May 2022, Selected Paper, Solid-state photophysical properties of chiral perylene diimide derivatives: AIEnh-circularly polarized luminescence from vacuum deposited thin films
A. Kanesaka;Y. Nishimura;A. Yamaguchi;Y. Imai;T. Mizokuro;H. Nishikawa
Official journal

Aggregation-induced circularly polarized phosphorescence of Pt(II) complexes with and axially chiral BINOL ligand
D. Tauchi; T. Koida; Y. Nojima; M. Hasegawa; Y. Mazaki; A. Inagaki; K. Sugiura; Y. Nagaya; K. Tsubaki; T. Shiga; Y. Nagata; H. Nishikawa, Last, Royal Chemical Society
Chemical Communications, Mar. 2023, [Reviewed]

Solid-state photophysical properties of chiral perlene diimide deirivatives: AIE properties of chiral perlene diimide deirivatives: AIEnh-circularly
A. Kanesaka; Y. Nishimura; A. Yamaguchi; Y. Imai; T. Mizokuro; H. Nishikawa, Last, The Chemical Society of Japan
Bull. Soc. Chem. Jpn., Mar. 2022, [Reviewed]

Circularly Polarized Luminescence from π-Conjugated Chiral Perylene Diimide Luminophores: The Bay Position Effect
Maho Kitahara; Kohei Mishima; Nobuyuki Hara; Motohiro Shizuma; Aoba Kanesaka; Hiroyuki Nishikawa; Yoshitane Imai, Three types of chiral perylene diimide luminophores bearing ethynyl, phenyl, and ethynylphenyl substituents (BPP-Ethy, BPP-Ph, and BPP-EthyPh) at the bay positions were prepared. The chiroptical properties of the compounds in their solution (in CHCl3) and polymethyl methacrylate (PMMA)-film solid states were investigated. Similar to the chiral BPP molecules bearing no substituents at the bay position, BPP-Ethy, BPP-Ph, and BPP-EthyPh luminophores emitted no clear circularly polarized luminescence (CPL) in CHCl3 solution. In contrast, the chiral BPP-Ethy, BPP-Ph, and BPP-EthyPh luminophores exhibited intense aggregation-induced enhanced CPL (AIEnh-CPL) in the PMMA-film state; BPP exhibited similar properties. Although the four luminophores were of the same absolute configurations, the CPL signs of the chiral BPP-EthyPh were opposite to those of BPP, BPP-Ethy, and BPP-Ph. This could be attributed to the effects of the substituents at the bay position., Wiley
Asian J. Org. Chem., Sep. 2021, [Reviewed]

Molecular arrangement in diphenylanthracene derivative films deposited under,vacuum on in-plane oriented polythiophene films
Toshiko Mizokuro; Aoba Kanesaka; Tetsuhiko Miyadera; Tomoyuki Koganezawa; Hirokazu Ohsawa; Kenji Kobayashi; Kenji Kamada; Hiroyuki Nishikawa; and Reiko Azumi, Molecular arrangements of 9,10-diphenylanthracene (DPA) and its derivatives inside films deposited under vacuum were investigated. Two DPA derivatives with alkyl chains, 9,10-Bis(4-methylphenyl)anthracene (diMe-DPA) and 9,10-Bis(4-octylphenyl)anthracene (diOct-DPA), were synthesized and structural analyses of their single crystals were performed. It was clarified that anthracene frames of diMe-DPA and diOct-DPA were arranged uniaxially inside the single crystals by introducing alkyl groups to the DPA. Thin films of these molecules were formed by evaporating them under vacuum on glass substrates and polythiophene (PT) films, in which PT chains were uniaxially aligned parallel to the substrates. The angle between anthracene frames of diMe-DPA and the substrate plane of the PT/glass was smaller than that on the glass substrates. In-plane molecular arrangements were also evaluated, and it was clarified that short axes of the anthracene frames inside diMe-DPA and diOct-DPA were nearly parallel to the PT molecular chain direction.
Jpn. J. Appl. Phys., Aug. 2021, [Reviewed]

Non-classical control of solid-state aggregation-induced enhanced circularly polarized luminescence in chiral perylene diimides　　　　　　　　　　　　　　　
Kouhei Watanabe; Ayano Taniguchi; Daiki Kaji; Nobuyuki Hara; Tomomasa Hosoya; Aoba Kanesaka; Takunori Harada; Hiroyuki Nishikawa; Yoshitane Imai, Corresponding
Tetrahedron, Apr. 2019, [Reviewed]

Solid-State AIEnh-Circularly Polarised Luminescence of Chiral Perylene Diimide Fluorophores
Ayano Taniguchi; Daiki Kaji; Nobuyuki Hara; Ryosuke Murata; Shogo Akiyama; Takunori Harada; Atsushi Sudo; Hiroyuki Nishikawa; Yoshitane Imai, Corresponding, Solid-state organic fluorescent materials are important for the development of electroluminescent sensing devices. Herein, we report that N,N'-bis((R)-1-phenylethyl) perylene-3,4,9,10-tetracarboxylic diimide [ (R,R)-BPP] and its antipode [ (S,S)-BPP], which contain extended pi-electrons through planar perylenes, emit solid-state aggregation-induced-enhanced (AIEnh) circularly polarised luminescence (CPL) in inorganic (KBr) pellets and organic-polymer-film (PMMA- and myo-IPU-film) states; this CPL is difficult to observe in solution. These chiral perylene fluorophores emit AIEnh-CPL with high dissymmetry factors (g(CPL)) (up to 2.4 x 10(-3)) and high quantum yields (Phi(F), up to 0.43) in the three solid matrices., ROYAL SOC CHEMISTRY
RSC Advances, Jan. 2019, [Reviewed]

Stable iodide doping induced by photonic curing for carbon nanotube transparent conductive films　　　　　　　　　　　　　　　
A. Wachi; H. Nishikawa; Y. Zhou; R. Azumi
Jap. J. Appl. Phys, 2018, [Reviewed]

Synthesis of Tetra(3-thienyl)biphenoquinone and its Charge Transfer Complex with Perylene
Ryotaro Fujii; Md. Awlad Hossain; Hisato Akimoto; Kazunori Hirabayashi; Toshio Shimizu; Kazuhiko Akiyama; Kenta Goto; Hiroyuki Nishikawa; Ken-Ichi Yamashita; Ken-Ichi Sugiura, Tetra(thienyl)biphenoquinones were designed and synthesized. An oxidative coupling of 2,6-bis(3-thienyl)phenol with PbO2 in acetic acid afforded the corresponding biphenoquinone along with 2,6-bis(3-thienyl)-p-benzoquinone. This biphenoquinone showed properties characteristic of a π-expanded quinone, that is, positively shifted reduction potential and light absorption in the visible region. In contrast to kinetically protected biphenoquinones with bulky substituents at the ortho-positions of carbonyls, the title compounds take a planar structure because of the small steric repulsion of the five-membered thiophene rings. Its charge transfer complex with perylene is characterized by a well-overlapped mixed stack., Wiley-VCH Verlag
Asian Journal of Organic Chemistry, Jan. 2018, [Reviewed]

Organic field-effect transistor based on paramagnetic Cu(II) neutral complexes coordinated by Schiff base-type TTF ligands
Atsushi Wachi; Yusuke Kudo; Aoba Kanesaka; Hiroyuki Nishikawa; Takuya Shiga; Hiroki Oshio; Masayuki Chikamatsu; Reiko Azumi, We have succeeded in preparation of novel paramagnetic Cu(II) complexes composed of tetrathiafulvalene (TTF)-based ligands as electrical conducting units, [Cu-II(Bz-OMe-Bu-t-sae-TTF)(2)], [Cu-II(EDT-bissae-TTF)] and [Cu-II(Bz-bis(OMe-Bu-t-sae)-TTF)]. Electrochemical measurements of these neutral complexes revealed that they exhibited two pairs of redox waves attributed to the oxidation of TTF moieties. Among the newly synthesized TTF complexes, only [Cu-II(EDT-bissae-TTF)] gave a radical salt by electrochemical crystallization, but its resistive behavior was insulating. Field-effect transistors (FET) were fabricated with spin-coated films of [Cu-II(Bz-OMe-Bu-t-sae-TTF)(2)] and [Cu-II(EDT-bissae-TTF)], and their FET performances were very low compared with the conventional organic thin film transistors (OTFT) based on TTF derivatives. Atomic force microscopy (AFM) images of the spin-coated films indicated the non-uniform film surfaces with many small grains leading to the large grain boundaries, which probably causes the low carrier mobility of the FET devices. (C) 2017 Published by Elsevier Ltd., PERGAMON-ELSEVIER SCIENCE LTD
POLYHEDRON, Nov. 2017, [Reviewed]

A Multi-Redox Responsive Cyanometalate-Based Metallogel
Kiyotaka Mitsumoto; Jamie M. Cameron; Rong-Jia Wei; Hiroyuki Nishikawa; Takuya Shiga; Masayuki Nihei; Graham N. Newton; Hiroki Oshio, A TTF-based (TTF= tetrathiafulvalene) tridentate ligand (alpha-(4'-methyl- 4,5-di- n-dodecylthylthiotetrathiafulvalene- 5'-ylthio)- a'-[ 2,2,2-tris(1-pyrazolyl) ethoxy]- p-xylene) (L) with long-chain alkyl moieties was prepared in order to obtain a new multi-redox active gelator based on a mixed-metal octanuclear complex [ FeIII 4NiII 4(CN) 12(tp) 4(L) 4](BF4) 4 (1). The magnetism, electrochemistry, and gelation behavior of 1 were studied and 1,2-dichlorobenzene solutions of 1 are shown to display thermoreversible gelation behavior at room temperature. Furthermore, the gel phase of 1 was shown to undergo room-temperature gel-to-sol transformations induced by both the oxidation and reduction of the gelator complex by F(4)TCNQ or [FeII(Cp*) 2], respectively., WILEY-V C H VERLAG GMBH
CHEMISTRY-A EUROPEAN JOURNAL, Jan. 2017, [Reviewed]

Development of organic thin film devices based on Cu(II) complex with tetrathiafulvalene moieties in the ligands
Hiroyuki Nishikawa; Atsushi Wachi; Masayuki Chikamatsu; Reiko Azumi, Paramagnetic metal complexes with tetrathiafulvalene moieties in its ligands, [Cu-II(EDT-sae-TTF)(2)] (1) and two new derivatives were investigated towards the potential application to the organic thin film transistor (OTFT) with magnetic field responsiveness. The complex 1 and its benzene substituted derivative, [Cu-II(Bz-sae-TTF)(2)] (2), gave semiconducting radical cation salts with fairly good electrical conductivity. A field effect transistor (FET) device fabricated with the spin-coated film of 1 was operative, but its performance was quite low. Atomic force microscopy (AFM) images revealed that the spin-coated film of 1 consists of very small grains with the size of about 10nm, which can be responsible for the low device performance., TAYLOR & FRANCIS LTD
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2016, [Reviewed]

Lability-Controlled Syntheses of Heterometallic Clusters
Graham N. Newton; Kiyotaka Mitsumoto; Rong-Jia Wei; Fumichika Iijima; Takuya Shiga; Hiroyuki Nishikawa; Hiroki Oshio, A bulky bidentate ligand was used to stabilize a macrocyclic [ (Fe8Co6II)-Co-III] cluster. Tuning the basicity of the ligand by derivatization with one or two methoxy groups led to the isolation of a homologous [ (Fe8Co6II)-Co-III] species and a [ (Fe6Fe2Co2Co2II)-Fe-III-Co-II-Co-III] complex, respectively. Lowering the reaction temperatures allowed isolation of [ (Fe6Fe2Co2Co2II)-Fe-III-Co-II-Co-III] clusters with all three ligands. Temperature-dependent absorption data and corresponding experiments with iron/nickel systems indicated that the iron/cobalt self-assembly process was directed by the occurrence of solution-state electron-transfer-coupled spin transition (ETCST) and its influence on reaction intermediate lability., WILEY-V C H VERLAG GMBH
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, Mar. 2014, [Reviewed]

Dimerized spin-crossover iron(II) complexes as supramolecular anion capsules
Takuya Shiga; Emiko Oshiro; Naoko Nakayama; Kiyotaka Mitsumoto; Graham N. Newton; Hiroyuki Nishikawa; Hiroki Oshio, Two dimerized iron(II) complexes, [{Fe(L)(HL)2},{Fe(HL) 3}]- (PF6)(BF4)2·5CH 3CN·4H2O (1) and [{Fe(L)(HL)2},{Fe(HL) 3}]- (PF6)(FeCl4)2 (2) {HL = 3-(2-pyridyl)-5-[4-(diphenylamino)- phenyl]-1H-pyrazole}, supported by triphenylamine-derivatized bidentate ligands and encapsulating hexafluorophosphate ions were synthesized. The complex iron ions have octahedral coordination geometries in which they interact with six nitrogen atoms from three bidentate ligands. Both compounds have capsule-like dimerized supramolecular structures, in which the arrangements of the bulky ligands of two discrete mononuclear complexes create a central cavity in which a single hexafluorophosphate ion is captured. The bidentate ligands interact with the anionic guest molecules through the hydrogen atoms of the ligand pyrazole moieties. Cryomagnetic studies reveal that both compounds show spin-crossover behavior. Complex 1 showed quasi-reversible spin-crossover around 200-300 K, hindered by desolvation effects, whereas 2 showed reversible gradual spin-crossover behavior. The electronic states of the iron ions resulting from the spin-crossover were confirmed by X-ray structure analyses and Mössbauer spectra. © 2013 Wiley-VCH Verlag GmbH &
Co. KGaA, Weinheim.
European Journal of Inorganic Chemistry, Feb. 2013, [Reviewed]

One-Pot Synthesis of Cu(II) Complex with Partially Oxidized TTF Moieties
Hiroyuki Nishikawa; Ryosuke Kitabatake; Kiyotaka Mitsumoto; Takuya Shiga; Hiroki Oshio, The one-pot synthesis of a Cu(II) complex with partially oxidized tetrathiafulvalene (TTF) moieties in its capping MT-Hsae-TTF ligands, [Cu-II(MT-sae-TTF)(2)] [ (CuCl2)-Cl-I] was realized by the simultaneous occurrence of Cu(II) complexation and (CuCl2)-Cl-II mediated oxidation of TTF moieties. The crystal structure was composed of one-dimensional columns formed by partially oxidized TTF moieties and thus the cation radical salt showed relatively high electrical conductivity. Tight binding band structure calculations indicated the existence of a Peierls gap due to the tetramerization of the TTF moieties in the one-dimensional stacking column at room temperature, which is consistent with the semiconducting behavior of this salt., MDPI AG
CRYSTALS, Sep. 2012, [Reviewed]

Face-to-Face Dimeric Tetrathiafulvalenes and Their Cation Radical and Dication Species as Models of Mixed Valence and pi-Dimer States
Masashi Hasegawa; Kota Daigoku; Kenro Hashimoto; Hiroyuki Nishikawa; Masahiko Iyoda, Intramolecular interactions of face-to-face tetrathiafulvalenes (TTFs) in 1,8-bis(tetrathiafulvalenyl)naphthalene frameworks were investigated in neutral and cationic states. From X-ray analysis and NMR spectroscopy on neutral 1,8-bis(tetrathiafulvalenyl)naphthalenes, which exist as a mixture of syn- and anti-isomers in solution, there is steric repulsion between TTF moieties. However, analysis of the cyclic voltammogram (CV) revealed that a strong attractive interaction was present in the cation radical state. Electronic spectra of the cation radical state showed the presence of a mixed-valence (MV) state with a strong charge resonance feature. ESR. spectra of the 1,8-bis(tetrathiaftilvalenyl)naplithalene cation radical showed a typical signal of an MV state. Furthermore, a pi-dimer, which exhibits pronounced Davydov splitting in the electronic spectra, was formed in the dication state. The observed absorption bands in the electronic spectra were characterized by using quantum chemical calculations of the cation radical and dication species. NMR spectra of both the pi-dimer and tetracation species show either a deshielding effect due to cationic charge or a shielding effect due to diamagnetic ring currents. To our knowledge, this is the first reported example of a H-1 NMR spectrum of TTF pi-dimer., CHEMICAL SOC JAPAN
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, Jan. 2012, [Reviewed]

Syntheses and properties of new metal complexes based on TTF-ligands with multidentate coordination sites
Hiroyuki Nishikawa; Ryosuke Kitabatake; Kiyotaka Mitsumoto; Hiroki Oshio, Several TTF-ligands with Schiff-base type coordination sites have been synthesized to develop new TTF-based metal complexes: tetradentate H(2)bsae-TTF [4,5-bis(2-salycylideneiminoethylthio)- TTF] and hexadentate macrocyclic-TTF. Both ligands yielded mononuclear metal complexes, [Cu-II(bsae-TTF)] and [M-II(macrocyclic-TTF)](BF4)(2) (M-II = Fe-II, Co-II, Ni-II, Zn-II). Electrochemical measurements revealed that both the bsae-TTF and macrocyclic-TTF complexes retained the redox properties of TTF moieties. All the metal complexes with macrocyclic-TTF ligand were isostructural octahedral coordination structure. Among them, Co(II) complex showed spin-crossover behaviour above room temperature. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, WILEY-V C H VERLAG GMBH
PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 9, NO 5, 2012, [Reviewed]

Encapsulation controlled single molecule magnetism in tetrathiafulvalene-capped cyanide-bridged cubes
Kiyotaka Mitsumoto; Hiroyuki Nishikawa; Graham N. Newton; Hiroki Oshio, New TTF-based (TTF = tetrathiafulvalene) ligands, L1 and L2 (L1 = alpha-(4'-methyl-4,5-ethylenedithiotetrathiafulvalene-5'-thio)-alpha'-[tris-2,2,2-(1-pyrazolyl)ethoxy]-p-xylene and L2 = alpha-(4'-methyl-4,5-dimethylthiotetrathiafulvalene-5'-thio)-alpha'-[tris-2,2,2-(1-pyrazolyl) ethoxy]-p-xylene), possessing tris-pyrazolyl coordination sites, were synthesized. The reactions of Ni(BF4)(2)center dot 6H(2)O with the TTF-ligands (L1 and L2), n-Bu4N[Fe(CN)(3)(tp or pztp)] (tp = hydrotris(pyrazol-1-yl) borate and pztp = tetrakis(pyrazol-1-yl) borate) in the presence of additional counter ions afforded two cyanide-bridged octanuclear complexes: [ (Fe4Ni4II)-Ni-III(CN)(12)(pztp)(4)(L1)(4)](BF4)(4) (1) and [ (Fe4Ni4II)-Ni-III(CN)(12)(pztp)(4)(L2)(4)](PF6)(4) (2). Using a similar procedure to that employed in the synthesis of complex 2, with the addition of sodium tetraphenylborate, yielded a two-electron-reduced compound, Na[ (Fe2Fe2Ni4II)-Fe-III-Ni-II(CN)(12)(tp)(4)(L2)(4)](BF4)(3) (3), in which a sodium ion was encapsulated by the cube. The host-guest complex 3 showed enhanced redox behaviour and while magnetic susceptibility measurements revealed ferromagnetic interactions to be operative in all three complexes, the cation encapsulation behaviour of 3 led it to exhibit single molecule magnet-type properties., ROYAL SOC CHEMISTRY
DALTON TRANSACTIONS, 2012, [Reviewed]

Cyanide bridged tetranuclear complex with a novel terthiophene based ligand
Kiyotaka Mitsumoto; Hiroyuki Nishikawa; Hiroki Oshio, A new terthiophene based ligand (L = 3-(2-pryridyl)-5-(2,2':5',2 ''-terthien-3'-yl) pyrazole was synthesized. The reaction of Ni(BF4)(2)center dot 6H(2)O, L and nBu(4)N[Fe(CN)(3)tpl(+)] (tp(+) = tris(3,5-dimethylpyrazol-1-yl)borohyrdide) with NaBPh4 in MeOH/acetone yielded a cyanide bridged tetranuclear complex [Fe2Ni2(CN)(6)(tp(+))(2)(L-4](BPh4)(2) (1). The electrochemical properties of both 1 and L were investigated, and magnetic susceptibility measurements of 1 were conducted, revealing that ferromagnetic interactions were operative within the tetranuclear core. (C) 2011 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
POLYHEDRON, Nov. 2011, [Reviewed]

Optical and structural studies of a two-dimensional organic Mott insulator dimethylphenazine-tetrafluorotetracyanoquinodimethane
M. Ohkura; Y. Ishige; R. Sawada; H. Matsuzaki; Y. Nogami; H. Nishikawa; M. Yamashita; S. Horiuchi; H. Okamoto, Electronic structure of an organic charge-transfer complex, M 2P-TCNQF4 (M2P: 5,10-dihydro-5,10- dimethylphenazine
TCNQF4: 2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane), was investigated by means of optical reflection spectroscopy and x-ray structural analyses. This is an ionic compound and has a unique quasi-two-dimensional (2D) crystal structure in which donor (D) molecules of M2P and acceptor (A) molecules of TCNQF4 stack respectively along the [100] direction, and D and A molecules also stack alternately along the [111] direction. We evaluated the transfer energy t(AA) between the neighboring A molecules, t(DD) between the neighboring D molecules along the [100] direction, and t(DA) between the neighboring D and A molecules along the [111] direction to be 43 meV, 29 meV, and 67 meV at room temperature, respectively. This demonstrates that an anisotropic 2D electronic structure is formed. By comparing the spectra of the imaginary part of the dielectric constant ε2 obtained from the polarized reflectivity spectra with the absorption spectrum of K-TCNQF4 and the ε2 spectra of M2P-PF6, which are composed of 1D A stacks and D stacks, respectively, it was revealed that in M2P-TCNQF4 the optical gap corresponds to the Mott gap transition from A- to A-, and the D+ to D+ transition and the A - to D+ transition or equivalently the charge-transfer (CT) transition located at the higher energies. Below the structural and magnetic phase transition temperature Tc ∼ 122 K, spin-singlet states are formed via displacements of both D and A molecules. The pattern of molecular displacements was found to be very unique, indicating that the phase transition cannot be attributed to a spin-Peierls-like mechanism. The nature of the phase transition is discussed from the temperature dependences of molecular displacements as well as of the Mott-gap transition and the CT transition. © 2011 American Physical Society.
Physical Review B - Condensed Matter and Materials Physics, Aug. 2011, [Reviewed]

