within the crystal. The intramolecular bond lengths and polarized reflectance spectra indicate the localization of a unit charge on the B unit rather than A or C. The charge separated A(0)-B+-C-0 electronic structure is confirmed.
  • T Hasegawa, T Akutagawa, T Nakamura, Y Sasou, R Kondo, S Kagoshima, T Mochida, G Saito, Y Iwasa
    SYNTHETIC METALS 103 (1-3) 1804 - 1805 0379-6779 1999/06 [Refereed][Not invited]
     
    The BEDT-TTF based mixed-stack charge-transfer (CT) complexes have been investigated for a series of isostructural compounds. The ionic complex of (BEDO-TTF)(Cl(2)TCNQ) is a magnetic insulator with showing Curie-Weiss behavior in magnetic susceptibility, in sharp contrast to the conventional mixed-stack CT complexes. The (BEDT-TTF)(ClMeTCNQ) compound undergoes neutral-ionic (NI) phase transition at high pressure.
  • Y Abe, T Akutagawa, T Hasegawa, T Nakamura, K Sugiura, Y Sakata, T Inabe, CA Christensen, J Becher
    SYNTHETIC METALS 102 (1-3) 1599 - 1600 0379-6779 1999/06 [Refereed][Not invited]
     
    Charge transfer (CT) complexes of tetrathiafulvalene bisannulated 24-crown-8 (1) with tetrafluoro (F-4)-, 2,5-dibromo (Br-2)-. 2,5-dichloro (CI 2)-tetracyanoquinodi methane (TCNQ), and 2,3-dicyano-5,6-dichloro-p-benzoquinone (DDQ) were prepared. The electronic ground state of the acceptor varies from the completely ionic to partial charge transfer state. Within the CT complexes the donor 1 was completely oxidized to the divalent cationic state 1(2+) The molecular conformation of 1(2+) in Cl-2-TCNQ complex was an intra-dimer form folded over the flexible part of macrocyclic 24-crown-8.
  • T Yumoto, T Akutagawa, T Hasegawa, T Nakamura, H Ikegami, G Saito
    SYNTHETIC METALS 102 (1-3) 1733 - 1734 0379-6779 1999/06 [Refereed][Not invited]
     
    The monolayers and LB films of BEDO-TTF . CF(3)TCNQ charge transfer (CT) complex mixed with matrix molecule, arachidic acid, were prepared A strong CT band was observed in the IR region due to the conduction electron. The average charges of the CF(3)TCNQ and BEDO-TTF in the LB film were -1 and +0.5, respectively, determined from the shift of the bands in IR region. The LB film showed a metal-like conductivity at around room temperature.
  • T Nakamura, T Akutagawa, T Hasegawa, T Kikukawa, T Araiso, M Higuchi, K Hiratani
    SYNTHETIC METALS 101 (1-3) 78 - 79 0379-6779 1999/05 [Refereed][Not invited]
     
    Oxidative polymerization of pyrrole derivatives in a microgravity environment was curried out using the JAMIC (Japan Microgravity Center) drop shaft where 10-seconds microgravity condition is available. The structural and electronic properties of the polymers were compared with those obtained in IG.
  • A clay-metal complex ultrathin film as prepared by the Langmuir-Blodgett technique
    K Tamura, H Setsuda, M Taniguchi, T Nakamura, A Yamagishi
    CHEMISTRY LETTERS (2) 121 - 122 0366-7022 1999/02 [Refereed][Not invited]
     
    A clay-metal complex hybrid film with the thickness of 5.0 +/- 1.0 nm was prepared by the Langmuir-Blodgett technique. According to the method, a hectorite clay dispersed in an aqueous subphase was adsorbed by a cationic monolayer of amphiphilic Ru(II) complex. The surface structure of a film deposited onto a hydrophilic glass plate was studied with an atomic force microscope (AFM).
  • T Nakamura, T Yumoto, T Suzuki, T Akutagawa, T Hasegawa, H Tachibana, M Matsumoto, S Horiuchi, H Ikegami, H Yamochi, G Saito
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 327 83 - 86 1058-725X 1999 [Refereed][Not invited]
     
    A series of donors and accepters are synthesized and, by combing these molecules, Langmuir-Blodgett (LB) films of the charge transfer (CT) complexes are prepared. Ionic CT complexes with partial CT state exhibit high conductivity in the form of LB films. The second nonlinear optical properties of the films are examined using electro-apsorption method.
  • T Akutagawa, Y Nezu, T Hasegawa, K Sugiura, T Nakamura, T Inabe, Y Sakata, AE Underhill
    CHEMICAL COMMUNICATIONS (23) 2599 - 2600 1359-7345 1998/12 [Refereed][Not invited]
     
    The X-ray structural analysis of the title compound revealed the formation of segregated [Ni(dmit)(2)] (dmit = 2-thioxo-1,3-dithiol-4,5-dithiolate) columns and dimeric K-2(+)[PEG]2 (PEG = pentaethylene glycol) supramolecular cations in the crystal; the interaction between K+ and acyclic PEG was found to be weaker that that between K+ and cyclic polyether 18-crown-6.
  • T Akutagawa, T Nakamura, T Inabe, AE Underhill
    THIN SOLID FILMS 331 (1-2) 264 - 271 0040-6090 1998/10 [Refereed][Not invited]
     
    Three kinds of [Wi(dmit)(2)] (dmit = 2-thioxo-1.3-ditiol-4,5-dithiolate) salts containing 12-crown-4, 15-crown-5 or 18-crown-6 were prepared. In the crystal. the crown ethers form supramolecular assemblies in which counter cations are included. Lithium ions are located in the dimeric penta-coordinated ion cavity of [Li+](2)[12-crown-4](3) unit of the [Li+](2)[12-crown-4][Ni(dmit)(2)](7)[acetone](2) crystal. Each Li+ cation is coordinated by four oxygen atoms of a 12-crown-4 molecule and the oxygen of a second 12-crown-4 molecule which form a bridge to a further Li+ cation. Two 15-crown-5 molecules sandwich a NH4+ cation in the salt of [NH4+][15-crown-5](2)[Ni(dmit)(2)]. The NH4+ ion is deca-coordinated by oxygen atoms of 15-crown-5 through weak hydrogen bonding. The cation-crown ether unit forms a dimer resulting in a barrel-like. supramolecular cation. The [NH4+][18-crown-6][Ni(dmit)(2)](3) complex is composed of segregated trimer stacks of Ni(dmit)(2) and isolated ion-captured cavities of [NH4+][18-crown-6]. The NH4+ ion is fully included in the cavity, and is tightly bounded through strong hydrogen bonds to the oxygen atoms of 18-crown-6, resulting in a disk-shaped supramolecular cation. The salts of [Li+](2)[12-crown4](3)[Ni(dmit)(2])7[acetone](2) and [NH4+][18-crown-6][Ni(dmit)(2)](3) show semiconducting behaviour with the room-temperature conductivities of 30 and 0:4 S/cm. respectively. while [NH4+][15-crown-5](2)[Ni(dmit)(2)] is insulating due to the mono-cation state of [Ni(dmit)(2)]. (C) 1998 Elsevier Science S.A. All rights reserved.
  • K Ikegami, S Kuroda, T Akutagawa, T Konuma, T Nakamura, M Matsumoto, S Horiuchi, H Yamochi, G Saito
    THIN SOLID FILMS 327 391 - 394 0040-6090 1998/08 [Refereed][Not invited]
     
    The electron spin resonance (ESR) measurements made on the highly conducting Langmuir-Blodgett (LB) films of a charge-transfer complex of bis(ethylenedioxy)tetrathiafulvalene (BO) and decyltetracyanoquinodimethane (C(10)TCNQ), mixed with icosanoic acid, revealed microscopically the metallic nature of the system in a wide temperature range. Further, an anomalous increase in the ESR linewidth was detected around 140 K. To elucidate the origin of this anomaly, in situ ESR experiments upon annealing at low temperatures have been performed. The temperature dependence of the infrared spectrum has been also measured. The obtained results indicate a possible low-temperature phase transition of the present conducting LB system. (C) 1998 Elsevier Science S.A. All rights reserved.
  • T Konuma, T Akutagawa, T Yumoto, T Nakamura, J Kawamata, K Inoue, T Nakamura, H Tachibana, M Matsumoto, H Ikegami, S Horiuchi, H Yamochi, G Saito
    THIN SOLID FILMS 327 348 - 352 0040-6090 1998/08 [Refereed][Not invited]
     
    Charge-transfer (CT) interactions of tetrathiafulvalene (TTF)-based Langmuir-Blodgett (LB) films with non-centrosymmetrical structure were examined from the viewpoint of nonlinear optics. Five kinds of LB films of CT complexes were prepared using TTF-based electron donors and accepters of 7,7,8,8-tetracyanoquinodimethane and p-benzoquinone derivatives. The difference of the dipole moments between ground and excited states of these LB films was evaluated from the measurements of electroabsorption spectra. (C) 1998 Elsevier Science S.A. All rights reserved.
  • T Nakamura, T Akutagawa, K Honda, AE Underhill, AT Coomber, RH Friend
    NATURE 394 (6689) 159 - 162 0028-0836 1998/07 [Refereed][Not invited]
     
    Metallic behaviour is well known in charge-transfer complexes that contain stacks of planar, partially oxidized (or reduced) pi-conjugated molecules. Electronic conduction occurs in the partially occupied, delocalized pi bands formed by intermolecular orbital overlap, and some of these materials exhibit superconductivity(1,2). Counter-ions, present to achieve charge neutrality, usually play a passive role, although in some cases they couple to the electronic structure, for example by imposing a new structural periodicity (a superlattice) by orientational ordering(1). The development of molecular solids that can simultaneously support the transport of both electrons and ions is important for several fields, including the development of solid-state batteries(3,4), electroluminescent devices(5) and biomimetic systems(6,7). Crown ethers are promising components for such systems, as they provide cavities through which ion motion might occur. Here we report that the charge-transfer salt Li(0.6)(15-crown-5-ether) [Ni(dmit)(2)](2).H(2)O exhibits both electron and ion conductivity: the stacks of the nickel complex (dmit is an organic molecule) provide a pathway for electron conduction, and stacks of the crown ethers provide channels for lithium-ion motion. Evidence for the latter above 250 K is provided by NMR and conductivity studies. We also see evidence for coupling of the electron and ion motions. This compound might serve as a model for the development of other hybrid electronic/ionic conducting materials.
  • K Ikegami, T Nakamura
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 37 (5A) L550 - L552 1998/05 [Refereed][Not invited]
     
    An alkylated N,N'-dicyanoquinonediimine (alkylDCNQI) derivative has been synthesized and the Langmuir-Blodgett (LB) technique has been applied to this material and its mixture with CuI, aiming at the construction of a DCNQI-Cu system in two dimensions. No chemical reaction could be detected for alkylDCNQI-CuI mixed solutions. However, optical measurements have shown that the LB films obtained from the mixture contain a partially reduced DCNQI group, suggesting that a new CT complex is obtained by in situ reaction of alkylDCNQI and CuI at the air-water interface.
  • T Akutagawa, Y Abe, Y Nezu, T Nakamura, M Kataoka, A Yamanaka, K Inoue, T Inabe, CA Christensen, J Becher
    INORGANIC CHEMISTRY 37 (10) 2330 - 2331 0020-1669 1998/05 [Refereed][Not invited]
  • T Akutagawa, T Nakamura, T Inabe, AE Underhill
    JOURNAL OF MATERIALS CHEMISTRY 7 (2) 183 - 185 0959-9428 1997/02 [Refereed][Not invited]
     
    A novel dimeric penta-coordinated ion cavity of [Li+](2) [12-crown-4-ether](3) has been formed in the highly conducting Ni(dmit)(2) salt. This salt showed a room-temperature conductivity of 30 S cm(-1) and exhibited a semiconductor-semiconductor phase transition on the application of pressure or on lowering the temperature.
  • T Nakamura, T Konuma, T Akutagawa
    SYNTHETIC METALS 86 (1-3) 1903 - 1904 0379-6779 1997/02 [Refereed][Not invited]
     
    The Langmuir-Blodgett films were prepared using binary mixture of amphiphilic donors and amphiphilic accepters. Strong intermolecular charge transfer took place in the mixed LB films of 2-hexadecyl-3-heptadecyl-6,7-dimetyltetrathiafulvalene (C16C17DMTTF) and 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (C(18)TCNQ). On the other hand, charge transfer associated with hydrogen bonding was observed in the mixed films of 2-octadecyl-5-methyl-1,4-dihydroxybenzene (C(18)HQ) and 2-octadecyl-5-methyl-1,4-benzaquinone (C(18)Q).
  • T Akutagawa, T Konuma, T Nakamura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 296 383 - 395 1058-725X 1997 [Refereed][Not invited]
     
    Intra- and interlayer charge transfer properties were examined in the mixed and the alternate-layer Langmuir-Blodgett (LB) films of 2-methyl-5-octadecyl-1,4-dihydroxybenzene (C(18)HQ) and 2-methyl-5-octadecyl-1,4-benzoquinone (C(18)Q), which is an example of the ''neutral'' charge transfer complex, and 2-hexadecyl-3-heptadecyl-6,7-dimethyltetrathiafulvalene (C16C17DMTTF) and 2-octadecyl-7,7,8,8 -tetracyanoquinodimethane (C(18)TCNQ) for the ''ionic'' complex. In the former case, intermolecular charge transfer took place in both types of LB films. The charge transfer band between C(18)HQ and C(18)Q appeared at 590 nm even for the bilayer film. The charge transferred state should be accompanied by hydrogen bonding, although the IR spectra revealed that a certain amount of non-hydrogen bonded C=O group exists in the film. The 1:1 mixture of C16C17DMTTF and C(18)TCNQ gave an ionic charge transfer complex in the form of mixed LB films. UV-visible and IR spectra revealed the strong complex formation during the film-forming process. On the other hand, the charge transfer interaction between the adjacent layer of the interleaved LB films essentially did not take place.
  • T Konuma, T Akutagawa, T Nakamura
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 294 209 - 212 1058-725X 1997 [Refereed][Not invited]
     
    The charge transfer (CT) properties were examined in the mixed and the alternate-layer Langmuir-Blodgett (LB) films of 2-methyl-5-octadecyl-1,4-dihydroxybenzene (C(18)HQ) and 2-methyl-5-octadecyl-1,4-benzoquinone (C(18)Q). Intermolecular CT took place in both types of LB films. The CT band between C(18)HQ and C(18)Q appeared at 590 nm suggested the neutral CT state as in the case of unsubstituted quinhydrone. The direction of CT was examined by the polarized spectra. The CT state was accompanied by hydrogen bonding, which was confirmed by the hydrogen bonded and non-hydrogen bonded C=O stretching bands appeared in the IR spectra.
  • T Nakamura, H Isotalo, T Akutagawa, H Tachibana, R Azumi, M Matsumoto, S Horiuchi, H Yamochi, G Saito
    THIN SOLID FILMS 284 508 - 511 0040-6090 1996/09 [Refereed][Not invited]
     
    The conductivity of floating monolayers of a charge transfer complex between bisethylenedioxytetrathiafulvalene (BEDO-TTF) and decyltetracyanoquinodimethane (C(10)TCNQ) mixed with icosanoic acid (C-20) was examined at the air-water interface as a function of the mixing ratio, The conductivity of the film in the region in which the surface pressure increased rapidly showed different behaviour in a.c. and d.c. measurements. This was related to the domain structure of the monolayer. The relationship between the surface pressure and the conductivity is discussed in terms of the surface structure of the monolayer.
  • M Matsumoto, M Tanaka, E Manda, T Nakamura, M Sugi
    LANGMUIR 12 (13) 3365 - 3365 0743-7463 1996/06 [Refereed][Not invited]
  • T Nakamura, H Isotalo, T Akutagawa, H Tachibana, R Azumi, M Matsumoto, S Horiuchi, H Yamochi, G Saito
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 284 235 - 246 1058-725X 1996 [Refereed][Not invited]
     
    The Langmuir-Blodgett (LB) films based on BEDOTTF-C(10)TCNQ (bisethylenedioxytetrathiafulvalene-decyltetracyanoquinodimethane) complex have an essentially metallic nature. Physical properties of the LB films are briefly summarised in addition to those of the monolayers at the air-water interface.
  • T Akutagawa, G Saito, T Nakamura, KI Sakaguchi, M Kusunoki
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS 276 257 - 266 1058-725X 1996 [Refereed][Not invited]
     
    The characters of hydrogen-bond of 2,2'-bi-1H-imidazole (H2BIM) system were examined from a viewpoint of the proton-transfer (PT) and electron-transfer (CT) interactions. To make the effects of the dibenzo substitution of H2BIM molecule clear, we prepared the charge-transfer complexes of dibenzo-2,2'-bi-1H-imidazole (H2BBIM) and H2BIM systems with 7,7,8,8-tetracyanoquinodimethane (TCNQ). The one-dimensional column of TCNQ was confirmed by the crystal structural analysis, however, the packing forms of the H2BIM and H2BBIM systems were entirely different to each other. The H2BBIM system in the TCNQ complex formed the one-dimensional column which is parallel to the TCNQ stack, while the H2BIM system was constructed by the hydrogen-bonded dimer unit along the perpendicular direction to the TCNQ column.
  • R Azumi, K Honda, M Goto, J Akimoto, Y Oosawa, H Tachibana, T Nakamura, M Tanaka, M Matsumoto
    ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 51 2534 - 2537 0108-2701 1995/12 [Refereed][Not invited]
     
    An aromatic cation-based perovskite-type layered crystal of bis(4-nitroanilinium) tetrachlorocadmate, (C6H7N2O2)(2)[CdCl4], was obtained. X-ray diffraction analysis of a single crystal revealed it to have a layered structure consisting of alternating organic bilayers and inorganic sheets. Cd ions and Cl anions form six-coordinate octahedra whose equatorial corner anions are shared with the neighbouring octahedra, The organic bilayer has a 'tail-to-tail' structure, showing that the molecular arrangement is mainly determined by the inorganic layer structure, not by the intermolecular dipolar interaction of the 'push-pull' type molecule.
  • H Matsuzaki, K Ogasawara, T Ishiguro, Y Nogami, M Taoda, H Tachibana, M Matsumoto, T Nakamura
    SYNTHETIC METALS 74 (3) 251 - 255 0379-6779 1995/10 [Refereed][Not invited]
     
    The structure of the conductive Langmuir-Blodgett (LB) film consisting of tridecylmethylammonium-Au(dmit)(2) (3C10-Au) and arachidic acid is studied by the X-ray diffraction method and atomic force microscopy (AFM). The electrochemically ClO4--doped film is found to possess four phases with different interlayer spacings by the X-ray diffraction method. The intralayer molecular arrangement is found for the 3C10-Au matrix by AFM.
  • K IKEGAMI, S KURODA, M MATSUMOTO, T NAKAMURA
    JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 34 (9B) L1227 - L1229 0021-4922 1995/09 [Refereed][Not invited]
     
    Various doping methods were used in order to realize the charge transfer between C-60 molecules and alkali-metal atoms in the Langmuir-Blodgett structure. ESR measurements have clearly indicated the charge transfer the samples heated with RbN3 powder. The development of the metallic region in these films, possibly in the form of o-Rb1C60, has been indicated, for the first time, by the obtained Pauli-like spin susceptibility and the Elliott-like ESR linewidth. Furthermore, hysteresis was observed in the low-magnetic-field microwave absorption signal (LFS) for a sample, showing the appearance of the superconducting phase with T-c approximate to 23 K in the sample tube.
  • K IKEGAMI, S KURODA, T NAKAMURA, R AZUMI, G YUNOME, M MATSUMOTO, S HORIUCHI, H YAMOCHI, G SAITO
    SYNTHETIC METALS 71 (1-3) 1909 - 1912 0379-6779 1995/04 [Refereed][Not invited]
     
    ESR and IR absorption measurements have been performed on Langmuir-Blodgett (LR) films based on a charge-transfer complex of bis(ethylenedioxy)tetrathiafulvalene (BO) and decyltetracyanoquinodimethane. Analyses of the anisotropic ESR and IR spectra have provided quantitative structural information of the system, which is consistent with the reported high conductivity of the films. The temperature dependent ESR spectra have clearly indicated that the system contains metallic domains, whose spin susceptibility is dominated by the Pauli susceptibility due to the conduction electrons on the BO stacks.
  • T NAKAMURA, G YUNOME, M MATSUMOTO, YF MIURA, S HORIUCHI, H YAMOCHI, G SAITO, H ISOTALO, H STUBB
    SYNTHETIC METALS 71 (1-3) 1993 - 1996 0379-6779 1995/04 [Refereed][Not invited]
     
    The conductivity of the Langmuir-Blodgett (LB) films was examined in terms of a granular structure. The conductivity of bis(ethylenedioxy)tetrathiafulvalene-dec (BO-C(10)TCNQ) LB film was well fitted by the formula, sigma = AT(alpha)p(-E(a)/kT), where the behavior is determined by the semiconducting domain boundaries in the granular-structured film. The metallic nature of the domains was revealed by thermoelectric power measurements: the temperature dependence of the thermoelectric power was almost linear with T. The temperature dependence of the conductivity in tridecylmethylammonium-Au(dmit)(2)(3C10-Au) LB film is well explained by a linear combination of Sheng's model and common metal, R = C(1)exp[T-1/(T+T-0)] + C2T. The conduction was governed by the fluctuation-induced tunneling between metallic domains.
  • H ISOTALO, G YUNOME, R AZUMI, M MATSUMOTO, T NAKAMURA, S HORIUCHI, H YAMOCHI, G SAITO
    SYNTHETIC METALS 70 (1-3) 1229 - 1230 0379-6779 1995/03 [Refereed][Not invited]
     
    The conductivity as a function of pressure of bis(ethylenedioxy)tetrathiafulvalene 2-decyl-7,7,8,8-tetracyanoquinodimethane mono/multilayer film is reported, First conductivity is measured on the water in the Langmuir-Blodgett trough starting from separate molecules. Secondly monolayers were collected on a solid substrate and separate conductivity measurements under hydrostatic pressure (0 - 14.5 kbar) were made. The ambient pressure conductivity of the 20 monolayer films increased more than one order of magnitude from that of the monolayer conductivity at the air/water interface: similar to 0.6 S/cm. The conductivity was further increased by the hydrostatic pressure (similar to 2 at 10 kbar). At the same time the temperature of the maximum conductivity begun to shift to higher temperatures after 6 - 8 kbar. Thermal fluctuation induced tunnelling model describes well the conductivity behaviour under hydrostatic pressure at low temperatures.
  • T NAKAMURA, AE UNDERHILL, AT COOMBER, RH FRIEND, H TAJIMA, A KOBAYASHI, H KOBAYSHI
    SYNTHETIC METALS 70 (1-3) 1061 - 1062 0379-6779 1995/03 [Refereed][Not invited]
     
    The structure and physical properties of TPP(tetraphenylghosphonium)(1/3)[Ni(dmit)(2)] complex were examined. The crystal has a layered structure where the conducting sheets of the dmit complex are separated by the layers of the large counter cation. Within the layer, two of the three Ni(dmit)(2) species form a dimer which stacks in [010] direction. The remaining Ni(dmit)(2) unit is disposed almost perpendicular to the stack and separates adjacent columns of Ni(dmit)(2) dimers. The crystal shows a room-temperature conductivity of ca. 10 S/cm along the long axis (column direction) and a semiconducting temperature dependence below room temperature. The in-plane anisotropy of conductivity was of the order of 1:100. The magnetic susceptibility measurement showed Curie-like behavior below room temperature.
  • M MATSUMOTO, H TACHIBANA, R AZUMI, M TANAKA, T NAKAMURA, G YUNOME, M ABE, S YAMAGO, E NAKAMURA
    LANGMUIR 11 (2) 660 - 665 0743-7463 1995/02 [Refereed][Not invited]
     
    An amphiphilic C-60 molecule with a substituent having a hydrophilic carboxylic group at the end was found to form a monolayer at the air-water interface and the structure of the Langmuir-Blodgett (LB) film (Z-type) was elucidated. The shortest distance between the C-60 was estimated to be 0.95 nm using a limiting area per molecule of 0.78 nm(2) at the air-water interface, assuming the close packing of the C-60 moiety in two dimensions. Adjacent C-60 moieties have an electronic interaction which was shown in the red-shift of the characteristic bands in the UV/vis absorption spectrum of the LB film compared with that of a solution spectrum. Several lines of evidence suggested that the molecule has an oblique orientation in the LB film and exists in a pairwise manner due to the dimer formation of the carboxylic groups within a monolayer, not between the adjacent monolayers. The AFM observations revealed that the surface of a single-layer LB film, which consists of domains of ca. 0.1 mu m in diameter, is rather smooth and that the undulation is +/-1 nm for most of the surface except for defects such as vacancy and bilayer regions. The area fractions of the monolayer, the vacancy, and the bilayer regions were estimated to be 88 +/- 7, 7 +/- 5, 5 +/- 3%, respectively. The layer structure was also confirmed using X-ray diffraction analyses which indicate the repeat distance of ca. 2.6 nm along the surface normal of the multilayer LB film.
  • T NAKAMURA, AE UNDERHILL, AT COOMBER, RH FRIEND, H TAJIMA, A KOBAYASHI, H KOBAYASHI
    INORGANIC CHEMISTRY 34 (4) 870 - 876 0020-1669 1995/02 [Refereed][Not invited]
     
    Crystals of TPP-Ni[(dmit)(2)](3) (TPP = tetraphenylphosphonium, dmit = 2-thioxo-1,3-dithiol-4,5-dithiolate) were prepared. The structure of the crystal was determined as follows: monoclinic C2/c; a = 18.086(3) Angstrom, b = 7.184(2) Angstrom, c = 45.838(6) Angstrom, beta = 92.59(1)degrees, V = 5950(2) Angstrom(3), and Z = 4. In the crystal, the large counteractions separate the conducting sheet of Ni(dmit)(2) anions. Within the conducting sheet, two of the three Ni(dmit)(2) anions form columns, and remaining the Ni(dmit)(2) anion fills the spaces between the columns. The molecular plane of the Ni(dmit)(2) anions in the column is almost perpendicular to that of isolated Ni(dmit)(2). The electrical conductivity was nearly one-dimensional with the highest conductivity being observed parallel to the column direction. The inplane anisotropy of the conductivity was ca. 1:100. The crystal exhibited a conductivity of 10 S/cm at room temperature and semiconducting behavior at lower temperatures. Activation energies of 0.035 and 0.036 eV, respectively, were observed below and above 125 K. A deviation from Arrhenius behavior was observed above 160 K. The effect of pressure was relatively small. The crossover point between the two semiconducting regimes shifted to 80 K at 7 kbar and the activation energies decreased to 0.011 and 0.036 eV, respectively. The thermoelectric power was negative at room temperature in the column direction and showed an activation-type behavior with the crossover point around 125 K. Analysis of the reflectance spectra of the salt indicated that the gap was smaller than 0.09 eV, which is consistent with that of conductivity measurements and that the crystal is not exactly one-dimensional. The magnetic susceptibility obeyed the Curie-Weiss law below room temperature and one spin per three Ni(dmit)(2) units was calculated from the Curie constant. The distribution of electrons in the crystal is discussed.
  • H ISOTALO, J PALOHEIMO, YF MIURA, R AZUMI, M MATSUMOTO, T NAKAMURA
    PHYSICAL REVIEW B 51 (3) 1809 - 1816 0163-1829 1995/01 [Refereed][Not invited]
  • M TANAKA, R AZUMI, H TACHIBANA, T NAKAMURA, Y KAWABATA, M MATSUMOTO, T MIYASAKA, W TAGAKI, H NAKAHARA, K FUKUDA
    THIN SOLID FILMS 244 (1-2) 832 - 835 0040-6090 1994/05 [Refereed][Not invited]
     
    Recognition properties of the monolayers of amphiphilic cyclodextrins (CDs) at the air-water interface were investigated by using the Langmuir-Blodgett technique. The CD having amino groups interacted with water-soluble azobenzene, exhibiting an increase in area per molecule with repeated compression and expansion of the monolayer. By introducing one or three isomers of water-soluble azobenzene into the subphase after the formation of the CD monolayers, the amounts of the incorporated. azobenzene were obtained by the subsequent transfer of the monolayers. The results indicate that the CD cavity is not the only binding site for azobenzene and that the amounts of the incorporated azobenzene are governed not just by the relationship between the cavity size and the shape of the azobenzene molecule.
  • K KANAZAWA, H NAKANISHI, Y ISHIZUKA, T NAKAMURA, M MATSUMOTO
    FULLERENE SCIENCE AND TECHNOLOGY 2 (2) 189 - 194 1064-122X 1994 [Refereed][Not invited]
     
    NMR measurements have shown that C60 forms inclusion complexes with gamma-CD in aqueous solution at high temperatures but does not form the complexes with alpha-CD and beta-CD. The H-1 NMR spectral analyses indicate that in the complex, the C60 molecule intrudes into the hydrophobic cavity of gamma-CD.
  • T NAKAMURA, G YUNOME, R AZUMI, M TANAKA, M YUMURA, M MATSUMOTO, S HORIUCHI, H YAMOCHI, G SAITO
    SYNTHETIC METALS 57 (1) 3853 - 3858 0379-6779 1993/04 [Refereed][Not invited]
     
    The LB films of the charge transfer complexes of oxygen-containing BEDT-TTF type donor bisethylenedioxytetrathiafulvalene (BO) and long-chain derivatives of tetracyanoquinodimethane (C(n)TCNQ) are prepared with and without matrix molecules. The measurements of pi-A isotherm for the complex-icosanoic acid mixed system indicated the formation of mixed monolayers at the air-water interface. This was confirmed by the AFM measurements showing a granular structure of the film with the grain size of 100 nm in diameter and 3-4 nm in height. These grains are probably attributable to the BO complex. The conductivity of the LB films were strongly affected by the film-deposition method, the spreading solvent and the matrix. The mixed LB films of BO-C10TCNQ and BO-C14TCNQ with icosanoic acid under suitable conditions showed conductivities as high as 10 and 3 S/cm, respectively. The former LB film showed a metallic temperature dependence of conductivity down to 250 K. The conduction mechanism is discussed in terms of the film granuality.
  • T NAKAMURA, H TACHIBANA, M YUMURA, M MATSUMOTO, W TAGAKI
    SYNTHETIC METALS 56 (2-3) 3131 - 3136 0379-6779 1993/04 [Refereed][Not invited]
     
    Langmuir-Blodgett (LB) films Of the fullerene (C60) were formed with a variety of matrices. The pure C60 formed a collapsed film at the air-water interface and the transferred film had an inhomogeneous surface. By mixing with icosanoic acid, the monolayers were transferred onto substrates with good quality and the resultant LB films had a smooth surface. The 1:1 mixture with dioctadecyldimethylammonium-ClO4 was deposited as Z-type film onto substrates. The film is, however, composed of doughnut-shaped aggregates for a single-layered sample. Multilayered samples had undulations of ca. 100 nm. The absorption spectra of both of the mixed films were in good agreement with those of evaporated films. The LB films with a long-alkyl gamma-cyclodextrin were also examined.
  • K AWAGA, T INABE, Y MARUYAMA, T NAKAMURA, M MATSUMOTO
    SYNTHETIC METALS 56 (2-3) 3311 - 3316 0379-6779 1993/04 [Refereed][Not invited]
     
    Magnetic properties and crystal structures of pyridyl and pyridinium alpha-nitronyl notroxides have been studied. The intermolecular magnetic coupling is ferromagnetic in the crystal of p-pyridyl alpha-nitronyl nitroxide (PYNN), while it is antiferromagnetic in m- or o-PYNN. The ferromagnetic properties of p-PYNN can be understood in terms of an one-dimensional (1D) ferromagnetic chain which is consistent with the molecular arrangement in the crystal. The temperature dependence of the magnetic susceptibilities of the m- and p-N-methylpyridinium alpha-nitronyl nitroxide (MPYNN) iodide salts are well fitted by the singlet-triplet model, although their intradimer magnetic couplings are opposites: it is ferromagnetic in m-MPYNN and it is antiferromagnetic in p-MPYNN. X-ray crystal analysis has been carried out using a stable crystal, m-MPYNN.(BF4)x.I1-x (x=0.72), showing that the molecules exist as a dimer, and the dimer units form a 2D triangular lattice
  • M YUMURA, T NAKAMURA, M MATSUMOTO, S OHSHIMA, Y KURIKI, K HONDA, M KURAHASHI, YF MIURA
    SYNTHETIC METALS 57 (1) 3865 - 3870 0379-6779 1993/04 [Refereed][Not invited]
     
    The atomic force microscope (AFM) was used to obtain the images of the LB film of tridecylmethylammonium-Au(dmit)2 complex mixed with icosanoic acid. A single-layered sample of the as-deposited LB film revealed a heterogeneous structure with very thin plate-like crystallites of the order of mum distributed in the film surface. The height of the crystallite was about 18 nm measured from the planar region in which a monolayer of icosanoic acid was assumed to be present. This thickness corresponded to a stacking of ca. 10 molecules of Au(dmit)2 with each of the molecular plane almost parallel to the film surface, taking into account the molecular arrangement in a single crystal. No epitaxial deposition was observed for a multilayered sample, which was shown by the almost random stacking of the plate-like crystallites. The AFM image changed with the electrochemical oxidation that was necessary to make the film conductive. The blurring of the outline of the plate-like crystallites was observed, suggesting a structural change of the crystallites accompanied by the electrochemical oxidation.
  • T AKATSUKA, H TANAKA, J TOYAMA, T NAKAMURA, M MATSUMOTO, Y KAWABATA
    SYNTHETIC METALS 57 (1) 3859 - 3864 0379-6779 1993/04 [Refereed][Not invited]
     
    The mechanism of liquid crystal alignment on pyrolyzed polyimide Langmuir-Blodgett (PPI LB) films was investigated. Structural change of polyimide LB films caused by the pyrolysis was examined by monitoring the in-plane anisotropy of characteristic four vibrational bands. Before the pyrolysis, the polymer chain aligned preferentially along the dipping direction. The pyrolysis at 400-degrees-C caused the polymer chain to align more along the dipping direction. The C=O group of the imide ring was suggested to take a more random orientation after the heat treatment, which may be caused by the fission of the C-N bond of the imide ring. These four peaks disappeared when the pyrolyzing temperature was above 600-degrees-C. Microcrystals, several nm in size, were observed for a 201-layered PPI LB film pyrolyzed at 1000-degrees-C by TEM. The distribution of the lattice spacing and the distortion of the layered structure indicated the incomplete graphitization in the film, which was supported by the observed lattice spacings larger than 0.34 nm expected for a graphite. The molecular arrangement was suggested to be responsible for the liquid crystal alignment on the PPI LB films.
  • K IKEGAMI, S KURODA, M SUGI, T NAKAMURA, M MATSUMOTO, H TACHIBANA, Y KAWABATA
    SYNTHETIC METALS 56 (1) 1899 - 1904 0379-6779 1993/03 [Refereed][Not invited]
     
    The temperature dependent spin susceptibility of the LB films of a TCNQ salt with an alkylpyridinium was found to be explained by the random-exchange Heisenberg antiferromagnetic chain model, indicating the development of ID spin chains in the system. The ESR spectra of the films at the X and K bands show clear out-of-plane anisotropy. The analysis of these line shapes using the spectrum simulation method reveals that the linewidth anisotropy is dominated by the exchange-narrowed secular dipolar width peculiar to quasi-ID spin systems. This result provides further evidence for the development of the ID columnar structure of TCNQ molecules, and suggests that the chain axis lies in the film plane. In addition, the analysis yields the orientation of TCNQ molecules, which is consistent with the formation of the columnar structure.
  • MAGNETIC-PROPERTIES AND CRYSTAL-STRUCTURES OF 1,5-BIS(4-NITROPHENYL)-3-T-BUTYLVERDAZYL RADICALS
    T NAKAMURA, K AWAGA, T INABE, K HONDA, M MATSUMOTO, Y MARUYAMA
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 232 465 - 472 0140-6566 1993 [Refereed][Not invited]
     
    The crystal structures and magnetic properties of 1,5-bis(4-nitrophenyl) derivatives of verdazyl free radicals (1-3) are described. The magnetic properties of 1 are explained by the singlet-triplet model with the coupling constant 2J(AF)/K(B) = 93 K. The susceptibility of 2 was fitted by the Bonner-Fisher model with J(AF)/k(B) = 5.6 K. These results were in good agreement with the molecular arrangement in the crystal. The susceptibility of 3 obeyed the Curie-Weiss law with the Weiss constant theta = -0.5 K. The magnetic intermolecular interactions were significantly suppressed by introducing the substituent at the 6-position.
  • K AWAGA, T INABE, T NAKAMURA, M MATSUMOTO, Y MARUYAMA
    MOLECULAR CRYSTALS AND LIQUID CRYSTALS 232 69 - 78 0140-6566 1993 [Refereed][Not invited]
     
    Magnetic properties and crystal structures of N-alkylpyridinium alpha-nitronyl nitroxide cation radicals, has been studied. Some of them have been found to have ferromagnetic intermolecular interaction which are much stronger than those in the alpha-nitronyl nitroxide free radicals. Further, a m-N-methylpridinium alpha-nitronyl nitroxide salt crystallizes into a trigonal space group with a triangular lattice, which includes both of the ferromagnetic and antiferromagnetic interactions.
  • H TACHIBANA, Y NISHIO, T NAKAMURA, M MATSUMOTO, E MANDA, H NIINO, A YABE, Y KAWABATA
    THIN SOLID FILMS 210 (1-2) 293 - 295 0040-6090 1992/04 [Refereed][Not invited]
     
    Photochemical switching phenomena are very sensitive to the length of alkyl chain of the transmission unit. Conversion to the cis isomer in the photoisomerization of azobenzene in the switching unit increased with an increase in the length of the transmission unit. Change in conductivity of the LB films, however, showed a complicated behavior with variation in the length of the transmission unit.
  • M MATSUMOTO, M TANAKA, R AZUMI, H TACHIBANA, T NAKAMURA, Y KAWABATA, T MIYASAKA, W TAGAKI, H NAKAHARA, K FUKUDA
    THIN SOLID FILMS 210 (1-2) 803 - 805 0040-6090 1992/04 [Refereed][Not invited]
     
    Azobenzene derivatives were recognized by amphiphilic cyclodextrins (CDs) in LB films. The amount of ortho isomer of methyl red incorporated in the LB film was very small for any of the CDs used, whereas considerable amounts of the para and meta isomers were kept in the films, most of which were included in the cavity. The size of the cavity of the CDs was reflected in the out-of-plane anisotropy and the peak shift in the polarized absorption spectra of the LB films of the CDs containing the azobenzene derivatives.
  • K IKEGAMI, S KURODA, Y TABE, K SAITO, M SAITO, M SUGI, T NAKAMURA, H TACHIBANA, M MATSUMOTO, Y KAWABATA
    THIN SOLID FILMS 210 (1-2) 303 - 305 0040-6090 1992/04 [Refereed][Not invited]
     
    The molecular orientation in Langmuir-Blodgett films of a 3:2 charge-transfer complex of tetramethyltetrathiafulvalene and tetradecyltetracyanoquinodimethane [(TMTTF)3(C14TCNQ)2] is discussed from the observed anisotropic ESR spectra at the K and X bands. Anisotropy of g values shows the existence of in-plane preferential orientation of the complex with the p-pi-orbital axis and long axis of the TMTTF molecules parallel and perpendicular to the dipping direction of the substrate, respectively. The effect of aging on ESR spectra of the system is also reported. The decrease in the difference in linewidth at the K and X bands observed for the external magnetic field normal to the film plane indicates the reduction in the degree of misorientation of the molecules by aging.
  • T AKATSUKA, H TANAKA, J TOYAMA, T NAKAMURA, M MATSUMOTO, Y KAWABATA
    THIN SOLID FILMS 210 (1-2) 458 - 460 0040-6090 1992/04 [Refereed][Not invited]
     
    Dependence of the conductivity on the pyrolyzing temperature of pyrolyzed polyimide Langmuir-Blodgett (PPI LB) films was examined and compared with the results of absorption spectra of the films. The PPI LB films pyrolyzed at 1000-degrees-C showed good electro-optic properties as electrodes and aligning films for twisted nematic liquid crystal cells.
  • YF MIURA, M TAKENAGA, A KASAI, T NAKAMURA, Y NISHIO, M MATSUMOTO, Y KAWABATA
    THIN SOLID FILMS 210 (1-2) 306 - 308 0040-6090 1992/04 [Refereed][Not invited]
     
    Thermoelectric power in highly conductive Langmuir-Blodgett films of tridecylmethylammonium-Au(dmit)2(sigma(RT) 30-50 S/cm) was examined. The metallic nature of this material is suggested from the results of the thermoelectric power. The resistivity increased with aging, however the thermoelectric power was invariant. These results suggest that the metallic nature of the film is preserved after aging. The newly developed conductive LB films of didecyldimethylammonium-Pd(dmit)2 showed a high conductivity of 5.1 S/cm at room temperature. From the temperature dependence of the conductivity, semiconductor-like transport was suggested.
  • T NAKAMURA, M MATSUMOTO, H TACHIBANA, M TANAKA, Y KAWABATA, YF MIURA
    SYNTHETIC METALS 42 (1-2) 1487 - 1490 0379-6779 1991/05 [Refereed][Not invited]
     
    The structure and physical properties of highly conductive Langmuir-Blodgett films of tridecylmethylammonium-Au(dmit)2 (3C10-Au) are described. The layered structure of the film was revealed by X-ray diffraction method. The d-spacing was 1.9 and 2.7 nm for the film before and after oxidation, respectively. The conductivity of the LB films of 3C10-Au after oxidation was 30 - 50 S/cm at room temperature, showing a metallic temperature dependence down to around 150 K.
  • T AKATSUKA, H TANAKA, J TOYAMA, T NAKAMURA, Y KAWABATA
    SYNTHETIC METALS 42 (1-2) 1515 - 1518 0379-6779 1991/05 [Refereed][Not invited]
     
    The structure and electrical transport properties of the Langmuir-Blodgett (LB) films of polyimide are described. The highly conductive LB films were obtained by the pyrolysis of polyimide LB films at 1000-degrees-C in vacuum or under nitrogen atmosphere. The films showed the conductivity of as high as 300 S/cm, depending on the thickness of the precursor films. The surface of the film was smooth and uniform revealed by SEM. The films were stable under ambient conditions over months.
  • K IKEGAMI, S KURODA, Y TABE, K SAITO, M SAITO, M SUGI, H TACHIBANA, T NAKAMURA, Y KAWABATA
    JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 90-1 239 - 240 0304-8853 1990/12 [Refereed][Not invited]
     
    ESR measurements were performed on Langmuir-Blodgett (LB) films of 1:2 complex of long-chain pyridinium and TCNQ, where the long chain contains photo-active azobenzene group. Observed temperature dependence of the spin susceptibility is consistent with the formation of the random-exchange Heisenberg antiferromagnetic chains in the system.
  • K IKEGAMI, SI KURODA, K SAITO, M SAITO, M SUGI, T NAKAMURA, H TACHIBANA, M MATSUMOTO, Y KAWABATA
    THIN SOLID FILMS 179 245 - 250 0040-6090 1989/11 [Refereed][Not invited]
  • PHOTORESPONSIVE CONDUCTIVITY IN LANGMUIR-BLODGETT FILMS
    H TACHIBANA, A GOTO, T NAKAMURA, M MATSUMOTO, E MANDA, H NIINO, A YABE, Y KAWABATA
    THIN SOLID FILMS 179 207 - 213 0040-6090 1989/11 [Refereed][Not invited]
  • H TACHIBANA, H KOMIZU, T NAKAMURA, M MATSUMOTO, E MANDA, Y KAWABATA, T KATO
    THIN SOLID FILMS 179 239 - 243 0040-6090 1989/11 [Refereed][Not invited]
  • T NAKAMURA, M MATSUMOTO, H TACHIBANA, M TANAKA, E MANDA, Y KAWABATA
    THIN SOLID FILMS 178 413 - 419 0040-6090 1989/11 [Refereed][Not invited]
  • T NAKAMURA, H TANAKA, K KOJIMA, M MATSUMOTO, H TACHIBANA, M TANAKA, Y KAWABATA
    THIN SOLID FILMS 179 183 - 189 0040-6090 1989/11 [Refereed][Not invited]
  • K IKEGAMI, SI KURODA, K SAITO, M SAITO, M SUGI, T NAKAMURA, M MATSUMOTO, Y KAWABATA, G SAITO
    THIN SOLID FILMS 179 177 - 182 0040-6090 1989/11 [Refereed][Not invited]
  • M MATSUMOTO, H MIYASAKA, T SEKIGUCHI, M TANAKA, H TACHIBANA, T NAKAMURA, E MANDA, Y KAWABATA, M SUGI
    THIN SOLID FILMS 178 367 - 372 0040-6090 1989/11 [Refereed][Not invited]

Books etc

  • 『自己組織化ナノマテリアル』
    フロンティア出版 2007
  • 『進化する有機半導体』
    エヌ・ティー・エス 2006

MISC

  • Ken-ichi Sakai, Tomoyuki Akutagawa, Takayoshi Nakamura  EUROPEAN JOURNAL OF INORGANIC CHEMISTRY  (1)  116  -120  2011/01  [Not refereed][Not invited]
     
    Using the Cu-II-imidazole(Him) complex [Cu(Him)(4)Cl]Cl as the starting material, the imidazolate (im)- and azide-bridged Cu-II coordination polymer [Cu-3(Him)(4)(im)(2)(N-3)(4)](n) was successfully obtained. Single-crystal X-ray analysis revealed that it possesses an im-bridged linear-chain structure consisting of alternating dinuclear units with a symmetric endon azide-bridged [Cu(mu(1,1)-N-3)(2)Cu](2+) core and mononuclear units. All of the Cu ions adopt a square pyramidal geometry with an azide at the Jahn-Teller elongated apical position. Some of the azides act as end-to-end interchain bridging ligands from the mononuclear unit to the nearest neighbouring dinuclear unit of the adjacent chain forming a two-dimensional network. Temperature-variable magnetic susceptibility measurements showed that it exhibits one-dimensional ferrimagnetic-like behaviour, which can be ascribed to two types of exchange couplings with opposite signs, namely a weak ferromagnetic coupling through the end-on azide bridges within the dinuclear units and a stronger antiferromagnetic coupling through the im bridges between the di- and the mononuclear units.
  • Yuki Noda, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura  PHYSICAL REVIEW B  82-  (20)  205420/1-205420/6  2010/11  [Not refereed][Not invited]
     