Cyanide-Bridged [Fe8M6] Clusters Displaying Single-Molecule Magnetism (M = Ni) and Electron-Transfer-Coupled Spin Transitions (M = Co)
Kiyotaka Mitsumoto; Emiko Oshiro; Hiroyuki Nishikawa; Takuya Shiga; Yasuhisa Yamamura; Kazuya Saito; Hiroki Oshio, Cyanide-bridged metal complexes of [Fe8M6(mu-CN)(14)(CN)(10)(tp)(8)(HL)(10)(CH3CN)(2)][PF6](4)center dot nCH(3)CN center dot mH(2)O (HL=3-(2-pyridyl)-5-[4-(diphenylamino)phenyl]-1H-pyrazole), tp(-) = hydrotris(pyrazolylborate), 1: M = Ni with n = 11 and m = 7, and 2: M = Co with n = 14 and m = 5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2(1)/n. They have tetradecanuclear cores composed of eight low-spin (LS) Fe-III and six high-spin (HS) M-II ions (M = Ni and Co), all of which are bridged by cyanide ions, to form a crown-like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro-and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2, respectively. Ac magnetic susceptibility measurements of 1 showed frequency-dependent in- and out-of-phase signals, characteristic of single-molecule magnetism (SMM), while desolvated samples of 2 showed thermal- and photoinduced intramolecular electron-transfer-coupled spin transition (ETCST) between the [ (LS-Fe-II)(3)(LS-Fe-III)(5)(HS-Co-II)(3)(LS-Co-III)(3)] and the [ (LS-Fe-III)(8)(HS-Co-II)(6)] states., WILEY-BLACKWELL
CHEMISTRY-A EUROPEAN JOURNAL, Aug. 2011

Optical and structural studies of a two-dimensional organic Mott insulator dimethylphenazine-tetrafluorotetracyanoquinodimethane
M. Ohkura; Y. Ishige; R. Sawada; H. Matsuzaki; Y. Nogami; H. Nishikawa; M. Yamashita; S. Horiuchi; H. Okamoto, Electronic structure of an organic charge-transfer complex, M2P-TCNQF(4) (M2P: 5,10-dihydro-5,10-dimethylphenazine; TCNQF(4): 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane), was investigated by means of optical reflection spectroscopy and x-ray structural analyses. This is an ionic compound and has a unique quasi-two-dimensional (2D) crystal structure in which donor (D) molecules of M2P and acceptor (A) molecules of TCNQF(4) stack respectively along the [100] direction, and D and A molecules also stack alternately along the [111] direction. We evaluated the transfer energy t(AA) between the neighboring A molecules, t(DD) between the neighboring D molecules along the [100] direction, and t(DA) between the neighboring D and A molecules along the [111] direction to be 43 meV, 29 meV, and 67 meV at room temperature, respectively. This demonstrates that an anisotropic 2D electronic structure is formed. By comparing the spectra of the imaginary part of the dielectric constant epsilon 2 obtained from the polarized reflectivity spectra with the absorption spectrum of K-TCNQF(4) and the epsilon(2) spectra of M2P-PF6, which are composed of 1D A stacks and D stacks, respectively, it was revealed that in M2P-TCNQF(4) the optical gap corresponds to the Mott gap transition from A(-) to A(-), and the D+ to D+ transition and the A(-) to D+ transition or equivalently the charge-transfer (CT) transition located at the higher energies. Below the structural and magnetic phase transition temperature T-c similar to 122 K, spin-singlet states are formed via displacements of both D and A molecules. The pattern of molecular displacements was found to be very unique, indicating that the phase transition cannot be attributed to a spin-Peierls-like mechanism. The nature of the phase transition is discussed from the temperature dependences of molecular displacements as well as of the Mott-gap transition and the CT transition., AMER PHYSICAL SOC
PHYSICAL REVIEW B, Aug. 2011, [Reviewed]

Spin-crossover behavior and electrical conduction property in iron(II) complexes with tetrathiafulvalene moieties
Masayuki Nihei; Nobukazu Takahashi; Hiroyuki Nishikawa; Hiroki Oshio, Iron(II) complexes with neutral and oxidized tetrathiafulvalene (TTF) moieties were prepared and X-ray crystallographic analyses, magnetic and electrical resistivity measurements suggested an interaction of spin transition and electrical conductivity., ROYAL SOC CHEMISTRY
DALTON TRANSACTIONS, 2011, [Reviewed]

Syntheses of new TTF-based metal complexes for conducting and magnetic systems: Schiff base-type metal complex with partially oxidized TTF moiety
H. Nishikawa; H. Oshima; K. Narita; H. Oshio, New TTF-based ligands (TTF=tetrathiafulvalene) with Schiff base-type coordination sites have been synthesized 4 5-bis(4-salicylideneiminophenyl)-4' 5'-ethylenedithio-TTF (1a) 4 5-bis(4-picolinideneiminophenyl)-4',5'-ethylenedithio-TTF (1b) and 4-(2-salicylideneiminoethylthio)-5-methyl-4' 5'-ethylenedithio-TTF (Hsae-TTF) X-ray crystallography for la revealed that la has rigid structure around the coordination sites which prevents it to form metal complexes On the other hand Hsae-TTF ligand has flexibility around its coordination sites due to alkyl chain spacer and gave mononuclear complexes with Ni(II) and Cu(II) ions [M(II)(saeTTF)(2)] (M(II)=Ni(II) and Cu(II)) The metal ions in [M(II)(saeTTF)21 have a square planar coordination structure with two TTF-based ligands which was sandwiched by two neutral TTF moieties The Cu(II) complex [Cu(II)(saeTTF)(2)] yielded charge transfer (CT) complexes with acceptors such as F(4)TCNQ DDQ and iodine CT complexes with F(4)TCNQ and iodine were semiconductive but that with DDQ was insulator This is due to the difference of the degree of charge transfer TTF moiety in F(4)TCNQ salt was partially oxidized but that of DDQ salt was completely oxidized The radical cation salts of [Cu(II)(saeTTF)(2)] with PF(6) anion was also obtained in 1 1 donor and anion ratio by electrocrystallization The donor and anion ratio indicates that the oxidation state of TTF moieties in the radical salt [Cu(II)(saeTTF)(2)]PF(6) was partial oxidation state (C) 2009 Elsevier B V All rights reserved, ELSEVIER SCIENCE BV
PHYSICA B-CONDENSED MATTER, Jun. 2010, [Reviewed]

Electronic states of organic quasi-two dimensional conductor beta ''-(DODHT)(2)PF6 center dot Charge ordering and superconductivity
M. Higa; R. Kondo; A. Murata; S. Kagoshima; H. Nishikawa; K. Yakushi, In the title compound we made X-ray satellite reflection measurements up to 0 7 GPa and angle-dependent magnetoresistance (AMR) measurements at 1 9 GPa The purpose of the study is to clarify (1) how large the temperature-pressure regime is for the long-range charge ordering (CO) (2) whether or not the high pressure regime for the superconductivity is really a metallic state and (3) what the electronic properties are in the intermediate pressure regime between the long-range CO and the superconducting states The long-range CO was found to be stable up to 0 7 GPa and its temperature-pressure regime coincides with that expected from transport measurements AMR at 1 9 GPa 1 4K and 12T suggests the presence of Fermi surfaces consistent with band calculations based on X-ray structural analyses at room temperature and the same pressure Raman studies by one of the authors (K Y) suggest the presence of metallic state in the intermediate pressure regime where the resistance shows apparently insulating properties Discussion is made on the role of the charge-degree of freedom in causing the superconductivity (C) 2009 Elsevier B V All rights reserved, ELSEVIER SCIENCE BV
PHYSICA B-CONDENSED MATTER, Jun. 2010, [Reviewed]

Interplay of charge-density waves and superconductivity in the organic conductor beta ''-(BEDT-TTF)(2)AuBr2
Ryusuke Kondo; Momoka Higa; Seiichi Kagoshima; Noriaki Hanasaki; Yoshio Nogami; Hiroyuki Nishikawa, We studied the low-temperature electrical properties of the two-dimensional organic conductor beta ''-(BEDT-TTF)(2)AuBr2, whose electronic structure is similar to that of the pressure-induced superconductor beta ''-(DODHT)(2)PF6 having a charge-ordered transition at 255 K at ambient pressure. We found that the ground state of beta ''-(BEDT-TTF)(2)AuBr2 at ambient pressure has a charge-density-wave phase below 6.5 K accompanied by x-ray superlattice spots. We also discovered superconductivity in the vicinity of the charge-density-wave phase by applying uniaxial strain. Based on the obtained results, we propose a unified electronic phase diagram that suggests the relationships among the charge-ordered insulating state, the superconducting phase, and the charge-density-wave phase in beta ''-type organic conductors. The phase diagram shows that the superconducting phase is located near the charge-density-wave phase, which suggests that spin fluctuations play a minor role in the mechanism of the superconductivity and sheds light on the possibility of charge-fluctuation-mediated superconductivity in this type of organic conductor., AMER PHYSICAL SOC
PHYSICAL REVIEW B, Jan. 2010, [Reviewed]

Single chain magnet of a cyanide bridged Fe-II/Fe-III complex
Kiyotaka Mitsumoto; Mayumi Ui; Masayuki Nihei; Hiroyuki Nishikawa; Hiroki Oshio, A 1D compound composed of cyanide bridged iron(II,III) ions was prepared and magnetic measurements revealed it to be a single chain magnet., ROYAL SOC CHEMISTRY
CRYSTENGCOMM, 2010, [Reviewed]

Synthesis and physical properties of a new single-component molecular conductor [Au(dhdt)(2)]
Hiroyuki Nishikawa; Wataru Yasuoka; Kumiko Sakairi; Hiroki Oshio, We have succeeded in synthesizing a new Au(III) complex coordinated by a dihydro-TTF-ditiolato ligand, dhdt(2-) (4,5-dihydrotetrathiafulvalene-4,5-dithiolato) as a tetrabutlylammoium or tetra phenylphosphonium salt. Crystal structural analysis of (Ph4P)[Au(dhdt)(2)] revealed that the Au(III) ion adopts a square planar coordination and the mean Au-S bond length suggests the Au ions are in the trivalent Au(III) state. A neutral complex, [Au(dhdt)(2)], was obtained by the electrochemical oxidation of (n-Bu4N) [Au(dhdt)(2)]. Conducting behavior of [Au(dhdt)(2)] was semiconductive with conductivity at room temperature of 8.3 Scm(-1) and activation energy of 23 meV. Magnetic susceptibility of [Au(dhdt)(2)] was well explained by the SLIM of the Curie and temperature independent components. (C) 2008 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
POLYHEDRON, Jun. 2009, [Reviewed]

Spin Canting in a Cobalt(II) Radical Complex with an Acentric Counter Anion
Kiyotaka Mitsumoto; Takuya Shiga; Motohiro Nakano; Masayuki Nihei; Hiroyuki Nishikawa; Hiroki Oshio, Cobalt(II) radical complexes with centric and acentric counter anions, [CoCl(bisimpy)(MeOH)(2)]X [bisimpy = 2,6-bis(4',4',5',5'-tetramethyl-4',5'-dihydro-1'H-imidazol-1'-oxyl- 2'-yl)pyridine; X = PF(6) (1), and ClO(4) (2)], crystallize in the centrosymmetric and polar space groups, respectively. Compound 1 is paramagnetic, whereas spin canting in 2 leads to a metamagnetic transition with a critical field of 1300 Oe at 1.8 K. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008), WILEY-V C H VERLAG GMBH
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Nov. 2008, [Reviewed]

Charge-density-wave to Mott-Hubbard phase transition in quasi-one-dimensional bromo-bridged Pd compounds
Shinya Takaishi; Mitsuhito Takamura; Takashi Kajiwara; Hitoshi Miyasaka; Masahiro Yamashita; Muneaki Lwata; Hiroyuki Matsuzaki; Hiroshi Okamoto; Hisaaki Tanaka; Shin-ichi Kuroda; Hiroyuki Nishikawa; Hiroki Oshio; Kenichi Kato; Masaki Takata, A-Pd-III-Br-Pd-III-Mott-Hubbard state was observed in a quasi-one-dimensional bromo-bridged Pd compound [Pd(en)(2)Br](C-5-Y)(2)center dot H2O (en = ethylenediamine, C-5-Y = dipentylsulfosuccinate) for the first time. The phase transition between Mott-Hubbard and charge-density-wave states occurred at 206 +/- 2 K and was confirmed by using X-ray, ESR, Raman and electronic spectroscopies, electrical resistivity, and heat capacity. From X-ray powder diffraction patterns and Raman spectra of a series of Pd-Br compounds, [Pd(en)(2)Br](C-n-Y)(2)center dot H2O (n = 4, 5, 6, 7, 8, 9, and 12), chemical pressure from the alkyl chains of the counterions caused the phase transition., AMER CHEMICAL SOC
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Sep. 2008, [Reviewed]

Charge ordered metal and pressure-induced superconductivity in the two-dimensional organic conductor beta-(DODHT)(2)PF(6)
Akito Kobayashi; Yoshikazu Suzumura; Momoka Higa; Ryusuke Kondo; Seiichi Kagoshima; Hiroyuki Nishikawa, The superconductivity in a quasi-two-dimensional organic conductor, beta"-(DODHT)(2)PF(6) salt, which is expected to appear after the melting of a charge ordering (CO) state, has been examined using an extended Hubbard model with anisotropy for both the transfer energies and the nearest-neighbor repulsive interactions between the DODHT molecules. The fluctuation is treated by the random phase approximation based on mean-field calculation of the CO. When pressure is applied, an insulating state with CO (COI) changes into a metallic state with weakened CO (COM) at an intermediate pressure, and a normal state without CO emerges at higher pressures. For the COM state at intermediate pressure, the COI state and the normal state also exist as metastable states, and their free energies are nearly the same within a narrow energy range of 10(-3) eV. Thus these three states may coexist with each other by forming a phase separation at finite temperature. We find that the spin fluctuation around such a mean-field COM state gives rise to a superconducting state with a full gap. Further, we suggest that d-wave superconductivity mediated by the charge fluctuation occurs in the normal state with a quasi-one-dimensional Fermi surface when the nearest-neighbor interaction becomes as large as the on-site interaction., IOP PUBLISHING LTD
JOURNAL OF PHYSICS-CONDENSED MATTER, Mar. 2008, [Reviewed]

Charge ordered insulating phases of DODHT salts with octahedral anions and a new radical salt, b"-(DODHT)2TaF6　　　　　　　　　　　　　　　
H. Nishikawa; H. Oshio; M. Higa; R. Kondo; S. Kagoshima; A. Nakao; H. Sawa; S. Yasuzuka; K. Murata
J. Phys., 2008, [Reviewed]

Alkoxo-bridged cobalt(II) cube and its radical adduct
Kiyotaka Mitsumoto; Satoshi Koizumi; Takuya Shiga; Hiroyuki Nishikawa; Yun Chi; Hiroki Oshio, Tetranuclear cubic complexes of [Co-4(heiP)(4)(MeOH)(4)] (1) and [Co-4(heiP)(4)(nit-p-py)(4)] (2) (H(2)heip = 1,1,1,5,5,5-hexafluoro-4-[ (2-hydroxyethyl)imino]-2-pentanone and nit-p-py = 2-(p-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) were prepared. Complexes 1 and 2 have alkoxo-bridged cubic core structures. Magnetic susceptibility measurements revealed the occurrence of ferromagnetic interactions among Co-II ions in 1, while antiferromagnetic interactions were operative in 2., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Sep. 2007, [Reviewed]

Production and characterization of heteroatom-encapsulated metallofullerene, CaHo@C-82
Koichi Sakaguchi; Ryosuke Fujii; Takeshi Kodama; Hiroyuki Nishikawa; Isao Ikemoto; Yohji Achiba; Koichi Kikuchi, We produced two CaHo@C-82 isomers whose electronic states were characterized to be Ca2+Ho3+@C-82(5-) from the elution behavior of high-performance liquid chromatography., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Jul. 2007

Structural studies of pressure-induced organic superconductor beta ''-(DODHT)(2)PF6 having charge-ordering phase at ambient pressure
Momoka Higa; Ryusuke Kondo; Seiichi Kagoshima; Hiroyuki Nshikawa, We performed the crystal structure analyses of the pressure-induced organic superconductor ss"-(DODHT)(2)PF6 (DODHT denotes (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene) at the hydrostatic pressures of 0.75GPa and 1.9GPa in order to investigate the key parameter for inducing the superconductivity. At ambient pressure, ss"-(DODHT)(2)PF6 undergoes an insulator-to-insulator transition at 255 K accompanied by charge ordering. By applying pressure, this charge-ordering transition is suppressed and superconductivity is generated at around 3 K above 1.32 GPa. Using the obtained atomic coordinates, we estimated the transfer integrals t and intermolecular nearest-neighbor Coulomb interaction energies V between conduction electrons and found that one of V/vertical bar t vertical bar ratios perpendicular to charge-ordering stripes plays an important role in suppressing the charge-ordering phase., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Mar. 2007

Quantum Criticality in the Quasi 2D Conductor, (MeDH-TTP)(2)AsF6
Kensuke Kobayashi; Syuma Yasuzuka; Hiroyuki Nishikawa; Harukazu Yoshino; Keizo Murata, The temperature-pressure (T-P) phase diagram of the reduced p-donor system (MeDH-TTP)(2)AsF6 is studied using resistivity measurement, where MeDH-TTP is 2-methyl-5-(1,3-dithiolan- 2-yliden)-1,3,4,6-tetrathiapentalene. The insulating phase is suppressed completely beyond P-c = 2.4 GPa. Above P-c, we find two distinct metallic states that are regarded as the Fermi liquid (FL) state at lower temperatures and the "bad metal" at higher temperatures. Around P-c, remarkable enhancements in the residual resistivity rho(0) as well as in the T-2-term coefficient A associated with FL behavior are found. We discuss the possible quantum critical point at P-c in (MeDH-TTP)(2)AsF6., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Jan. 2007, [Reviewed]

Anisotropic superconducting transition in β"-(DODHT) 2PF6
Momoka Higa; Ryusuke Kondo; Seiichi Kagoshima; Hiroyuki Nishikawa, We report unique resistance behavior around the superconducting transition of a quasi-two- dimensional organic superconductor, β"-(DODHT) 2PF6 [DODHT = (1,4-dioxane-2,3-diyldithio) dihydrotetrathiafulvalene]. When the superconductivity appears, the interlayer resistance begins to decrease at a temperature higher than that for the intralayer resistance. Both resistances show a step-like decrease toward zero resistance. These unique phenomena are possibly related to the unique structural properties of the salt. © 2007 The Physical Society of Japan., Physical Society of Japan
Journal of the Physical Society of Japan, 2007, [Reviewed]

Pulsed magnetic field study of unconventional magnetoresistance of Q1D superconductors (TMTSF)2ClO4and (DMET)2I 3
H. Yoshino; Z. Bayindir; J. Roy; B. Show; H. I. Ha; A. G. Lebed; M. J. Naughton; K. Kikuchi; H. Nishikawa; K. Murata, Quasi-one-dimensional (Q1D) organic conductors with simple open Fermi surfaces have provided novel angular dependent magnetoresistance oscillation (AMRO) phenomena for the last two decades. Both semiclassical and quantum mechanical theories well explain these phenomena, but detailed study of the field dependence probably gives a crucial test. Recently it was proposed that a kind of AMRO that is known as "Lee-Naughton oscillations (LNO)" observed for (TMTSF)2ClO4 is a result of dimensional crossover of electronic system from oneto two-dimension on changing the field orientation. We have studied the field dependence of the magnetoresistance of Q1D superconductors (TMTSF)2ClO4 and (DMET) 2I3by using a 46-T pulsed magnetic field system and found the B1/2-behavior at minima of LNO. © 2006 IOP Publishing Ltd., Institute of Physics Publishing
Journal of Physics: Conference Series, Dec. 2006, [Reviewed]

Development of new D-A systems based on fullerene and TTF for organic devices
Hiroyuki Nishikawa; Hiroki Oshio; Atsushi Itakura; Takahiro Nakamura; Takeshi Kodama; Koichi Kikuchi; Isao Ikemoto; Masayuki Chikamatsu; Yuji Yoshida; Kiyoshi Yase, New C 60 -TTF dyads with several substituents on the TTF moiety were prepared to examine the substituent effect on the intramolecular charge transfer interaction. Cast films of the dyads with long alkyl chains were obtained with high quality and characterized. In X-ray diffraction study for the cast film of the derivative with -SC 16 H 33 groups ( 1g ), high ordered reflection peaks were observed. Analysis of the diffraction pattern revealed that 1g forms the multibilayer structure in condensed film.
Molecular Crystals and Liquid Crystals, Oct. 2006, [Reviewed]

Molecular conductor based on reduced pi-system donor: Insulating state of (MeDH-TTP)(2)AsF6
Hiroyuki Nishikawa; Hiromichi Sekiya; Akira Fujiwara; Takeshi Kodama; Isao Ikemoto; Koichi Kikuchi; Jun-ichi Yamada; Hiroki Oshio; Kensuke Kobayashi; Syuma Yasuzuka; Keizo Murata, The transport properties of (MeDH-TTP)(2)AsF6, which crystallized in the K-type structure, were investigated and found to be semiconductive with a small activation energy. ESR measurements suggested that the insulating state below 40 K should be anti ferromagnetic, similarly to the Mott transition system represented by quasi-two-dimensional K-ET [ET = bis(ethylenedithio)tetrathiafulvalene] salts., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Aug. 2006, [Reviewed]

Quantum criticality in reduced pi-donor system (MeDH-TTP)(2)AsF6
Syuma Yasuzuka; Kensuke Kobayashi; Hiroyuki Nishikawa; Harukazu Yoshino; Keizo Murata, The temperature-pressure (T-P) phase diagram of the reduced pi-donor system (MeDH-TTP)(2)AsF6 is studied using resistivity measurement, where MeDH-TTP stands for 2-methyl-5-(1,3-dithiolan-2-yliden)-1,3,4,6-tetrathiapentalene. The insulating phase is suppressed completely beyond P-c = 2.4 GPa. Above P-c, we find two distinct metallic states that are regarded as the Fermi liquid (FL) state at lower temperatures and the "bad metal" at higher temperatures. Around P-c, remarkable enhancements in the residual resistivity rho(0) as well as in the T-2-term coefficient A associated with FL behavior are found. We discuss the origin of the insulating phase and the possible quantum critical point at P-c in (MeDH-TTP)(2)AsF6., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Aug. 2006, [Reviewed]

Charge ordered insulating state in DODHT salts
H. Nishikawa; Y. Sato; T. Kodama; K. Kikuchi; I. Ikemoto; J. Yamada; H. Oshio; R. Kondo; S. Kagoshima, Radical salts based on DODHT [ (1,4-dioxane-2,3-diyldithio)dihydrotetra-thialulvalene] are semiconductors at ambient pressure, but some salts (PF6, AsF6, and BF4 center dot H2O salts) exhibit supuerconducting transition under hydrostatic pressure. X-ray diffraction and magnetic susceptibility measurements at ambient pressure for PF6 salt revealed that the insulating phase at ambient pressure corresponds to a charge ordering (CO) state with stripe-type charge pattern. While the similar magnetic behavior was observed for BF4 salt, temperature dependence of magnetic susceptibility of AsF6 salt is quite different from those of the other salts., SPRINGER/PLENUM PUBLISHERS
JOURNAL OF LOW TEMPERATURE PHYSICS, Feb. 2006, [Reviewed]

Quantum critical point in the quasi 2D conductor, (Me-DH-TTP)(2)AsF6
K. Kobayashi; S. Yasuzuka; T. Nakanishi; K. Yokogawa; H. Nishikawa; H. Yoshino; Keizo Murata, A new TTP donor, Me-DH-TTP (2-methyl-5-(1,3-dithiolan-2-yliden)-1,3,4,6-tetrathiapentalene), was designed to realize a system with large on-site Coulomb repulsion as compared with the previously known bis-fused type TTP donors. Probably as a consequence, (Me-DH-TTP)(2)AsF6 exhibits semiconducting behavior from room temperature to liquid helium temperature. By increasing pressure, metallic behavior appears below 300 K, and with distinct metal-insulator (M-I) transition up to 2.2 GPa. This M-I transition suddenly disappears beyond 2.5 GPa, and metallic state is stabilized down to 2.6 K. We discuss the possibility of quantum critical point around 2.4 GPa., SPRINGER/PLENUM PUBLISHERS
JOURNAL OF LOW TEMPERATURE PHYSICS, Feb. 2006, [Reviewed]

Detailed fermi surface topology of the quasi-one-dimensional conductor (DMET)(2)I-3
M. Kimata; Y. Oshima; K. Koyama; H. Ohta; M. Motokawa; H. Nishikawa; K. Kikuchi; I. Ikemoto, The detailed topology of the Fermi surface of the quasi-one-dimensional conductor (DMET)(2)I-3 was investigated by the magnetooptical measurements. A pair of planar Fermi surface which has higher corrugations of Fourier components was observed. This result seems to suggest that the metallic state of this salt is stabilized by the higher corrugations of the Fermi surface., SPRINGER/PLENUM PUBLISHERS
JOURNAL OF LOW TEMPERATURE PHYSICS, Feb. 2006, [Reviewed]

Electrical conducting bis(oxalato)platinate complex with direct connection of CuII ion　　　　　　　　　　　　　　　
C. Yamamoto; H. Nishikawa; M. Nihei; T. Shiga; M Hedo; Y. Uwatoko. H. Sawa; H. Kitagawa; Y. Taguchi; Y. Iwasa; H. Oshio
Inorg. Chem., 2006, [Reviewed]

Development of new D-A systems based on fullerene and TTF for organic device　　　　　　　　　　　　　　　
H. Nishiakawa; H. Oshio; A. Itakura; T. Nakamura; T. Kodama; K. Kikuchi; I. Ikemoto; M. Chikamatsu; Y. Yoshida; K. Yase
Mol. Cryst. Liq. Cryst., 2006, [Reviewed]

Crystal structure and physical properties of (DODHT)(2)FeCl4
H Nishikawa; Y Yasuda; T Kodama; K Kikuchi; Ikemoto, I; J Yamada; H Oshio, New organic conductor based on DODHT [ (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene], which gave superconducting salts under pressure, with an inorganic magnetic anion, FeCl4-, has been synthesized. A clear transition to an insulator was observed at 130 K in the temperature dependence of resistance, but no anomaly was seen in the magnetic susceptibility measurement in the same temperature range. Crystal structure analysis of (DODHT)(2)FeCl4 revealed that the salt crystallized in beta"-type crystal structure similarly to the superconducting DODHT salts, and as a result intermolecular interaction is quasi one-dimensional along molecular side-by-side direction. sigma 2005 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
POLYHEDRON, Nov. 2005, [Reviewed]

Magneto-optical measurement of organic conductor using rotational cavity system
H Ohta; M Kimata; K Koyama; Y Oshima; M Motokawa; H Nishikawa; K Kikuchi; Ikemoto, I, We have developed a new magneto-optical measurement system using a rotational cavity system equipped with a millimeter vector network analyzer and a 14 T solenoid type super conducting magnet. The measurement can be performed in the transmission configuration down to 1.6 K. The results of the precise angular dependence measurement of quasi-one-dimensional organic conductor (DMET)(2)I-3 using the new system are shown, and its Fermi surface will be discussed in connection with the previous reports., SPRINGER/PLENUM PUBLISHERS
INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES, Nov. 2005, [Reviewed]

Physical properties and crystal structures of MeDA-TTP salts
H Nishikawa; H Sekiya; D Watanabe; T Kodama; K Kikuchi; Ikemoto, I; J Yamada, A dithiane analogue of MeDH-TTP [2-isopropylidene-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene], MeDA-TTP [2-isopropylidene-5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene], has been prepared, and crystal structures and electrical properties of MeDA-TTP radical salts have been investigated. Although all the salts are isostructural, conducting behavior differs between the salt with an octahedral anion and the one with a tetrahedral anion; the salts with octahedral anions are metallic, but the ClO4 salt is semiconductive. A dithiane analogue of DODHT [ (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene], DADOT [2-(1,3-dithiane-2-ylidene)-4,5-(1,4-dioxane-2,3-diyldithio)-1,3-dithiole] has also been synthesized. Crystal structure of the DADOT salt is completely different from that of DODHT superconductors., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Sep. 2005, [Reviewed]

Crystal structures and physical properties of new BDA-TTP conductors
J Yamada; K Fujimoto; H Akutsu; S Nakatsuji; H Nishikawa; K Kikuchi, The TaF6 and FeBr4 salts of BDA-TTP [2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] have been prepared and characterized as beta-(BDA-TTP)(2)TaF6 and beta-(BDA-TTP)(2)FeBr4, respectively. The crystal structure of beta-(BDA-TTP)(2)TaF6 is isostructural to those of the ambient-pressure superconductors beta-(BDA-TTP)(2)X (X = SbF6, AsF6 and PF6), but this salt undergoes an MI (metal-to-insulator) transition instead of a superconducting transition at ambient pressure. The beta-(BDA-TTP)(2)FeBr4 salt, which is isomorphous to the superconductors beta-(BDA-TTP)(2)MCl4 (M = Fe and Ga) under applied pressures, exhibits a phase transition near 170 K and antiterromagnetic ordering with the Neel temperature (T-N) of about 9.5 K at ambient pressure., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Sep. 2005, [Reviewed]

Electronic structure of metallofullerene, Tm@C-82(II)
S Hino; N Wanita; K Iwasaki; D Yoshimura; N Ozawa; T Kodama; K Sakaguchi; H Nishikawa; Ikemoto, I; K Kikuchi, Ultraviolet photoelectron spectra of one of three Tm@C-82 isomers, Tm@C-82 (II), were measured with synchrotron radiation light source. The spectra resemble those of Ca@C-82 (III), which indicates that these two metallofullerenes have analogous valence electronic structures as well as the cage structures. The spectra of Tm@C-82 (II) and Ca@C-82 (III) are well reproduced by a simulated spectrum obtained with ab initio calculation based on the C-2 (no.5) cage geometry. This finding supports symmetry group determination carried out with NMR measured on Tm@C-82 (II). Because of spectral resemblance, the electronic structure of metallofullerenes seems to be determined solely by the fullerene cage and entrapped atom species., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Sep. 2005, [Reviewed]

Charge ordering and pressure-induced superconductivity in beta ''-(DODHT)(2)PF6
H Nishikawa; Y Sato; K Kikuchi; T Kodama; Ikemoto, I; J Yamada; H Oshio; R Kondo; S Kagoshima, Transport measurements of a pressure-induced organic superconductor, beta(")-(DODHT)(2)PF6 [DODHT=(1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene], were performed under various pressures to obtain a pressure-temperature phase diagram. The pressure application of 13.2 kbar induced superconductivity at 2.3 K. Due to a fractional existence of superconductivity, a resistive state was observed with decreasing temperature in a narrow pressure range above 13.2 kbar. X-ray and magnetic measurements at ambient pressure revealed that the insulating state has a charge disproportionation, or a charge ordering (CO) state, with stripes along the molecular side-by-side direction. These results suggest that the charge fluctuation may play a crucial role in the superconductivity in beta(")-(DODHT)(2)PF6., AMER PHYSICAL SOC
PHYSICAL REVIEW B, Aug. 2005, [Reviewed]

Proximity effect in a superconductor-metallofullerene-superconductor molecular junction
AY Kasumov; K Tsukagoshi; M Kawamura; T Kobayashi; Y Aoyagi; K Senba; T Kodama; H Nishikawa; Ikemoto, I; K Kikuchi; VT Volkov; YA Kasumov; R Deblock; S Gueron; H Bouchiat, We report low-temperature transport measurements through molecules of Gd metallofullerenes between superconducting suspended electrodes. The presence and number of molecules in the 2-nm-wide gap between electrodes was determined by high resolution transmission electron microscopy. We find that a junction containing a single metallofullerene dimer between superconducting electrodes displays signs of proximity-induced superconductivity. In contrast, no proximity effect develops in junctions containing a larger cluster of metallofullerenes. These results can be understood by taking into account multiple Andreev reflections, and the spin states of the Gd atoms., AMERICAN PHYSICAL SOC
PHYSICAL REVIEW B, Jul. 2005, [Reviewed]

Selective extraction of endohedral metallofullerenes using a mixed solvent of triethylamine and acetone
T Kodama; K Higashi; T Ichikawa; S Suzuki; H Nishikawa; Ikemoto, I; K Kikuchi; Y Achiba, We have developed a single-step method for selectively extracting endohedral metallofullerenes. In this new method, a mixed solvent of triethylamine and acetone is used to extract endohedral metallofullerenes from raw soot. The efficiency of extraction was investigated by extracting Ce-containing metallofullerenes, Ce@C-82 and Ce-2@C-80, from raw soot obtained by an arc discharge technique. The resultant extract contained little or no empty fullerenes such as C-60 or C-70, that is, the Ce-metallofullerenes were selectively extracted., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Apr. 2005, [Reviewed]

Paramagnetic platinum-rhodium octamers bridged by halogen ions to afford a quasi-1D system
K Uemura; K Fukui; H Nishikawa; S Arai; K Matsumoto; H Oshio, ハロゲン架橋Pt－Rh一次元錯体を合成し、構造と物性を明らかにした。, WILEY-V C H VERLAG GMBH
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 2005, [Reviewed]

New organic conductors and superconductors based on dihydro-TTF (DHTTF) donors
Jun-Ichi Yamada; Reiji Hayashi; Hiroki Akutsu; Shin'ichi Nakatsuji; Hiroyuki Nishikawa; Isao Ikemoto; Koichi Kikuchi, The synthesis of dihydrotetrathiafulvalene (DHTTF) donors and the preparation of their charge-transfer (CT) salts have been undertaken to develop new organic metals and superconductors. The molecular structures of methylenedithio-DHTTF (MDHT), 1,4-dioxane-2,3-diyldithio-DHTTF (DODHT), and methylmethylidenedithio-DHTTF (Me-MDHT) are secured by X-ray crystallographic analyses. These DHTTF donors provide CT salts characterized by a wide range of conducting behavior from semiconducting to metallic and superconducting. The crystal structures of CT salts from each category are described.
Molecular Crystals and Liquid Crystals, 2005, [Reviewed]

Development and applications of magnetooptical measurement system equipped with a rotational resonant cavity in the millimeter-wave region
M. Kimata; K. Koyama; H. Ohta; Y. Ohshima; M. Motokawa; H. Nishikawa; K. Kikuchi; I. Ikemoto, A rotational resonant cavity equipped with a millimeter vector network analyzer (MVNA) and a 14 T solenoid type superconducting magnet has been developed. The available frequency range is about 50–100 GHz. The temperature can decrease to 1.5 K. The cavity can rotate within the precision of one degree. As an example of the application of the new resonant cavity, we have performed detailed magnetooptical measurements of an organic conductor to estimate the Fermi surface topology. The Fermi surface of the quasi-one-dimensional conductor (DMET)2I3 is discussed., INSTITUTE OF PURE AND APPLIED PHYSICS
Jap. J. Appl. Phys., 2005, [Reviewed]

Ultraviolet photoelectron spectra of three Tm@C-82 isomers
S Hino; N Wanita; K Iwasaki; D Yoshimura; N Ozawa; T Kodama; K Sakaguchi; H Nishikawa; Ikemoto, I; K Kikuchi, Ultraviolet photoelectron spectra (UPS) of three Tm@C-82 isomers were measured with a synchrotron radiation light source. The upper valence band spectra (0-5 eV) of three isomers are different each other and they also differ from those of other trivalent metal atoms encapsulated metallofullerenes, such as La@C-82, Sc@C-82 and Gd@C-82. Resemblance of the spectra of Tm@C-82 (II) and Ca@C-82 (III) suggests identical cage structures of these two metallofullerenes. The UPS are well reproduced by simulated spectra obtained with ab initio calculation, which indicates that isomers I-III have C-s (No. 4), C-2 (No. 5) and C-2v (No. 9) cage structures. (C) 2004 Published by Elsevier B.V., ELSEVIER SCIENCE BV
CHEMICAL PHYSICS LETTERS, Jan. 2005, [Reviewed]

C-13 NMR study of Ca@C-74: the cage structure and the site-hopping motion of a Ca atom inside the cage
T Kodama; R Fujii; Y Miyake; S Suzuki; H Nishikawa; Ikemoto, I; K Kikuchi; Y Achiba, The C-13 NMR spectra of Ca@C-74 have been measured at 22 and 70 degreesC. The cage symmetry is assigned to be D-3h. Two distinct features of the C-13 NMR spectra, different linewidths of each line and line sharpening at higher temperature, indicate that the Ca atom hops between the several stable sites inside the D-3h cage. (C) 2004 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
CHEMICAL PHYSICS LETTERS, Nov. 2004, [Reviewed]

New trends in the synthesis of pi-electron donors for molecular conductors and superconductors
J Yamada; H Akutsu; H Nishikawa; K Kikuchi, 分子性導体と超伝導体における新しいπ電子系ドナーについて解説した。, AMER CHEMICAL SOC
CHEMICAL REVIEWS, Nov. 2004, [Reviewed]

Isolation and characterization of a new isomer of Ca@C-72
T Ichikawa; T Kodama; S Suzuki; R Fujii; H Nishikawa; Ikemoto, I; K Kikuchi; Y Achiba, We isolated a new (second) isomer of Ca@C-72. As a result of this discovery, it was confirmed that at least one of the two Ca@C-72 isomers has a C-72 cage that does not satisfy the so-called isolated pentagon rule (IPR), because C-72 has only one IPR cage structure., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Aug. 2004, [Reviewed]

Magnetic properties of superconducting salts, (DODHT)(2)X (X = AsF6, PF6 and BF4)
H Nishikawa; Y Sato; T Kodama; K Kikuchi; Ikemoto, I; JI Yamada, The magnetic properties of organic superconductors (DODHT)(2)X [ (1,4-dioxane-2,3-diyldithio)dihydro- tetrathiafulvalene; X = AsF6, PF6 and BF4.H2O] were investigated by ESR and magnetic susceptibility measurements. At ambient pressure, the salts exhibited semiconducting behavior with some anomalies. The ESR linewidth gradually decreased and showed an inflection at the temperature where resistive anomaly was observed. The temperature dependence of the spin susceptibility estimated from the ESR signal intensity showed a broad maximum at 150 - 200 K. The correspondence of the temperature dependence of the magnetic Susceptibility obtained by SQUID measurements to the ESR results and suggests low dimensional antiferromagnetic (AF) ordering, which is expected when charge ordering occurs in the semiconducting - insulating region., E D P SCIENCES
JOURNAL DE PHYSIQUE IV, Apr. 2004, [Reviewed]

New organic conductor (DMET)(2)CuCl2: Synthesis, structure and physical properties
M Umemiya; K Goto; S Takaishi; H Miyasaka; KI Sugiura; M Yamashita; H Nishikawa; K Kikuchi; Ikemoto, I; Y Yokochi; H Ito; S Kuroda, A new organic conducting salt, (DMET)(2)CuCl2, was prepared by a diffusion method, crystal and electrical structures of which were investigated. The single-crystal X-ray crystallography revealed that DMET molecules are alternately stacked to form quasi-one-dimensional (Q-1D) columns. This salt exhibited a metallic behavior with lowering temperature (sigma(RT) = 1.25 x 10(3) S(.)cm(-1)), where several resistance jumps were observed., E D P SCIENCES
JOURNAL DE PHYSIQUE IV, Apr. 2004, [Reviewed]

Photophysical study of new methanofullerene-TTF dyads: An obvious intramolecular charge transfer in the ground states
H Nishikawa; S Kojima; T Kodama; Ikemoto, I; S Suzuki; K Kikuchi; M Fujitsuka; HX Luo; Y Araki; O Ito, Three isomers of a new C-60-TTF dyad-C-60-X-TTF (X = ortho, meta, and para)-have been synthesized by changing the linking, positions (ortho, meta, and para) at a phenyl group that is attached to the methano[60]fullerene. The dyads showed clear intramolecular charge transfer (CT) absorption bands in the steady-state absorption spectra, which was indicative of an intramolecular CT interaction between the C-60 and TTF moieties in the ground state. The increase in intensity of the CT absorption bands followed the order C-60-ortho-TTF > C-60-meta-TTF much greater thanC(60)-para-TTF, which can be reasonably explained by the optimized molecular structures that are calculated at the ab initio level. Extreme quenching of the fluorescence intensity from the locally excited C-60 moiety was observed to follow the aforementioned order, which suggests that very fast excited singlet-state dynamics are dependent on the isomers. The quenching of the absorption intensities of the triplet state of the C-60 moiety detected in the nanosecond region was also observed to follow the same order, which suggests that competitive paths that are more efficient than intersystem crossing are present. From subpicosecond transient absorption measurements, very short-lived transient absorption bands attributed to the overlap of S-l-S-n with the excited CT state that has strong CT character were obtained for C-60-ortho-TTF (and C-60-meta-TTF); appreciable charge-separated (CS) species were generated for C-60-para-TTF. The lifetimes of the CT and CS states increased in the order of C-60-ortho-TTF < C-60-meta-TTF < C(60)para-TTF. Overall, it was revealed that the ground and excited states are controlled by the difference in proximity between the C-60 and TTF moieties, depending on the linking positions., AMER CHEMICAL SOC
JOURNAL OF PHYSICAL CHEMISTRY A, Mar. 2004, [Reviewed]

Millimeter wave magneto-optical measurement of organic conductors using a rotational cavity
H Ohta; M Kimata; K Koyama; Y Oshima; M Motokava; H Nishikawa; K Kikuchi; Ikemoto, I, We have developed a rotational resonant cavity equipped with the millimetre vector network analyser and the 14 T superconducting solenoid magnet. The measurement can be performed down to 1.6 K and the frequency range is about 50100 GHz. As an example of its application, the results of the precise angular dependence measurements of the quasi one dimensional organic conductor (DMET)(2)I-3 are presented., IEEE
CONFERENCE DIGEST OF THE 2004 JOINT 29TH INTERNATIONAL CONFERENCE ON INFRARED AND MILLIMETER WAVES AND 12TH INTERNATIONAL CONFERENCE ON TERAHERTZ ELECTRONICS, 2004, [Reviewed]

Observation of high-order quasi-one- dimensional periodic orbit resonance in (DMET)2I3 and its fermi surface.　　　　　　　　　　　　　　　
Y. Oshima; M. Kimata; K. Kishigi; H. Ohta; K. Koyama; M. Motokawa; H. Nishikawa; K. Kikuchi; I. Ikemoto, 表題物質のサイクロトロン共鳴を測定することにより、フェルミ面について考察した。
Physica B, 2004, [Reviewed]

Structural study of four Ca@C-82 isomers by C-13 NMR spectroscopy
T Kodama; R Fujii; Y Miyake; K Sakaguchi; H Nishikawa; Ikemoto, I; K Kikuchi; Y Achiba, The C-13 NMR spectra of four Ca@C-82 isomers have been measured. The symmetry of isomers I, II, III, and IV are assigned to be C-5, C-3v, C-2, and C-2v, respectively. For isomer IV, the cage is specified to be C-2v(9). (C) 2003 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV
CHEMICAL PHYSICS LETTERS, Aug. 2003, [Reviewed]