    Gold nanoparticles stabilized by meso-5,10,15,20-tetrakis(2-thienyl)porphyrin (2T) via physisorption (2T-AuNP) were synthesized, and the electronic transport of assemblies of these films was studied. The adsorption mechanism of 2T on gold nanoparticles was examined using UV-vis-NIR, IR, Raman, and (1)H-NMR spectroscopy, which showed no evidence of any covalent bonding between 2T and the gold nanoparticles. In temperature-dependent resistivity measurements, a crossover from thermally assisted hopping to Efros-Shklovskii-type variable-range hopping (ES-VRH) was observed around 50 K on decreasing the temperature. At higher temperatures, the 2T-AuNP assembly structure followed an Arrhenius plot (E(A)=15 meV) with ohmic I-V characteristics at each measurement point. On the other hand, the activation energy at lower temperatures decreased nonlinearly in a T(-1) plot, and the logarithm of the resistance obeyed a T(-1/2) law, corresponding to an ES-VRH mechanism, which is predicted for disordered materials as a variable-range hopping mechanism influenced by strong Coulomb interactions. ES-VRH behavior has been observed previously in saturated molecule/gold nanoparticle assemblies and was confirmed in our 2T-AuNP assembly. Electronically active conjugated molecules were successfully incorporated between the nanoparticles, keeping the electronic structure of the gold nanoparticle and 2T moieties isolated from each other.
  • Qiong Ye, Tomoyuki Akutagawa, Shin-ichiro Noro, Takayoshi Nakamura, Ren-Gen Xiong  CRYSTAL GROWTH & DESIGN  10-  (11)  4856  -4860  2010/11  [Not refereed][Not invited]
     
    Supramolecular cationic structures of (CHDA(2+))(DCH[18]crown-6)(2) were introduced into [Ni(dmit)(2)](-) salts (where CHDA(2+), DCH[18]crown-6, and dmit(2-) represent cis-cyclohexane-1,4-diammonium, meso-dicyclohexanol[18]crown-6. and 2-thioxo-1,3-dithiole-4,5-dithiolate, respectively). The crystal polymorphs of (CHDA(2+))(DCH[18]crown-6)(2)[Ni(dmit)(2)](2) (crystals 1 and 2) within the same crystallization batch were classified in the space groups P2(1)/n (1) and PT (2). The N-11(+)similar to O hydrogen-bonding interactions between the axial- and equatorial-ammonium moieties of the CHDA(2+) cation and the oxygen atoms of DCH[18]crown-6 yielded a sandwich-type 1:2 adduct of the supramolecular cation in 1 and 2. Although the overall cationic structures in 1 and 2 resembled one another, the [Ni(dmit)(2)](-) anion arrangements were distinctively different from each other. The lateral [Ni(dmit)(2)](-) dimer along the short axis of the anion was observed in 1. whereas two types of [Ni(dmit)(2)](-) pi-dimer existed independently in 2. The weak intermolecular interactions between the [Ni(dmit)(2)](-) anions in 1 was reflected by the temperature dependent magnetic susceptibility, which followed the Curie-Weiss model. For 2, two different magnetic exchange energies arising from the different strengths of the pi-dimer units dominated the magnetic properties.
  • Qiong Ye, Tomoyuki Akutagawa, Toru Endo, Shin-ichiro Noro, Takayoshi Nakamura, Ren-Gen Xiong  INORGANIC CHEMISTRY  49-  (18)  8591  -8600  2010/09  [Not refereed][Not invited]
     
    Structurally flexible (1R,2R)-cyclohexanediammonium (CHDA(2+)) dication formed hydrogen-bonding supramolecules with [18]crown-6, benzo[18]crown-6 (B[18]crown-6), dibenzo[18]crown-6 (DB[18]crown-6), and dicyclohexano-[18]crown-6 (DCH[18]crown-6) in [Ni(dmit)(2)](-) salts (dmit(2-)=2-thioxo-1,3-dithiole-4,5-dithiolate). The two ammonium moieties of CHDA2+ interacted with the crown ethers to form open-mouth-shaped sandwich-type cationic structures of (CHDA(2+))(crown ethers)(2), that is, (CHDA(2+))([18]crown-6)(2)[Ni(dmit)(2)](2)(-) (1), (CHDA(2+))(B[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (2), (CHDA(2+))(DB[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (3), and (CHDA(2+))(DCH[18]crown-6)(2)[Ni(dmit)(2)](2)(-) (4). The chiral structure of CHDA(2+) induced asymmetrical [Ni(dmit)(2)](-) arrangements in the crystals. A large frequency and temperature dependence of the dielectric response was observed in (CHDA(2+)) B[18]crown-6)(2), due to the pendulum motion of the cyclohexane ring along the nitrogen-nitrogen direction of CHDA(2+). Since the inversion center of the [Ni(dmit)(2)](-) arrangements was lost in the unit cell due to the chiral space group, the salts 1-4 showed rather complicated magnetic behaviors. The temperature-dependent magnetic properties of salts 3 and 4 were explained by the sum of the Cube Weiss and singlet-triplet thermal excitation models, with positive (ferromagnetic) and negative (antiferromagnetic) magnetic exchange energies, respectively.
  • Yoko Tatewaki, Shuji Okada, Ryosuke Itagaki, Takayoshi Nakamura, Atsuhiro Fujimori  JOURNAL OF COLLOID AND INTERFACE SCIENCE  343-  (1)  281  -290  2010/03  [Not refereed][Not invited]
     
    We investigated the molecular arrangement and Surface morphology of organized molecular films Of alkylammonium-M bis(1,3-dithiole-2-thione-4,5-dithiolate) ((dmit)(2), M = Ni, Au, and Pd) charge-transfer complexes using the Surface pressure-area (pi-A) isotherm, polarized visible spectroscopy, in-plane and out-of-plane X-ray diffractions (XRD), and atomic force microscopy (AFM). Since Langmuir-Blodgett films of alkylammonium-M(dmit)(2) generally exhibit superconductivity, it may be possible to develop novel electronic molecular devices on the subnanometer scale. In the bulk state, several alkylammonium-M(dmit)(2) molecules Could not form a highly ordered layered Structure along the c-axis and a subcell structure of the alkyl chain in the ab-plane; however, almost all molecules formed a layered structure in the film multilayers. Monolayers of alkylammonium-M(dmit)(2) molecules on the water Surface were extremely condensed. Out-of-plane and in-plane XRD measurements revealed that over a long period, systematic changes occurred in the two-dimensional lattice structure of alkylammonium-M(dmit)(2) molecules and not in their bulk state. These structural changes appear to be Caused by enhancement of the van der Waals interaction among long hydrocarbons and the pi-pi interaction among (dmit)(2) units arranged two dimensionally. In addition, both the molecular arrangement and the Structural morphology of the films showed dependence on the hydrocarbon chain length, number of long alkyl chains, and kind of central metal. In particular, the molecular arrangement of materials having didecyl chains changed drastically and (dmit)(2) units were highly oriented in the ab-plane. Such Structural formations are suggested to significantly influence the stacking Of functional dmit units presiding over the conductive properties. (c) 2010 Published by Elsevier Inc.
  • Takuya Hosokai, Noritaka Mitsuo, Shin-ichiro Noro, Takayoshi Nakamura, Satoshi Kera, Kazuyuki Sakamoto, Nobuo Ueno  CHEMICAL PHYSICS LETTERS  487-  (1-3)  67  -70  2010/02  [Not refereed][Not invited]
     
    We studied the thickness dependence of electronic structure and molecular orientation of neutral, square planar, diamagnetic diradical metal complex, bis(o-diiminobenzosemiquinonate) nickel(II) complexes (Ni(DIBSQ)(2)), thin films grown on a SiO2 substrate by using ultraviolet photoelectron spectroscopy in combination with metastable atom electron spectroscopy. We observed that the small hole-injection barrier of 0.46 eV for the monolayer film, and the barrier increases continuously with the film thickness and becomes larger than the electron-injection barrier. We further found that molecules are oriented with their long-axes nearly perpendicular to the surface both in the monolayer and multilayer films independent of the film thickness. (C) 2010 Elsevier B.V. All rights reserved.
  • Subbalakshmi Jayanty, Tomoyuki Akutagawa, Takayoshi Nakamura  CRYSTENGCOMM  12-  (12)  4087  -4090  2010  [Not refereed][Not invited]
     
    Highly polar 7,7-bis(N, N-dimethylpiperazinium)-8,8-dicyanoquinodimethane (BDPDQ) was introduced into the [Ni(dmit)(2)](-) crystal as a counter cation. The (BDPDQ)[Ni(dmit)(2)](-)(2)(CH3OH) crystal has two independent types of [Ni(dmit)(2)](-) intermolecular interactions; those of pi-dimers and two-dimensional layer. The magnetic properties of the crystal were explained by the sum of two types of intermolecular magnetic interactions that corresponded to singlet-triplet dimer and Curie-Weiss models.
  • Ken-ichi Sakai, Sami Takahashi, Ataru Kobayashi, Tomoyuki Akutagawa, Takayoshi Nakamura, Masaaki Dosen, Masako Kato, Umpei Nagashima  DALTON TRANSACTIONS  39-  (8)  1989  -1995  2010  [Not refereed][Not invited]
     
    Zinc(II)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties. The pyridine complex is strongly fluorescent (fluorescence quantum yield Phi = 0.22), giving rise to a significantly Stokes-shifted spectrum. From its thin film photopumped by a nitrogen gas laser, amplified spontaneous emission was observed. These results suggest that the fluorescence occurs by way of excited-state intramolecular proton-transfer (ESIPT) in the hydrogen bond of hqxc. On the other hand, the DMSO complex shows fluorescent intensity (Phi = 0.08) lower than that of the pyridine complex, and shows normal emission in addition to ESIPT emission. From IR measurements for these complexes, it is concluded that axial ligands influence the hydrogen bond strength of the equatorial hqxc ligand via zinc and thus the ESIPT efficiency.
  • Tomoyuki Akutagawa, Hiroyuki Koshinaka, Qiong Ye, Shin-ichiro Noro, Jun Kawamata, Hiroshi Yamaki, Takayoshi Nakamura  CHEMISTRY-AN ASIAN JOURNAL  5-  (3)  520  -529  2010  [Not refereed][Not invited]
     
    The supramolecular (HOPD+)(DB[18]crown-6) cation, in which HOPD+ and DB[18]crown-6 are o-aminoanilinium and dibenzo[18]crown-6, respectively, was introduced into [Ni(dmit)(2)](-) salts (dmit(2-) = 2-thioxo-1,3-dithiole-4,5 - dithiolate). Conformational polymorphs were observed as tetragonal (HOPD+)(DB[18]crown-6)[Ni(dmit)(2)](-) (1) and monoclinic (HOPD+)(DB[18]crown-6)[Ni(dmit)(2)](-) (2). The ammonium group of HOPD+ in salts 1 and 2 formed the N-H+center dot center dot center dot O hydrogen bonds at the bottom and upper positions of V-shaped DB[1.8]crown-6, respectively, thereby producing a different supramolecular conformation. The [Ni(dmit)(2)](-) anion arrangements in salts 1 and 2 were 4(1)-helical pi stacking and a two-dimensional layer, respectively, depending on the conformation of the supramolecular cations. The magnetic behavior of salts 1 and 2 obeyed the Curie-Weiss law at room temperature with S = 1/2 spin on the [Ni(dmit)(2)](-) anion. However, the g value and line width in the electron resonance spectra of salt 1 showed a magnetic anomaly at 28 K, which was owing to antiferromagnetic ordering in the 4(1)-helical [Ni(dmit)(2)](-) a stack. Large temperature- and frequency-dependent dielectric responses were observed for salt 2 at temperatures above 200 K, whereas no particular dielectric responses were observed in salt 1. The molecular motion of HOPD+ within the cationic layer of salt 2 contributed to the dielectric response, and this was supported by ab initio calculations showing the potential-energy curve for pendulum motion and by the large thermal parameters in the X-ray crystal structure analysis. The fixed (HOPD+)(DB[18]crown-6) arrangement in the crystal of salt 1 was consistent with the small dielectric response. The steric hindrance of the o-amino group of HOPD+ in the supramolecular cation structure yielded the conformational polymorph with different dielectric and magnetic properties.
  • Tomoyuki Akutagawa, Daisuke Sato, Qiong Ye, Toru Endo, Shin-Ichiro Noro, Sadamu Takeda, Takayoshi Nakamura  DALTON TRANSACTIONS  39-  (35)  8219  -8227  2010  [Not refereed][Not invited]
     
    Supramolecular cations of HOPD+([18]crown-6) and HMPD+([18] crown-6) were introduced into [Ni(dmit)(2)](-) salts (HOPD+: o-aminoanilinium, HMPD+: m-aminoanilinium, and dmit(2-): 2-thioxo-1,3-dithiole-4,5-dithiolate). Alternate layers of cations and anions were observed in the two new salts of (HOPD+)([18]crown-6)[Ni(dmit)(2)](-) (1) and (HMPD+)([18] crown-6)[Ni(dmit)(2)](-) (2). From X-ray crystal structural analyses, solid state H-1 nuclear magnetic resonance (NMR) spectra, and dielectric constants, the thermal rotations of [18]crown-6 in both of the (HOPD+)([18]crown-6) and (HMPD+)([18]crown-6) supramolecules occurred at temperatures above similar to 200 K based on the orientational disorder in the crystal structures. The two-fold flip-flop motions of HOPD+ and HMPD+ cations in salts 1 and 2 were suppressed, due to the relatively large potential energy barriers. The [Ni(dmit)(2)](-) anion formed pi-dimer arrangements in both salts, with a layer structure by lateral sulfur-sulfur interatomic contacts. Although the simple dimer model reproduced the magnetic properties of salt 1, the ladder arrangement of the p-dimer in salt 2 yielded the magnetic behavior of a spin-ladder with a spin-gap of 92.5 K. The temperature dependent magnetic susceptibility of salt 2 was well reproduced by the magnetic anisotropy of J(1)/J(2) approximate to 8 between the ladder-leg (J(1): intra-dimer interaction) and ladder-rung (J(2): inter-dimer interaction). The [18] crown-6 supramolecular rotator of (HMPD+)([18] crown-6) was coexistent with the spin-ladder chain of [Ni(dmit)(2)]- anions in salt 2.
  • Tomoyuki Akutagawa, Daisuke Sato, Qiong Ye, Shin-ichiro Noro, Takayoshi Nakamura  DALTON TRANSACTIONS  39-  (9)  2191  -2193  2010  [Not refereed][Not invited]
     
    Ferromagnetic coupling of the [Ni(dmit)(2)](-) anion layer through lateral sulfur -sulfur interactions along the short-axis of the anion was achieved using the flexible supramolecular cation of (m-fluoroanilinium(+))(meso-dicyclohexano[18]crown-6).
  • NORO Shin‐ichiro, AKUTAGAWA Tomoyuki, NAKAMURA Takayoshi  Chemical Communications  46-  (18)  3134  -3136  2010  [Not refereed][Not invited]
  • Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura  CHEMICAL COMMUNICATIONS  46-  (25)  4619  -4621  2010  [Not refereed][Not invited]
     
    The dinuclear Cu(II) complex bridged by a single F- anion has orthogonal Jahn-Teller axes, which induce a ferromagnetic interaction between the intramolecular Cu(II) ions.
  • Hiroyuki Imai, Tomoyuki Akutagawa, Fumito Kudo, Mitsuhiro Ito, Kazuhiro Toyoda, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY  131-  (38)  13578  -+  2009/09  [Not refereed][Not invited]
     
    Single crystals of the nanoscale polyoxomolybdate wheel, Na15Fe3Co16[Mo176O528(H2O)(80)]Cl-27 center dot 450H(2)O, was synthesized by the condensation reaction of Na0.4Co0.8[MoO4]center dot 1.5H(2)O at low pH and in the presence of an iron-based reducing agent, and these crystals were characterized by the synchrotron-based X-ray single crystal analysis, magnetic susceptibility, and ionic conductivity measurements.
  • Toru Endo, Tomoyuki Akutagawa, Teppei Kajiwara, Keiko Kakiuchi, Yoko Tatewaki, Shin-ichiro Noro, Takayoshi Nakamura  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN  82-  (8)  968  -974  2009/08  [Not refereed][Not invited]
     
    Charge-transfer (CT) complexes between ethylenedithio-substituted bis-TTF macrocycle 1a, as an amphiphilic electron donor, and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) derivatives, as electron acceptors, were fabricated as Langmuir-Blodgett (LB) films. For the 1a-F(4)TCNQ LB film deposited at a surface pressure of 5 mN m(-1) onto a substrate surface, the stoichiometry between the donor and acceptor was determined as 1:2 using XPS measurements. In contrast, a donor/acceptor ratio of 1:0.3 was observed for the 1a-Br(2)TCNQ LB film, indicating that a fraction of Br(2)TCNQ was lost during the LB film fort-nation process. Similarity of the round-shaped domains that cover the surfaces of the 1a-Br(2)TCNQ and neutral la LB films indicates the presence of neutral la within the 1a-Br(2)TCNQ LB film. For the (1a(2+))(F(4)TCNQ(-))(2) LB film, the presence of a CN-stretching frequency signifies the formation of a fully ionic electronic ground state. The LB film of 1a-Br(2)TCNQ exhibited a broad absorption at ca. 3 x 10(3) cm(-1), which is characteristic of an intermolecular CT transition for a partial CT state. 1a-Br(2)TCNQ LB film consisted of neutral 1 a and CT complex of 1a-Br(2)TCNQ. The room temperature conductivity of the 1a-Br(2)TCNQ LB film (1.2 x 10(-2) S cm(-1)) was two orders of magnitude higher than that of 1a-F(4)TCNQ (3.9 x 10(-4) S cm(-1)).
  • Shin-ichiro Noro, Daisuke Tanaka, Hirotoshi Sakamoto, Satoru Shimomura, Susumu Kitagawa, Sadamu Takeda, Kazuhiro Uemura, Hidetoshi Kita, Tomoyuki Akutagawa, Takayoshi Nakamura  CHEMISTRY OF MATERIALS  21-  (14)  3346  -3355  2009/07  [Not refereed][Not invited]
     
    Introducing polar Cu-PF6 parts into a coordination framework will open new routes in the fabrication of high-performance and/or novel functional porous materials. We have designed and synthesized the one-dimensional Cu-II coordination polymer [Cu(PF6)(2)(bpetha)(2)](n) (1), with weak and flexible Cu-PF6 parts. 1 shows the property of highly selective adsorption for CO2 and C2H2 gases, which interact with the F atoms of the polar Cu-PF6 parts. Crystallographic characterization of [Cu(PF6)(2)(4-mepy)(4)] (2) with a basic [Cu(PF6)(2)(pyridine)(4)] structure indicates that 2 forms weak Cu-PF6 bonds at its axial sites and the polarity of the surface in 2 is higher than that in alpha-[Ni(NCS)(2)(4-mepy)(4)]. The axial ligand-exchanged frameworks, [Cu(PF6)(1.4)(BF4)(0.6)(bpetha)(2)](n) (3) and {[Cu(bpetha)(2)(DMF)(2)]center dot 2PF(6)}(n) (4), enable us to control the onset pressure and maximum adsorption amount for targeted CO2 gases, showing the first case of finely controlled adsorption properties using one-dimensional porous coordination polymers.
  • Tomoyuki Akutagawa, Kozo Shitagami, Masaki Aonuma, Shin-ichiro Noro, Takayoshi Nakamura  INORGANIC CHEMISTRY  48-  (10)  4454  -4461  2009/05  [Not refereed][Not invited]
     
    Sandwich-type (Cs+)(2)(benzo[18]crown-6)(3) and (Cs+)(dibenzo[18]crown-6)(2) supramolecular cations were introduced as counterions of [Ni(dMit)(2)](-) (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate) anions to induce unique [Ni(dmit)(2)](-) anion (S = 1/2) arrangements and magnetic properties. The magnetic exchange energy ( between the [Ni(dmit)(2)](-) anions was dependent on the mode of the intermolecular interactions. In the case of (Cs+)(2)(benzo[18]crown-6)(3)[Ni(dmit)(2)](-)(2) (1), the asymmetric arrangement of the [Ni(dMit)(2)](-) anions involved the coexistence of a pi-dimer chain along with a two-dimensional layer via lateral S center dot center dot center dot S contacts, in which the magnetic properties of the T-dimer chain and the two-dimensional layer were characterized by antiferromagnetic (J = -5.2 K) and ferromagnetic coupling (Weiss temperature = +1.1 K), respectively. The unique [Ni(dMit)(2)](-) arrangements and magnetic behaviors for crystal 1 can be attributed to the asymmetrical benzo[18]crown-6. In the case of Cs+(dibenzo[18]crown6)(2)[Ni(dmit)(2)](-) (2), however, the formation of the lateral [Ni(dmit)(2)](-) dimer via S center dot center dot center dot S contacts yielded antiferromagnetic coupling corresponding to the dimer model (J = -25.5 K).
  • Tomoyuki Akutagawa, Hiroyuki Koshinaka, Daisuke Sato, Sadamu Takeda, Shin-Ichiro Noro, Hiroyuki Takahashi, Reiji Kumai, Yoshinori Tokura, Takayoshi Nakamura  NATURE MATERIALS  8-  (4)  342  -347  2009/04  [Not refereed][Not invited]
     
    Molecular rotation has attracted much attention with respect to the development of artificial molecular motors, in an attempt to mimic the intelligent and useful functions of biological molecular motors. Random motion of molecular rotators-for example the 180 degrees flip-flop motion of a rotatory unit-causes a rotation of the local structure. Here, we show that such motion is controllable using an external electric field and demonstrate how such molecular rotators can be used as polarization rotation units in ferroelectric molecules. In particular, m-fluoroanilinium forms a hydrogen-bonding assembly with dibenzo[18]crown-6, which was introduced as the counter cation of [Ni(dmit)(2)](-) anions (dmit(2-) = 2-thioxo-1,3-dithiole-4,5-dithiolate). The supramolecular rotator of m-fluoroanilinium exhibited dipole rotation by the application of an electric field, and the crystal showed a ferroelectric transition at 348 K. These findings will open up new strategies for ferroelectric molecules where a chemically designed dipole unit enables control of the nature of the ferroelectric transition temperature.
  • Carsten Streb, Ryo Tsunashima, Donald A. MacLaren, Thomas McGlone, Tomoyuki Akutagawa, Takayoshi Nakamura, Antonino Scandurra, Bruno Pignataro, Nikolaj Gadegaard, Leroy Cronin  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION  48-  (35)  6490  -6493  2009  [Not refereed][Not invited]
  • Shin-ichiro Noro, Taishi Takenobu, Yoshihiro Iwasa, Ho-Chol Chang, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura  ADVANCED MATERIALS  20-  (18)  3399  -+  2008/09  [Not refereed][Not invited]
     