Fermi surface study of quasi-one-dimensional metals using magneto-optical techniques
Y Oshima; M Kimata; K Kishigi; H Ohta; K Koyama; M Motokawa; H Nishikawa; K Kikuchi; Ikemoto, I, Magneto-optical measurements of a quasi-one-dimensional (q1D) organic superconductor (DMET)(2)I-3 have been performed by using a cavity perturbation technique. Several resonant absorption lines, which can be attributed to the q1D periodic orbit resonance (q1D POR), were observed as well as quite unusual high order q1D PORs coming from its corrugated Fermi surface (FS) in the interlayer direction. Moreover, these resonances seem to disappear when the magnetic field is applied close to the conducting axis due to the FS topological effect, and the transfer integral ratio can be obtained from the angular dependence of q1D POR. The FS of (DMET)(2)I-3 can be estimated from these analyses of q1D PORs, and we will show that it has a characteristic FS structure. The observed results also indicate that the interlayer transport of (DMET)(2)I-3 is coherent., AMERICAN PHYSICAL SOC
PHYSICAL REVIEW B, Aug. 2003, [Reviewed]

Structure and properties of radical salts of DODHT derivatives
H Nishikawa; T Morimoto; A Machida; T Kodama; Ikemoto, I; K Kikuchi; J Yamada; H Yoshino; K Murata, A sulfur substituted derivative and the dithiane analogue of DODHT [DODHT = (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvatene], which comprised superconducting salts, were newly synthesized to investigate the effect of molecular size on the intermolecular overlap interaction in their salts. While the DODHT salts showed superconducting transition, all the salts composed of sulfur-substituted derivative obtained so far were semiconductors., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Apr. 2003, [Reviewed]

Crystal structures and physical properties of new Ni complexes with dihydro-TTF dithiolato
K Yokoyama; H Nishikawa; T Kodama; Ikemoto, I; K Kikuchi; J Yamada, We have succeeded in synthesizing new neutral Ni complexes with dithiolato ligands, Ni(dhdt)(2) (dhdt(2)- = 4,5-dihydrotetrathiafulvalene4,5-dithiolato), Ni(dtdt)(2) (dtdt(2-) = 1,3-dithian-2-ylidene-1,3-dithiole-4,5-dithiolato), which are semiconductors with room temperature conductivities of 8.4x10(-2) and 1.8x10(-5) S cm(-1), respectively. Crystal structural analysis of Ni(dtdt)(2) revealed that two-dimensional interaction through sulfur contacts exists., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Apr. 2003, [Reviewed]

Synthesis and physical properties of new C-60 derivatives linked with TTF
S Kojima; H Nishikawa; T Kodama; Ikemoto, I; K Kikuchi, New TTF-linked C-60 derivatives were synthesised from the viewpoint of the development of materials with multi-functionality. The electrochemical measurements revealed that the derivatives maintain redox characters of both C-60 and TTF. Obvious new broad bands were observed in the electronic spectra of the C-60 derivatives. This band is attributed to the intramolecular charge transfer between C-60 and TTF., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Apr. 2003, [Reviewed]

Organic conductors based on unsymmetrical BDY donors
J Yamada; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The synthesis of new unsymmetrical BDY donors DHDE-TTP [2-(1,3-dithiolan-2-ylidene)-5-(1,3-dithiepan-2-ylidene)-1,3,4,6-tetrathiaplentalene] and DADE-TTP [2-(1,3-dithian-2-ylidene)-5-(1,3-dithiepan-2-ylidene)-1,3,4,6-tetrathiaplentalene], each containing the bis-fused 1,3-dithiol-2-ylidene (BDY) unit as a pi-electron system, the conducting behavior of DHDE-TTP salts, and the crystal structure of kappa-(DHDA-TTP)(4)AuI2 [DHDA-TTP = 2-(1,3-dithiolan-2-ylidene)-5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiaplentalene] are described., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Apr. 2003, [Reviewed]

Structural studies of DODHT superconductor and related salts
K Kikuchi; H Nishikawa; T Morimoto; T Kodama; Ikemoto, I; J Yamada, The crystal structures of organic superconductors (DODHT)(2)AsF6 and (DODHT)(2)BF4 . H2O were investigated both at room and low temperatures. In the AsFb salt, the lattice constant of b axis is minimized around 250 K, while other constants contract on decreasing temperature. In the BF4 salt, the thermal movement of the anions is observed at room temperature, but it stops at low temperature. The relationship between the change in the crystal structures of the salts and their electrical behaviours is discussed., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Apr. 2003, [Reviewed]

New organic superconductors from a donor with reduced pi-system
H Nishikawa; T Morimoto; T Kodama; Ikemoto, I; K Kikuchi; J Yamada; H Yoshino; K Murata, The synthesis, electrochemical properties and molecular structure of a new organic donor, (1,4-dioxan-2,3-diyldithio)dihydrotetrathiafulvalene (DODHT), which possesses only one 1,3-dithiol-2-ylidene unit as a pi-electron system, has been investigated to explore new organic superconductors. The AsF6 and PF6 salts of DODHT are isostructural, which exhibited superconducting transition under 16.5 kbar. (C) 2002 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2003, [Reviewed]

Physical properties and crystal structures of BDA-TTP conductors
J Yamada; M Watanabe; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The preparation of charge-transfer (CT) salts composed of a new non-TTF donor 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has been investigated to develop new molecular-based organic superconductors and magnetic conductors. The BDA-TTP donor produces the superconducting beta-(BDA-TTP)(2)X (X = SbF6, AsF6, and PF6) salts, and beta-(BDA-TTP)(2)FeCl4 exhibits metallic conducting behavior with a metal-to-insulator (MI) transition at 113 K, as well as antiferromagnetism below the Neel temperature of near 8.5 K. (C) 2002 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2003, [Reviewed]

Syntheses and physical properties of new charge-transfer salts consisting of a conducting BEDT-TTF column and magnetic 1D or 2D Fe(III) networks
R Kanehama; Y Yoshino; T Ishii; T Manabe; H Hara; H Miyasaka; H Matsuzaka; M Yamashita; M Katada; H Nishikawa; Ikemoto, I, Two new molecular-based charge-transfer salts of bis(ethylenedithio)tetrathiafulvalene have been prepared, that is (BEDTTTF)(3)Fe(CN)(6).4H(2)O and (BEDT-TTF)(4)Fe(C2O4)(3)K.PhCl. Their crystal structures and physical properties have been investigated. Their structures consist of conducting columns of BEDT-TTF and magnetic 1D or 2D networks containing Fe(IH) ions connected by cyano- or oxalate-bridges. The d-pi interactions are discussed. (C) 2002 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2003, [Reviewed]

C-13 NMR study of Ca@C-74: Cage structure and dynamics of a Ca atom inside the cage
T Kodama; R Fujii; Y Miyake; S Suzuki; H Nishikawa; Ikemoto, I; K Kikuchi; Y Achiba, Ca@C-74 was isolated and its C-13 NMR spectra were measured. It was found that the symmetry of its cage is D-3h. In addition, it was suggested that the site-hopping motion of a Ca atom occurs inside the cage., ELECTROCHEMICAL SOCIETY INC
FULLERENES AND NANOTUBES: THE BUILDING BLOCKS OF NEXT GENERATION NANODEVICES, 2003, [Reviewed]

Chemical pressure effect on bandwidth and dimensionality of quasi-one-dimensional organic conductors: (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) and SCN]
Harukazu Yoshino; Keizo Murata; Kazuya Saito; Hiroyuki Nishikawa; Koichi Kikuchi; Isao Ikemoto, Thermopower is systematically studied for quasi-one-dimensional (Q1D) organic conductors (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) (formula presented) and SCN]. The field-orientation dependence of magnetoresistance of (formula presented) was measured by rotating magnetic field within its most conducting plane and the third angular effect (TAE) was observed at and below 4.2 K. Bandwidth estimated from the thermopower and its anisotropy (or dimensionality) from TAE are compared among (formula presented) to discuss chemical pressure effect on the low temperature state of Q1D conductors. It was found that bandwidth varies drastically (25 %) by changing the counter anions, while the dimensionality is almost the same for (formula presented) (formula presented) and (formula presented) which show different temperature dependence of the electric resistivity at low temperature from one another. An analytical formula is presented for the thermopower of dimerized one-dimensional (1D) metals within the tight-binding and the relaxation time approximations. It is shown that the effect of the dimerization is small on magnitude and sign of the thermopower of 1/4-filled 1D metals, while large deviation from the uniform case is predicted if band filling is changed. An approximate simple expression is also given for the angular width of the TAE anomaly as a function of the anisotropy of the transfer integrals and the lattice constants of a triclinic crystal for easy application of this new method. © 2003 The American Physical Society.
Physical Review B - Condensed Matter and Materials Physics, 2003, [Reviewed]

Chemical pressure effect on bandwidth and dimensionality of quasi-one-dimensional organic conductors: (DMET)(2)X [X = Au(CN)(2), AuI2, AuCl2, IBr2, I-3, AuBr2, and SCN]
H Yoshino; K Murata; K Saito; H Nishikawa; K Kikuchi; Ikemoto, I, Thermopower is systematically studied for quasi-one-dimensional (Q1D) organic conductors (DMET)(2)X [X=Au(CN)(2), AuI2, AuCl2, IBr2, I-3, AuBr2 (Z=1), and SCN]. The field-orientation dependence of magnetoresistance of (DMET)(2)AuCl2 was measured by rotating magnetic field within its most conducting plane and the third angular effect (TAE) was observed at and below 4.2 K. Bandwidth estimated from the thermopower and its anisotropy (or dimensionality) from TAE are compared among (DMET)(2)X to discuss chemical pressure effect on the low temperature state of Q1D conductors. It was found that bandwidth varies drastically (25 %) by changing the counter anions, while the dimensionality is almost the same for (DMET)(2)AuBr2, (DMET)(2)AuCl2, and (DMET)(2)I-3, which show different temperature dependence of the electric resistivity at low temperature from one another. An analytical formula is presented for the thermopower of dimerized one-dimensional (1D) metals within the tight-binding and the relaxation time approximations. It is shown that the effect of the dimerization is small on magnitude and sign of the thermopower of 1/4-filled 1D metals, while large deviation from the uniform case is predicted if band filling is changed. An approximate simple expression is also given for the angular width of the TAE anomaly as a function of the anisotropy of the transfer integrals and the lattice constants of a triclinic crystal for easy application of this new method., AMERICAN PHYSICAL SOC
PHYSICAL REVIEW B, Jan. 2003, [Reviewed]

Design of novel inorganic-organic hybrid materials based on iron-chloranilate mononuclear complexes: Characteristics of hydrogen-bond-supported layers toward the intercalation of guests
K Nagayoshi; MK Kabir; H Tobita; K Honda; M Kawahara; M Katada; K Adachi; H Nishikawa; Ikemoto, I; H Kumagai; Y Hosokoshi; K Inoue; S Kitagawa; S Kawata, Novel intercalation compounds constructed from the common two-dimensional hydrogen-bond-supported layers and functional guests {(H(0.5)phz)(2)[Fe(CA)(2)(H2O)(2)].2H(2)O}(n) (1), {[Fe(Cp)(2)][Fe(CA)(2)(H2O)(2)]}(n) (2), {[Fe(Cp*)(2)][Fe(CA)(2)(H2O)(2)]}(n) (3), and {(TTF)(2)[Fe(CA)(2)(H2O)(2)]}(n) (4) (H(2)CA = chloranilic acid, phz = phenazine, [Fe(CP)(2)] = ferrocene, [Fe(Cp*)(2)] = decamethylferrocene, TTF = tetrathiafulvalene) are described. The guest cations are introduced between the [Fe(CA)(2)(H2O)(2)](m-)} layers by electrostatic (1-4) and pi-pi stacking (3, 4) interactions. [Fe(Cp*)(2)](+) cations in 3 are stacked on each other making tilted columns which are included in the channel created by the chlorine atoms of CA(2-) dianions. TTF cations in 4 are stacked face to face with two types of S...S distances (type A; 3.579(3) Angstrom, and type B; 3.618(3) Angstrom) making a columnar structure. The TTF cations in the stacked column have a head-to-tail arrangement with respect to the iron-chloranilate layer. Mossbauer spectroscopy suggests that [Fe(CA)(2)(H2O)(2)](m-) anion in 3 is consistent with high-spin (S = 5/2) iron(III) ions and [Fe(CP*)(2)](+) in the low-spin (S = 1/2) iron(III) ions. In 4, Mossbauer spectroscopy shows high-spin iron(II) ions (IS 1.10 mm.s(-1) and QS = 1.66 mm.s(-1) at 297 K) and high-spin iron(III) ions (IS = 0.42 mm.s(-1) and QS = 1.27 mm.s(-1) at 297 K), suggesting that the anionic layer of iron-chloranilate has a valence-trapped mixed-valence state. At the temperature range of 77-300 K, the compounds 1, 2, and 3 are EPR silent, whereas the EPR spectrum of 4 shows two types of signals with g = 2.008 indicating the radical form of TTF., AMER CHEMICAL SOC
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Jan. 2003, [Reviewed]

Development of new organic metals and superconductors from a non-TTF donor system
JI Yamada; M Watanabe; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The study of three kinds of non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA), 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH), and. 2-(1,3-dithiolan-2-ylidene)-5(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (DHDA), which contain the bis-fused 1,3-dithiole-2-ylidene unit instead of the TTF unit as a pi-electron system, has been undertaken to develop new molecular-based organic superconductors, magnetic conductors, and organic metals. The BDA donor produces the superconducting SbF6, AsF6, and PF6 salts. ne kappa-(BDH)(2)FeCl4 salt is a paramagnetic organic metal stable down to 1.5 K, whereas beta-(BDA)2FeCl4 exhibits metallic conducting behavior with a sharp metal-to-insulator (MI) transition (T-MI = 113 K), and antiferromagnetic ordering with a Neel temperature of near 8.5 K. Several salts of DHDA, a hybrid of BDA and BDH, are found to be metallic., TAYLOR & FRANCIS LTD
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2003, [Reviewed]

Magnetooptical measurements of quasi-one- dimensional conductor (DMET)2I3.　　　　　　　　　　　　　　　
Y. Oshima; H. Ohta; K. Koyama; M. Motokawa; H. Nishikawa; K. Kikuchi; I. Ikemoto, 擬一次元導体である表題物質の磁気光学効果の測定を行った。
Synth. Met., 2003, [Reviewed]

A new organic superconductor, beta-(BDA-TTP)(2)GaCl4 [BDA-TTP=2,5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene]
J Yamada; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi; ES Choi; D Graf; JS Brooks, The preparation, crystal structure and physical properties of beta-(BDA-TTP)(2)GaCl4 has been investigated; the salt exhibits superconductivity at 3.1 K ( onset) under a hydrostatic pressure of 7.6 kbar., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, 2003, [Reviewed]

A new organic superconductor, (DODHT)(2)BF4 center dot H2O
H Nishikawa; A Machida; T Morimoto; K Kikuchi; T Kodama; Ikemoto, I; J Yamada; H Yoshino; K Murata, In addition to two organic superconductors (DODHT)(2)X [DODHT = (1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene; X = PF6 and AsF6] previously reported by us, the BF4 salt of DODHT containing one water molecule [ (DODHT)(2)BF4.H2O] has been found to undergo a superconducting transition at 3.2 K under a hydrostatic pressure of 15.5 kbar., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, 2003, [Reviewed]

Magnetic/conducting hybrid compound composed of 1-D chain [ (Mn2Cl5)-Cl-II(EtOH)](-)(infinity) and BEDT-TTF stacking layer
H Miyasaka; Y Yoshino; T Ishii; R Kanehama; T Manabe; M Yamashita; H Nishikawa; Ikemoto, I; H Kishida; H Matsuzaki; H Okamotot, An assembled compound (BEDT-TTF)(2)]Mn2Cl5(EtOH)] (1) consisting of two structural lattices of Mn(II)-Cl one-dimensional (I-D) chains and bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) stacking layers was synthesized by electrochemical crystallization. Compound 1 crystallized in triclinic space group P-1. (#2) with a = 13.1628(5) Angstrom, b = 20.3985(9) Angstrom, c = 7.4966(3) Angstrom, alpha = 98.3498(8)degrees, beta = 104.980(1)degrees, gamma =74.602(2)degrees, V = 1868.3(1)Angstrom(3), and Z = 2. The 1-D chains and the stacking layers are aligned along the c-axis of the unit cell. The I-D chain is described as [Mn2Cl5(EtOH)]- in which two Mn(II) ions and four Cl- ions form a ladder-like chain with Kagome (cuboidal) sublattices, and the remaining Cl- ion and an ethanol molecule cap the edge-positioned Mn(II) ions of the chains. The BEDT-TTF molecules are packed between the Mn-Cl chains (ac-plane), the intermolecular S (. . .) S contacts of which are approximately found in the range 3.440(2)-3.599(2) Angstrom. The packing feature of BEDT-TTF molecules is very similar to that of (BEDT-TTF)(2)ClO4(TCE)(0.5) (TCE=1,1,2-trichloroethane) (J. Am. Chem. Soc., 105, 297 (1983)). Regarding the electronic state of each BEDT-TTF molecule, Raman spectroscopic analysis and ESR study revealed the presence of half-valence BEDT-TTF molecules (charge delocalization) in 1. Magnetic measurements clearly demonstrated that the paramagnetic spins on the 1-D chain [Mn2Cl5(EtOH)](infinity)(-) arrange antiferromagnetically in the low-temperature region. Additionally, 1 exhibits metallic conductivity in the temperature range 2.0-300 K (sigma = 21 S cm(-1) at 300 K and 1719 S cm(-1) at 2.0 K), due to the contribution of the stacked BEDT-TTFs. Consequently, these peculiarities that correspond to antiferromagnetic/metallic conductivity demonstrate the "bi-functionality" of 1. (C) 2002 Elsevier Science (USA)., ACADEMIC PRESS INC ELSEVIER SCIENCE
JOURNAL OF SOLID STATE CHEMISTRY, Nov. 2002, [Reviewed]

Tetrachloroferrate (III) salts of BDH-TTP [2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] and BDA-TTP [2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene]: Crystal structures and physical properties
K Kikuchi; H Nishikawa; Ikemoto, I; T Toita; H Akutsu; S Nakatsuji; J Yamada, Three FeCl4 salts based on non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP) and 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), have been prepared and characterized as kappa-(BDH-TTP)(2)FeCl4, beta-(BDA-TTP)(2)FeCl4, and (BDA-TTP)(3)FeCl4 - PhCl. The kappa-(BDH-TTP)(2)FeCl4 salt, with a room-temperature conductivity (sigma(rt)) of 39Scm(-1), is metallic down to 1.5 K, and its magnetic susceptibility obeys the Curie-Weiss law with a Curie constant (C) of 4.25 emu K mol(-1) and a Weiss constant (theta) of 0.041K. beta-(BDA-TTP)(2)FeCl4 exhibits metallic behavior (sigma(rt)=9.4Scm(-1)) with a sharp metal-to-insulator (MI) transition (T-MI=113K) and antiferromagnetic ordering with the Neel temperature of near 8.5K, whereas the solvated (BDA-TTP)(3)FeCl4 - PhCl salt is a semiconductor with a thermal activation energy of 0.11eV (sigma(rt)= 2.0 x 10(-2)Scm(-1)) and exhibits Curie-Weiss behavior (C = 4.42 emu K mol(-1), theta = -0.35 K). (C) 2002 Elsevier Science (USA)., ACADEMIC PRESS INC ELSEVIER SCIENCE
JOURNAL OF SOLID STATE CHEMISTRY, Nov. 2002, [Reviewed]

Synthesis and electroconductive properties of radical salts derived from tetrathiafulvalene dimers
M Iyoda; K Hara; E Ogura; T Takano; M Hasegawa; M Yoshida; Y Kuwatani; H Nishikawa; K Kikuchi; Ikemoto, I; T Mori, TTFダイマーからなる伝導性錯体の合成と電気伝導挙動について議論した。, ACADEMIC PRESS INC ELSEVIER SCIENCE
JOURNAL OF SOLID STATE CHEMISTRY, Nov. 2002, [Reviewed]

New tetrathiapentalene-derived charge transfer salts with paramagnetic transition metal complex anion: kappa-(EDDH-TTP)(3)[Cr(phen)(NCS)(4)]center dot 2CH(2)Cl(2) and kappa(21)-(BDH-TTP)(5)[Cr(phen)(NCS)(4)](2)center dot 2CH(2)Cl(2)
F Setifi; L Ouahab; S Golhen; O Hernandez; A Miyazaki; T Enoki; T Toita; J Yamada; H Nishikawa; A Lapinski; R Swietlik, The preparation, crystal structures, and optical and magnetic properties of two new charge-transfer salts kappa-(EDDH-TTP)(3)[Cr(phen)(NCS)(4)].2CH(2)Cl(2) (1) and kappa(21)-(BDH-TTP)(5)[Cr(phen)(NCS)(4)](2).2CH(2)Cl(2) (2), where phen = 1,10-phenanthroline, EDDH-TTP = 2-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, and BDH-TTP = 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, are reported. Crystal data: (1) monoclinic P2(1)/a, a = 25.0752(5) Angstrom, b 10.6732(3) Angstrom, c = 28.1601(6) Angstrom, beta = 95.195(2)degrees, Z = 4, R = 0.0585 for 6741 independent reflections with I > 3sigma(I); (2) monoclinic P2(1)/a, a = 23.8275(4) Angstrom, b = 9.1015 (2) Angstrom, c = 27.0420(1) Angstrom, beta = 99.9297(8)degrees, Z = 4, R = 0.0530 for 4565 independent reflections with I > 2sigma(I). The crystal structures for both compounds consist of alternating organic and inorganic layers. The organic layer in compound 1 is characterized as kappa-type, while the organic layer in 2 resembles the kappa-type but it contains orthogonal dimers and monomers, and it is therefore called kappa(21). Compound 1 shows metallic behavior down to low temperature. Salt 2 shows semiconductive behavior, which is explained as the result of either charge ordering owing to the kappa(21)-type structure or Peierls distortion due to the one-dimensional electronic nature. However, weak metallic behavior could be observed at 10 kbar above ca. 150 K and at 15 kbar above 170 K. The magnetic susceptibilities for both compounds show Curie-Weiss behavior, showing that the exchange interactions between the magnetic anions are weak. Polarized reflectance spectra of single crystals were measured over the spectral range from 650 to 7000 cm(-1). Moreover, absorption and diffusion reflectance spectra of powdered crystals dispersed in KBr (from 400 to 7000 cm(-1)) were recorded. Vibrational and electronic features are discussed., AMER CHEMICAL SOC
INORGANIC CHEMISTRY, Jul. 2002, [Reviewed]