    High and balanced mobilities: Metal-organic thin-film transistors (MOTFTs) that employ metal complexes with narrow band gaps and less pi-conjugated structures are fabricated. These devices show high-performance ambipolar characteristics in comparison with other reported single-component ambipolar TFTs.
  • Shin-ichiro Noro, Nobuhiro Yanai, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura  INORGANIC CHEMISTRY  47-  (16)  7360  -7365  2008/08  [Not refereed][Not invited]
     
    The solvatochromic indicator [Cu(acac)(tmen)(H2O)] center dot PF6 (1 center dot H2O) has been synthesized and crystallographically characterized. 1 center dot H2O binds an H2O molecule at the Cu(II) axial site, while the PF6- anion is coordination free. The binding properties of [Cu(PF6)(acac)(tmen)] (1) and [Cu(BF4)(acac)(tmen)] (2) have been investigated in solution and the solid state. The donor number of the PF6- anion (DNPF6) was determined from the UV-vis spectra of 1 in 1,2-dichloroethane. The value of DNPF6 of the PF6- anion is slightly larger than that of the tetraphenylborate anion (BPh4-), which is known as a noncoordinating anion. In the solid state, 1 and 2 reversibly bind and release H2O molecules at the Cu(II) axial sites. The coordinated H2O molecules in 2 are more easily removed than those in 1 because of the strong Lewis basicity of the BF4- anion compared to the PF6- ion. The lower melting point of 1 versus 2 is attributed to the loose binding of the PF6- anions to the Cu(II) centers, which induces the dynamic nature of the crystal.
  • Tomoyuki Akutagawa, Daisuke Sato, Hiroyuki Koshinaka, Masaaki Aonuma, Shin-ichiro Noro, Sadamu Takeda, Takayoshi Nakamura  INORGANIC CHEMISTRY  47-  (13)  5951  -5962  2008/07  [Not refereed][Not invited]
     
    Supramolecular rotators of hydrogen-bonding Assemblies between anilinium (Ph-NH3+) or adamantylammonium (AD-NH3+) and dibenzo[18]crown-6 (DB[18]crown-6) or meso-dicyclohexano[18]crown-6 (DCH[18]crown-6) were introduced into [Ni(dMit)(2)] salts (dmit(2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The ammonium moieties of Ph-NH3+ and AD-NH3+ cations were interacted through N-H+similar to O hydrogen bonding with the six oxygen atoms of crown ethers, forming 1:1 supramolecular rotator-stator. structures. X-ray crystal-structure analyses revealed a jackknife-shaped conformation of DB[18]crown-6, in which two benzene rings were twisted along the same direction, in (Ph-NH3+)(DB[18]crown-6)[Ni(dmit)(2)](-) (1) and (AD-NH3+)(DB[18]crown-6)[Ni(dmit)(2)](-) (3), whereas the conformational flexibility of two dicyclohexyl rings was observed in (Ph-NH3+)(DCH[18]crown-6)[Ni(dmit)(2)](-) (2) and (AD-NH3+)(DCH[18]crown-6)[Ni(dMit)(2)](-) (4). Sufficient space for the molecular rotation of the adamantyl group was achieved in the crystals of salts 3 and 4, whereas the rotation of the phenyl group in salts 1 and 2 was rather restricted by the nearest neighboring molecules. The rotation of the adamantyl group in salts 3 and 4 was evidenced from the temperature-dependent wide-line H-1 NMR spectra, dielectric properties, and X-ray crystal structure analysis. ab initio calculations showed that the potential energy barriers for the rotations of adamantyl groups in salts 3 (Delta E approximate to 18 kJmol(-1)) and 4 (Delta E approximate to 15 kJmol(-1)) were similar to those of ethane (similar to 12 kJmol(-1)) and butane (17-25 kJmol-1) around the C-C single bond, which were 1 order of magnitude smaller than those of phenyl groups in salts 1 (Delta E approximate to 180 kJmol(-1)) and 2 (Delta E approximate to 340 kJmol(-1)). 1D or 2D [Ni(dmit)(2)](-) anion arrangements were observed in the crystals according to the shape of crown ether derivatives. The 2D weak intermolecular interactions between [Ni(dMit)21- anions in salts 1 and 3 led to Curie-Weiss behavior with weak antiferromagnetic interaction, whereas 1 D interactions through lateral sulfur-sulfur atomic contacts between [Ni(dMit)(2)](-) anions were observed in salts 2 and 4, whose magnetic behaviors were dictated by ferromagnetic (salt 2) and singlet-triplet (salt 4) intermolecular magnetic interactions, respectively.
  • Tomoyuki Akutagawa, Daigoro Endo, Fumito Kudo, Shin-ichiro Noro, Sadamu Takeda, Leroy Cronin, Takayoshi Nakamura  CRYSTAL GROWTH & DESIGN  8-  (3)  812  -816  2008/03  [Not refereed][Not invited]
     
    A solid-state molecular rotator comprising [18]crown-6 was assembled into a crystalline array of (Cs+)(3)([18]crown-6)(3)(H+)(2) [PMo12O40](5-) whereby two Cs+([18]crown-6) supramolecular rotators were complexed with a two-electron-reduced alpha-[PMo12O40](5-) Keggin cluster. The size-compatible rotators of [18]crown-6 were directly complexed to an alpha-[PMo12O40](5-) axle through Cs+-O interactions. The investigation of the dynamics of the system revealed that two rotation frequencies for [18]crown-6 were observed by using temperature-dependent H-1 NMR studies, and these were dominated by intermolecular interactions in the solid state.
  • Tomoyuki Akutagawa, Reina Jin, Ryo Tunashima, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura  LANGMUIR  24-  (1)  231  -238  2008/01  [Not refereed][Not invited]
     
    Clusters based on the mixed-valence gigantic inorganic ring [Mo154O462H14(H2O)(70)](14-) ({Mo-154}-ring) and dimethyldioctadecylammonium (DODA) were combined to form novel molecular assemblies of an inorganic-organic hybrid molecular system as Langmuir-Blodgett (LB) and cast films. (DODA)(20)[MO154O462H8(H2O)(70)] (2) was prepared by cation exchange and was characterized by a combination of thermogravimetry, IR, UV-vis-NIR, H-1 NMR, and XRD measurements. The salt 2 was soluble in common organic solvents, and the chemical stability Of {Mo-154}-ring encapsulated by DODA cationic surfactants in CHCl3 was found to be higher than that of the "native" sodium salt of the {Mo-154}-ring in H2O. Uniform spherical vesicle-like molecular assemblies of (DODA)(20)[Mo154O462H8(H2O)(70)] were observed in dilute THF, whose average diameter of 95 nm and a normalized variance of 5.7% were confirmed by a X-ray small-angle scattering. Deposition of 2 as a cast film showed circular domains with a typical diameter of similar to 100 nm, indicating possible similarities between solution and surface-deposited structures. The resulting LB films of salt 2 were transferred from an acidic buffer subphase with pH = 1.5 onto mica, giving a two-dimensional film surface with a unity transfer ratio. Further, the electronic absorption spectra of the LB multilayer were consistent with the classic type II mixed-valence Mo-V/Mo-VI electronic state well know for molybdenum blue {Mo-154}-ring systems, and it appears that on the surface the plane of the {Mo-154}-ring is approximately parallel to the substrate surface, as indicated by polarized electronic spectra, while the alkyl chains of DODA were relatively normal to the substrate surface. Therefore, the layer between the {Mo-154}-rings and DODA cations was alternately stacked along the direction of film propagation. Finally, it was found that the surface morphology of the cast and LB films was determined by the molecular assembly of (DODA)(20)[Mo154O462H8(H2O)70] in solution and the air-water interface, respectively.
  • Applied Physics Letters  (93)  173102 1-173102 3  2008  [Not refereed][Not invited]
     
    Electrical Resistivity of Individual Molecular-Assembly Nanowires of Amphiphilic Bis-tetrathiafulvalene Macrocycle/2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane Charge Transfer Complex Characterized by Point-Contact Current-Imaging Atomic Force Microscopy
  • Ryo Tsunashima, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura, Hiroko Kawakami, Kazunori Toma  CHEMISTRY-A EUROPEAN JOURNAL  14-  (27)  8169  -8176  2008  [Not refereed][Not invited]
     
    Fullerene derivative C60TT, which is substituted with the low-molecular-weight organogelator tris(dodecyloxy)benzamide, formed nanowire structures on application of the Langmuir-Blodgett (LB) method. The surface morphology of the C60TT LB film was dependent on the holding time before deposition at a surface pressure of 5 mN m(-1); it changed from a homogeneous monolayer to a bilayer fibrous structure via a fibrous monolayer structure, which was estimated to have dimensions of 1.2 nm in height, 8 nm in width, and 5-10 mu m in length. From the structural and spectroscopic data, it is inferred that close packing of the fullerene moiety occurs along with intermolecular hydrogen bonding within the monolayer fibrous structure. The morphological changes in the LB film are explained kinetically by the Avrami theory, based on the decrease in the surface area of the monolayer at the air/water interface. The growth of the quasi-one-dimensional fibrous monolayer structures at holding times from 0 to 0.2 h is considered to be an interface-controlled process, whereas the growth of the quasi-one-dimensional bilayer fibrous structures from 0.2 to 18 h is thought to be a diffusion-controlled process.
  • Guo-Xi Wang, Guang-Fan Han, Qiong Ye, Ren-Gen Xiong, Tomoyuki Akutagawa, Takayoshi Nakamura, Philip Wai Hong Chan, Songping D. Huang  DALTON TRANSACTIONS  (19)  2527  -2530  2008  [Not refereed][Not invited]
     
    A homochiral rare-earth metal Tb complex that exhibited a very large dielectric anisotropic property with a temperature-independent feature is obtained. Our findings on high-dielectric anisotropy will provide a new impetus in this field of materials science.
  • Yoko Tatewaki, Yuki Noda, Tomoyuki Akutagawa, Ryo Tunashima, Shin-ichiro Noro, Takayoshi Nakamura, Hiroyuki Hasegawa, Shinro Mashiko, Jan Becher  JOURNAL OF PHYSICAL CHEMISTRY C  111-  (51)  18871  -18877  2007/12  [Not refereed][Not invited]
     
    A charge-transfer complex between an amphiphilic bis(tetrathiafulvalene) (bis-TTF) annulated macrocycle (1) and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane (F4-TCNQ), (1(2+))(F-4-TCNQ(-))(2), which can form molecular-assembly nanowires by application-of the Langmuir-Blodgett (LB) method, was hybridized with gold nanoparticles with an average diameter of 13 nm. LB films of (1(2+))(F-4-TCNQ)(2) were transferred onto a substrate surface from a subphase containing gold nanoparticles at concentrations ranging from 10(-6) to 10(-4) M, based on the number of gold atoms in the subphase (C-Au). One-dimensional nanowires and zero-dimensional gold nanoparticles were found to coexist in films transferred onto mica by a single withdrawal from a subphase with CAu less than 1 x 10(-5) M, whereas films transferred from a subphase with CAu greater than 1 x 10(-4) M formed network structures of gold nanoparticles, which was confirmed by AFM measurements as well as electronic spectroscopy The room-temperature electrical conductivities of the latter LB films (C-Au > 1 x 10(-4) M) were 2 or 3 orders of magnitude higher than those of the former (C-Au< 1 x 10(-5) M). The films, which contained nanoparticle network structures, showed two types of conducting behavior depending on the temperature range (above and below similar to 150 K). At higher temperatures, conduction was dominated by (1(2+))(F-4-TCNQ(-))(2), which is an intrinsic semiconductor, whereas collective tunneling charge transport in the gold nanoparticle network structure was observed at lower temperatures. In the prepared films, the gold nanoparticles were randomly connected to each other, and a random single electron tunneling array yielded a finite threshold voltage (V-th) at lower temperatures due to Coulomb blockade behavior and three-dimensional correlation of the conducting paths.
  • X. M. Ren, S. Nishihara, S. Noro, T. Akutagawa, T. Nakamura  POLYHEDRON  26-  (9-11)  1787  -1792  2007/06  [Not refereed][Not invited]
     
    Two new H-bonding molecular magnets based on [Ni(mnt)(2)](-) monoanion have been synthesized and characterized structurally. In crystal of 1, [Ni(mnt)(2)](-) monoanions form the pi-stacked sheets and the neighboring anionic sheets are held together via H-bonding interactions between -NH groups of diprotonated benzene-1,4-diamine and CN groups of mnt(2-) ligands. In crystal of 2, the neighboring anionic dimers form an anionic column via Ni... S contacting interactions, and these anionic stacks arrange into a sheet which is parallel to crystallographic ab-plane. The H-bonding interactions between diprotonated 1,4-diazabicyclo[2.2.2]octane cations and [Ni(mnt)(2)](-) monoanions as well as between cations and solvent MeCN molecules stabilize the lattice. Magnetic susceptibility measurement for 1 indicates an activated magnetic behavior in the high-temperature range together with a Curie tail at the lower temperature range, but the magnetic feature deviates from the magnetic exchange model for a spin dimer with S = 1/2. The magnetic nature of 2 reveals the presence of strongly antiferromagnetic interactions between the nearest-neighboring spins, the larger energy gap between spin ground and excited states results in a weakly paramagnetic property. (c) 2006 Published by Elsevier Ltd.
  • Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura  CRYSTAL GROWTH & DESIGN  7-  (6)  1205  -1208  2007/06  [Not refereed][Not invited]
     
    The nickel 1,3,5-benzenetricarboxylate (1,3,5-btc(3-)) coordination polymer, [Ni-6(mu-OH2)(4)(1,3,5-btc)(4)(H2O)(12)](n) (1), has been synthesized using a hydrothermal reaction. Trinuclear nickel cores constructed from the mu-OH2 and carboxylate bridges are linked by the 1,3,5-btc(3-) ligands, forming a two-dimensional network. The mu-OH2 molecules form strong hydrogen bonds with the free oxygens of the carboxylate groups in the trinuclear clusters. A structural phase transition occurs around 373 K and is categorized as a second-order phase transition.
  • X. M. Ren, S. Nishihara, T. Akutagawa, S. Noro, T. Nakamura, W. Fujita, K. Awaga  CHEMICAL PHYSICS LETTERS  439-  (4-6)  318  -322  2007/05  [Not refereed][Not invited]
     
    Two quasi-ID molecular magnets, [RBzPy][Ni(mnt)(2)] (RBzPy(+) = 1-(4'-nitrobenzyl)pyridinium (1) and 1-(4'-brominobenzyl)pyridinium (2); mnt(2-) = maleonitriledithiolate), are isostructural and possess a spin-Peierls-like transition at T-c approximate to 184 K for 1 and approximate to 112 K for 2 at ambient pressure. The magnetic susceptibility measurements under different applied pressures disclosed two compounds exhibiting similar magnetic behaviors. For each compound, the spin transition shifts to higher temperature with pressure and the paramagnetism in high-temperature phase is suppressed. These trends seem to be explicable by the shortened distances induced by the pressure between magnetic [Ni(mnt)(2)](-) anions and thus leading to enhancements of antiferromagnetic interactions. (C) 2007 Elsevier B.V. All rights reserved.
  • Da-Wei Fu, Yu-Mei Song, Guo-Xi Wang, Qiong Ye, Ren-Gen Xiong, Tomoyuki Akutagawa, Takayoshi Nakamura, Philip Wai Hong Chan, Songping D. Huang  JOURNAL OF THE AMERICAN CHEMICAL SOCIETY  129-  (17)  5346  -+  2007/05  [Not refereed][Not invited]
     
    Hydrothermal reaction of (S)-1,1'1' '-2,4,6-trimethylbenzene-1,3,5-triyl-tris(methylene)-tris-pyrrolidine-2-carboxylic acid (TBPLA) with Ni(ClO4)(2)center dot 6H(2)O gave pale green block crystals of 1. X-ray crystal structure analysis showed the complex to be a trinuclear descrete homochiral molecule with each Ni center sitting in distorted octahedron geometries. Anisotropic permittivity measurements reveal that 1 exhibits huge dielectric anisotropy along its three different crystal axes that is ca. 3.5 times of epsilon(r) (E//c)/epsilon(r) (E//b) with temperature and frequency independence.
  • Sadafumi Nishihara, Tomoyuki Akutagawa, Daisuke Sato, Sadamu Takeda, Shin-ichiro Noro, Takayoshi Nakamura  CHEMISTRY-AN ASIAN JOURNAL  2-  (9)  1083  -1090  2007  [Not refereed][Not invited]
     
    A solid-state dynamic supramolecular structure consisting of (anilinium)([18]crown-6) was arranged as the cation in a salt of [Ni(dmit)2](-)(dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate). With the ammonium moiety of anilinium located within the cavity of [18]crown-6, a hydrogen-bonded supramolecular. structure is formed, with an orthogonal arrangement between the a plane of anilinium and the mean 06 plane of [18]crown-6. In this supramolecular cation, both anilinium and [18]crown-6 act as dynamic units with different rotational modes in the solid state. The uniform stacks of cations form an antiparallel arrangement, thus producing a layer structure. Sufficient space for the 180 degrees flip-flop motion of the phenyl ring and the rotation of [18]crown-6 was observed in the cation layer. Thermally activated 180 degrees flip-flop motions, with a frequency of 6 MHz at room temperature and an activation energy of 31 kJmol(-1), were confirmed by temperature-dependent H-2 NMR spectra of ([D-5]anilinium)([18]crown-6)[Ni(dmit)(2)]. A double-minimum potential for the molecular rotation of anilinium, with a barrier of approximately 40 kJmol(-1), was indicated by ab initio calculations. The wideline H-1 NMR spectra indicated a thermally activated rotation of [18]crown-6 at temperatures above 250 K. Therefore, multiple molecular motions of the 180 degrees flip-flop motion of the phenyl ring and the rotation of [18]crown-6 occur simultaneously in the solid state. The temperature-dependent dielectric constants revealed that the molecular motion of [1,8]crown-6, other than the flip-flop motion, dominates the dielectric response in the measured temperature and frequency range.
  • Qiong Ye, Hong Zhao, Zhi-Rong Qu, Da-Wei Fu, Ren-Gen Xiong, Yi-Ping Cui, Tomoyuki Akutagawa, Philip Wai Hong Chan, Takayoshi Nakamura  ANGEWANDTE CHEMIE-INTERNATIONAL EDITION  46-  (36)  6852  -6856  2007  [Not refereed][Not invited]
  • Organic - Inorganic Hybrid Molecular-Assemblies of Phenylenediamines - Crown ethers - [PMo12O40]4- Salts
    Coord. Chem. Rev  251-  2547  -2561  2007  [Not refereed][Not invited]
  • Daisuke Sato, Tomoyuki Akutagawa, Sadamu Takeda, Shin-ichiro Noro, Takayoshi Nakamura  INORGANIC CHEMISTRY  46-  (2)  363  -365  2007/01  [Not refereed][Not invited]
     
    Adamantylammonium (ADNH(3)(+)) was complexed with [18]crown-6, forming a supramolecular cation of (ADNH(3)(+))([18]crown6), which was introduced into a [Ni(dmit)(2)](-) salt as a supramolecular rotor. The cation layers were alternately arranged with [Ni(dmit)(2)](-) layers in the crystal, in which the molecular rotation of (ADNH(3)(+))([18]crown-6) was confirmed from the temperature-dependent solid-state H-1 NMR.
  • Ryo Tsunashima, Shin-ichiro Noro, Tomoyuki Akutagawa, Takayoshi Nakamura, Tomohiro Karasawa, Hiroko Kawakami, Kazunori Toma  JOURNAL OF PHYSICAL CHEMISTRY C  111-  (2)  901  -907  2007/01  [Not refereed][Not invited]
     
    The Langmuir-Blodgett (LB) method was applied to low molecular weight organogelator N-[N-(6-hydroxyhexyl)-3-carbamoylpropyl]-3,4,5-tris(dodecyloxy)benzamide (1) to form molecular-assembly fibers on a solid substrate. Molecule 1 formed a stable monolayer up to 40 mN/m at the air-water interface. The monolayer was transferred onto a mica surface at 35 mN/m. In the transferred film, fibrous structures with typical dimensions of 1.2 nm (height) x 50-100 nm (width) x 5-10 mu m (length) were observed by atomic force microscopy. These structures were ordered in specific directions, reflecting the C-6 surface crystal symmetry of mica. Lateral modulation frictional force microscope measurements revealed that the fibrous structures had high crystallinity and that the surface groups were hydrophilic. These results enabled us to construct functional fibers by introducing functional units into the hydrophilic part of molecule 1. N-[N-(6-Aminohexyl)3-carbamoylpropyl]-3,4,5-tris(dodecyloxy)benzamide hydrochloride (2) has an ammonium moiety instead of the terminal alcohol moiety of 1. By adding 2 to 1, we introduced adsorption sites for Au nanoparticles on the surface of the fibrous structure. By casting a Au nanoparticle suspension onto this fibrous structure, we successfully constructed An nanoparticle arrays in which Au nanoparticles were adsorbed on a mixed fibrous structure of 1 and 2 on mica substrates.
  • X. M. Ren, Z. P. Ni, S. Noro, T. Akutagawa, S. Nishihara, T. Nakamura, Y. X. Sui, Y. Song  CRYSTAL GROWTH & DESIGN  6-  (11)  2530  -2537  2006/11  [Not refereed][Not invited]
     
    Four new ion-pair complexes, consisting of bis(maleonitriledithiolato) cuprate dianion with the derivatives of benzylpyridinium (1-3) or monoprotonated 1,4-diazabicyclo-[2.2.2] octane ( 4), have been prepared and characterized structurally and magnetically, and a diversity of the coordination geometry at Cu2+ center of [Cu(mnt)(2)](2-) was observed. Highly distorted square-planar geometry at the tetracoordination Cu2+ center of [Cu(mnt)(2)](2-) was found in 1 and 4. Two chelate rings make a dihedral angle of 27.2 degrees in 1 and 20.5, 34.3, and 19.7 degrees for three crystallographically independent [Cu(mnt)(2)](2-) molecules in 4. Interestingly, the distortion is not ascribed to steric repulsion between ligands or weakly coordinating interaction from the nearest anions, countercations, or solvent molecules but to the weak supramolecular interactions between anion and cations [such as S center dot center dot center dot H, N center dot center dot center dot H, or S center dot center dot center dot I]. In 2, the Cu2+ center in [Cu(mnt)(2)](2-) possesses approximate square-planar coordination geometry, and the dihedral angle between two chelate rings is 5.8 degrees. In 3, the Cu2+ ion of [Cu(mnt)(2)](2-) lies on a symmetric center (2/m), and the anion has C-2h symmetry. The coordination S atoms and central Cu2+ ion of [Cu(mnt)(2)](2-) are strictly coplanar with perfect square-planar coordination geometry because of the symmetric constraint. However, the anion is nonplanar because the ligand fragment is bent away from the CuS4 plane with a dihedral angle of 13.8 degrees. X-band EPR spectra at 293 and 110 K failed to give any available information about the electronic structural difference between the anions of square-planar and distorted square-planar geometries because no hyperfine splitting was detected. Density functional theory (DFT) has been implemented to calculate the single-point energy for each [Cu(mnt)(2)](2-) in 1-4 and optimize the molecular geometry of [Cu(mnt)(2)](2-). On the basis of these theoretic analyses, the reasons for the structural fluctuations between square-planar and distorted square-planar coordination geometry were explored.
  • Shin-ichiro Noro, Satoshi Horike, Daisuke Tanaka, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura  INORGANIC CHEMISTRY  45-  (23)  9290  -9300  2006/11  [Not refereed][Not invited]
     