New organic superconductors consisting of an unprecedented pi-electron donor
H Nishikawa; T Morimoto; T Kodama; Ikemoto, I; K Kikuchi; J Yamada; H Yoshino; K Murata, 縮小π電子系ドナーであるDODHTからなる新規超伝導体の合成に成功し、構造と物性を解明した。, AMER CHEMICAL SOC
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Feb. 2002, [Reviewed]

Electrical and optical properties of a potassiumdoped film of a long alkyl chain-linked C60
Masayuki Chikamatsu; Said Kazaoui; Nobutsugu Minami; Kiyoshi Yase; Takeshi Kodama; Hiroyuki Nishikawa; Isao Ikemoto; Koichi Kikuchi, Electrical and optical properties of a potassium (K) -doped film of a hexadecyl chain-linked C60, (C60-C16) were evaluated by electric conductivity, UV-visible near-IR and Raman spectra. The conductivity of the pristine film (3 × 10-7 S cm-1) largely increased to 0.1 S cm-1after doping. The absorption band of C60-C16 anion was observed around 900 nm in the K-doped film. As a result of Raman spectra measurement, it was confirmed that tri- and/or tetra-anions of C60-C16 are formed in the film.
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals, 2002, [Reviewed]

2-(1,3-Dithiolan-2-ylidene)-5-(1,3-dithian-2-ylidene) 1,3,4,6-tetrathiapentalene(DHDA-TTP), a hybrid of BDH-TTP and BDA-TTP, and its metallic cation-radical salts
J Yamada; M Watanabe; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The synthesis and electrochemical properties of the DHDA-TTP donor, a hybrid of 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH-TTP) and 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), has been investigated, and its ability to form metallic cation-radical salts is elucidated., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, 2002, [Reviewed]

Low temperature physical properties of the organic conductor, (DIMET)(2)I-3 after thermal treatment
H Yoshino; K Murata; Y Yamamura; T Tsuji; H Nishikawa; K Kikuchi; Ikemoto, I, The effect of thermal treatment on the electrical conductivity was studied for a quasi-one-dimensional organic conductor, (DIMET)(2)I-3 (DIMET=dimethyl(ethylenedithio)tetrathiafulvalene). After heating the samples up to a temperature between 340 and 370 K, the electric resistivity was measured at low temperature down to 2 K and under pressure up to 1.6 Gpa. (DIMET)(2)I-3 shows irreversible decrease in the electric resistivity between 350 and 356 K on heating. It was found that the heating above 350 K suppresses the spin-density-wave transition at 40 K and another metal-insulator transition appears at 18 K., KLUWER ACADEMIC PUBL
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 2002, [Reviewed]

Electrical properties of organic conductors at high temperature
H Yoshino; K Murata; Y Yamamura; T Tsuji; JI Yamada; S Nakatsuji; H Anzai; H Nishikawa; K Kikuchi; Ikemoto, I; K Saito, Physical properties up to 600 K are studied for (TMTSF)(2)PF6, (TMTTF)(2)PF6, (DMET)(2)I-3, (DMET)(2)AuI2, (DIMET)(2)I-3, (DIMET)(2)AuI2 and kappa-(ET)(2)Cu(NCS)(2). It has been found that all the compounds decompose between 450 and 500 K by TG-DTA measurement. Electric resistivity and thermopower of the TMTSF and DMET salts are metallic as were expected from their temperature dependence below 300 K The TMTTF and DIMET salts show constant thermopower, though their resistivity is metallic. This suggests that Me TMTTFand DIMET salts are intrinsically non-metallic even above room temperature. Rapid decrease in resistivity found for many of the Q1D salts before their decomposition suggests the partial escape of anions and change in the carrier concentration. kappa-(BEDT-TTF)(2)Cu(NCS)(2) shows hysteretic temperature dependence of the resistivity above 300 K., TAYLOR & FRANCIS LTD
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2002, [Reviewed]

New organic superconductors from a non-TTF donor, BDA-TTP
JI Yamada; M Watanabe; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, A new pi-electron donor, 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathia-pentalene (BDA-TTP), which contains no teirathiafulvalene (TTF) molecule, produces a series ambient-pressure superconductors beta-(BDA-TTP)(2)X(X = SbF6-, AsF6-, and PF6-), in which the values of intermolecular overlap integrals suggest loose donor parking motifs., TAYLOR & FRANCIS LTD
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2002, [Reviewed]

Structural study of three isomiers of Tm@C82 by 13C NMR spectroscopy.　　　　　　　　　　　　　　　
T. Kodama; N. Ozawa; Y. Miyake; K. Sakaguchi; H. Nishikawa; I. Ikemoto; K. Kikuchi; Y. Achiba, 表題の金属内包フラーレンの３つの異性体について13C NMR測定を行い、構造を決定した。
J. Am. Chem. Soc., 2002, [Reviewed]

The crystal structure and physical properties of beta-(BDA-TTP)(2)FeCl4 [BDA-TTP=2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene]
J Yamada; T Toita; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The title charge-transfer (CT) salt exhibits metallic conducting behavior with a metal-to-insulator (MI) transition at 113 K, and its magnetic properties reveal that it is an antiferromagnet below the Neel temperature, T-N = 8.5 K., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, Dec. 2001, [Reviewed]

Effects of molecular association in the radical-cations of 1,8-bis(ethylenedithiotetrathiafulvalenyl)naphthalene
M Iyoda; M Hasegawa; Y Kuwatani; H Nishikawa; K Fukami; S Nagase; G Yamamoto, The pi-pi interaction of the tetrathiafulvalenyl groups in 1,8-bis(ethylenedithiotetrathiafulvalenyl)naphthalene was investigated. The novel electronic properties of neutral and cationic tetrathiafulvalenes have been revealed on the basis of the X-ray analysis, spectral analyses, and DFT calculations., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Nov. 2001, [Reviewed]

Valence change of Tm atom in metallofullerenes
Koichi Kikuchi; Koichi Sakaguchi; Ozawa Norio; Takeshi Kodama; Hiroyuki Nishikawa; Isao Ikemoto; Kenji Kohdate; Daiju Matsumura; Toshihiko Yokoyama; Toshiaki Ohta, The Tm LIII-edge XANES spectra were examined on Tm@C82(I), Tm@C82(III) and Tm@C82(I). The absorption edge of Tm@C82 is observed almost at the same position of Tm2O3, but those of Tm@C82 and Tm@C84 shifted about 7eV to the lower energy side. The 8eV energy shift was reported between the edges of TmS and TmTe, where Tm atom takes a trivalent and divalent state, respectively. Therefore Tm atom was confirmed to take the trivalent state in di-metallofullerenes, contrary to the divalent state in mono-metallofullerenes.
AIP Conference Proceedings, Oct. 2001

Out-of-plane and in-plane structures of the cast films of long alkyl chain-linked C 60 via phenyl ring
M. Chikamatsu; K. Kikuchi; T. Kodama; H. Nishikawa; I. Ikemoto; N. Yoshimoto; T. Hanada; Y. Yoshida; N. Tanigaki; K. Yase, The films of dodecyl chain-linked C60 via ortho, meta and para positions on a phenyl group (o-C12, m-C12 and p-C12) were prepared by casting the carbon disulfide solutions on the amorphous carbon coated silicon substrates. Out-of-plane and in-plane structures of these cast films were characterized by X-ray diffraction (XRD) and grazing incidence X-ray diffraction (GIXD) methods, respectively. As a result of XRD measurement, it was revealed that all the cast films take multilayer structures and the period of the layer structure of the o-C12 film (32.5 Å) is much larger than that of the m-C12 (23.2 Å) or the p-C12 (23.3 Å) film. By GIXD measurement, it was found that C60 moieties form two-dimensional arrangement of the square lattice (a=10.1 Å,γ=90°) and pack densely in all the cast films., American Institute of Physics Inc.
AIP Conference Proceedings, Oct. 2001, [Reviewed]

ac calorimetry and EPR study on metal-insulator transition and glass transition in an organic conductor with double-column structure, (DIMET)(2)BF4
K Saito; H Akutsu; K Kikuchi; H Nishikawa; Ikemoto, I; M Sorai, Successive metal-insulator transitions in (DIMET)(2)BF4 were studied by chopped-light ac calorimetry and electron paramagnetic resonance (EPR) measurement. All anomaly due to the metal-insulator transitions has been clearly detected in ac calorimetry between 20 and 35 K. In contrast to other double-column salts (DMET)(2)BF4 and (DMET)(2)ClO4, successive metal-insulator transitions detected in transport properties are shown to be thermodynamic phase transitions. The EPR detected an anomaly only for the lowest transition around 12 K. The properties of the metal-insulator transitions are compared among the DIMET and DMET salts having the double-column structure. A frequency-dependent step in heat capacity was detected around 110 K. The step-like anomaly is attributed to a glass transition due to freezing of the intramolecular motion of the ethylene group in the ET moiety within a DIMET molecule., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Jun. 2001, [Reviewed]

New organic superconductors beta-(BDA-TTP)(2)X [BDA-TTP=2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene ; X- = SbF6-, AsF6-, and PF6-]
J Yamada; M Watanabe; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The synthesis, electrochemical properties, and molecular structure of a new pi -electron donor, 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), is described. In contrast to the hitherto-known tetrachalcogenafulvalene pi -donors providing organic superconductors, this donor contains only the bis-fused I,3-dithiole-2-ylidene unit as a pi -electron system, yet produces a series of ambient-pressure superconductors beta-(BDA-TTP)(2)X [X = SbF6 (magnetic T-c = 6.9 K, resistive T-c = 7.5 K), AsF6 (magnetic T-c = 5.9 K, resistive T-c = 5.8 K), and PF6 (magnetic T-c = 5.9 K)], which are isostructural. The values of the intermolecular overlap integrals calculated on the donor layers of these superconductors suggest a two-dimensional (2D) electronic structure with loose donor packing. Tight-binding band calculations also indicate that these superconductors have the 2D band dispersion relations and closed Fermi surfaces., AMER CHEMICAL SOC
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, May 2001, [Reviewed]

Tetrathiafulvalene derivatives linking a dichalcogenolane ring through the sigma-bond: New donor components far organic metals
J Yamada; R Oka; T Mangetsu; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, A synthetic study of the dioxolane derivatives of methylenedithio(ethylenedithio)tetrathiafulvalene (MET), bis(methylenedithio)tetrathiafulvalene (MT), and methylenedithiotetrathiafulvalene, their dithiolane analogues, and the oxathiolane derivative of MET has been undertaken to explore new organic metals. A practically useful preparation of the biheterocycle-fused 1,3-dithiol-2-ones as building blacks for these dichalcagenolane-linked tetrathiafulvalene (TTF) donors has been realized via the newly developed BF3-promoted reactions. The effect of the additional linked dichalcogenolane ring on the electron-donating ability is investigated by cyclic voltammetry. An X-ray crystallographic analysis of the oxathiolane-linked MET reveals that its molecular structure is isostructural with that of its dithiolane analogue but not bulkier than that of its dioxolane analogue. Several of the present TTP donors have produced metallic charge-transfer materials, two of which are characterized by X-ray crystallography. In the crystal structure of the 7,7,8,8-tetracyanoquinodimethane complex of the dioxolane-linked MT that exhibits metallic-like behavior around room temperature, the donor molecules are stacked head-to-tail to form the dimers, which are connected by C-H . . .O hydrogen bonds. On the other hand, in the metallic AsF6 salt of the dioxolane-linked MET stable down to 2.0 K, the donor molecules are stacked head-to-head to form two-dimensional sheets despite the dioxolane ring being perpendicularly attached to the MET molecule., AMER CHEMICAL SOC
CHEMISTRY OF MATERIALS, May 2001, [Reviewed]

Synthesis and properties of new type TTP donors
H Nishikawa; T Isaka; T Kodama; Ikemoto, I; K Kikuchi; J Yamada; Y Misaki, New type TTP donors. alkyl-DH-TTPs (2-alkylidene-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene) were newly synthesized. From the electrochemical study, these donors have larger onsite Coulomb repulsion compared with the previously known his-fused type TTP donors in accordance with reduction of the pi -system. Nevertheless Me-DH-TTP makes metallic salts down to quite low temperature., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2001, [Reviewed]

Oxygen and selenium substituted derivatives of DOET donor: synthesis and properties
K Kikuchi; S Ikeda; H Nishikawa; T Kodama; Ikemoto, I; J Yamada, Oxygen and selenium substituted derivatives of DOET were newly synthesized to investigate the effect of molecular size on the intermolecular overlap interaction in their salts. The oxygen-substituted derivative, DOEO (1) produced metallic salts down to 2K, whereas radical-cation salts of the selenium derivative, ETDO (2) were all semiconductors., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2001, [Reviewed]

Oxygen-substituted derivatives of DHTTF-fused donors: synthesis and properties
J Yamada; S Kawagishi; T Shinomaru; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The synthesis and electrochemical properties of novel oxygen-containing pi -electron donors (3a,b and 4), in which only one outer sulfur atom of the DHTTF (dihydrotetrathiafulvalene)-fused donors (1a,b and 2) is replaced by oxygen atom, has been investigated to explore new organic metals. Among the 3a-based CT (charge-transfer) complexes and salts, the TCNQ (tetracyanoquinodimethane) complex and the BF4 salt exhibited metallic conducting behavior., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2001, [Reviewed]

Direct evidence of dimensionality enhancement of Q1D TMTSF and DMET salts
H Yoshino; A Oda; K Murata; H Nishikawa; K Kikuchi; Ikemoto, I, Magnetoresistance measurement was carried out for quasi-one-dimensional (Q1D) organic superconductors, (TMTSF)(2)PF6, (DMET)(2)AuI2 and (DMET)(2)I-3 at 1.2 K up to about 15 kbar. The third angular effect (TAE) is observed in their metallic state as an hump anomaly of the angular dependence of the magnetoresistance. It has been found that the angular width of the TAE hump anomaly increases with increasing hydrostatic pressure. This is the first direct evidence of the dimensionality enhancement by pressure for the Q1D superconductors, where the dimensionality is defined as the anisotropy of the transfer integrals, t(y)/t(x)., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 2001, [Reviewed]

Syntheses, structure and conducting properties of halogenated ethylenedioxytetrathiafulvalenes
M Iyoda; Y Kuwatani; E Ogura; K Hara; H Suzuki; T Takano; K Takeda; J Takano; K Ugawa; M Yoshida; H Matsuyama; H Nishikawa; Ikemoto, I; T Kato; N Yoneyama; J Nishijo; A Miyazaki; T Enoki, 4,5-Diiodo-, 4,5-dibromo-, and 4,5-dichloro-4',5'-ethylenedioxytetra-thiafulvalenes (EDO-TTFI2, EDO-TTFBr2, and EDO-TTFCl2) were synthesized in moderate to good yields by the two routes. The first route contains the reaction of EDO-TTF with LDA, followed by quenching with halogenated reagents, and the second route consists of the P(OR)(3)-mediated cross-coupling of 4,5-dihalogenated 1,3-dithiole-2-ones with 4,5-ethylenedioxy-1,3-dithiole-2-thione. The structures of EDO-TTFI2 and EDO-TTFCl2 were determined by X-Ray analysis. The radical-cation salts derived from EDO-TTFI2, EDO-TTFBr2, and EDO-TTFCl2 show high conductivities, although these compounds contain electron-withdrawing halogens as the substituent., PERGAMON-ELSEVIER SCIENCE LTD
HETEROCYCLES, Feb. 2001, [Reviewed]

Development of organic metals based on the extended TTF donors by the sigma-bond framework
JI Yamada; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, Investigations of the tetrathiafulvalene (TTF) derivatives extended by the sigma -bond frameworks, such as saturated heterocycles (3-8) and alkyl groups (9), have been undertaken to explore new molecular-based organic metals. TTF donors with the periphery extended by the cis-fused dioxane ring (3) and by linkage of a dichalocogenolane or dioxane ring (4-6 or 7) produce metallic radical-cation salts. While radical-cation salts of the methylated TTF donor (9a) are semiconductive, the ClO4 and PF6 salts of the ethylated one (9b) exhibit metallic conducting behavior for compressed pellets. The crystal structure of the metallic (4)(2)AsF6 salt is also presented., GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP
MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 2001, [Reviewed]

Dichalcogenane derivatives of methylenedithio(ethylenedithio)tetrathiafulvalene (MET) and a derived metallic cation-radical salt with screwed donor stacks
J Yamada; T Mangetsu; H Akutsu; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, The synthesis of the dichalcogenane derivatives of MET, (1,3-dioxan-2-yl)methylenedithio(ethylenedithio)tetrathiafulvalene (DOA-MET) and (1.3-dithian-2-yl)methylenedithio(ethyl-enedithio)tetrathiafulvalene (DTA-MET), and the preparation of their charge-transfer (CT) materials are investigated to explore new organic metals. The resulting (DOA-MET)(3)AuI2 salt exhibits weak metallic conducting behavior, and has screwed donor stacks., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Jan. 2001, [Reviewed]

Spectroscopic studies of endohedral metallofullerenes
T Kodama; M Kusuda; N Ozawa; R Fujii; K Sakaguchi; H Nishikawa; Ikemoto, I; K Kikuchi; Y Miyake; Y Achiba, We have measured the absorption spectra of the cations of La@C-82 and Ce@C-82, which are trivalent-type metallofullerenes. The obtained spectra resemble not only each other but also those of the neutral species of Ca@C-12(IV) and Tm@C-82(III), which are divalent-type metallofullerenes. Moreover, we found that the four metallofullerenes have an identical cage. To assign the absorption spectra, we performed a semi-empirical calculation at the level of single configuration interaction for Ca@C-82(IV). It was revealed that any charge transfer transitions from the C-82 cage to the encapsulated metal atom cannot have large oscillator strength., MYU K K
NEW DIAMOND AND FRONTIER CARBON TECHNOLOGY, 2001, [Reviewed]

Calorimetric study of metal-insulator transition in (DIMET)(2)I-3
K Saito; A Sato; K Kikuchi; H Nishikawa; Ikemoto, I; M Sorai, Heat capacity of a quasi-one-dimensional organic conductor (DIMET)(2)I-3 has been measured by chopped-light ac calorimetry below room temperature. An anomaly due to a metal-insulator transition has been clearly detected around 40K. The magnitude of the anomaly is analyzed through comparison with other Q1D conductors. A possible SDW mechanism is suggested., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Nov. 2000, [Reviewed]

Production and isolation of the isomers of dimetallofulerenes, HoTm@C-82 and Tm-2@C-82
K Kikuchi; K Akiyama; K Sakaguchi; T Kodama; H Nishikawa; Ikemoto, I; T Ishigaki; Y Achiba; K Sueki; H Nakahara, Metallofullerenes encapsulating Ho and Tm atoms were isolated by using the HPLC method with two different columns. Three isomers of HoTm@C-82 and five isomers of Tm-2@C-82 were identified. The UV-VIS-MR absorption spectra of these isomer species were similar to those of the corresponding isomers of Er-2@C-82. This suggests that the cages of HoTm@C-82 and Tm-2@C-82 have the same charge as that of Er-2@C-82 and that Tm takes the trivalent state in HoTm@C-82 and Tm-2@C-82, contrary to the divalent state in Tm@C-82. (C) 2000 Elsevier Science B.V. All rights reserved., ELSEVIER SCIENCE BV
CHEMICAL PHYSICS LETTERS, Mar. 2000, [Reviewed]

Preparation of 4,5-(alkylmethylenedithio)-1,3-dithiole-2-chalcogenones: Building blocks for the mono-alkylated TTF donors
J Yamada; K Aoki; S Nakatsuji; H Nishikawa; Ikemoto, I; K Kikuchi, 4,5-(Methoxymethylenedithio)-1,3-dithiole-2-chalcogenones 3 and 4 have been alkylated by using R3Al and RMgX (X = Cl or Br)TiCl4 complex reagent to give the title compounds 1 and 2. Cross-coupling of 1a-d with 5 furnished the mono-alkylated MET derivatives 6a-d, and the ClO4 and PF6 Salts of 6b exhibited metallic conducting behavior for compressed pellets. (C) 1999 Elsevier Science Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
TETRAHEDRON LETTERS, Sep. 1999, [Reviewed]

Preparation and properties of DOET derivatives and their salts
H Nishikawa; T Sato; T Kodama; Ikemoto, I; K Kikuchi; H Anzai; J Yamada, The selenium containing TTF donors condensed with a 1,4-dioxane or a 1,4-dithiane ring by cis fusion were synthesized as organic donors with a bulky substituent. X-ray diffractional analysis of Ic (DOES) revealed that the conformation at the 1,4-dioxane ring fusion site is cis similar to the case of DOET. Several cation-radical salts based on Ib and Ic exhibited metallic conducting behavior., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