    A series of guest-binding Cu-parallel to coordination polymers, {[Cu(bpetha)(2)(acetone)(2)]center dot 2PF(6)}(n) (bpetha = 1,2-bis(4-pyridyl)ethane) (1), {[Cu(bpetha)(2)(DMF)(2)]center dot 2PF(6)}(n) (2), {[Cu(bpetha)(2)(MeCN)(2)]center dot 2PF(6)center dot 2MeCN}(n) (3), {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 3THF center dot 2H(2)O}(n) (4), {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 3dioxane}(n) (5), and {[Cu(bpetha)(2)(H2O)(2)]center dot 2PF(6)center dot 2-PrOH center dot 2H(2)O}(n) ( 6), have been synthesized and crystallographically characterized. Their framework stabilities and guest-exchange properties have also been investigated. All compounds form a similar framework motif, a "double chain", in which the bpetha ligands bridge Cu-parallel to centers to form 1-D [Cu(bpetha)(2)](n) double chains. A variety of Lewis base guest molecules, such as H2O, acetone, DMF, MeCN, THF, dioxane, and 2-PrOH, are incorporated into the assembly of the 1-D double chains. These chains flexibly change their forms of assembly in a guest-dependent manner. Interestingly, acetone, DMF, and MeCN guests with a carbonyl or cyanide group coordinate directly to the axial sites of the Cu-parallel to centers; in contrast, THF, dioxane, and 2-PrOH guests with an ether or alcohol group are incorporated into the frameworks not via coordination bonds but via weak interactions (hydrogen bonds and van der Waals forces). This selectivity is probably due to steric effects at coordinated oxygen or nitrogen atoms of the guests. Crystal-to-crystal transformations triggered by guests are observed, during which guests coordinated to the Cu-parallel to axial sites are readily removed and replaced by other guests.
  • M. Hiraoka, T. Hasegawa, Y. Abe, T. Yamada, Y. Tokura, H. Yamochi, G. Saito, T. Akutagawa, T. Nakamura  APPLIED PHYSICS LETTERS  89-  (17)  173504  -173506  2006/10  [Not refereed][Not invited]
     
    In this work the authors fabricated patterned thin films made of highly conductive organic charge-transfer complexes using the ink-jet printing technique. The overprinted films of BO9(C-14-TCNQ)(4) exhibit low sheet resistivity and are available for carrier injection and interconnection of organic field-effect transistors (FETs). The performance of pentacene thin film FETs, where the top contact and bottom contact are ink-jet-printed organic electrodes, demonstrates the potential of organic/organic heterointerfaces. (c) 2006 American Institute of Physics.
  • Shin-ichiro Noro, Ryo Kitaura, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura  INORGANIC CHEMISTRY  45-  (22)  8990  -8997  2006/10  [Not refereed][Not invited]
     
    Ni(II) coordination polymers with a 4,4 '-azobis(pyridine) (azpy) ligand, {[Ni(2)(NCX)(4)(azpy)(4)]center dot G}(n) (X = S, G (guest molecule) = MeOH (1 center dot MeOH); X = S, G = EtOH (1 center dot EtOH); X = S, G = H(2)O (1 center dot H(2)O); X = S, G = no guest (1); X = Se, G = MeOH (2 center dot MeOH); X = Se, G = H(2)O (2 center dot H(2)O); X = Se, G = no guest ( 2)), have been synthesized and structurally characterized with their porosity. These compounds have one-dimensional periodic ultramicropores that contain the small guest molecules, H(2)O, MeOH, or EtOH, whose hydroxy groups interact with the S or Se atoms of isothiocyanate or isoselenocyanate, respectively, via-S(Se)center dot center dot center dot HO-hydrogen bonds. Although the molecular dimensions of the MeOH guest are considerably larger than the window size of the ultramicropore, 1, MeOH and 2, MeOH easily release their guest molecules without decomposition of the framework to form 1 and 2 without any guest molecules. This shows that 1 and 2 have dynamic ultramicropores constructed from the interpenetrating framework. The guest desorption experiments using 1 center dot MeOH and 1 center dot EtOH reveal that the difference in the desorption behavior is due to van der Waals interactions that depend on the molecular shape of the guest molecule in the ultramicropores and/or an entrance blocking effect that depends on the minimum dimensions of the guest molecule for the pore windows. A marked difference in the N(2) and CH(4) adsorption isotherms was observed and is associated with the strength of the host-guest interaction.
  • Tomoyuki Akutagawa, Daigoro Endo, Hiroyuki Imai, Shin-ichiro Noro, Leroy Cronin, Takayoshi Nakamura  INORGANIC CHEMISTRY  45-  (21)  8628  -8637  2006/10  [Not refereed][Not invited]
     
    Electron transfer from the electron donor of p-phenylenediamine (PPD) to the electron acceptor of (H+)(3)[PMo12O40](3-) forms a one-electron-reduced Keggin cluster of [PMo12O40](4-), bearing a S) (1)/(2) spin, while proton transfer from the proton donor of (H+)(3)[PMo12O40](3-) to the proton acceptor of PPD yielded mono- and diprotonated cations of 4- aminoanilinium (HPPD+) and p- phenylenediammonium (H2PPD(2+)). By introduction of crown ether receptors during the crystallization process, supramolecular cations of (HPPD+)(crown ethers) and/or (H2PPD(2+))(crown ethers) were successfully introduced into three new alpha-[PMo12O40](4-) salts of (H2PPD2+)(2)([12] crown-4)(4)[PMo12O40](4-) (1), (HPPD+)(4)-[ 15] crown-5)(4)[PMo12O40](4-) (2), and (HPPD+)(2)(H2PPD2+)([18]crown-6)(4)[PMo12O40](4-) (3) as the countercation. The protonated states of PPD and molecular-assembly structures of the supramolecular cations depended on the size of the crown ethers. In salt 3, a novel mixed- protonated state of HPPD+ and H2PPD2+ was confirmed to be complexed in the cation structure. According to the changes in the cation structures, the anion arrangements were modulated from those of the two-dimensional layer for salt 1 to the isolated cluster for salts 2 and 3. The temperature-dependent magnetic susceptibilities of salts 1-3 were consistent with the isolated spin arrangements of [PMo12O40](4-). The electronic spectra of salts 1-3 indicated the intervalence optical transition from pentavalent MoV to hexavalent Mo-VI ions within the [PMo12O40](4-)cluster. Temperature-dependent electron spin resonance spectra of salt 2 revealed the delocalization-localization transition of the S = (1)/(2) spin at 60 K. The spin on the [PMo12O40](4-) cluster was localized on a specific MoV site below 60 K, which was thermally activated with an activation energy of 0.015 eV.
  • Takayoshi Nakamura, Hideto Miyata, Keisuke Wakahara, Tomoyuki Akutagawa, Tatsuo Hasegawa, Hiroyuki Hasegawa, Shinro Mashiko, Christian A. Christensen, Jan Becher  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY  6-  (6)  1833  -1837  2006/06  [Not refereed][Not invited]
     
    Structures and electronic states of a 1:1 mixture of bis-tetrathiafulvalene annulated macrocycle (1) and C-60. in Langmuir films at the air-water interface and Langmuir-Blodgett (LB) films on solid substrates were examined. Compression of the Langmuir films induced for the first time a phase transition from a weakly interacting state without charge transfer (CT) to a neutral CT state. The scanning force microscope images of LB films transferred onto mica by a single withdrawal showed quite different spatial patterns depending on the CT states. When deposited at around 1 mNm(-1), a domain structure with 3 nm height was obtained, which corresponded to the state without CT interaction. Contrastingly, once the CT interaction was induced by applying surface pressure, a network structure was observed with a height of 6 nm. The CT band, whose transition moment was almost parallel to the substrate surface, was observed at 11.5 x 10(3) cm(-1) in the polarized UV-VIS-NIR spectra of the films deposited at 9 mNm-1. The phase transition was irreversible, although the surface pressure-area isotherm showed a reversible behavior below 9 mNm-1. The morphology and electronic state of the film was controllable merely by changing the surface pressure at the air-water interface.
  • XM Ren, T Akutagawa, S Noro, S Nishihara, T Nakamura, Y Yoshida, K Inoue  JOURNAL OF PHYSICAL CHEMISTRY B  110-  (15)  7671  -7677  2006/04  [Not refereed][Not invited]
     
    A nonmagnetic Compound, [NO(2)BzPy][Au(mnt)(2)](NO(2)BzPy(+) = 1-(4'-nitrobenzyl)pyridinium; mnt(2-) = maleonitriledithiolate), was synthesized and characterized structurally, which is isostructural with [NO(2)BzPy][Ni(mnt)(2)] that is a quasi-one-dimensional magnet and possesses a spin-Peierls-like transition with J = 192 K in the gapless state and spin energy gap 738 K in the dimerization state, respectively. Further, ten nonmagnetic impurity doped compounds with a formula [NO(2)BzPy][Au(x)Ni(1-x)(mnt)(2)] (x = 0.01-0.73) were prepared and investigated by crystal structural determinations and magnetic susceptibility measurements. The nonmagnetic doping causes the suppression of the spin transition with an average rate of 221(12) K/percentage of dopant concentration. From the plots of chi(m)-T, the transition collapse (the characteristic of the transition is the sudden drop of upon cooling, and the disappearance of this characteristic is considered as the criterion for the transition collapse) is estimated at around x > 0.27. In heavier doped system x = 0.49, the spin gap vanishes and a gapless phase is achieved again.
  • T Akutagawa, T Motokizawa, K Matsuura, S Nishihara, SI Noro, T Nakamura  JOURNAL OF PHYSICAL CHEMISTRY B  110-  (12)  5897  -5904  2006/03  [Not refereed][Not invited]
     
    Sandwich-type supramolecular cation structures of (M+)([12]crown-4)(2) complexes (M+ = Li+, Na+, K+, and Rb+) were introduced as countercations to the [Ni(dmit)(2)](-) anion, which bears an S = 1/2 spin, to form novel magnetic crystals (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate). The zigzag arrangement of Li+([12]crown-4)(2) cations in Li+([12]crown-4)(2)[Ni(dmit)(2)](-) salt induced weak intermolecular interactions of [Ni(dmit)(2)](-) dimers, whose magnetic spins were isolated from each other. The molecular arrangements of cations and anions in M+([12]crown-4)(2)[Ni(dmit)(2)](-) salts (M+ = Na+, K+, and Rb+) were isostructural to each other. In the case of Na+([12]crown-4)(2)[Ni(dmit)(2)](-), the space group C2/m changed to C2/c with a lowering in temperature from 298 to 100 K. This structural change occurred at 222.5 K as a first-order phase transition. The space group C2/m (T = 298 K) in the salt K+([12]crown-4)(2)[Ni(dmit)(2)](-) also changed to C2/c (T = 100 K), which transition occurred at 270 K. Crystal structural analyses at 298 and 100 K revealed changes in both supramolecular cation conformation and [Ni(dmit)(2)](-) anion arrangements. The transition from C2/m to C2/c crystals generated a dipole mornent in the Na+([12]crown-4)(2) and K+([12]crown-4)(2) structures, which were reconstructed to cancel the net dipole moment of the C2/c crystals. These cation transformations led to changes in intermolecular interactions between the [Ni(dmit)(2)](-) anions via structural rearrangements. The crystal structure of C2/c was stabilized in Rb+([12]crown-4)(2)[Ni(dmit)(2)](-) at 298 K. The [Ni(dmit)(2)](-) configuration in these salts with the C2/c space group was a one-dimensional uniform chain, which showed the temperature-dependent magnetic susceptibility of a one-dimensional linear Heisenberg anti ferromagnetic chain.
  • XM Ren, S Nishihara, T Akutagawa, S Noro, T Nakamura  INORGANIC CHEMISTRY  45-  (5)  2229  -2234  2006/03  [Not refereed][Not invited]
     
    Crystal structures and magnetic properties were determined for two novel polymorphs of the complex [H(2)DABCO]-[Ni(mnt)(2)] [(H(2)DABCO)(2+) = diprotonated 1,4-diazabicyclo[2.2.2]octane; mnt(2-) = maleonitriledithiolate]. For each polymorph, anions form a layered structure in which two kinds of dimers were observed. The adjacent anionic sheets are held together by cations via H-bonding interactions between protons of cations and CN groups of anions. Two polymorphs possess spin bistability; namely, upon cooling, a magnetic transition happens at around 120 K with about 1 K hysteresis on heating for the alpha phase and at 112 K with about 10 K hysteresis for the beta phase. Above the transition, the magnetic behaviors of two polymorphs can be approximately interpreted by a singlet-triplet model of an antiferromagnetically coupled S = (1)/(2) dimer, which is supported by the crystal structures and spin dimer analyses based on extended Huckel molecular orbital calculations.
  • S Kitagawa, S Noro, T Nakamura  CHEMICAL COMMUNICATIONS  (7)  701  -707  2006/02  [Not refereed][Not invited]
     
    Pore surface control of microporous coordination polymers is of great interest due to the potentially exciting functionalities it presents, such as highly selective separation, chemisorption, and novel catalysts and sensors. A discussion of our unique strategy aimed at surface engineering using metalloligands, i.e., introduction of coordinatively unsaturated metal centers, is presented.
  • AKUTAGAWA Tomoyuki, NAKAMURA Takayoshi, BECHER Jan  Mol. Cryst. Liq. Cryst  455-  71  -74  2006  [Not refereed][Not invited]
  • Molecular-assembly Nanostructures of 1:1 Mixed Langmuir-Blodgett Films of Amphiphilic Bis-TTF Macrocycle and F4-TCNQ
    Colloids and Surfaces A  284  -285  2006  [Not refereed][Not invited]
  • XM Ren, S Nishihara, T Akutagawa, S Noro, T Nakamura, W Fujita, K Awaga, ZP Ni, JL Xie, QJ Meng, RK Kremer  DALTON TRANSACTIONS  (16)  1988  -1994  2006  [Not refereed][Not invited]
     
    The syntheses, structural characterizations and magnetic behaviors of three new complexes, 1-(3', 4', 5'- trifluorobenzyl) pyridinium [M(mnt)(2)](-) [M = Ni (1), Pd (2) or Pt (3)], are reported. These complexes are isomorphous and their prominent structural character is that the [ M( mnt) 2]- anions form columnar stacks, in which the dimerization was observed. Complexes 2 and 3 are diamagnetic, while 1 possesses an energy gap of 2474 K. For crystal 4, 1-(4'-fluorobenzyl)pyridinium [Ni(mnt)(2)] (its structure and magnetic susceptibility were briefly reported earlier), the magnetic behavior can be divided into two regimes, namely, weakly ferromagnetic coupling above 93 K and strongly antiferromagnetic coupling below 93 K. A transition occurs at 93 K which switches the magnetic exchange nature from ferromagnetic to antiferromagnetic. A sharp thermal abnormality with lambda-shape, associated with the transition, appears from its heat capacity measurement to indicate that the transition is first order. The temperature dependences of the superlattice diffractions revealed the existence of the pretransitional phenomena up to at least 140 K. The unusual magnetic behavior of 4, such as the origin of the ferromagnetic interaction in the high temperature phase and what causes the spin transition, are discussed further.
  • T Akutagawa, T Nakamura  CRYSTAL GROWTH & DESIGN  6-  (1)  70  -74  2006/01  [Not refereed][Not invited]
     
    Shiny green-colored single crystals of 2,5-diamino-3,6-dihydroxy-p-benzoquinone (1) were prepared from 2,3,5,6-tetrahydroxy-p-phenylenediammonium dichloride. X-ray crystal structural analysis and ab initio calculations revealed that the molecular structure of 1, a highly polarized zwitterionic structure, was similar to that of p-benzoquinone rather than that of p-quinodiimine. Furthermore, a regular pi-stack and an intermolecular two-dimensional hydrogen-bonding network were observed within the crystals of 1. The green color in the solid state was attributable to the intermolecular charge-transfer interactions.
  • S Ikeuchi, Y Miyazaki, S Takeda, T Akutagawa, S Nishihara, T Nakamura, K Saito  JOURNAL OF CHEMICAL PHYSICS  123-  (4)  2005/07  [Not refereed][Not invited]
     
    Heat capacity of Cs-2(18-crown-6)(3)[Ni(dmit)(2)](2) was measured by adiabatic calorimetry. A broad thermal anomaly was observed around 225 K. The entropy gain (about 52 J K-1 mol(-1)) is much larger than that expected for twofold disordering of 18-crown-6 assumed in the previous structure analysis. The shape of thermal anomaly was qualitatively explained by a linear Ising model developed for cooperative disordering in polymers. The 18-crown-6 molecules forming a one-dimensional chain in the crystal are orientationally disordered with moderate cooperativity. (C) 2005 American Institute of Physics.
  • XM Ren, T Akutagawa, S Nishihara, T Nakamura  SYNTHETIC METALS  150-  (1)  57  -61  2005/04  [Not refereed][Not invited]
     
    Four ion-pair compounds that are based on the [Pd(mnt)(2)](-) anion were synthesized and structurally characterized. Crystal structure determinations revealed that, in all four cases, the anions and cations stack as segregated columns, and that adjacent [Pd(mnt)(2)](-) anions exhibit a strong tendency of dimerization within an anionic column. Values of chi(m)(T) in 2-350 K indicated that these compounds are nearly diamagnetic. Results of the spin dimer analyses for the magnetic exchange interactions between the nearest-neighbor spins qualitatively illustrated the magnetic behaviors of these compounds. (c) 2005 Elsevier B.V. All rights reserved.
  • 2005  [Not refereed][Not invited]
     
    “Metal-Organic Thin-Film Transistor (MOTFT) Based on a Bis(o-diiminobenzosemiquinonate) Nickel(II) Complex” S. Noro, H. C. Chang, T. Takenobu, Y. Murayama, T. Kanbara, T. Aoyama, T. Sassa, T. Wada, D. Tanaka, S. Kitagawa, Y. Iwasa, T. Akutagawa, and T. Nakamura; J. Am. Chem. Soc., 127, 10012-10013 (2005).*
  • “Molecular Assembly Nanostructures of a Redox-Active Organogelator” T. Akutagawa, K. Kakiuchi, T. Hasegawa, S. Noro, T. Nakamura, H. Hasegawa, S. Mashiko and J. Becher; Angew. Chem. Int. Ed., 44, 7283-7287 (2005).*
    2005  [Not refereed][Not invited]
  • "Langmuir Layers and Langmuir–Blodgett Films of Bis-tetrathiafulvalene Annelated Macrocycle" T. Nakamura, Y. Tatewaki, T. Ohta, K. Wakahara, T. Akutagawa, T. Hasegawa, H. Tachibana, R. Azumi, M. Matsumoto, C. A. Christensen and J. Becher, Bull. Chem. S・・・
    2005  [Not refereed][Not invited]
     
    "Langmuir Layers and Langmuir–Blodgett Films of Bis-tetrathiafulvalene Annelated Macrocycle" T. Nakamura, Y. Tatewaki, T. Ohta, K. Wakahara, T. Akutagawa, T. Hasegawa, H. Tachibana, R. Azumi, M. Matsumoto, C. A. Christensen and J. Becher, Bull. Chem. Soc. Jpn., 78, 247-254 (2005)*
  • 2005  [Not refereed][Not invited]
     
    “Crystal Structures and Magnetic Properties of [Ni(dmit)2]– Salts Including (4- fluoroanilinium)([18]crown-6) and (4-methylanilinium)([18]crown-6) Supramolecular Cations” S. Nishihara, X. M. Ren, T. Akutagawa and T. Nakamura; Polyhedron, 24, 2844-2848 (2005).*
  • “Laser Induced SHG Decay in a Langmuir-Blodgett Film: Arresting by Polyelectrolyte Templating” M. Sharath Chandra, M. Ghanashyam Krishna, H. Mimata, J. Kawamata, T. Nakamura and T. P. Radhakrishnan; Advanced Materials, 17, 1937-1941 (2005).
    2005  [Not refereed][Not invited]
  • “Synthesis and Crystallographic Characterization of Low-Dimensional and Porous Coordination Compounds Capable of Supramolecular Aromatic Interaction Using the 4,4’-Azobis(pyridine) Ligand” S. Noro, S. Kitagawa, T. Nakamura and T. Wada; Inorg. Chem., 44・・・
    2005  [Not refereed][Not invited]
     
    “Synthesis and Crystallographic Characterization of Low-Dimensional and Porous Coordination Compounds Capable of Supramolecular Aromatic Interaction Using the 4,4’-Azobis(pyridine) Ligand” S. Noro, S. Kitagawa, T. Nakamura and T. Wada; Inorg. Chem., 44, 3960-3971 (2005).*
  • 2005  [Not refereed][Not invited]
     
    “Molecular Rotor of Cs2([18]crown-6)3 in the Solid State Coupled with the Magnetism of [Ni(dmit)2]” T. Akutagawa, K. Shitagami, S. Nishihara, S. Takeda, T. Hasegawa, T. Nakamura, Y. Hosokoshi, K. Inoue, S. Ikeuchi, Y. Miyazaki and K.Saito; J. Am. Chem. Soc., 127, 4397-4402 (2005).*
  • “Structural Phase Transition Driven by Spin-Lattice Interaction in a Quasi-one-dimensional Spin System of [1-(4-iodobenzyl)pyridinium][Ni(mnt)2]” X. M. Ren, T. Akutagawa, S. Nishihara, T. Nakamura, W. Fujita and K. Awaga; J. Phys. Chem., 109, 16610-166・・・
    2005  [Not refereed][Not invited]
     
    “Structural Phase Transition Driven by Spin-Lattice Interaction in a Quasi-one-dimensional Spin System of [1-(4-iodobenzyl)pyridinium][Ni(mnt)2]” X. M. Ren, T. Akutagawa, S. Nishihara, T. Nakamura, W. Fujita and K. Awaga; J. Phys. Chem., 109, 16610-16615 (2005).*
  • “The First Proton-Conducting Metallic Ion-Radical Salts” A. Akutsu-Sato, H. Akutsu, S. S. Turner, P. Day, M. R. Probert , J. A. K. Howard, T. Akutagawa, S. Takeda, T. Nakamura and T. Mori, Angew. Chem. Int. Ed., 44, 292-295 (2005).*
    2005  [Not refereed][Not invited]
  • 『有機結晶材料の最新技術』
    シーエムシー出版  2005  [Not refereed][Not invited]
  • T Sato, T Hasegawa, T Akutagawa, T Nakamura, R Kondo  PHYSICAL REVIEW B  69-  (7)  2004/02  [Not refereed][Not invited]
     
    Structural and magnetic properties were investigated in a series of isomorphous 2:1 donor-acceptor-type organic charge-transfer (CT) complexes of (DMET)(2)(X(1)X(2)TCNQ) [DMET denotes dimethyl(ethylenedithio)diselenadithiafulvalene, TCNQ denotes tetracyanoquinodimethane, X(1),X(2)=Br,Cl,F,CH(3),H]. In these complexes, donors (D's) formed quasi-one-dimensional (Q1D) molecular stacks (D=+1/2), which were bridged with each other, by acceptor molecules whose molecular planes were parallel to the stacking axes. By the magnetic measurements, we found that the compounds could be classified into two groups in terms of the 2k(F) transitions of the donor stacks: two complexes exhibited the transitions at around room temperature, while the other two at lower temperature below 10 K. We discuss the origin of the difference in the observed 2k(F) transitions in terms of the subsidiary lattice effect by the acceptor molecules on the Q1D donor stacks.
  • “Langmuir-Blodgett Films of Amphiphilic Bis(Tetrathiafulvalene) Macrocycles with Four Alkyl Chains” T. Akutagawa, K. Kakiuchi, T. Hasegawa, T. Nakamura, C. A. Christensen and J. Becher, Langmuir, 20, 4187-4195 (2004)
    2004  [Not refereed][Not invited]
  • “Structural Change in Langmuir-Blodgett Films of Bis-tetrathiafulvalene Annelated Macrocycle-Tetrafuluorotetracyanoquinodimethane Charge Transfer Complex” Y. Tatewaki, T. Akutagawa, T. Hasegawa, T. Nakamura, C. A. Christensen and J. Becher; Mol. Cryst.・・・
    2004  [Not refereed][Not invited]
     
    “Structural Change in Langmuir-Blodgett Films of Bis-tetrathiafulvalene Annelated Macrocycle-Tetrafuluorotetracyanoquinodimethane Charge Transfer Complex” Y. Tatewaki, T. Akutagawa, T. Hasegawa, T. Nakamura, C. A. Christensen and J. Becher; Mol. Cryst. Liq. Cryst., 424, 17-23 (2004).
  • Y Tatewaki, T Akutagawa, T Hasegawa, T Nakamura, J Becher  SYNTHETIC METALS  137-  (1-3)  933  -934  2003/04  [Not refereed][Not invited]
     
    DialkylmacrocyclicbisTTF-F(4)TCNQ complex forms molecular nanowires on mica substrate. The morphology of nanowires changed according to the surface pressure and the deposition conditions.
  • “Structures and Physical Properties of BEDT-TTF Salts Containing Channels of Protons” A. Akutsu-Sato, H. Akutsu, S. S. Turner, D. Le Pevelen, P. Day, M. E. Light, M. B. Hursthouse, T. Akutagawa and T. Nakamura; Synthetic Metals, 135-136, 597-598 (2003)*
    2003  [Not refereed][Not invited]
  • "Langmuir-Blodgett Films of Bis-Tetrathiafulvalene Substituted Macrocycle and TCNQ Derivatives" H. Miyata, Y. Tatewaki, T. Akutagawa, T. Ohta, T. Hasegawa, T. Nakamura, C. A. Christensen and J. Becher, Thin Solid Films, 438-439, 1-6 (2003).*
    2003  [Not refereed][Not invited]
  • "Langmuir-Blodgett Films of Charge Transfer Complex between an Amphiphilic Monopyrrolo-TTF and TCNQ Derivatives" T. Akutagawa, M. Uchigata, T. Hasegawa, T. Nakamura, K. A. Nielsen, J. O. Jeppesen T. Brimert and J. Becher, J. Phys. Chem. B, 107, 13929-1・・・
    2003  [Not refereed][Not invited]
     
    "Langmuir-Blodgett Films of Charge Transfer Complex between an Amphiphilic Monopyrrolo-TTF and TCNQ Derivatives" T. Akutagawa, M. Uchigata, T. Hasegawa, T. Nakamura, K. A. Nielsen, J. O. Jeppesen T. Brimert and J. Becher, J. Phys. Chem. B, 107, 13929-13938 (2003).*
  • "Dynamic behavior of ammonium ion in the crown ether cavity within Ni(dmit)2 salt as studied by solid-state NMR" S. Takeda, G. Maruta, T. Akutagawa, T. Hasegawa and T. Nakamura, Synthetic Metals, 133-134, 427-429 (2003)*
    2003  [Not refereed][Not invited]
  • "Novel Magnet-Lattice Transition in the Mixed-Stack Charge-Transfer Complexes with Inter-Columner Networks" T. Hasegawa, T. Akutagawa and T. Nakamura, Synthetic Metals, 133-134, 623-625 (2003)*
    2003  [Not refereed][Not invited]
  • 2003  [Not refereed][Not invited]
     
    "The d-L()- Type of Charge-Transfer Salt [Cu(Me-tri)2][Ni(dmit)2]2: Correlation between Copper(II) d- and Ni(dmit)2 -Electrons via -conjugated Macrocyclic Ligands; K. Sakai, T. Akutagawa, T. Hasegawa and T. Nakamura, PhysChemChemPhys, 5, 2469-2475 (2003).*
  • "Molecular Orientation of Langmuir-Blodgett Films of AlkylDCNQI-Cu and AlkylTCNQ-Cu Complexes" K. Ikegami, T. P. Majumder, M. Lan and T. Nakamura; Transactions of the Materials Research Society of Japan, 28, 51-54 (2003).*
    2003  [Not refereed][Not invited]
  • "1H-NMR of [Ph(NH3)](18-crown-6)[Ni(dmit)2] Having Molecular Spin Ladder Structure" S. Nishihara, T. Akutagawa, T. Hasegawa, S. Fujiyama, T. Nakamura and T. Nakamura; Synthetic Metals, 137, 1279-1280 (2003).*
    2003  [Not refereed][Not invited]
  • 『有機トランジスタの動作性向上技術[材料開発、作製法、素子設計]』<工藤一浩監修>
    技術情報協会  2003  [Not refereed][Not invited]
  • T. Akutagawa, A. Hashimoto, S. Nishihara, T. Hasegawa, T. Nakamura  Journal of Supramolecular Chemistry  2-  (1-3)  175  -186  2002/01  [Not refereed][Not invited]
     
    Supramolecular dication structures, (CHDA 2+)(crown ethers) and (CHDMA 2+)(crown ethers) complexes, were introduced as counter cations to [Ni(dmit) 2] - anions (S=1/2 spin) (CHDA 2+=trans-1,4-cyclohexanediammonium CHDMA 2+=1,4-bis(methylammonium)cyclohexane dmit 2-=2-thioxo-1,3-dithiole-4,5-dithiolate crown ethers=[12]crown-4, [15]crown-5, or [18]crown-6). The cyclohexane rings, with the -NH 3 + or -CH 2-NH 3 + substituents at trans-1,4-positions, arrange into the crown ethers complexes within the [Ni(dmit) 2] - salts. The cyclohexane rings adopt chair conformations, resulting in sandwich-type (CHDA 2+ or CHDMA 2+)(crown ethers) 2 structures, through N-H... O hydrogen-bonding interactions within the crystals between the ammonium moieties of cations (-NH 3 + or -CH 2-NH 3 +) and the oxygen atoms of the crown ethers. Formations of π-π dimer structures of [Ni(dmit) 2] - anions were observed in all salts. The selections of the dication structures (CHDA 2+ or CHDMA 2+) and the crown ethers, due to the various ring sizes, can influence the intra and interdimer interactions of the [Ni(dmit) 2] - anions in the crystals. © 2003 Elsevier Ltd. All rights reserved.
  • Tomoyuki Akutagawa, N,Takamatsu, Tatsuo Hasegawa, Takayoshi Nakamura and T.Inabe:"Crystal Structure and Magnetism of[Ni(dimit)2]-Salts with Supramolecular Cations of M+(15-crown-5)", Cryst.Liq.Cryst.,376:39-46(2002)*
    2002  [Not refereed][Not invited]
  • S.Nishihara, Tomoyuki Akutagawa, Tatsuo Hasegawa and Takayoshi Nakamura:"Formation of Molecular Spin Ladder Induced by Supramolecular Cation Structure", Chem.Commun.,408-409(2002)*
    2002  [Not refereed][Not invited]
  • Tomoyuki Akutagawa, A.Hashimoto, S.Nishihara, Tatsuo Hasegawa and Takayoshi Nakamura:"Magnetic Properties of [Ni(dmit)2]-Anions Induced by Flexible Hydrogen-bonded Supramolecular Cations(p-Xylylenediammonium2+)(Crown Ethers)2", J.Phys.Chem.B,107:66-74(・・・
    2002  [Not refereed][Not invited]
     
    Tomoyuki Akutagawa, A.Hashimoto, S.Nishihara, Tatsuo Hasegawa and Takayoshi Nakamura:"Magnetic Properties of [Ni(dmit)2]-Anions Induced by Flexible Hydrogen-bonded Supramolecular Cations(p-Xylylenediammonium2+)(Crown Ethers)2", J.Phys.Chem.B,107:66-74(2002)*
  • Tomoyuki Akutagawa, T.Ohta, Tatsuo Hasegawa and Takayoshi Nakamura:"Formation of Oriented Molecular Nanowires on Mica Surface", Pro.Natl.Acad.Sci.USA, 99:5028-5033(2002)*
    2002  [Not refereed][Not invited]
  • Tomoyuki Akutagawa and Takayoshi Nakamura:"Semiconductor and Molecular-Assembly Nanowires",Springer Verlarg(Berlin),123-147(2002)
    2002  [Not refereed][Not invited]
  • 応用物理ハンドブック<第2版 応用物理学会編>
    丸善  2002  [Not refereed][Not invited]
  • Takayoshi Nakamura, T.Matsumoto, H.Tada and K.I.Sugiura:"Chemistry of Nanomolecular Systems;Toward the Realization of Molecular Devices"Springer Verlag(Berlin),(2002)
    2002  [Not refereed][Not invited]
  • Shitagami, K., Akutagawa, T., Hasegawa, T., Nakamura, T. and Robertson, N.: "An Infinite Supramolecular Array Structure in Metal Dithiolate Complexes: Crystal Structure of K(Dibenzo-18-crown-6)[M(dmit)2](CH3CN)2 (M: Ni, Au)", Cryst. Eng. Commun., 3: 25・・・
    2001  [Not refereed][Not invited]
     
    Shitagami, K., Akutagawa, T., Hasegawa, T., Nakamura, T. and Robertson, N.: "An Infinite Supramolecular Array Structure in Metal Dithiolate Complexes: Crystal Structure of K(Dibenzo-18-crown-6)[M(dmit)2](CH3CN)2 (M: Ni, Au)", Cryst. Eng. Commun., 3: 255-258 (2001).*
  • Shitagami, K., Akutagawa, T., Hasegawa, T., Nakamura, T. and Robertson, N.: "Potassium Bis(4,5-dimercapto-1,3-dithiole-2-thionato)nickelate (1,4,7,10,13,16-hexaoxa-2,3:11,12-dibenzocyclooctadeca-2,11-diene) Propanone Solvate", Acta Crystallographica Se・・・
    2001  [Not refereed][Not invited]
     
    Shitagami, K., Akutagawa, T., Hasegawa, T., Nakamura, T. and Robertson, N.: "Potassium Bis(4,5-dimercapto-1,3-dithiole-2-thionato)nickelate (1,4,7,10,13,16-hexaoxa-2,3:11,12-dibenzocyclooctadeca-2,11-diene) Propanone Solvate", Acta Crystallographica Section C, 57: 1271-1273 (2001).*
  • Sakai, K., Akutagawa, T., Hasegawa, T. and Nakamura,T.: "Partially-Oxidized Ni(dmit)2 Salt with Copper Ions" Synthetic Metals, 120: 805-806 (2001)*
    2001  [Not refereed][Not invited]
  • Akutagawa, T., Takamatsu, N., Shitagami, K., Hasegawa, T., Nakamura, T., Inabe, T., Fujita, W. and Awaga, K.: "Diversity in 1/2 spin arrangement of [Ni(dmit)2]- anions in divalent Ca2+(crown ethers) supramolecular cation salts", J. Mater. Chem., 11: 21・・・
    2001  [Not refereed][Not invited]
     
    Akutagawa, T., Takamatsu, N., Shitagami, K., Hasegawa, T., Nakamura, T., Inabe, T., Fujita, W. and Awaga, K.: "Diversity in 1/2 spin arrangement of [Ni(dmit)2]- anions in divalent Ca2+(crown ethers) supramolecular cation salts", J. Mater. Chem., 11: 2128-2124 (2001).*
  • Takahashi, T., Sakai, K., Yumoto, T., Akutagawa, T., Hasegawa, T. and Nakamura, T.:"Structure and Electronic Properties of Bis[bis(methylthio)tetrathiafulvalenedithiolate)-Gold(III) Langmuir-Blodgett Films", Thin Solid Films, 393: 7-11 (2001).*
    2001  [Not refereed][Not invited]
  • Mikami, S., Sugiura, K., Maruta, T., Maeda, Y., Ohba, M., Usuki, N., Okawa, H., Akutagawa, T., Nisihara, S., Nakamura, T., Iwasaki, K., Miyazaki, N., Hino, S., Asato, E., Miller J. S. and Sakata, Y. : "Structure, optical and magnetic behaviour of meso-・・・
    2001  [Not refereed][Not invited]
     
    Mikami, S., Sugiura, K., Maruta, T., Maeda, Y., Ohba, M., Usuki, N., Okawa, H., Akutagawa, T., Nisihara, S., Nakamura, T., Iwasaki, K., Miyazaki, N., Hino, S., Asato, E., Miller J. S. and Sakata, Y. : "Structure, optical and magnetic behaviour of meso-tetraphenylporphyrinatoiron(III) tetracyanoethenide, [FeIII(TPP)]+[TCNE]•-", J. Chem. Soc. Dalton Trans., 448-455 (2001).*
  • 2001  [Not refereed][Not invited]
     
    Cronin, L., Clark, S. J., Parsons, S., Nakamura, T. and Robertson,N.: "Unique Structural Topologies Involving Metal-Metal and Metal-Sulphur Interactions: Salts of [Ni(dmit)2]x- with cis-anti-cis-dicyclohexyl-18-crown-6 Complexed Counterions", J. Chem. Soc. Dalton Trans., 1347-1351 (2001).*
  • Naito, T., Inabe, T., Takeda, K., Awaga, K., Akutagawa, T., Hasegawa, T. Nakamura, T., Kakiuchi, T., Sawa, H., Yamamoto, T. and Tajima, H.: "''-(ET)3(MnCl4)(1,1,2-C2H3Cl3) (ET = bis(ethylenedithio)tetrathiafulvalene); A Pressure-Sensitive New Molecul・・・
    2001  [Not refereed][Not invited]
     
    Naito, T., Inabe, T., Takeda, K., Awaga, K., Akutagawa, T., Hasegawa, T. Nakamura, T., Kakiuchi, T., Sawa, H., Yamamoto, T. and Tajima, H.: "''-(ET)3(MnCl4)(1,1,2-C2H3Cl3) (ET = bis(ethylenedithio)tetrathiafulvalene); A Pressure-Sensitive New Molecular Conductor with Localized Spins", J. Mater. Chem., 11: 2221-2227 (2001).*
  • Akutagawa, T., Hasegawa, T., Nakamura, T., Takeda, S., Inabe, T., Sugiura, K., Sakata, Y. and Underhill, A. E.: "Ion Channel Structures in M+(18-Crown-6)[Ni(dmit)2] Molecular Conductors", Chem. Eur. J., 7: 4902-4912 (2001).*
    2001  [Not refereed][Not invited]
  • T. Akutagawa, T. Hasegawa and T. Nakamura, "Supramolecular Aspects of Organic Conductors" pp. 267-301, Handbook of Advanced Electronic and Photonic Materials, ed. H. S. Nalwa, Volume 3: High Tc Superconductors and Organic Conductors, Academic Press, Sa・・・
    2001  [Not refereed][Not invited]
     
    T. Akutagawa, T. Hasegawa and T. Nakamura, "Supramolecular Aspects of Organic Conductors" pp. 267-301, Handbook of Advanced Electronic and Photonic Materials, ed. H. S. Nalwa, Volume 3: High Tc Superconductors and Organic Conductors, Academic Press, San Diego (2001).
  • Kawamata, J., Akutagawa, T., Hasegawa, T., Inoue, K. and Nakamura, T.: "Nonlinear Optical Properties of the Langmuir-Blodgett Films of an Intermolecular Charge Transfer Complex" Nonlinear Optics, 25, 425-430 (2000)*
    2000  [Not refereed][Not invited]
  • Akutagawa, T., Hasegawa, T., Nakamura, T., Takeda, S., Inabe, T., Sugiura, K., Sakata, Y. and Underhill, A. E.: "M+(12crown-4) Supramolecular Cations (M+ = Na+, K+, Rb+ and NH4+) within Ni(dmit)2 Molecular Conductor" Inorg. Chem., 39, 2645-2651 (2000)*
    2000  [Not refereed][Not invited]
  • Abe, Y., Takamatsu, N., Yumoto, T., Suzuki, T., Akutagawa, T., Hasegawa, T., Nakamura, T., Higuchi, M., Hiratani, K.: " Polymerization of Pyrrole under Microgravity Conditions" Space Forum, 6, 221-226 (2000)*
    2000  [Not refereed][Not invited]
  • "Crystal Structure of Tetrathiafulvalene Multiannulated Macrocycles in Open-Shell Electronic State" Akutagawa, T., Abe, Y., Ohta, T., Hasegawa, T., Nakamura, T., Christensen, C. A. and Becher, J.: Mol. Cryst. Liq. Cryst., 349, 379-382 (2000)*
    2000  [Not refereed][Not invited]
  • Takamatsu, N., Akutagawa, T., Hasegawa, T., Nakamura, T., Inabe, T., Fujita, W. and Awaga, K.: "M+(Crown Ether) Supramolecular Cations (M+ = K+, Rb+, NH4+) for Controlling Magnetic Properties of Monovalent [Ni(dmit)2] Salts" Mol. Cryst. Liq. Cryst., 34・・・
    2000  [Not refereed][Not invited]
     
    Takamatsu, N., Akutagawa, T., Hasegawa, T., Nakamura, T., Inabe, T., Fujita, W. and Awaga, K.: "M+(Crown Ether) Supramolecular Cations (M+ = K+, Rb+, NH4+) for Controlling Magnetic Properties of Monovalent [Ni(dmit)2] Salts" Mol. Cryst. Liq. Cryst., 343, 163-168 (2000)*
  • Akutagawa, T., Nishihara, S., Takamatsu, N., Hasegawa, T., Nakamura, T. and Inabe, T.: "Co2+(15-crown-5) Magnetic Supramolecular Cation in [Ni(dmit)2]- p-spin System" J. Phys. Chem, 104, 5871-5873 (2000)*
    2000  [Not refereed][Not invited]
  • Uesugi, K., Suemune, I., Hasegawa, T., Akutagawa, T. and Nakamura, T.: "Temperature Dependence of Band Gap Energies of GaAsN Alloys" Appl. Phys. Lett., 76, 1285-1287 (2000)*
    2000  [Not refereed][Not invited]
  • Akutagawa, T., Abe, Y., Hasegawa, T., Nakamura, T., Inabe, T., Christensen, C. A. and Becher, "Tuning of Intramolecular p-p Overlap Mode of Tetrathiafulvalene bisannulated Macrocycles in the Open-Shell Electronic State" J.: Chem. Lett., 132-133 (2000)*
    2000  [Not refereed][Not invited]
  • Hasegawa, T., T. Mochida, R. Kondo, S. Kagoshima, Iwasa, Y., Akutagawa, T., Nakamura, T. and Saito, G.: "Mixed-Stack Organic Charge-Transfer Complexes with Intercolumnar Networks" Phys. Rev. B, 62, 10059-10066 (2000)*
    2000  [Not refereed][Not invited]
  • "Valance-Modulation-Induced Optical Nonlinearlity of Intermolecular Charge-Transfer Langmuir-Blodgett Films" T. Hasegawa, T. Akutagawa, T. Konuma, T. Nakamura, J. Kawamata and K. Inoue; Nonlinear Optics, 22, 143-146 (1999)
    1999  [Not refereed][Not invited]
  • "Langmuir-Blodgett Films of BEDO-TTFoCF3TCNQ" T. Yumoto, T. Akutagawa, T. Hasegawa, T. Nakamura, H. Ikegami and G. Saito; Synthetic Metals, 102, 1733-1734 (1999)
    1999  [Not refereed][Not invited]
  • "Nonlinear Optical Properties of Langmuir-Blodgett Films of Pyrazine-based Dye Molecule" T. Akutagawa, T. Hasegawa, T. Konuma, T. Nakamura and M. Matsuoka; Nonlinear Optics, 22, 127-130 (1999)
    1999  [Not refereed][Not invited]
  • "A New Method for Evaluating Third-Order Nonlinear Optical Efficiency of Powder Crystals" J. Kawamata, M. Kiguchi, T. Nakamura and K. Inoue; Nonlinear Optics, 22, 349-352 (1999)
    1999  [Not refereed][Not invited]
  • "Crystal Structure and Optical Properties of Cation Radical Salts of Tetrathiafulvalene Tris-annulated Macrocycles" T. Akutagawa, Y. Abe, T. Hasegawa, T. Nakamura, T. Inabe, K. Sugiura, Y. Sakata, C. A. Christensen and J. Becher; J. Mater. Chem., 9, 27・・・
    1999  [Not refereed][Not invited]
     
    "Crystal Structure and Optical Properties of Cation Radical Salts of Tetrathiafulvalene Tris-annulated Macrocycles" T. Akutagawa, Y. Abe, T. Hasegawa, T. Nakamura, T. Inabe, K. Sugiura, Y. Sakata, C. A. Christensen and J. Becher; J. Mater. Chem., 9, 2737-2742 (1999).
  • "Electrical and Nonlinear Optical Properties of Langmuir-Blodgett Films of Charge Transfer Complexes" T. Nakamura, T. Yumoto, T. Suzuki, T. Akutagawa, T. Hasegawa, H. Tachibana, M. Matsumoto, S. Horiuchi, H. Ikegami, H. Yamochi and G. Saito; Mol. Cryst・・・
    1999  [Not refereed][Not invited]
     