Synthesis and properties of dimethoxy-substituted unsymmetrical TTF derivatives
H Nishikawa; Y Misaki; T Yamabe; M Shiro, Preparation of a series of unsymmetrical tetrathiafulvalenes substituted with two methoxy groups (2a-f), and their electrochemical properties are described. X-Ray crystal structure analysis of methylenedithio derivative 2c reveals that there are side-by-side S...S contacts shorter than the sum of the van der Waals radii (3.70 Angstrom). The TCNQ complex of ethylendithio-2 (2d) and I-3 salt of 2e showed low conductivity of 10(-5) S cm(-1) at room temperature., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

Crystal structures and properties of DHTTF salts
K Kikuchi; H Nishikawa; T Sato; T Isaka; T Kodama; Ikemoto, I; H Anzai; J Yamada, The conductivities of (MDHT)(n)X (X=AuCl2, AuBr2 and Au(CN)(2)) were measured. These salts have fairly high conductiviites at room temperature and small activation energies. Especially AuBr2 and Au(CN)t salts are conducting even at low temperature. The crystal structures of(MDHT)(2)AuCl2 was reported. This salt has a columnar structure of donor molecules and largely different crystal parameters from those of AuI2 salt suggesting that AuI2 salt has different structure., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

Synthesis and properties of the TTF donors with a five-membered cyclic O,O-, S,S-, or O,S-acetal
J Yamada; R Oka; H Anzai; H Nishikawa; Ikemoto, I; K Kikuchi, Synthesis of the TTF (tetrathiafulvalene) donors with a 1,3-dioxolane, 1,3-dithiolane, or 1,3-oxathiolane ring (1-3) has been accomplished via (MeO)(3)P-promoted cross-coupling reaction of the corresponding new ketones (6-8) and thiones (9a-c). Although an X-ray diffraction analysis of the neutral 2a revealed that its molecular structure is nonplanar, its radical-cation salts with AuI2-, BF4-, and AsF6- exhibited metallic conducting behavior., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

BDH-TTP as a structural isomer of BEDT-TTF, and its analogue: synthesis and properties
J Yamada; M Watanabe; H Anzai; H Nishikawa; Ikemoto, I; K Kikuchi, Synthesis of a structural isomer of BEDT-TTF [bis(ethylenedithio)tetrathiafulvalene], namely BDH-TTP [2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene 1], and its related donor DHDA-TTP [2-(1,3-dithiolan-2-ylidene)-5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene 2] was accomplished via the Me3Al-promoted reaction. A new donor 1 produced the metallic radical-cation salts stable down to very low temperatures with the anions examined, one of which possessed the kappa-type donor arrangement., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

Photoconductivity of C-60 derivatives with a long alkyl chain
M Chikamatsu; K Kikuchi; H Nishikawa; T Kodama; Ikemoto, I; S Kazaoui; K Yase; N Minami, Cast and spin coat films of C-60 derivatives with a long alkyl chain were prepared. The X-ray analysis confirmed that the cast film formed a layer structure and the spin coat film has an amorphous structure. In the photocurrent spectra of both films, a peak around 720 nm was detected, which corresponds to an absorption peak in its solution. The peak, due to the interaction between the C-60 moieties, is not observed clearly. I (photocurrent) /I (darkcurrent) of the cast film is much larger than that of the spin coat film., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Jun. 1999, [Reviewed]

Metal-insulator, SDW, and glass transitions in the organic conductors, (DMET)(2)BF4 and (DMET)(2)ClO4, studied by ac calorimetry
H Akutsu; K Saito; Y Yamamura; K Kikuchi; H Nishikawa; Ikemoto, I; M Sorai, Temperature dependence of the heat capacities of two organic conductors, (DMET)(2)BF4 and (DMET)(2)ClO4, was measured by chopped-light ac calorimetry between 10 and 300 K. A "Mott-like" nature of the metal-insulator transition around 32 K was confirmed by the absence of thermal anomaly. A magnetic transition showed an anomaly around 18 K for the ClO4 salt and at 19 K for the BF4- salt. The smallness of the anomaly due to the transition is consistent with the suggested SDW formation. A frequency-dependent step in heat capacity uas detected around 110 K. The step-like anomaly is attributed to a glass transition due to the freezing of the intramolecular motion of the ethylene group in the BEDT-TTF moiety within a DMET molecule., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Jun. 1999, [Reviewed]

Heat capacity of TTF-TCNQ and TSF-TCNQ
K Saito; Y Yamamura; H Akutsu; M Takeda; H Asaoka; H Nishikawa; Ikemoto, I; M Sorai, Heat capacity of TTF-TCNQ was measured bl adiabatic and chopped-light ac calorimetries below room temperature. A thermal anomaly due to the Peierls transition of the TCNQ column was clearly detected around 52 K while that due to the TTF column (around 48 It) was not detected in both methods. A small but sharp peak due to the fir sl-order transition at 37 K caused by the phase locking of the CDW's on both columns Ras detected in calorimetry for the first time. Heat capacity of TSF-TCNQ was measured by adiabatic calorimetry below room temperature. Two steps due to the Peierls transitions on TSF and TCNQ columns were detected. The absence of the anomaly around 48 It in TTF-TCNQ was discussed through comparison of the thermal anomalies of two compounds. Standard thermodynamic functions are tabulated., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Apr. 1999, [Reviewed]

Newly modified TTF and DSDTF donors for developing molecular-based organic metals
J Yamada; H Nishikawa; K Kikuchi, The development of organic metals based on newly modified TTF (tetrathiafulvalene) and DSDTF (diselenadithiafulvalene) donors via the Lewis acid-promoted reactions of organotin compounds with electrophiles is described. The Me3Al-promoted reaction is versatile for construction of 1,3-dichalcogenol-2-ylidene moieties, and the BF3-promoted reaction is utilized to prepare the 1,3-dithiole-2-chalcogenone derivatives condensed with a his-fused six-membered heterocycle. The use of these reactions enables us to synthesize DHTTF (dihydrotetrathiafulvalene) donors, DHTTF-fused donors, DSDTF donors incorporating the vinylenedithio end group, and TTF donors with an extended periphery by addition of aliphatic heterocycles. The crystal structures of radical-cation salts derived from these pi-electron donors, including some new kappa-type salts with a 2:1 (donor:anion) stoichiometry, are also disclosed., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Mar. 1999, [Reviewed]

Electrical properties and crystal structures of metallic TMVT salts
H Nishikawa; T Sato; T Kodama; Ikemoto, I; K Kikuchi; H Anzai; J Yamada, The TMVT-based salts (TMVT)(2)X (X- = AsF6- and ClO4-) have been characterized by X-ray crystallography, electrical resistivity measurements, thermoelectric power measurements and EPR studies. Although an increase in resistivity was observed in both salts, the thermoelectric power indicated that these salts retain essentially metallic states. In contrast with this result, the tight-binding band calculation of these salts suggested that their Fermi surfaces are quasi-one-dimensional and inclined to be nested. The X-ray crystallographic analyses revealed that their structures are similar to that of (TMVT)(2)PF6, and consist of donor stacks with no dimerization, wherein there are several chalcogen chalcogen contacts shorter than the sum of the van der Waals radii within and between the stacks., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Mar. 1999, [Reviewed]

Conducting charge-transfer and radical ion salts based on bitetrathiafulvalenes; an approach to organic metals using stoichiometry control
M Iyoda; E Ogura; K Hara; Y Kuwatani; H Nishikawa; T Sato; K Kikuchi; Ikemoto, I; T Mori, Charge-transfer and radical ion salts of 4,5,4''',5'''-tetram-ethylthio-, 4,5,4''',5'''-bis (ethylenedithio)-, and 4,5,4"',5"'-bis (ethylenedioxy)-4',4 "-bitetrathiafulvalenes showed fairly high electric conductivities, reflecting the effect of stoichiometry control., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Feb. 1999, [Reviewed]

Metal-Insulator, SDW and Glass Transitions in (DMET)2BF4 and (DMET)2ClO4 Studied by ac Calorimetry　　　　　　　　　　　　　　　
H., Akutsu; K., Saito; Y., Yamamura; K., Kikuchi; H., Nishikawa; I., Ikemoto; and; M. Sorai
J. Phys. Soc. Jpn., Jan. 1999, [Reviewed]

BDH-TTP as a structural isomer of BEDT-TTF and its two-dimensional hexafluorophosphate salt
J Yamada; M Watanabe; H Anzai; H Nishikawa; Ikemoto, I; K Kikuchi, 二重結合の一部が飽和したTTP誘導体であるBDH-TTPを合成し、PF6塩の構造と物性を解明した。, WILEY-V C H VERLAG GMBH
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 1999, [Reviewed]

Novel molecular magnets based on organic complexes
A Miyazaki; T Umeyama; T Enoki; E Ogura; Y Kuwatani; M Iyoda; H Nishikawa; Ikemoto, I; K Kikuchi, The crystal structure and the physical properties of the radical ion salts BMT-TTFI2. FeX4 (X = Br, Cl) and (DMET)(2)FeBr4 are investigated. The structures of BMT-TTFI2. FeX4 are characterized as the sheets made of dimerized donor molecules and one-dimensional anion chains. These salts show three-dimensional Curie-Weiss behavior accompanied with antiferromagnetic transitions, with the highest Neel temperature (T-N = 15 K) among the pi-d interaction based magnets for the FeBr4 salt. Within a crystal of (DMET)(2)FeBr4, the donor molecules form one-dimensional columns, between which magnetic anion sheets are inserted. This salt is metallic down to T-MI = 200 K, above which the Curie-Weiss type magnetism is described in terms of donor and anion spins, in spite of the metallic conduction of the salt. Below T-MI the magnetism is governed by anion spins, and an antiferromagnetic phase transition takes place at T-N = 3.5 K., GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP
MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1999, [Reviewed]

Alternative synthesis of TTF donors with a dioxolane ring, and synthesis of their dithiolane and oxathiolane analogues
J Yamada; R Oka; H Anzai; H Nishikawa; Ikemoto, I; K Kikuchi, Synthesis of the TTF (tetrathiafulvalene) donors with a 1,3-dioxolane, 1,3-dithiolane, or 1,3-oxathiolane ring (1-3) has been accomplished via the (MeO)(3)P-promoted cross-coupling reaction of the corresponding new ketones (6-8) and thiones (9a-c). The radical-cation salts derived from 2a with AuI2-, BF4-, and AsF6- exhibited metallic conducting behavior for single crystals. (C) 1998 Elsevier Science Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
TETRAHEDRON LETTERS, Oct. 1998, [Reviewed]

Novel metallic state carrying localized spins in the molecular conductor (DMET)(2)FeBr4
T Enoki; T Umeyama; A Miyazaki; H Nishikawa; Ikemoto, I; K Kikuchi, (DMET)(2)FeBr4 which undergoes a metal-insulator transition at T-c= 200 K has an alternating stacked structure of DMET donor conducting sheets and FeBr4 magnetic sheets. Above T-c it is in a quasi-1D quarter-filled metallic state, where the Curie-Weiss type magnetism is described in terms of DMET+ donor spins and Fe3+ spins. Below T-c the magnetism, governed only by Fe3+ spins, shows antiferromagnetic order at T-N = 3.5 K. The localized spin feature of pi carriers above T-c, which contradicts metallic conduction, is reasonably well understood in terms of the sliding motion of a Wigner lattice state. [S0031-9007(98)07440-7]., AMERICAN PHYSICAL SOC
PHYSICAL REVIEW LETTERS, Oct. 1998, [Reviewed]

New tetrathiafulvalene donors with extended peripheral substituents by addition of heterocycles: Synthesis, properties, and molecular structures
J Yamada; S Tanaka; J Segawa; M Hamasaki; K Hagiya; H Anzai; H Nishikawa; Ikemoto, I; K Kikuchi, Syntheses of the bis(heterocycle)-fused bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives 7 and 8, the heterocycle-fused BEDT-TTF, methylenedithio(ethylenedithio)tetrathiafulvalene (MET), and ethylenedithiotetrathiafulvalene derivatives 9-11, and the 1,3-dioxolane derivative of MET 12a and its analogues 12b-d are described. The heterocycle-fused ketones 17 and 19 with cis ring fusions could be prepared by the BF3-promoted reaction of tin dithiolate 13 with dihaloheterocycles 15 and 16 in good yields, respectively, and served as key intermediates for the (RO)(3)P- and/or Me3Al-promoted coupling syntheses of these new tetrathiafulvalene donors 7-12. Further, the electrochemical properties of new donors 8-12 by the use of cyclic voltammetry and the molecular structures of 9a, 10a, ii, and 12a by X-ray crystallographic analyses are also reported., AMER CHEMICAL SOC
JOURNAL OF ORGANIC CHEMISTRY, Jun. 1998, [Reviewed]

The selenium analogue of DOET and its conducting salts
H Nishikawa; H Ishikawa; T Sato; T Kodama; Ikemoto, I; K Kikuchi; S Tanaka; H Anzai; J Yamada, Synthesis and electrochemical properties of the title donor (DOES), electrical conductivities of its radical-cation salts, and crystal structure of(DOES)(2)(AuI2)(0.75) are described., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Jun. 1998, [Reviewed]

X-ray crystal structure, magnetic and electric properties of TTF trimer-based salts of FeCl4-, [TTF7(FeCl4)(2)]
M Umeya; S Kawata; H Matsuzaka; S Kitagawa; H Nishikawa; K Kikuchi; Ikemoto, I, A new TTF trimer-based charge transfer salt, TTF7(FeCl4)(2), has been synthesized and characterized. It belongs to the monoclinic space group C2/m, M = 1812.75, a = 28.433(5), b = 16.524(3), c = 16.981(3) Angstrom, beta = 121.17(2)degrees, V = 6826(2) Angstrom(3) and Z = 4. The crystal structure shows the two types of layers O and I; the layer O is composed of two sets of TTF trimers orthogonal to each other, providing a two-dimensional interacting network of TTF molecules, while the layer I consists of TTF molecules and FeCl4 anions. The FeCl4 anions can interact magnetically with the TTF molecules in both the layers O and I because of the short S ... Cl distance. Single-crystal temperature-dependent conductivity measurements show that this material is a semiconductor with a room-temperature conductivity of 0.055 S cm(-1) and a thermal activation energy of 0.15 eV. The temperature dependence of magnetic susceptibilities indicates antiferromagnetic behavior based on FeCl4- anions and radical cations. Two EPR signals were observed for the microcrystals; the broader signal afforded a large temperature dependence of the g value ranging from 2.15 (292 K) to 1.86 (5 K)., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Feb. 1998, [Reviewed]

Structural Study on Cast Films of C(60) Derivatives with Long Alkyl Chains
Masayuki Chikamatsu; Takeshi Hanada; Yuji Yoshida; Nobutaka Tanigaki; Kiyoshi Yase; Hiroyuki Nishikawa; Takeshi Kodama; Isao Ikemoto; Koichi Kikuchi, Cast films of C(60) derivatives with a long alkyl chain were prepared and characterized. The high ordered reflection peaks were observed in cast films. As a alkyl chain was longer, the two-dimensional layer structure was more stabilized., GORDON BREACH PUBLISHING, TAYLOR & FRANCIS GROUP
MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1998, [Reviewed]

New organic metals based on a BEDT-TTF derivative with steric hindrance
J Yamada; S Tanaka; H Anzai; T Sato; H Nishikawa; Ikemoto, I; K Kikuchi, The conducting behaviour of radical cation salts based on the dioxane-fused BEDT-TTF derivative is reported, two of which show metallic conducting properties., ROYAL SOC CHEMISTRY
JOURNAL OF MATERIALS CHEMISTRY, Aug. 1997, [Reviewed]

In-plane angular effect of magnetoresistance of quasi-one-dimensional organic metals, (DMET)(2)AuBr2 and (TMTSF)(2)ClO4
H Yoshino; K Saito; H Nishikawa; K Kikuchi; K Kobayashi; Ikemoto, I, Comparative study is presented for the in-plane angular effect of magnetoresistance of quasi-one-dimensional organic conductors, (DMET)(2)AuBr2 and (TMTSF)(2)ClO4. The magnetoresistance for the magnetic and electrical fields parallel and perpendicular to the most conducting plane, respectively, was measured at 4.2K and up to 7.0T. (DMET)(2)AuBr2 shows an anomalous hump in the field-orientation dependence of the magnetoresistance for the magnetic field nearly parallel to the most conducting asis and this is very similar to what previously reported for (DMET)(2)I-3. Weak anomaly was detected for the magnetoresistance of (TMTSF)(2)ClO4 in the Relaxed state, while no anomaly was observed in the SDW phase in the Quenched state. By comparing the numerical angular derivatives of the magnetoresistance, it is shown that the anomaly in the in-plane angular effect continuously develops from zero magnetic field and is closely related to the quasi-one-dimensional Fermi surface. A simple method is proposed to estimate the anisotropy of the transfer integral from the width of the hump anomaly., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Aug. 1997, [Reviewed]

Fine structure of in-plane angular effect of magnetoresistance of (DMET)(2)I-3
H Yoshino; K Murata; T Sasaki; KS Saito; H Nishikawa; K Kikuchi; K Kobayashi; Ikemoto, I, The magnetoresistance of a quasi-one-dimensional (Q1D) organic superconductor, (DMET)(2)I-3, where DMET is dimethyl(ethylenedithio)diselenadithiafulvalene, was measured up to 30 T at 1.5 K. An electrical current was applied perpendicular to the conducting ab plane and a magnetic field is rotated in the ab plane. An anomalous hump of the magnetoresistance reported previously Ras observed at 7T between -15 degrees and 15 degrees from the most conducting b-axis. It was found that the hump has a line structure at higher magnetic fields with two additional sharp local minima at about +/-3 degrees. Partial disappearance of the Q1D Fermi surface at a critical angle, where a kind of quantum limit is realized, is proposed to interpret the fine structure., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Aug. 1997, [Reviewed]

4,5-diiodo-4',5'-ethylenedioxytetrathiafulvalene and its metallic radical salts
Y Kuwatani; E Ogura; H Nishikawa; Ikemoto, I; M Iyoda, 4,5-Diiodo-4',5'-ethylenedioxy-TTF (EDO-TTFI2) was synthesized in moderate yield by the reaction of EDO-TTF with LDA, followed by quenching with CF3(CF2)(5)I Although EDO-TTF contains electron-withdrawing iodine as the substituent, this compound has a similar donor ability to BEDT-TTF. The radical-cation salt (EDO-TTFI2)(2) . ClO4 shows a metallic conductivity down to 50 K, reflecting the strong I ... O interaction., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, 1997, [Reviewed]

Radical-cation salts based on TTF(s)-DHTTF (dihydrotetrathiafulvalene) fused donors: Electrical conductivities and crystal structure
J Yamada; S Mishima; H Anzai; M Tamura; Y Nishio; K Kajita; T Sato; H Nishikawa; Ikemoto, I; K Kikuchi, The electrochemical properties of TTF(s)-DHTTF fused donors, the electrical conductivities of their radical-cation salts, and the crystal structure of (3)(2)AuI2 are described., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, Nov. 1996, [Reviewed]

Sharp anomaly in magnetoresistance of the spin-density-wave state of (TMTSF)(2)PF6
H Yoshino; K Murata; K Saito; H Nishikawa; K Kikuchi; Ikemoto, I, Magnetoresistance of an organic superconductor, (TMTSF)(2)PF6, where TMTSF is tetramethyltetraselenafulvalene, was measured in the spin-density-wave state for the electrical current perpendicular to the conducting ab-plane and the magnetic field within the plane. The magnetic field dependence of the magnetoresistance shows an anomalous dip at 1.2T (B-d). The value of B-d is independent of temperature and field orientation within the ab-plane below 4.2 K and the dip anomaly is more distinct at lower temperature. Clear negative magnetoresistance appears below 4.2 K. We attempted to interpret the angular-independent dip anomaly in terms of the closed orbital motion of the carriers on the side of the Fermi tube and its disappearance at a kind of quantum limit., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Oct. 1996, [Reviewed]

Field-orientation dependence of magnetoresistance of a double-column organic conductor, (DMET)(2)ClO4
H Yoshino; K Saito; K Kikuchi; H Nishikawa; K Kobayashi; Ikemoto, I, An organic conductor, (DMET)(2)ClO4 (DMET = dimethyl(ethylenedithio) diselenadithiafulvalene), has two types of DMET columns along the a- and b-axes of the crystal lattice, respectively. The salt undergoes a metal-to-semiconductor transition at 32 K. Its resistivity and thermopower both along the a- and b-axes show anomalies at 18 and 7 K in addition to that at 32 K. Magnetoresistance along the c*-axis was measured while rotating the magnetic field within the ab plane above and below temperatures of the anomalies. The identification of the column that is mainly related to each anomaly is tried using the change in the peak position of the field-orientation dependence of the magnetoresistance. The resistivity along the c*-axis and thermopower along the c-axis show anomalies at 70 and 110 K in addition to those at low temperatures., ELSEVIER SCIENCE SA LAUSANNE
SYNTHETIC METALS, Sep. 1996, [Reviewed]

New organic metals based on vinylenedithio-annulated diselenadithiafulvalene derivatives
J Yamada; S Satoki; H Anzai; K Hagiya; M Tamura; Y Nishio; K Kajita; E Watanabe; M Konno; T Sato; H Nishikawa; K Kikuchi, The synthesis of vinylenedithio-annulated DSDTF (diselenadithiafulvalene) derivatives 1-3 and their radical cation. salts are investigated, several of which exhibit metallic conducting behaviour., ROYAL SOC CHEMISTRY
CHEMICAL COMMUNICATIONS, Aug. 1996, [Reviewed]

Synthesis and properties of alkylthio-substituted tris-fused tetrathiafulvalenes
H Nishikawa; S Kawauchi; Y Misaki; T Yamabe, Several derivatives of title donors (1a-c) have been synthesized. The cyclic voltammogram of tetrakis(hexylthio) derivative 1c exhibited three pairs of double-electron transfer waves. The iodine complexes of 1a-c showed relatively high conductivities of 10(-1) - 10(1) S cm(-1) at room temperature., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, 1996, [Reviewed]