    "Electrical and Nonlinear Optical Properties of Langmuir-Blodgett Films of Charge Transfer Complexes" T. Nakamura, T. Yumoto, T. Suzuki, T. Akutagawa, T. Hasegawa, H. Tachibana, M. Matsumoto, S. Horiuchi, H. Ikegami, H. Yamochi and G. Saito; Mol. Cryst. Liq. Cryst., 327, 83-86 (1999)
  • "Observation of Third-Order Nonlinear Optical Effects of Metallo-Dimethylglyoxime Complexes by Methods Using the Evanescent Wave" J. Kawamata, T. Akutagawa, T. Hasegawa, T. Nakamura, K. Inoue, M. Kiguchi and G. Saito; Nonlinear Optics, 22, 373-376 (1999).
    1999  [Not refereed][Not invited]
  • "A Clay-Metal Complex Ultrathin Film as Prepared by the Langmuir-Blodgett Technique" K. Tamura, H. Setsuda, M. Taniguchi, T. Nakamura and A. Yamagishi; Chem. Lett., 121-122 (1999).
    1999  [Not refereed][Not invited]
  • "Polymerization of pyrrole in microgravity" T. Nakamura, T. Akutagawa, T. Hasegawa, T. Kikukawa, T. Araiso, M. Higuchi and K. Hiratani; Synthetic Metals, 101, 78-79 (1999).
    1999  [Not refereed][Not invited]
  • "Electronic Phase Transition of BEDT-TTF Based Mixed-Stack Charge-Transfer Complexes" T. Hasegawa, T. Akutagawa, T. Nakamura, Y. Sasou, R. Kondo, S. Kagoshima, T. Mochida, G. Saito and Y. Iwasa; Synthetic Metals, 103, 1804-1805 (1999).
    1999  [Not refereed][Not invited]
  • 1998  [Not refereed][Not invited]
     
    Nakamura, T., Yumoto, T., Akutagawa, T., Azumi, R., Tachibana, H., Matsumoto, M., Horiuchi, S., Yamochi, H. and Saito, G.: "Electrical Conduction in Monolayers and LB films of BEDOTTF- C10TCNQ / Arachidic Acid Mixed System" Thin Solid Films, 327-329, 450-453 (1998)*
  • Ikegami, K., Kuroda, S., Akutagawa, T., Konuma, T., Nakamura, T., Matsumoto, M., Horiuchi, S., Yamochi, H. and Saito, G.: "Possible Low-Temperature Phase Transition of Langmuir-Blodgett Films of a Charge-Transfer Complex Detected by ESR" Thin Solid Fil・・・
    1998  [Not refereed][Not invited]
     
    Ikegami, K., Kuroda, S., Akutagawa, T., Konuma, T., Nakamura, T., Matsumoto, M., Horiuchi, S., Yamochi, H. and Saito, G.: "Possible Low-Temperature Phase Transition of Langmuir-Blodgett Films of a Charge-Transfer Complex Detected by ESR" Thin Solid Films, 327-329, 391-394 (1998)*
  • Akutagawa, T., Nakamura, T., Inabe, T. and Underhill, A. E.: "Structures of Ni(dmit)2 (dmit = 2-thioxo-1,3-ditiol-4,5-dithiolate) Salts of Lithium or Ammonium Included in Crown Ether Assemblies" Thin Sold Films, 331, 264-271 (1998)*
    1998  [Not refereed][Not invited]
  • Nakamura, T., Akutagawa, T., Honda, K., Underhill, A. E., Coomber, A. T. and Friend, R. H.: "A Molecular Metal with an Ion-Conducting Channel" Nature, 394, 159-161 (1998)*
    1998  [Not refereed][Not invited]
  • Konuma, T., Akutagawa, Yumoto, T., T., Nakamura, T., Kawamata, J., Inoue, K., Nakamura, T., Tachibana, H., Matsumoto, M., Ikegami, K., Horiuchi, S., Yamochi, H. and Saito, G.: "Charge-Transfer Interactions and Nonlinear Optical Properties of Tetrathiaf・・・
    1998  [Not refereed][Not invited]
     
    Konuma, T., Akutagawa, Yumoto, T., T., Nakamura, T., Kawamata, J., Inoue, K., Nakamura, T., Tachibana, H., Matsumoto, M., Ikegami, K., Horiuchi, S., Yamochi, H. and Saito, G.: "Charge-Transfer Interactions and Nonlinear Optical Properties of Tetrathiafulvalene-based Langmuir-Blodgett Films" Thin Solid Films, 327-329, 348-352 (1998)*
  • 1998  [Not refereed][Not invited]
     
    Hasegawa, H., Naito, T., Inabe, T., Akutagawa, T., Nakamura, T.: "A Highly Conducting Partially Oxidized Salt of Axially Substituted Phthalocyanine. Structure and Physical Properties of TPP[Co(Pc)(CN)2]2 (TPP = tetraphenylphosphonium and [Co(Pc)(CN)2] = dicyano(phtalocyaninato)cobalt(III))" J. Mater. Chem., 8, 1567-1570 (1998)*
  • Akutagawa, T., Nezu, Y., Hasegawa, T., Sugiura, K., Nakamura, T., Inabe, T., Sakata, Y. and Underhill, A. E.: "Supramolecular Cation of Acyclic Polyether: Potassium (pentaethyleneglycoal) in Molecular Conductor of Nickel Dithiolate Salt" J. Chem. Soc. ・・・
    1998  [Not refereed][Not invited]
     
    Akutagawa, T., Nezu, Y., Hasegawa, T., Sugiura, K., Nakamura, T., Inabe, T., Sakata, Y. and Underhill, A. E.: "Supramolecular Cation of Acyclic Polyether: Potassium (pentaethyleneglycoal) in Molecular Conductor of Nickel Dithiolate Salt" J. Chem. Soc. Chem. Commun., 2599-2600 (1998)*
  • Akutagawa, T., Nezu, Y., Abe, Y., Nakamura, T., Yamanaka, A., Inoue, K., Inabe, T., Christensen, C. A., Becher, J.: "Linear Pentaidodide in the Radical Cation Salt of Tetrathiafulvalene Bisannulated Macrocycle" Inorg. Chem., 37, 2330-2331 (1998)*
    1998  [Not refereed][Not invited]
  • Akutagawa, T., Konuma, T. and Nakamura, T. : "Intermolecular Charge Transfer in the Langmuir-Blodgett Films : Formation of Mixed and Alternate-Layer LB films of Quinhydrone and TTF-TCNQ Derivatives", Mol. Cryst. Liq. Cryst., 296, 383-395 (1997)*
    1997  [Not refereed][Not invited]
  • 1997  [Not refereed][Not invited]
     
    Nakamura, T., Konuma, T., Akutagawa, T., Tachibana, H., Azumi, R., Matsumoto, M., Isotalo, H., Horiuchi, S., Yamochi, H. and Saito, G. : "Langmuir-Blodgett Films of Molecular Conductors based on AlkylTCNQ Derivatives", Synthetic Metals, 86, 1843-1844 (1997)*
  • Nakamura, T., Konuma, T. and Akutagawa, T. : "Langmuir-Blodgett Films of Binary Mixture of Donors and Acceptors with Long Alkyl Chains", Synthetic Metals, 86, 1903-1904 (1997)*
    1997  [Not refereed][Not invited]
  • Konuma, T., Akutagawa, T. and Nakamura, T. : "Langmuir-Blodgett Films of Alkyl-Substituted Quinhydrone", Mol. Cryst. Liq. Cryst., 294, 209-212 (1997)*
    1997  [Not refereed][Not invited]
  • Akutagawa, T., Nakamura, T., Inabe, T. and Underhill, A. E. : "A Supramolecular Cation in an Electrically Conducting Nickel-dithiolate Salt", J. Mater. Chem., 7, 183-185 (1997)*
    1997  [Not refereed][Not invited]
  • Nakamura, T. : "Electrically Conductive Langmuir-Blodgett Films", pp. 727-780 H. S. Nalwa (ed.), Handbook of Organic Conductive Molecules and Polymers vol. 1, John Wiley & Sons., Chichester (1997)
    1997  [Not refereed][Not invited]
  • T. Nakamura, H. Isotalo, T. Akutagawa, H. Tachibana, R. Azumi, M. Matsumoto, S. Horiuchi, H. Yamochi and G. Saito : "Conductivity of Floating Monolayers Based on BEDO-TTF Charge Transfer Complex at the Air-Water Interface", Thin Solid Films, 284-285 : ・・・
    1996  [Not refereed][Not invited]
     
    T. Nakamura, H. Isotalo, T. Akutagawa, H. Tachibana, R. Azumi, M. Matsumoto, S. Horiuchi, H. Yamochi and G. Saito : "Conductivity of Floating Monolayers Based on BEDO-TTF Charge Transfer Complex at the Air-Water Interface", Thin Solid Films, 284-285 : 508-511 (1996)*
  • T. Nakamura, H. Isotalo, T. Akutagawa, H. Tachibana, R. Azumi, M. Matsumoto, S. Horiuchi, H. Yamochi and G. Saito : "Conducting Monolayers and Langmuir-Blodgett Films Based on BEDO-TTF and Decyl-TCNQ Complex", Mol. Cryst. Liq. Cryst., 284 : 235-246 (19・・・
    1996  [Not refereed][Not invited]
     
    T. Nakamura, H. Isotalo, T. Akutagawa, H. Tachibana, R. Azumi, M. Matsumoto, S. Horiuchi, H. Yamochi and G. Saito : "Conducting Monolayers and Langmuir-Blodgett Films Based on BEDO-TTF and Decyl-TCNQ Complex", Mol. Cryst. Liq. Cryst., 284 : 235-246 (1996)*
  • T. Akutagawa, G. Saito, T. Nakamura, K. Sakaguchi and M. Kusunoki : "Hydrogen-Bond Character of 2,2'-bi-1H-imidazole Systems", Mo1. Cryst Liq. Cryst., 276 : 257-266 (1996)*
    1996  [Not refereed][Not invited]

Industrial Property Rights

Research Grants & Projects

  • 文部科学省:科学研究費補助金(基盤研究(A))
    Date (from‐to) : 2014 -2017 
    Author : 中村 貴義
  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型))
    Date (from‐to) : 2013 -2014 
    Author : 中村 貴義
  • 文部科学省:科学研究費補助金(基盤研究(B))
    Date (from‐to) : 2011 -2013 
    Author : 中村 貴義
     
    以下の項目について検討を行った。1.分子のfilp-flop運動に基づく強誘電性発現既にm-fluoroanilinium/dibenzo[18]crown-6において、分子回転に伴うdipoleのflip-flopを利用した強誘電体を実現している。それを基に、他のアニリニウム等の回転子および種々のクラウンエーテルの組み合わせから結晶を作製し、分子回転および強誘電性について系統的に精査した。対アニオンは主として[Ni(dmit)2]を用いた。filp-flop運動に基づく誘電応答を示す系を複数見出した。2.ケージ内の分子回転に基づく強誘電性発現の探索特定の回転軸をもたずに、ケージ状の超分子構造の中である程度自由な回転を発現する系を探索する。クラウンエーテルにサンドイッチされた空間にpyazineが包接された系をターゲットとし、複数の結晶を得た。プロトンを介してpyazineはクラウンエーテルと弱く水素結合しており、これを軸としてflip-flop運動や振り子運動を示し、外部電場に応答する事を明らかにした。3.球状分子の回転に基づく強誘電性発現アダマンタンを利用した回転が可能な新規分子系を開拓した。まず、フルオロアダマンタンアンモニウム(FADH)の単純塩の合成を開始した。4.ポテンシャル曲線の設計による分極軸の複数化回転子がある程度高い対称性をもつFDAHを用いて3極小ポテンシャルを実現した。誘電応答にリラクサー的な傾向がみられ、精査を開始した。5.複合回転系の実現および6.回転子への機能付与と複合機能化この2項目については、予備実験から通常の分子設計では実現が困難である事が判明したので、新たな分子設計に向けた検討を開始した。但し項目5について、fluoroadamantane carboxylic acidの銅錯体系については有望であると判断し、今後検討を進める。
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    Date (from‐to) : 2011 -2013 
    Author : 中村 貴義
     
    強相関電子系を形成する単結晶内に超分子ローター構造を構築し、ブラウンラチェット機構による一方向回転の実現、およびエネルギー変換のための基礎物性評価を行うことを目標とし、以下の項目について順次検討を行う。1,2を期間内に達成することを目指すとともに、3,4の可能性を評価する。1. 超分子ローター構造のパーツとしてキラルなクラウンエーテル等を用いることで、ノコギリ歯型ポテンシャルを導入する。(必要条件1)2. 置換アニリニウム等、ダイポールをもつ回転子を導入し、外部電場により分子回転を摂動できる仕組みを用意する。(必要条件2)3. 光学測定や熱力学測定を駆使して、一方向回転を検証する。4. 分子回転に伴う磁性・電気伝導性の異常を評価し、それを端緒としてエネルギー変換素子構築への道筋を示す。 23年度については、非対称ポテンシャルの導入およびダイポールを持つ回転子の導入を中心に検討を進めた。 クラウンエーテルの分子設計により非対称ポテンシャルの導入を試みた。dicyclohexano[18]crown-6は、4つのキラルセンターを持っているため、meso体を用いても結晶内で歪むことによりノコギリ型ポテンシャルを形成する可能性がある。そこで、trans-syn-trans型のdicyclohexano[18]crown-6誘導体を新たに合成し、結晶内への導入を行った。また、ダイポールを持つ回転子として、m-fluoroaniliniumを選び、結晶作製を行った。得られた結晶は、複雑な構造を持ち、現在引き続き構造評価を行っている。
  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型))
    Date (from‐to) : 2011 -2012 
    Author : 中村 貴義
     
    平成23年度においては以下の項目について、重点的に研究を進めた。・金ナノ粒子複合体の形成金ナノ粒子複合体の作製は金ナノ粒子合成で広く利用されているBrust法で行った。この方法の利点は作製条件により金ナノ粒子のサイズを比較的容易に変えることができる点である。粒子サイズにより帯電エネルギーが大きく変化し、結果として導電挙動に大きく影響するが、ボルフィリン誘導体を用いた場合の結果から、量子伝導を評価するに当たり、2nm-4nm程度の粒径が好適であると考えられ、本研究においてもこの程度の粒径をもつ単分散の金ナノ粒子を得るための条件検討を行った。TEMによる観察から2nm-5nm程度の粒径のナノ粒子が生成している事を確認した。・金ナノ粒子複合体の評価UV-vis-NIRおよびRamanスペクトルにおけるフタロシアニン誘導体に対応する吸収から、複合体の中でのフタロシアニン誘導体の電子状態を評価した。また、金ナノ粒子複合体の組成から、フタロシアニン誘導体の表面吸着状態を評価した。組成を元素分析決定し、1粒子あたりのフタロシアニン誘導体分子数を求めることで、金ナノ粒子表面に単分子層がflat-on配向で存在している事を推定することができた。・金ナノ粒子集積構造の作製と評価伝導度測定は、金電極上に金ナノ粒子複合体をドロップキャストすることでサンプルを作製した。低温での電気伝導度測定の予備実験から、collective-tunnelingが起こっている事、fスピンによりトンネル電子が散乱されている可能性がある事などが推定され、24年度において精査する予定である。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 2007 -2010 
    Author : Takayoshi NAKAMURA, Sadamu TAKEDA
     
    Supramolecular cations composed of organic ammonium/[18]crown-6 derivatives were introduced in crystals of anionic species such as [Ni(dmit)2] which showed magnetic properties. Molecular rotations were examined by NMR measurements, theoretical calculation, etc. Among others, (m-fluoroanillinium)(dibenzo[18]crown-6)[Ni(dmit)2] crystal showed ferroelectric properties based on flip-flop motion of aryl groups. Possibility of application to multiferroic compounds was also studied.
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(特定領域研究)
    Date (from‐to) : 2004 -2007 
    Author : Takayoshi NAKAMURA
     
    In this project, we aim at the developments of novel molecular systems based on molecular conductors and magnets with supramolecular cations having dynamic feature. As for the building blocks for molecular conductors and magnets, we are using [Ni (dmit) 2] and other metal complexes. Suplamoleclar structures based on crown ethers are combined with the complexes to form novel molecular systems. In this study, we mainly examined molecular rotator structures of organic ammonium and [18]crown-6 derivatives in [Ni (dmit) 2] salts.We introduced -NH2 at o-position of the anilinium and synthesized (HOPD)+([18]crown-6) [Ni (dmit) 2] crystals. Strong dipole-dipole interaction induced the tight packing of cation layers, which prevented flip-flop motion of aryl rings. On the other hand, [18]crown-6 was rotating in the crystal as in the case of (PhNH3) ([18] crown-6) (Ni (dmit) 2).We introduced -F and -NH2 at m-position of the anilinium and synthesized (HMFA)+(dibenzo[18]crown-6) [Ni (dmit) 2] and (HMPD)+(dibenzo [18] crown-6) [Ni (dmi1) 2] crystals. HMFA and HMPD salts gave the same composition and crystal structures.Since HMFA and HMPD have dipole moments, it was possible to control the flip-flop motion of these molecular rotators by applying external electric field. It was proved that the crystal was the ferroelectrics with the Curie temperature of at around 350 K. Adamantylammonium was introduced in the supuramolecular structure instead of arylammonium derivatives. In the crystals, the rotation of adamantly group was maintained below 120 K, which was confirmed by 1H-NMR measurements.In conclusion, we introduced supramolecular rotator structures in electronic active crystals, which is one of the key steps to realize highly efficient energy conversion systems. In addition, we could develop novel ferroelectrics based on molecular rotator structures.
  • 文部科学省:科学研究費補助金(萌芽研究)
    Date (from‐to) : 2005 -2006 
    Author : 中村 貴義
     
    典型的なドーナツ型POMに長鎖アルキルアンモニウムをカウンターカチオ:ンとして導入し、LB法およびスピンコート法により薄膜を作製し、これらの膜について、AFM等により引き続き構造評価を行った。その結果、LB膜では均一な層状構造が得られた。粉末X線から、ラメラ構造における面間隔を求めることができた。一方、スピンコート法により得られた膜においては、球状のナノドメインが観察された。そこで、出発物質の溶液について詳細に検討したところ、溶液内で均一なミセルを形成していることが判明し、その構造が膜構造に反映していることが分かった。製膜法を変えることにより、膜のナノ構造を制御することができた。POMに存在するモリブデンイオンの一部を鉄イオンなどに置き換えることで、 POMに磁性・導電性等の機能を付加することを目指した。通常のPOMにおいてはモリブデンスピン間に反強磁性的な相互作用が存在するため、磁気機能の発現はあまり望めない。一部のイオンを置換することで、巨大分子内に磁気モーメントを生じさせ、分子内の金属イオン間に強磁性的あるいはフェリ磁性的な相互作用をもたらす。本年度も引き続き、磁性イオンを共存させ、POMの合成を試みた。その結果、新たな構造をもつ巨大POMを合成することができた。特に、隣接するPOM間に共有結合を持つと思われる結晶が2種類得られ、詳細な構造評価を進めた。また、カウンターカチオンに磁性イオンを含む系について、物性評価を行った。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 2002 -2004 
    Author : Takayoshi NAKAMURA, Tomoyuki AKUTAGAWA, Tatsuo HASEGAWA
     
    1.Synthesis of macrocyclic TTF derivatives for molecular nanowiresMacrocyclic derivatives were synthesized and combined with acceptor molecules to obtain conducting molecular assembly nanowires. Thiomethyl, BEDT-TTF and BEDO-TTF type molecules were synthesized Thiomethyl-type molecules formed nanowires and used for the subject 2 and 3 described below. BEDT-TTF type molecule was extensively studied and it was found that the molecule formed organogels and that its iodine complex formed nanodot structures. The molecules with three TTF units were also synthesized and subjected to form Langmuir-Blodgett(LB) films. Complex with C60 successfully formed LB films.2.Wiring techniqueMechanism of wire formation was evaluated and the best condition for forming wires was fixed. We found that gel and wire formation are closely related to each other. Best on this, molecular design was carried out for novel wire formation. Hybrid structure with gold nanoparticles was prepared and the detailed electrical properties were evaluated.3.Structural evaluation of nanowire networksStructure of nanowire network was evaluated by probe maicroscopes. It was found that the C60-macrocyclic TTF showed surface-pressure induced charge-transfer transition in thin film form.
  • 文部科学省:科学研究費補助金(萌芽研究)
    Date (from‐to) : 2002 -2003 
    Author : 中村 貴義, 武田 定
     
    1.[Ni(dmit)_2]結晶内に分子ローター構造を構築した。種々のクラウンエーテルおよびアリールアンモニウムを組み合わせ、構造を形成した。本年度は、アニリニウムと18-crown-6からなる分子ローター構造を導入した系について、μSRを用いて詳細な物性測定を行ったところ、Ni(dmit)_2が示す磁性は低温でオーダーせず、スピンラダー的な磁性を保つことを明らかにした。また、18-crown-6自体が回転している系について高圧下での磁性を検討することにより、回転と磁性の関連について詳細に検討を行った。高圧SQUIDに関する実験から、回転は4kbar程度の加圧により止まることが判明した。また、新たに12-crown-4を導入した系について検討を開始した。2.[Ni(dmit)_2]結晶内にキラルなカチオンを導入した。分子の1方向への回転を目指し、まず、キラルな環境を導入するため、キラルカチオンをカウンターカチオンとする、Ni(dmit)_2塩を作製した。昨年度までに得られている1,2-diphenylethylene-diamine、2-ammo-1-phenylethanol及び、1-Aminoindanの4級塩を導入した系について結晶構造と電子物性の相関について検討を行った。また、S, R体およびdl体の1-Indanのアンモニウム塩を導入した系を新たに作製し、カウンターカチオンのキラリテイとNi(dmit)_2の配列との相関について検討を行った。
  • 文部科学省:科学研究費補助金(基盤研究(C))
    Date (from‐to) : 2001 -2001 
    Author : 中村 貴義, 松本 卓也, 小川 琢治, 杉浦 健一, 渡邉 聡, 夛田 博一
     
    分子エレクトロニクスに関する多様なアプローチからの研究成果を報告し、現在までに提起されている課題を整理し議論を深めることで、将来へ向けての研究の方向性を提示すると共に、今後の分子エレクトロニクス研究の目標・テーマ設定を行った。そのためのワークショップを開催し、分野を越えた共同研究の端緒とした。特に、化学以外の分野に積極的に参加を呼びかけたところ、学際的・分野横断的な共同研究の萌芽を数多く作り出すことができた。具体的には以下の項目を重点的に検討した。1.単分子エレクトロニクスデバイスへのアプローチデバイスを構成する機能性分子の合成。スイッチ、ロジックゲートなどの設計。分子と電極とのコンタクトの形成、界面の評価。ナノ電極の作製。単分子の電子物性評価、プロープ顕微鏡等の開発と単一分子計測。単分子の電子物性理論。2.分子集合体からのアプローチ有機導体のデバイス展開。有機磁性体のデバイス展開。ナノ構造の構築と表面・界面の構造・物性。周期性が破綻した領域での機能設計と物性評価。強相関電子系のデバイス展開のための物性理論。3.自己集積化と自己組織化分子および分子集合体の集積化。分子間相互作用と機能の複合化。自己集積化によるデバイス構造の構築。表面・界面への分子集合体の吸着。分子集合体の構造および機能の時空間制御。分子集合体の自己組織化(散逸構造形成)。4.コンピューテイングアーキテクチャと分子エレクトロニクス量子コンピューティング。デバイスの非線形性、熱揺動と確率共鳴。欠陥耐性のあるコンピューティングシステム。また分子エレクトロニクス研究の現状と将来展望について、議論の結果を冊子にまとめ、今後の研究領域の発展に資するべく、単行本の編集を行った。
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 2001 -2001 
    Author : 中村 貴義
     