Synthesis and properties of higher homologues of bis-fused TTF
Y Misaki; K Kawakami; N Higuchi; H Nishikawa; T Miura; T Yamabe, Several derivatives of higher homologues of bis-fused TTF, BDT-TTPY (1) and DT-TTP (2), have been synthesized. Cyclic voltammograms of 1 and 2 consist of three-pairs of double-electron and five-pairs of single electron redox waves, respectively. Most of cation radical salts obtained by the chemical doping with appropriate oxidants showed relatively high conductivity (sigma(rt) = 10(-2)-10(1) S cm(-1) on compressed pellets)., GORDON BREACH SCI PUBL LTD
MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS, 1996, [Reviewed]

ANOMALOUS ANGULAR-DEPENDENCE OF MAGNETORESISTANCE OF AN ORGANIC SUPERCONDUCTOR, (DMET)(2)I-3
H YOSHINO; K SAITO; K KIKUCHI; H NISHIKAWA; K KOBAYASHI; IKEMOTO, I, Angular dependence of magnetoresistance of a quasi-one-dimensional organic superconductor, (DMET)(2)I-3 has been measured at 4.2 K for magnetic fields up to 7.0 T. For the field of 1.0 T, the angular dependence of the magnetoresistance is smooth over the entire range of angles, reflecting the quasi-one-dimensional band structure of the salt. When the magnetic field of 7.0 T was rotated in the most conducting ab plane, the magnetoresistance for the current along both the b- and c*-axes showed discontinuous changes in its slope at the angles of +/-15 degrees from the most conducting axis. The anomaly occurring at 7.0 T is considered to be due to a change in electronic state induced by the magnetic field almost perpendicular to the quasi-1D Fermi surface., PHYSICAL SOC JAPAN
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, Jul. 1995, [Reviewed]

CRYSTAL-STRUCTURES AND PHYSICAL-PROPERTIES OF DTET-TTF SALTS
Y MISAKI; H NISHIKAWA; H FUJIWARA; T YAMABE; T MORI; H MORI; S TANAKA, Several cation radical salts of MeDTET showed metallic conducting behavior down to low temperature. X-Ray crystal structure analysis of (MeDTET)(3)PF(6)TCE(x) reveals that the donors have ''kappa-type'' arrangement in the conducting sheet. The results of ESR spectra are consistent with metallic conductivity., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 1995, [Reviewed]

CRYSTAL-STRUCTURES AND CONDUCTING PROPERTIES OF TTM-TTP SALTS
Y MISAKI; H NISHIKAWA; T YAMABE; T MORI; H MORI; S TANAKA, Conducting properties of various cation radical salts of the title donor have been investigated. Among them (TTM-TTP)I-3 and beta-(TTM-TTP)(2)I-3 show metallic conductivity down to T-MI = 160 and 20 K, respectively. The results of X-ray crystal structure analysis of (TTM-TTP)I-3 and (TTM-TTP)(PF6)(0.267)(THF)(0.6) are also presented., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 1995, [Reviewed]

CRYSTAL-STRUCTURES AND PHYSICAL-PROPERTIES OF BIS-FUSED TTF DONORS
T MORI; Y MISAKI; H NISHIKAWA; K KAWAKAMI; T YAMABE; H MORI; S TANAKA, Bis-fused TTF donors make many highly-conducting radical-cation salts with metallic conductivities down to He-3 temperatures. An overview of crystal structures and physical properties is given., ELSEVIER SCIENCE SA
SYNTHETIC METALS, Mar. 1995, [Reviewed]

Crystal structures and physical properties of TMEO-TTP salts
T. Mori; Y. Misaki; H. Nishikawa; T. Yamabe; H. Mori; S. Tanaka, TMEO-TTP makes many salts metallic down to 3He temperatures. Crystal structures of semiconducting phases of (TMEO-TTP)2PF6 and (TMEO-TTP)3SbF6, temperature dependence of the lattice constants of (TMEO-TTP)2Au(CN)2, and thermoelectric power and ESR of the metallic phases of the PF6 and SbF6 salts are reported., Elsevier Science S.A.
Synthetic Metals, 1995, [Reviewed]

CRYSTAL-STRUCTURES OF TMEO-TTP AND (TMEO-TTP)[AUBR2].THF
Y MISAKI; H NISHIKAWA; T YAMABE; T MORI; H INOKUCHI, The molecular and crystal structures of the title compounds, where TMEO-TTP is 2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-[4,5-ethylenedioxy-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene, have been investigated by X-ray crystal structure analysis. The BDT-TTP skeleton of neutral TMEO-TTP adopts a slightly flat chair conformation. The crystal has a columnar structure, in which the molecules dimerize in a head-to-tail manner. Several S...S contacts shorter than the sum of the van der Waals radii (3.70 angstrom)) are observed along the transverse direction. (TMEO-TTP)[AuBr2].THF also has a columnar structure in which the donor molecules dimerize. However, ''side-by-side'' interaction between the donors is prohibited because the AuBr2 anions and the THF molecules are located at the sides of the donor molecules., CHEMICAL SOC JAPAN
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN, Sep. 1994, [Reviewed]

ETHYLENEDIOXY SUBSTITUTED 2,5-BIS(1',3'-DITHIOL-2'-YLIDENE)-1,3,4,6-TETRATHIAPENTALENES AND THEIR CONDUCTING SALTS
Y MISAKI; H NISHIKAWA; K KAWAKAMI; T YAMABE; T MORI; H INOKUCHI; H MORI; S TANAKA, The title compounds were prepared and their electrochemical properties were investigated. Several cation radical salts composed of them showed metallic conductive behavior down to 0.6 K. The X-ray crystal structure of AsF6 salt of ethylenedithio derivative, (EOET-TTP)3AsF6, revealed that the donors have ''kappa-type'' arrangement in the conducting sheet., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Dec. 1993, [Reviewed]

STRUCTURE AND PHYSICAL-PROPERTIES OF (TMEO-TTP)2AU(CN)2
T MORI; H INOKUCHI; Y MISAKI; H NISHIKAWA; T YAMABE; H MORI; S TANAKA, Radical cation salts of TMEO-TTP with linear and octahedral anions exhibit metallic conductivity down to 0.6 K. The title salt has two-dimensional donor arrangement, and the measurements of electrical conductivity, thermoelectric power, and ESR show a characteristic metal-to-metal transition., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Dec. 1993, [Reviewed]

2,5-BIS(1',3'-DITHIOL-2'-YLIDENE)-1,3,4,6-TETRATHIAPENTALENE AND ITS RELATED UNSYMMETRICAL DONORS
Y MISAKI; T MATSUI; K KAWAKAMI; H NISHIKAWA; T YAMABE; M SHIRO, The title compound (1a) and its related unsymmetrical derivatives were prepared as new donors for organic conductors, and electrochemical properties and crystal structure of la were investigated. Several charge-transfer complexes and cation radical salts using them showed metallic temperature dependence of conductivity down to ca. 100 K., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Aug. 1993

STRUCTURE AND ELECTRICAL-PROPERTIES OF MEDTET SALTS
Y MISAKI; H NISHIKAWA; T YAMABE; T MORI; H INOKUCHI; H MORI; S TANAKA, Several cation radical salts of MeDTET (2-isopropylidene-1,3-dithiolo[4,5-d]ethylenedithiotetrathiafulvalene) showed metallic temperature dependence of conductivity down to 0.6-0.9 K. X-Ray crystal structure of (MeDTET)3PF6TCEx revealed that the donors have ''kappa-type'' arrangement in the conducting sheet. This is the first example of a kappa-type salt that has a composition other than 2:1., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Aug. 1993, [Reviewed]

BIS(METHYLTHIO) SUBSTITUTED UNSYMMETRICAL 2,5-BIS(1',3'-DITHIOL-2'-YLIDENE)-1,3,4,6-TETRATHIAPENTALENES
Y MISAKI; H NISHIKAWA; T YAMABE; T MORI; H INOKUCHI; H MORI; S TANAKA, The title compounds (2) were synthesized as the donor components for organic conductors, and preparation and electrical properties of their cation radical salts were investigated. Among various cation radical salts obtained so far, AsF6 salt of ethylenedithio-2 and SbF6 salt of ethylenedioxy-2 showed metallic temperature dependence of conductivities down to 0.6 K., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Apr. 1993, [Reviewed]

STRUCTURE AND CONDUCTING PROPERTIES OF TMET-TTP RADICAL-CATION SALTS
T MORI; H INOKUCHI; Y MISAKI; H NISHIKAWA; T YAMABE; H MORI; S TANAKA, Radical cation salts of TMET-TTP (2-(4',5'-bis(thiomethyl)-1',3'-dithiol-2'-ylidene)-5-(4'',5''-ethylenedithio-1'',3''-dithiol-2''-ylidene)-1,3,4,6-tetrathiapentalene) with various anions show high electrical conductivity. Many of them have a similar structure with two-dimensional donor arrangement., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Apr. 1993, [Reviewed]

PREPARATION, CRYSTAL-STRUCTURE AND ELECTRICAL-PROPERTIES OF 2-CYCLOPENTANYLIDENE-1,3-DITHIOLO[4,5-D]TETRATHIAFULVALENE DERIVATIVES
Y MISAKI; K KAWAKAMI; H NISHIKAWA; H FUJIWARA; T YAMABE; M SHIRO, The title compounds (1) were prepared as the donor components for organic conductors. The molecular and crystal structures of bis(methylthio) derivative were determined by X-ray diffractional analysis. Among charge-transfer complexes and cation radical salts of 1 prepared so far, I3- salt of unsubstituted-1 and IBr2- salt of methylenedithio-1 showed metallic temperature dependence of conductivities., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Mar. 1993, [Reviewed]

SYNTHESIS AND PROPERTIES OF NEW TETRATHIAFULVALENES CONDENSED WITH 1,3-DITHIOL-2-YLIDENES
H NISHIKAWA; K KAWAKAMI; H FUJIWARA; T UEHARA; Y MISAKI; T YAMABE; T MORI; M SHIRO, New TTF derivatives, bis(2-methylidene-1,3-dithiolo[4.5-d])tetrathiafulvalenes (BDT-TTF's, 1), and their unsymmetrical derivatives, (2-methylidene-1,3-dithiolo[4,5-d])tetrathiafulvalenes (MeDT-TTF's, 2, CpDT-TTF's, 3) which are condensed with one or two 1,3-dithiol-2-ylidene moieties, were synthesized. The electrochemical properties of these donors were investigated by means of cyclic voltammetry. The X-ray structure of dimethylthio derivative of CpDT-TTF showed that the molecule is almost planar except for cyclopentane ring and there were shorter S ... S contacts than the sum of van der Waals radii. BDT-TTF's formed charge-transfer complexes with TCNQF4 whose electrical conductivities were 10(-3)-10(-4) Scm-1. On the other hand, DT-TTF's afforded several metallic cation radical salts, in particular, I3 and ClO4 salts of ethylenedithio-MeDT-TTF exhibited metallic behavior down to 0.5 K., ELSEVIER SCIENCE SA LAUSANNE
SYNTHETIC METALS, Mar. 1993, [Reviewed]

METHYLTHIO SUBSTITUTED 2,5-BIS(1',3'-DITHIOL-2'-YLIDENE)-1,3,4,6-TETRATHIAPENTALENE - A BIS-FUSED TETRATHIAFULVALENE
Y MISAKI; H NISHIKAWA; K KAWAKAMI; S KOYANAGI; T YAMABE; M SHIRO, Synthesis of the title compound (1), and its molecular structure determined by X-ray crystallographic analysis, and electrochemical property investigated by cyclic voltammetry are described. Several cation radical salts of 1 have been prepared by electrochemical oxidation method, and their electrical properties are also presented., CHEMICAL SOC JAPAN
CHEMISTRY LETTERS, Dec. 1992, [Reviewed]

(2-METHYLIDENE-1,3-DITHIOLO[4,5-D])TETRATHIAFULVALENE (DT-TTF) - NEW UNSYMMETRICAL TTFS CONDENSED WITH 1,3-DITHIOL-2-YLIDENE MOIETIES
Y MISAKI; H NISHIKAWA; H FUJIWARA; K KAWAKAMI; T YAMABE; H YAMOCHI; G SAITO, The synthesis and properties of the unsymmetrical tetrathiafulvalenes condensed with 1,3-dithiol-2-ylidene moieties are described; the electrical properties of several cation radical salts are also presented., ROYAL SOC CHEMISTRY
JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, Oct. 1992, [Reviewed]

TETRAMETHOXYTETRATHIAFULVALENE (TMO-TTF) - A NEW OXYGEN-SUBSTITUTED TETRATHIAFULVALENE
Y MISAKI; H NISHIKAWA; K NOMURA; T YAMABE; H YAMOCHI; G SAITO; T SATO; M SHIRO, Tetramethoxytetrathiafulvalene, a new pi-electron donor for organic conductors, has been synthesized; the molecular structure determined by X-ray diffractional analysis is reported and electrochemical properties are also presented., ROYAL SOC CHEMISTRY
JOURNAL OF THE CHEMICAL SOCIETY-CHEMICAL COMMUNICATIONS, Oct. 1992, [Reviewed]

BIS(2-METHYLIDENE-1,3-DITHIOLO[4,5-D])TETRATHIAFULVALENE (BDT-TTF) - A TETRATHIAFULVALENE CONDENSED WITH 1,3-DITHIOL-2-YLIDENE MOIETIES
Y MISAKI; H NISHIKAWA; K KAWAKAMI; T UEHARA; T YAMABE, Four alkyl derivatives of the title donor (1a-d) have been synthesized. The electrochemical properties investigated by cyclic voltammetry and the electrical conductivities of charge-transfer complexes with tetrafluoro-tetracyanoquinodimethane and 2-3-dichloro-5,6-dicyano-p-benzoquinone are also presented., PERGAMON-ELSEVIER SCIENCE LTD
TETRAHEDRON LETTERS, Jul. 1992, [Reviewed]

DIMER FORMATION IN THE CRYSTAL-STRUCTURE OF (DITHIOBENZOATO)-(TRITHIOPEROXYBENZOATO)PLATINUM(II)
T KAWAMURA; M EBIHARA; H KATAYAMA; H NISHIKAWA; T YAMABE, (Dithiobenzoato)(trithioperoxybenzoato)platinum(II) was obtained through reactions of [Pt2(S2CEt)4] and PhC(O)SH and of K2[PtCl4], CF3SO3Ag and PhC(O)SH. It crystallizes in the monoclinic space group C2/c with a = 16.629(2), b = 6.296(1), c = 29.182(2) angstrom, beta = 91.85(1)-degrees, and Z = 8. The complex has four- and five-membered chelate rings with a normal square-planar PtS4 arrangement. The structure consists of dimers with a configuration in which the five-membered chelate ring of one molecule lies over the four-membered ring of the other. An extended-Huckel molecular orbital calculation suggests intradimer charge-transfer interaction as the driving force for the formation of the dimer. The diffuse reflectance spectrum of a powder sample of the complex gives new bands which are absent from the solution spectra., ROYAL SOC CHEMISTRY
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, Oct. 1991, [Reviewed]

LIGAND DEPENDENCE OF ELECTRONIC CONFIGURATION OF THE RH RH BOND IN RH25+ COMPLEXES AS STUDIED BY ELECTRON-SPIN RESONANCE AND ELECTROCHEMISTRY
T KAWAMURA; H KATAYAMA; H NISHIKAWA; T YAMABE, Rh複核錯体の金属－金属間結合をESRならびに電気化学的に明らかにした。, AMER CHEMICAL SOC
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Oct. 1989, [Reviewed]

25aYC-10 Electronic Properties of β"-(DODHT)_2PF_6 in the Charge Fluctuating Phase (II)
Kondo Ryusuke; Higa M.; Murata A.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 18 Aug. 2009

30aYF-4 Electronic Property of β"-(DODHT)_2PF_6 in the Charge Fluctuating Phase
Higa M.; Murata A.; Kondo R.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 03 Mar. 2009

21aRA-3 Anisotropic superconductivity in β"-(DODHT)2_PF_6
Higa M.; Kondo R.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 21 Aug. 2007

21pRA-6 Non-linior transport of β" and θ type salts under pressure
Higa M.; Kondo R.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 28 Feb. 2007

25pYF-16 Crystal structure of β"-(DODHT)_2AsF_6 at low temperature
Higa M.; Kondo R.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 18 Aug. 2006

30pRB-3 Crystal structure of β"-(DODHT)_2PF_6 under hydrostatic pressure
Higa M.; Kondo R.; Kagoshima S.; Nishikawa H.
Meeting abstracts of the Physical Society of Japan, 04 Mar. 2006

Structural evolutions of carbon nano-peapods under electron microscopic observation
A Gloter; K Suenaga; H Kataura; R Fujii; T Kodama; H Nishikawa; Ikemoto, I; K Kikuchi; S Suzuki; Y Achiba; S Iijima
CHEMICAL PHYSICS LETTERS, Jun. 2004

Temperature-pressure phase diagrams of double-column organic conductors: (DMET)(2)BF4, (DMET)(2)ClO4 and (DIMET)(2)BF4
H Yoshino; K Saito; T Sato; H Nishikawa; K Kikuchi; K Kobayashi; Ikemoto, I
SYNTHETIC METALS, Jul. 1998

Structure and Physical Properties of (TMEO-TTP)┣D22┫D2Au(CN)┣D22┫D2
T. Mori; H. Inokuchi; Y. Misaki; H. Nishikawa; T. Yamabe
Chemistry Letters, 1993

Encyclopedia of Physical Organic Chemistry　　　　　　　　　　　　　　　
Jun-ichi Yamada; Hiroyuki Nishikawa, Joint work
Wiley-VCH, 2016

One-dimensional alternating anti- ferromagnetic chain accompanying charge ordering in DODHT organic Superconductors.Multifunctional Conducting Molecular Materials　　　　　　　　　　　　　　　
H. Nishikawa; A. Machida; T. Kodama; I. Ikemoto; K. Kikuchi; J. Yamada; H. Oshio, Joint work
RSC Publishing, 2007

TTF derivatives linking a dimethyldioxolane ring and their charge-transfer salts. Multifunctional Conducting Molecular Materials　　　　　　　　　　　　　　　
J. Yamada; Y. Kuri; R. Oka; H. Akutsu; S. Nakatsuji; H. Nishikawa; K. Kikuchi, Joint work
RSC Publishing, 2007

Dihydro-TTFs and bis-fused 1,3-dithiol-2- ylidene donors.TTF chemistry: Fundamentals and application of tetrathiafulvalene　　　　　　　　　　　　　　　
J. Yamada; H. Nishikawa; K. Kikuchi, Joint work
Kodansha & Springer, 2004

Achiba13C NMR study of Ca@C74: cage structure and dynamics of a Ca atom inside the cage.Fullerenes and nanotubes vol 13 The Building Blocks of Next Generaion Nanodevices　　　　　　　　　　　　　　　
T. Kodama; R. Fujii; Y. Miyake; S. Suzuki; H. Nishikawa; I. Ikemoto; K. Kikuchi; Y., Joint work
Pennington, 2003

Synthesis and properties of new fullerene-tetrathiafulvalene dyads. Fullerenes vol 12 The exciting world of nonocages and nanotubes　　　　　　　　　　　　　　　
H. Nishikawa; S. Kojima; K. Kodama; K. Kikuchi; I. Ikemoto; M. Fujitsuka; O. Ito, Joint work
Pennington, 2002

ポリフルオレン-ペリレンジイミド誘導体混合薄膜の光物性とデバイス化　　　　　　　　　　　　　　　
西村 悠紀、長谷川 真士、真崎 康博、西川 浩之
日本化学会第103春季年会, Mar. 2023

コレステロール誘導体でキラルドープしたポリフルオレン薄膜の光物性　　　　　　　　　　　　　　　
朝日宗将、長谷川真士、真崎康博、西川浩之
第103回日本化学会春季学会, Mar. 2023

新規ペリレン発光体の合成と外部環境依存円偏光発光(CPL)特性　　　　　　　　　　　　　　　
鈴木 聖香、北原 真穂、金子 光佑、西川 浩之、花崎 知則、今井 喜胤
日本化学会第103春季年会, Mar. 2023

軸不斉を有するシッフ塩基型亜鉛(II)単核錯体の合成と光物性　　　　　　　　　　　　　　　
田内大喜,長谷川真士,真崎康博,杉浦健一,西川浩之
日本化学会第103春季年会, Mar. 2023
202303, 202303

凝集状態で円偏光発光を示すキラル材料の開発と発光デバイス　　　　　　　　　　　　　　　
西川浩之
E-USE研究会2023, Mar. 2023, [Invited]

Synthesis and photophysical properties of zinc(II) mononuclear complex coordinated by axially chiral Schiff-base ligands　　　　　　　　　　　　　　　
International CPL and CPEL Conference 2023, Mar. 2023
202303, 202303

Photophysical properties of polyfluorene thin films chirally doped by cholesterol derivative　　　　　　　　　　　　　　　
Kazuyuki Asahi; Masashi Hasegawa; Yasuhiro Mazaki; Hiroyuki Nishikawa
International CPL and CPEL Conference 2023 in Osaka, Mar. 2023

Physical properties and electronic structures of Schiff-base type TTF-paramagnetic metal complexes　　　　　　　　　　　　　　　
Daiki Tauchi; Hiroyuki Nishikawa
The 7th International Symposium of Quantum Beam Science (ISQBS) at Ibaraki University, Dec. 2022
202212, 202212

Structures and Physical properties of Schiff-base type TTF-metal complexes　　　　　　　　　　　　　　　
Daiki Tauchi; Takuya Shiga; Hiroki Oshio; Norihisa Hoshino; Tomoyuki Akutagawa; Hiroyuki Nishikawa
The 73rd Yamada Conference, Oct. 2022
202210, 202210