    1.クラウンエーテルと有機アンモニウムカチオンを用いて[Ni(dmit)_2]結晶内に超分子構造を構築した。種々のクラウンエーテルおよび有機アンモニウムを組み合わせ、[Ni(dmit)_2]のカウンターカチオンとして結晶内に導入することで超分子構造を形成した。特に、アリールアンモニウムやシクロヘキサン環をもつアンモニウムカチオンを中心に検討を加え、20種類程度の新規結晶を得た。この中で、アニリニウムを用いた場合に、結晶内でベンゼン環が回転していることを見出し、NMRを用いて、その機序を明らかにした。また、この分子回転と結晶の示す誘電率との関係について検討を加えた。さらに、セシウムイオンをサンドイッチした18-crown-6からなる超分子カチオン構造を導入した[Ni(dmit)_2]結晶において、結晶内で18-crown-6自体が回転し、さらに、その回転が[Ni(dmit)_2]の磁性に大きく影響する系を見出した。また、この回転の停止には、水素結合の形成が関連していることも明らかとなった。2.超分子構造を利用して[Ni(dmit)_2]の配列制御を行い新規な電子機能を開拓した。超分子カチオン構造を利用して、[Ni(dmit)_2]の結晶内の配列を制御した。実際に、[Ni(dmit)_2]^-(S=1/2スピンを持つ)のスピンラダー構造を実現することができた。さらに、スピンラダー構造へのキャリアドープを行い、室温での電気伝導度が数桁向上することを見出した。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(A))
    Date (from‐to) : 1998 -2001 
    Author : Takayoshi NAKAMURA, Sadamu TAKEDA, Kunio AWAGA, Tamotsu INABE, Tomoyuki AKUTAGAWA, Tatsuo HASEGAWA
     
    We introduced supramolecular cations composed of inorganic cations and crown ethers into [Ni(dmit)2 crystals and developed novel molecular systems in which electronic condction and ionic conduction coexisted.We also regulated [Ni(dmit)_2]^- assemblies in the crystal utilizing supramolecular cation structures and revealed that we could control magnetic and electronic properties through the molecular-assembly control.To develop nanometer-size materials and devices from molecular charge transfer complexes, we investigated the formation of molecular films of charge transfer complexes. Especially, we used Langmuir-Blodgett method and succeeded in forming single-component conducting films. In addition, we studied self-assembly monolayers in which TTF skeleton directly attached to gold surface. We found that when we apply the Langmuir-Blodgett method to macrocyclic TTF molecule that has ion-recognition ability, the molecules forms nanowire structures. Moreover, when we used mica substrates, the nanowires recognized ionic array of the surface and oriented specific directions. These results strongly indicate that the molecular charge transfer complexes are quite useful to developing future molecular electronic devices.
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 2000 -2000 
    Author : 中村 貴義
     
    TTF誘導体がフレキシブルなアルキル基等で結合した環状物質に注目して研究を進めている。このような系に期待されることは、(1)結合部位のフレキシビリティに由来した、TTF部位の空間的な位置制御とそれに伴う新奇物性の発現、(2)環状部分への金属イオンの包接によるTTF部位の物性制御、あるいは、TTF部位のレドックス制御による金属イオンの包接挙動の制御である。1.単結晶系におけるTTFの空間位置制御24員環および30員環を有するマクロサイクリックTTFを合成し、TCNQ系アクセプターとの錯体を作製した。結晶中でドナー分子は2価、すなわちTTF分子は完全電荷移動状態になっていた。TTFが+1価であるため、結晶中ではボリエーテル部分が折れたたまり、いずれの場合もZ型のコンフォメーションを有していた。しかしながら、分子内のTTFオーバーラップ形式は異なり、結合部分のフレキシビリティを利用して、TTF部位の重なり制御ができた。さらに、TCNQ部位が部分酸化状態にある塩も得られ、導電性分子集合体を構築することが出来た。2.マクロサイクリックTTF誘導体単分子膜のイオン認識単結晶と比較してイオンの出し入れがより容易であると考えられる超薄膜系を、マクロサイクリックTTF誘導体を用いて構築し、膜のイオン認識と構造物性相関について検討した。成膜物質としては2および4鎖型マクロサイクリックTTF誘導体を用いた。いずれの場合も良好なπ-A曲線を与えた。また、下層水にアルカリ金属イオンを添加したところ、イオン濃度に対応したπ-A曲線の変化が観測された。π-A曲線の挙動変化の原因を探索するために、水面上でのBAM(Brustar Angle Microscope)観察および単分子膜をマイカ基板上に写し取ってAFM測定を行った。その結果、下層水のイオンにより、膜のモルホロジーが大きく変化することが分かり、さらに条件を整えることによりかなり長いファイバー構造が得られることが判明した。
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 2000 -2000 
    Author : 中村 貴義
     
    1.単成分導電体のLB法による超薄膜形成単成分導電体の前駆体である(C_<10>H_<21>)_3NCH_3[Ni(tmdt)_2]を合成し,LB法を用いて超薄膜化した。高度に秩序化した膜が固体基板上に形成された。中心金属としては比較的空気による酸化を受けにくい金を用いたが、製膜中に酸化が進行し、中性の[Ni(tmdt)_2]と思われる化学種からなる膜が形成した。膜形成後、電気化学的酸化により膜に導電性を付与することが可能であった。さらに、メタノールで洗浄することにより、膜中のアルキルアンモニウム部位を除去できることが明らかとなり、Au錯体同様、単成分導電体LB膜を得ることが出来た2.超薄膜系の構造および電子物性評価薄膜の構造評価は、偏光UV-Vis-NIR、透過IRおよびIR-RASを用いて行った。膜の酸化状態を検討したところ、LB膜の形成過程で、膜が中性状態に酸化されていることが判明した。また、ESRを用いてスピン状態の評価を試みたが、膜からのシグナルは観測出来なかった。マイカ基板上に1層累積した膜は、1ミクロン程度のドメイン構造を有しており、このようなドメイン構造が膜の導電性に影響を与えているものと示唆される。3.無機-有機へテロ界面における新規d-π複合電子系の構築新規d-π複合電子系を、無機-有機へテロ界面において構築した。TTF系ジチオレートアニオンを用い、金電極上に酸化的に薄膜を構築した。電極電位を規制することで、膜の形成および酸化状態の制御が可能である。これまでは、電位を固定して膜を作製していたが、QCMを用いた膜の形成過程の検討から、多層膜の形成が優先することが判明した。そこで、CV過程を直接用いることで膜を作製したところ、単分子膜レベルで膜の生成が止まった。QCMにおける質量変化の測定値から、分子は基板上でflat-onの配向をとっているものと考えられ、これは別途行ったSHG測定の結果と一致した。
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 1999 -1999 
    Author : 中村 貴義
     
    TTF誘導体がフレキシブルなアルキル基等で結合した環状物質に注目して研究を進めている。このような系に期待されることは、(1")"結合部位のフレキシビリティに由来した、TTF部位の空間的な位置制御とそれに伴う新奇物性の発現、(2")"環状部分への金属イオンの包接によるTTF部位の物性制御、あるいは、TTF部位のレドックス制御による金属イオンの包接挙動の制御である。1.単結晶系におけるTTFの空間位置制御24員環および30員環を有するマクロサイクリックTTFを合成し、TCNQ系アクセプターとの錯体を作製した。結晶中でドナー分子は2価、すなわちTTF分子は完全電荷移動状態になっていた。TTFが+1価であるため、結晶中ではポリエーテル部分が折れたたまり、いずれの場合もZ型のコンフォメーションを有している。しかしながら、分子内のTTFオーバーラップ形式は異なり、結合部分のフレキシビリティを利用して、TTF部位の重なり制御ができた。2.マクロサイクリックTTF誘導体単分子膜のイオン認識単結晶と比較してイオンの出し入れがより容易であると考えられる起薄膜系を、マクロサイクリックTTF誘導体を用いて構築し、膜のイオン認識と構造物性相関について検討した。成膜物質としては2および4鎖型マクロサイクリックTTF誘導体を用いた。いずれの場合も良好なπ-A曲線を与えた。また、下層水のアルカリ金属イオンを添加したところ、イオン濃度に対応したπ-A曲線の変化が観測された。π-A曲線の挙動変化の原因を探索するために、水面上でのBAM(Brustar Angle Microscope)観測および単分子膜をマイカ基板上に写し取ってAFM測定を行った。
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 1999 -1999 
    Author : 中村 貴義
     
    1.単成分導電体のLB法による超薄膜形成単成分導電体の前駆体である(C_<10>H_<21>)_3NCH_3[Au(tmdt)_2]を合成し,LB法を用いて超薄膜化した。高度に秩序化した膜が固定基板上に形成された。中心金属としては比較的空気による酸化を受けにくい金を用いたが、製膜中に酸化が進行し、中性の[Au(tmdt)_2]と思われる化学種からなる膜が形成した。膜形成後、電気化学的酸化により膜に導電性を付与することが可能であった。さらに、メタノールで洗浄することにより、膜中のアルキルアンモニウム部位を付与することが明らかとなり、単成分導電体LB膜形成の足がかりが得られた。2.超薄膜系の構造および電子物性評価薄膜の構造評価は、偏光UV-Vis-NIR、透過IRおよびIR-RASを用いて行った。膜の酸化状態を検討したところ、上述のようにフッ化カルシウム結晶上では、LB膜の形成過程で、膜が中性状態に酸化されていることが判明したが、金蒸着膜表面に累積を行った場合、monovalent塩のLB膜が形成していることがわかった。マイカ基板上に1層累積した膜は、1ミクロン程度のドメイン構造を有しており、このようなドメイン構造が膜の導電性に影響を与えているものと示唆される。3.無線―有機ヘテロ界面における新規d-π複合電子系の構築新規d-π複合電子系を、無機―有機ヘテロ界面において構築した。TTF系ジチオレートアニオンを用い、金電極上に酸化的に薄膜を構築した。電極部位を規制することで、膜の形成および酸化状態の制御が可能である。昨年度に引き続き、膜の形成及びその酸化状態について、IR-RASを用いての評価を行った。また、OCMを用いた膜の形成過程の検討を開始した。
  • 文部科学省:科学研究費補助金(萌芽的研究)
    Date (from‐to) : 1998 -1999 
    Author : 中村 貴義, 芥川 智行, 長谷川 達生
     
    1.導電性分子組織体の構築LB法を用いて微小電極上に導電性超薄膜を形成することを目標に、新たな導電性薄膜の開発を行った。前年度までに、BEDO-TTF・CF_3TCNQ錯体、Au(tmdt)_2錯体およびを用いて導電性を有するLB膜を作製した。これらの錯体のうち、有望なAu(tmdt)_2錯体、TTF-macrocycles誘導体を中心に検討を行った。2.LB膜分子組織体の構造・電気物性評価得られた分子組織体について、AFMにより構造評価を行った。Au(tmdt)_2についてはミクロンオーダ-のドメイン構造が確認された。この膜は、後処理なしに1S/cm程度の導電性を示した。一方、TTF-macrocycles誘導体は、LB膜作製時の下層水のイオンを認識し、モルホロジーを変化させた。そこで、膜構造を単分子膜についてはBAM,LB膜については偏光スペクトル、透過およびRAS-IR用いてさらに詳細に評価した。現在、電流同時測定AFMにより、膜のモルホロジーと微小領域の電気伝導性との関連について評価を進めている。3.微小電極の構築これらのLB膜とのインターフェースをとるための微小電極について、フィンランドの中央技術研究所のグループと協力して、現在電極幅100ミクロン程度の電極を作製している。この電極の上に電気伝導性LB膜を作製して、そのインターフェース特性等をインピーダンスアナライザを用いて評価する予定である。
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    Date (from‐to) : 1998 -1998 
    Author : 中村 貴義
     
    1.単成分導電体のLB法による超薄膜形成単成分導電体の前駆体である(C_<10>H_<21>)_3NCH_3[AU(tmdt)_2]を合成し,LB法を用いて超薄膜化した。アンモニウムのアルキル鎖間の相互作用により、高度に秩序化した膜が固体基板上に形成された。中心金属としては比較的空気による酸化を受けにくい金を用いた。膜形成後、電気化学的酸化により膜の秩序状態をなるべく維持しながら単成分導電体に変換することを試みた。2.超薄膜系の構造および電子物性評価薄膜の構造評価は、偏光UV一Vis-NIR、透過IRおよびIR-RASを用いて行った。その結果、金蒸着膜表面に累積を行った場合、monovalent塩のLB膜が形成していることが判明した。引き続く電気化学処理により、LBまくは中性塩に酸化されることが示唆された。一方、ガラスやフッ化カルシウム結晶上では、LB膜の形成過程で、膜が中性状態に酸化されていることが判明した。LB膜の電気化学的酸化により、2S/cm程度の電気伝導性が得られた。3.無機-有機へテロ界面における新規d-π複合電子系の構築新規d-π複合電子系を、無機-有機へテロ界面において構築した。TTF系ジチオレートアニオンを用い、金電極上に酸化的に薄膜を構築した。電極電位を規制することで、膜の形成および酸化状態の制御が可能である。膜の形成及びその酸化状態についてはIR-RASを用いての評価も行った。現在、AFMを用いて膜の構造について検討を行っている。
  • Ministry of Education, Culture, Sports, Science and Technology:Grants-in-Aid for Scientific Research(基盤研究(B))
    Date (from‐to) : 1997 -1998 
    Author : Takayoshi NAKAMURA, 斎藤 軍治, 木口 雅史, Tomoyuki AKUTAGAWA, Jun KAWAMATA, Kuon INOUE, HASEGAWA, Masashi KIGUCHI
     
    In this work, we developed the equipment based on FWMEW to determine the third optical non-linearity precisely of the powder samples having a large absorption band in the visible range. We measured the chi^<(3)> values of the powder or thin-film samples using this equipment and confirmed the effectiveness of the method. At present, due to the large reflection from the prism surface and the diffraction at the prism-sample interface, the application of FWMEW method is limited to the large chi^<(3)> samples such as VO-Pc or Pt-dimethylglyoxim. Although the THEW method has much higher sensitivity, the FWMEW method has the merit that the measurements under non-resonant conditions are easy. Now, we are improving the SIN on the measurements of FWMEW.In the mean time, we developed the charge-trensfer-complex LB films having optical non-linearity. The preliminary studies on the second order effect by the field modulating spectroscopy were performed. The evaluation of the optical non-linearlity on the power samples of charge transfer compleses such as (TBA)(EtO-C[C(CN)_2]_2and (EtO-TCA) is also started.
  • 文部科学省:科学研究費補助金(萌芽的研究)
    Date (from‐to) : 1996 -1997 
    Author : 中村 貴義, 芥川 智行, 稲辺 保
     
    分子性導体であるNi(dmit)_2とクラウンエーテルの組合せを中心に、カウンターカチオンとしてLi^+,Na^+,K^+,Rb^+,NH_4^+,Cs^+を用いて、錯体形成を行った。多くの組合せにおいて、イオンチャネル構造が出現した。クラウンエーテルとの間の錯形成定数が小さいイオンを用いると、イオンチャンネル構造が形成しやすいことが判明した。実際に、結晶作製時の溶媒を変え、錯形成定数を変化させるて、イオンチャネル構造を持つ錯体を優先的に晶出させることも可能であった。イオンチャンネル内へのイオンのド-ピング(バンドフィリング制御)は、Cs^+錯体について、結晶作製条件を変化させることで可能であった。イオンチャネル構造が出現しない錯体についても、結晶内で特異な構造をもつ超分子イオン場が形成されることが明らかとなった。クラウンエーテルだけでなく、直鎖のポリエーテルを用いても結晶内に類似の超分子イオン場が形成した。中心金属として、Niの代わりにPd,Pt,Auを用いた系を検討した。結晶構造の解析には至らなかったが、結晶内にクラウンエーテルが取り込まれることを確認した。結晶の電気伝導特性と超分子イオン場の構造との間に相関が見られた。特に、イオンチャンネル内のイオンの動的挙動に伴い、電気伝導挙動が変化する系も存在することが示唆され、将来の分子デバイス構築へ向けての展開の足がかりが得られた。
  • 文部科学省:科学研究費補助金(重点領域研究)
    Date (from‐to) : 1996 -1996 
    Author : 中村 貴義, 芥川 智行
     
    分子間の電荷移動およびその光励起状態を用いると、2次の分子超分極率(β)を極めて大きくできる可能性があることが指摘されている。これは基底状態と励起状態が例えば錯体の中性状態とイオン性状態に対応するため、両者の双極子モーメントの差が大きくできる為である。本研究では、高い非線形感受率が期待できるドナー・アクセプターの系をLB法を用いて配列制御し、分子間の電荷移動励起状態を利用した非線形光学材料の構築を試みた。2次への非線形性を得るために、膜に非対称構造を持たせる必要がある。そこで、1)ドナー・アクセプターの交互ヘテロ膜、2)長鎖アクセプターと無置換ドナーとの錯体のX型膜を形成した。前者について前年度までに合成した4種(C_<17>C_<18>DMTTF,C_<18>DCNQI,C_<18>Q,C_18HQ)の分子を用いてLB膜を作製した。この中でC_<18>HQとC_<18>Qの組み合わせについて分子間電荷移動が確認できた。この膜について電場変調スペクトルおよびメーカーフリンジ法を用いて2次の非線形光学特性を評価した。後者についてはOMTTF-C_<10>TCNQおよびBEDOTTF-C_<10>TCNQ錯体を合成し、水平付着法でLB膜を形成した。得られた膜について電場変調スペクトルおよびメーカーフリンジ法で評価した。BEDOTTF-C_<10>TCNQについては比較的大きな2次の非線形光学特性が観察された。一方、OMTTF-C_<10>TCNQは、スペクトル特性からN-I転移近傍に存在することが判り、現在詳細な物性測定を進めている。
  • 文部科学省:科学研究費補助金(重点領域研究)
    Date (from‐to) : 1995 -1995 
    Author : 中村 貴義
     
    BEDO-decylTCNQ錯体を用いて金属的な導電性を有するLB膜を作製し、この膜の物性を詳細に検討した。また、この錯体の水面上の単分子膜について電気伝導度を測定し、膜の構造との関連を明らかにした。LB膜はアラキン酸(C_<20>のカルボン酸)と1:1に混合し作製した。この膜の電気伝導度は室温から250K付近まで温度の低下とともにわずかながら上昇するが、それ以下の温度ではほぼ活性化型の導電挙動を示し、全体の温度依存性は狭ギャップ半導体の式で良く近似することができた。AFMの測定から、この膜はドメイン構造を有していることが判明している。この場合、電気伝導度の温度依存性はドメイン境界に主として支配される。一方、ドメイン内の電気的性質は熱電能測定およびESR測定から金属的であることが示唆された。水面上の単分子膜の電気伝導度をアラキン酸との混合比を変化させながら測定した。膜の表面圧-面積曲線の挙動は錯体の混合率が0.56付近で変化した。それに伴い、膜の導電率-面積曲線も大きく変化し、混合比の大きいところでは比較的高い導電率を与えた。これらの結果は、アラキン酸の含有量が低い場合、単分子膜が一種の超単分子膜構造をとると仮定することで良く説明できた。クラウンエーテルを含む導電性の金属錯体を18-crown-6を中心に系統的に探索した。アルカリ金属としてリチウム、ナトリウム、カリウム、ルビジウム、セシウムさらにアンモニウムを用いたが、いずれの場合も導電性の錯体を得ることが出来、X線構造解析を行ったところ、このうち3種については結晶内にイオンチャンネル類似のクラウンエーテルのカラム構造が形成していることが明らかとなった。
  • 文部科学省:科学研究費補助金(重点領域研究)
    Date (from‐to) : 1995 -1995 
    Author : 中村 貴義
     
    分子間の電荷移動およびその光励起状態を用いると、2次の分子超分極率(β)を極めて大きくできる可能性があることが指摘されている。これは基底状態と励起状態が例えば錯体の中性状態とイオン性状態に対応するため、両者の双極子モーメントの差が大きくできる為である。本研究では、高い非線形感受率が期待できるドナー・アクセプターの系をLB法を用いて配列制御し、分子間の電荷移動励起状態を利用した非線形光学材料の構築を試みた。分子間電荷移動を利用する場合、βは電荷移動量(ρ)によって左右される。適当な電荷移動量を得るためにはドナーおよびアクセプターが適当なイオン化ポテンシャル(l_P)および電子親和力(E_A)を持っている必要がある。さらにLB膜化を行うために長鎖アルキル基等の疎水基が必要である。本年度はこの様な条件を満たす分子として4種(C_<17>C_<18>DMTTF,C_<18>DCNQI,C_<18>Q,C_18HQ)を合成した。得られた分子およびこれまでに合成したCnTCNQを用いてLB膜の作製を行った。膜の品質の向上のために、アラキン酸カドミウムをマトリックス分子として使用した。いずれの場合も比較的均質な膜を得ることができた。次に、ドナー・アクセプターを同一のLB膜内に導入し、電荷移動を起こさせる必要があるが、本年度はまずC_<18>HQとC_<18>Qの組み合わせについて検討を行った。キノン(Q)とハイドロキノン(HQ)からなる錯体はキンヒドロンと呼ばれ古くから知られている。しかしながら、この錯体においては電荷移動のみならずHQからQへのプロトン移動も起こり得ることから、近年特異な物性を発現する可能性のあるものとして注目されている。HQからQへの電荷移動は比較的少量であり、比較的大きなβが期待される。アラキン酸カドミウムと1:1に混合した膜について吸収スペクトルを測定した結果、C_<18>HQとC_<18>Qを混合し同一層内に存在させた場合には比較的大きな電荷移動吸収帯が600nm付近に現れた。一方、C_<18>HQとC_<18>Qを交互に累積したヘテロ膜においては電荷移動吸収帯はかなり弱いものの観測可能であり、極性構造を持つLB膜においても分子間電荷移動が生じていることが示唆された。現在これらの膜の特性を電場変調分光を用いて検討中である。
  • 分子性有機物質の自己組織化を利用した、分子エレクトロニクス、分子フォトニクス材料・デバイスの開発
  • Molecular Electronics, Molecular Conductors and Magnets, Langmuir-Blodgett Films

Educational Activities

Teaching Experience

  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : ナノ構造、微細加工、光機能性材料、光化学、液晶、分子性物質、導電性、磁性、薄膜、電子顕微鏡、走査型プローブ顕微鏡、ナノワイヤー、二次元電子ガス、物性理論
  • Advanced Course in Molecular Photonics and Electronics Science II
    開講年度 : 2018
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 固体化学、結晶構造、伝導性、磁性、金属錯体 Solid state chemistry, Crystal strutcure, Conductivity, Magnetism, Coordination chemistry
  • Chemistry II
    開講年度 : 2018
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 有機化合物、官能基、分子構造、化学的性質、化学反応、機能性有機物、生体関連有機物質

Campus Position History

  • 2013年10月1日 
    2015年3月31日 
    電子科学研究所副所長

Position History

  • 2013年10月1日 
    2015年3月31日 
    電子科学研究所副所長


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