Structures and photophysical properties of phosphorescent chiral Pt(II) complexes　　　　　　　　　　　　　　　
Hiroyuki Nishikawa; Daiki Tauchi; Taiki Koida; Kazunori Tsubaki; Masashi Hasegawa; Yasuhiro Mazaki; Akiko Inagaki; Ken-ichi Sugiura
The 73rd Yamada Conference, Oct. 2022

軸不斉を有する発光性白金(II)錯体の構造と光物性　　　　　　　　　　　　　　　
田内 大喜,長屋 勇輝,福井 敬大; 長谷川 真士; 真崎 康博; 稲垣 昭子; 鈴木 仁子; 椿 一典; 杉浦 健一; 西川 浩之
第16回分子科学討論会, Sep. 2022
202209, 202209

液晶性キラルドーパントをドープした発光性ポリマー薄膜の分光学的性質　　　　　　　　　　　　　　　
朝日宗将、西村悠紀、長谷川真士、真崎康博、西川浩之
第16回分子科学討論会, Sep. 2022

キラルペリレンジイミド誘導体をキラルドープした薄膜発光デバイス　　　　　　　　　　　　　　　
西村 悠紀,長谷川 真士,真崎 康博,今井 喜胤,西川 浩之
第16回分子科学討論会, Sep. 2022

Electrical and Magnetic Properties of Paramagnetic TTF-metal complexes　　　　　　　　　　　　　　　
Daiki Tauchi; Takuya Shiga; Hiroki Oshio; Norihisa Hoshino; Tomoyuki Akutagawa; Hiroyuki Nishikawa
8th Asian Conference on Coordination Chemistry, Aug. 2022
202208, 202208

軸不斉を有するキラル亜鉛(II)三核錯体の光物理化学的性質　　　　　　　　　　　　　　　
田内大喜 金坂青葉 杉浦健一 西川浩之
日本化学会第102春季年会, Mar. 2022
202203, 202203

凝集誘起円偏光発光材料を用いた円偏光発光有機ELの開発及び測定装置の開発　　　　　　　　　　　　　　　
金坂青葉、西村悠紀、山口央、今井喜胤、西川浩之
日本化学会第102春季年会, Mar. 2022
202203, 202203

Solid-State Photophysical Properties of Chiral Perylene Diimide Derivatives　　　　　　　　　　　　　　　
International CREST-CPL Conference 2022, Mar. 2022, [Invited]
202203, 202203

"Synthesis and physical properties of chiral metal complexes as,CPL emitters"　　　　　　　　　　　　　　　
Daiki Tauchi; Hiroyuki Nishikawa
International CREST-CPL Conference 2022, Mar. 2022
202203, 202203

キラリティを有するシッフ塩基型TTF-金属錯体の構造と物性　　　　　　　　　　　　　　　
田内大喜,志賀拓也,大塩寛紀,西川浩之
第31回茨城地区研究交流会, Dec. 2021
202112

Development of circularly polarized organic light-emitting diode (CP-OLED) with chiral device structure　　　　　　　　　　　　　　　
Aoba Kanesaka; Tomomasa Hosoya; Yoshitane Imai; Hiroyuki Nishikawa
The International Chemical Congress of Pacific Basin Societies 2021, Dec. 2021
202112, 202112

Development of circularly polarized organic light-emitting diode (CP-OLED) using aggregation-induced enhanced CPL (AIEnh-CPL) materials　　　　　　　　　　　　　　　
Aoba Kanesaka; Tomomasa Hosoya; Yoshitane Imai; Hiroyuki Nishikawa
The International Chemical Congress of Pacific Basin Societies 2021, Dec. 2021
202112, 202112

Photophysical properties and light emitting devices of chiral perylene diimide derivatives　　　　　　　　　　　　　　　
Hiroyuki Nishikawa; Aoba Kanesaka; Tomomasa Hosoya; Ryosuke Isaka; Akira Yamaguchi; Yoshitane Imai
The International Chemical Congress of Pacific Basin Societies 2021, Dec. 2021, [Invited]
202112, 202112

Physical properties and electronic structures of Schiff-base type metal complexes　　　　　　　　　　　　　　　
Daiki Tauchi; Aoba Kanesaka; Hiroyuki Nishikawa
The 4th Asian Workshop of Experiments and Theory in Quantum Beam Molecular Sciences, Oct. 2021
202110, 202110

軸不斉を有する亜鉛(Ⅱ)２核錯体の合成と物性　　　　　　　　　　　　　　　
田内大喜,今井喜胤,西川浩之
第15回分子科学討論会, Sep. 2021
202109, 202109

キラルPDI誘導体を発光層のゲスト材料に用いた有機ELの作製　　　　　　　　　　　　　　　
金坂青葉,西村悠紀,今井喜胤,西川浩之
第15回分子科学討論会, Sep. 2021
202109, 202109

発光性ポリマーにキラル材料をドープした薄膜の作製　　　　　　　　　　　　　　　
朝日宗将,西川浩之
CREST「円偏光発光材料の開発に向けた革新的基盤技術の創成」第１回研究推進シンポジウム, Aug. 2021
202108

凝集誘起円偏光発光材料を用いた有機ELの作製と光物性　　　　　　　　　　　　　　　
金坂青葉,西川浩之
CREST「円偏光発光材料の開発に向けた革新的基盤技術の創成」第１回研究推進シンポジウム, Aug. 2021
202108

キラルPDI誘導体を発光層のゲスト材料に用いた有機ELの作製　　　　　　　　　　　　　　　
西村悠紀,西川浩之
CREST「円偏光発光材料の開発に向けた革新的基盤技術の創成」第１回研究推進シンポジウム, Aug. 2021
202108

水素結合部位を有するキラルペリレンジイミド誘導体の合成と光物性　　　　　　　　　　　　　　　
井坂亮輔,金坂青葉,細谷知正,今井喜胤,山口 央,西川浩之
日本化学会第101春季年会, Mar. 2021
202103, 202103

拡張パイ電子系を有するペリレン発光体の合成と円偏光発光(CPL)特性　　　　　　　　　　　　　　　
金坂青葉,細谷知正,井坂亮輔,西村悠紀,山口 央,今井喜胤,西川浩之
日本化学会第101春季年会, Mar. 2021
202103, 202103

ベイポジションを置換したキラルPDI誘導体の物性と有機ELの作製　　　　　　　　　　　　　　　
北原真穂,三嶋康平,原伸行,静間基博,金坂青葉,西川浩之,今井喜胤
日本化学会第101春季年会, Mar. 2021
202103, 202103

キラリティを有する新規シッフ塩基型TTF-金属錯体の構造と物性　　　　　　　　　　　　　　　
田内大喜,志賀拓也,大塩寛紀,西川浩之
日本化学会第101春季年会, Mar. 2021, 日本化学会
202103, 202103

Molecular magnetic semiconductors based on paramagnetic Cu(II) complexes coordinated TTF-ligands　　　　　　　　　　　　　　　
Hiroyuki Nishikawa
The 1st Asian Conference on Molecluar Magnetism, Mar. 2021
202103, 202103

Magnetic properites of conjugated type TTF-metal complex [Cu(TTF-Salphen)]　　　　　　　　　　　　　　　
Daiki Tauchi; Aoba Kanesaka; Takuya Shiga; Hiroki Oshio; Hiroyuki Nishikawa
The 1st Asian Conference on Molecluar Magnetism, Mar. 2021
202103, 202103

[Cu(TTF-Salphen)]のラジカル塩の物性　　　　　　　　　　　　　　　
田内大喜,金坂青葉,志賀拓也,大塩寛紀,星野哲久,芥川智行,西川浩之
日本化学会関東支部茨城地区研究交流会, Dec. 2020
202012

凝集誘起円偏光発光材料を用いた有機ELの作製と光物性　　　　　　　　　　　　　　　
金坂青葉; 細谷知正; 井坂亮輔,山口央; 今井喜胤,西川浩之
第１４分子科学討論会, Sep. 2020, 分子科学会
202009, 202009

[Cu(TTF-Salphen)]のラジカル塩の物性　　　　　　　　　　　　　　　
田内大喜,金坂青葉,志賀拓也,大塩寛紀,西川浩之
第１４回分子科学討論会, Sep. 2020, 分子科学会
202009, 202009

不斉を有するペリレンジイミド誘導体の光物理化学的性質　　　　　　　　　　　　　　　
細谷知正; 金坂青葉; 今井喜胤,山口央; 西川浩之
第１４回分子科学討論会, Sep. 2020, 分子科学会
202009, 202009

凝集誘起円偏光発光材料を用いた有機ELの作製と光物性　　　　　　　　　　　　　　　
金坂青葉; 細谷知正; 井坂亮輔; 溝黒登志子; 阿澄玲子; 山口 央; 今井喜胤; 西川浩之
日本化学会第100春季年会, Mar. 2020
202003, 202003

[Cu(TTF-Salphen)]のラジカル塩の合成と物性　　　　　　　　　　　　　　　
田内大喜; 金坂青葉; 志賀拓也; 大塩寛紀; 西川浩之
日本化学会第100春季年会, Mar. 2020
202003, 202003

不斉を有するペリレンジイミド誘導体の光物理化学的性質　　　　　　　　　　　　　　　
細谷知正; 金坂青葉; 山口 央; 今井喜胤; 西川浩之
日本化学会第100春季年会, Mar. 2020
202003, 202003

拡張パイ電子系を有する光学活性ペリレン発光体の円偏光発光(CPL)特性　　　　　　　　　　　　　　　
三嶋康平; 原伸行; 静間基博; 西川浩之; 今井喜胤
日本化学会第100春季年会, Mar. 2020
202003, 202003

水素結合部位を有するキラルペリレンジイミド誘導体の合成と光物理化学的性質　　　　　　　　　　　　　　　
井坂亮輔; 細谷知正; 金坂青葉; 今井喜胤; 山口 央; 西川浩之
日本化学会第100春季年会, Mar. 2020
202003, 202003

キラルおよびラセミDM-MeDH-TTP塩の電子状態と圧力下電気物性　　　　　　　　　　　　　　　
小林研都; 西川浩之
日本化学会第100春季年会, Mar. 2020
202003, 202003

１次元有機伝導体[DM-MeDH-TTP]2X系の低温電子物性　　　　　　　　　　　　　　　
中村敏和; 江幡健太; 宮本 尚; 西川浩之
日本物理学会第75回年次大会, Mar. 2020
202003, 202003

Solid State Photophysical Properties of Chiral Perylene Diimide Derivatives　　　　　　　　　　　　　　　
Hiroyuki Nishikawa
Pure and Applied Chemistry International Conference 2020, Feb. 2020, [Invited]
202002, 202002

共役型TTF-常磁性金属錯体[Cu(TTF-Salphen)]の磁気物性　　　　　　　　　　　　　　　
田内大喜; 金坂青葉; 志賀拓也; 大塩寛紀; 西川浩之
茨城地区研究交流会, Dec. 2019
201912, 201912

新規TTF-金属錯体[Cu(TTF-Salphen)]の電子状態　　　　　　　　　　　　　　　
加藤 祐; 田内大喜; 金坂青葉; 志賀拓也; 大塩寛紀; 西川浩之
茨城地区研究交流会, Dec. 2019
201912, 201912

キラルなペリレンジイミド誘導体の光物理化学的性質　　　　　　　　　　　　　　　
井坂亮輔; 細谷知正; 村田亨友; 金坂青葉; 今井喜胤; 西川浩之
茨城地区研究交流会, Dec. 2019
201912, 201912

不斉を有するペリレンジイミド誘導体の合成と光物理化学的性質　　　　　　　　　　　　　　　
細谷知正; 金坂青葉; 村田亨友; 西川浩之
有機合成化学協会関東支部シンポジウム, Dec. 2019
201911, 201912

ジナフトフラン多量体の合成及び性質　　　　　　　　　　　　　　　
本多理沙; 平林一徳; 清水敏夫; 西川浩之; 杉浦健一
有機合成化学協会関東支部シンポジウム, Dec. 2019
201911, 201912

New Chiral Perylene Diimide Derivative for Higher Intermolecular Interaction　　　　　　　　　　　　　　　
Hiroyuki Nishikawa
International Symposium on Circularly Polarized Luminescence and Related Phenomena, Nov. 2019
201911, 201911

Intermolecular Interaction of Perylene Diimide Derivatives with Host Materials in Solid States　　　　　　　　　　　　　　　
A. Kanesaka; H. Nishikawa
International Symposium on Circularly Polarized Luminescence and Related Phenomena, Nov. 2019
201911, 201911

[DM-MeDH-TTP]2X系の示す異常なESR挙動　　　　　　　　　　　　　　　
中村敏和; 江幡健太; 宮本 尚; 西川浩之
電子スピンサイエンス学会年会, Nov. 2019
201911, 201911

CP-OLEDを指向したジイミド円偏光発光（CPL）体の開発　　　　　　　　　　　　　　　
中島 岳; 原伸行; 西川浩之; 今井喜胤
基礎有機化学討論会, Sep. 2019
201909, 201909

Aggregation-Induced Enhanced Circularly Polarized Luminescence of Chiral Perylene Diimides and Fabrication of Light Emitting Diodes　　　　　　　　　　　　　　　
Aoba Kanesaka; Tomomasa Hosoya; Akira Yamaguchi; Takuya Shiga; Hiroki Oshio; Toshiko Mizokuro; Reiko Azumi; Yoshitane Imai; Hiroyuki Nishikawa
International Symposium on Crystalline Organic Metals, Superconductors and Magnets, Sep. 2019
201909, 201909

共役型TTF-常磁性金属錯体[Cu(TTF-Salphen)]の磁気物性　　　　　　　　　　　　　　　
田内大喜; 金坂青葉; 志賀拓也; 大塩寛紀; 西川浩之
分子科学討論会, Sep. 2019
201909, 201909

[DM-MeDH-TTP]2X系のESR　　　　　　　　　　　　　　　
中村敏和; 江幡健太; 宮本 尚; 西川浩之
分子科学討論会, Sep. 2019
201909, 201909

ナフチル基を有するキラルペリレンジイミド誘導体の光物理化学的性質　　　　　　　　　　　　　　　
細谷知正; 金坂青葉; 溝黒登志子; 阿澄玲子; 渡邉広平; 今井喜胤; 西川浩之
分子科学討論会, Sep. 2019
201909, 201909

(±)-DM-MeDH-TTPのラジカル塩の結晶構造と電子状態　　　　　　　　　　　　　　　
江幡健太; 宮本 尚; 志賀拓也; 大塩寛紀; 西川浩之
分子科学討論会, Sep. 2019
201909, 201909

凝集誘起円偏光発光材料を用いた有機ELデバイスの開発　　　　　　　　　　　　　　　
金坂青葉; 細谷知正; 溝黒登志子; 阿澄玲子; 山口 央; 今井喜胤; 西川浩之
分子科学討論会, Sep. 2019
201909, 201909

CP-OLEDを指向したジイミド発光体の円偏光発光（CPL）特性　　　　　　　　　　　　　　　
中島 岳; 木元隆裕; 三嶋康平; 原伸行; 西川浩之; 今井喜胤
光科学討論会, Sep. 2019
201909, 201909

キラルPDI誘導体を用いた有機EL素子の開発　　　　　　　　　　　　　　　
西川浩之
日本化学会第99春季年会, Mar. 2019, [Invited]
201903, 201903

(S,S)-および(±)-DM-MeDH-TTPのラジカル塩の物性　　　　　　　　　　　　　　　
宮本 尚; 志賀 拓也; 大塩 寛紀; 西川 浩之
日本化学会第99春季年会, Mar. 2019
201903, 201903

新規シッフ塩基型TTF金属錯体[Cu(TTF-Salphen)]の構造と性質　　　　　　　　　　　　　　　
田内大喜; 金坂青葉; 志賀拓也; 大塩寛紀; 西川浩之
日本化学会第99春季年会, Mar. 2019
201903, 201903

円偏光発光するキラルペリレンジイミド誘導体を用いた有機EL素子の作製　　　　　　　　　　　　　　　
金坂青葉; 村田亨友; 細谷知正; 溝黒登志子; 阿澄玲子; 山口 央; 渡邉広平; 今井喜胤; 西川浩之
日本化学会第99春季年会, Mar. 2019
201903, 201903

面内配向したポリチオフェン膜上に真空蒸着したジフェニルアントラセン誘導体分子の配向評価　　　　　　　　　　　　　　　
金坂 青葉; 溝黒 登志子; 宮寺 哲彦; 小金澤 智之; 小林 健二; 鎌田 賢司; 西川 浩之; 阿澄 玲子
日本化学会第99春季年会, Mar. 2019
201903, 201903

Tunability of Aggregation-Induced Emission enhanced(AIEnh)-Circularly Polarized Luminesecence(CPL) of chiral perylenediimide for CP-OLEDs　　　　　　　　　　　　　　　
HARA; Nobuyuki; TANIGUTHI; Ayano; WATANABE; Kouhei; MURATA; Ryosuke; HARADA; Takunori; NISHIKAWA; Hiroyuki; IMAI; Yoshitane
日本化学会第99春季年会, Mar. 2019
201903, 201903

2004, 分子科学会

2004, 日本物理学会

2003, 錯体学会

1998, アメリカ化学会

1983, 日本化学会

円偏光発光材料の開発に向けた革新的基盤技術の創成　　　　　　　　　　　　　　　
CREST
Oct. 2020 - Mar. 2026

キラル発光性物質群の創製と次世代有機光学材料の開発　　　　　　　　　　　　　　　
CREST
Oct. 2019 - Mar. 2025

光励起配列構造変化を利用した動的円偏光発光(CPL)材料の開発　　　　　　　　　　　　　　　
国際共同研究加速基金（国際共同研究強化(B)）
Nov. 2020 - Mar. 2024

キラリティを基盤とした円偏光発光と誘電性の融合物性の開拓　　　　　　　　　　　　　　　
クロスオーバー共同研究
Oct. 2022 - Mar. 2023

キロプティカルテクノロジーの基盤を創る革新的物質群の創製　　　　　　　　　　　　　　　
学術変革領域研究（総括班）
Oct. 2020 - Mar. 2023

スピン偏極効果を利用した革新的発光デバイスの創発　　　　　　　　　　　　　　　
学術変革領域研究 (B) （計画研究）
Sep. 2020 - Mar. 2023

キラル誘起スピン選択性効果を利用した革新的発光デバイスの開発　　　　　　　　　　　　　　　
挑戦的研究（萌芽）
Apr. 2020 - Mar. 2023

光励起状態の深化による動的円偏光発光(CPL)材料の開発　　　　　　　　　　　　　　　
科学研究費補助金 国際共同研究加速基金（国際共同 研究強化(B)
Nov. 2019 - Mar. 2023

円偏光照射による薄膜中のキラル構造増幅に基づく円偏光発光デバイスの高性能化　　　　　　　　　　　　　　　
提案型
Dec. 2022 - Jan. 2023

キラリティを導入した有機半導体を基盤とする円偏光応答型薄膜デバイスの創出　　　　　　　　　　　　　　　
挑戦的研究（萌芽）
Apr. 2019 - Mar. 2022

磁性伝導体を用いた有機デバイスを基盤とする分子スピントロニクス材料の開発　　　　　　　　　　　　　　　
基盤研究(B)
Apr. 2018 - Mar. 2022

TTF-Cu(II)錯体における磁性‐伝導性間の相互作用の解明　　　　　　　　　　　　　　　
基盤共同研究
東北大学多元物質科学研究所
Apr. 2019 - Mar. 2020

Development of magnetic field responsive transistor based on molecular conductors
Grant-in-Aid for Challenging Exploratory Research
Ibaraki University
01 Apr. 2015 - 31 Mar. 2018

Exploration of physical properties acompanied by strongly correlated electron systems based on organic chiral conductors
Grant-in-Aid for Scientific Research (B)
Ibaraki University
01 Apr. 2015 - 31 Mar. 2018

Control of intermolecular interaction for novel electronic functionalities
Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
The University of Tokyo
13 Nov. 2008 - 31 Mar. 2013

Molecular spintronics based on hybrid compounds between organic conductors and transition metal complexes.
Grant-in-Aid for Challenging Exploratory Research
Ibaraki University
2011 - 2012

Development of Molecular Conductors Linked with Magnetic Metal Ions and Their Application to Spin-electronics Materials
Grant-in-Aid for Scientific Research (C)
University of Tsukuba
2008 - 2010

次世代ドナー分子系の創製と有機超伝導体の開発
特定領域研究
2003 - 2007

金属微粒子に分散した超分子機能体を用いた次世代太陽電池材料の創製
萌芽研究
筑波大学
2005 - 2006

Development of Chiral Molecular Superconductors
Grant-in-Aid for Scientific Research (B)
Tokyo Metropolitan University
2003 - 2005

Development of organic superconductors and multifunctional supramolecules based on new π-elecfron systems
Grant-in-Aid for Scientific Research (C)
2003 - 2004

テルルを含む非対称有機伝導体の開発
奨励研究(A)
東京都立大学
1998 - 1999

分子認識能を有する新規分子性導体の探求
奨励研究(A)
東京都立大学
1995 - 1995

球状ファンデルワールス分子の誘導体による超構造の創成
重点領域研究
東京都立大学
1995 - 1995

特願2022-025984, 光学測定システム，及び光学測定方法
西川浩之,金坂青葉,田内大喜

日本化学会物理化学ディビジョン委員　　　　　　　　　　　　　　　
Others
01 Apr. 2022 - Present

分子科学会 Molecular Science 編集委員　　　　　　　　　　　　　　　
Others
01 Apr. 2013 - Present

日本学術振興会 分子系の複合電子機能第181委員会 委員　　　　　　　　　　　　　　　
Others
01 Apr. 2008 - 31 Mar. 2023

The 5th International Symposium of Quantum Beam Science
Planning etc
西川浩之, 茨城大学, 19 Nov. 2020 - 21 Nov. 2020