Wataru Fujita

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Name
Wataru Fujita
Affiliation
Seikei University
Section
Faculty of Science and Technology

Research Areas

 
 

Published Papers

 
Magnetic, Thermal and Neutron Diffraction Studies of a Coordination Polymer, Bis(glycolato)cobalt(II).
T. Nakane, S. Yoneyama, T. Kodama, K. Kikuchi, T. Ohhara, A. Nakao, R. Higashinaka, T. D. Matsuda, W. Fujita*
Dalton Trans.   48 333-338   2019   [Refereed]
Crystal structure, Hirshfeld surface analysis, and physicochemical studies of a new Cu(II) complex with 2-amino-4-methylpyrimidine.
K. Klai, S. Soudani C. Jelsch, F. Lefebvre, W. Kaminsky, W. Fujita, C. Ben Nasr, K. Kaabi
J. Mol. Struct.   1194 297-304   2018
Crystal Structures, and Magnetic and Thermal Properties of Basic Copper Formates with Two-dimensional Triangular-lattice Magnetic Networks.
Wataru Fujita
RSC Adv.   8 32490-34296   2018   [Refereed]
A Hirshfeld surface analysis, crystal structure and physicochemical studies of a new Cu(II) complex with the 1,10-phenanthroline ligand.
W. Nbili, K. kaabi, F. Lefebvre, W. Fujita, C. Jelsch, C. Ben Nasr
J. Coord. Chem.   71 2526-2539   2018   [Refereed]
A Hirshfeld surface analysis, crystal and geometry-optimized structure, and solid state NMR studies of two novel α-hydroxyphosphonates C17H21O4P (I) and C19H25O4P(II).
I. Essid, S. Soudani, F. Lefebvre, W. Kaminsky, W. Fujita, C. Ben Nasr, S. Touila
J. Mol. Struct.   1149 99-111   2017   [Refereed]
Wataru Fujita, Akio Tokumitu, Yutaka Fujii, Hikomitsu Kikuchi
CrystEngComm   18 8614-8621   Jan 2016
©2016 The Royal Society of Chemistry.Single crystals of copper hydroxide compounds (1-7) containing organic sulfonate ions (ethane-1,2-disulfonate, 1-octanesulfonate, p-toluenesulfonate, p-ethylbenzenesulfonate, 2-naphthalenesulfonate, 1,5-naphtha...
Shota Yoneyama, Takeshi Kodama, Koichi Kikuchi, Takumi Fujisawa, Akira Yamaguchi, Akihiko Sumiyama, Yoshiaki Shuku, Shinobu Aoyagi, Wataru Fujita
Dalton Transactions   45 16774-16778   Jan 2016
© 2016 The Royal Society of Chemistry.Bis(glycolato)copper(ii) [Cu(HOCH2CO2)2] shows a structural phase transition around 220 K under cooling and 270 K under heating, and ferromagnetic ordering at 1.1 K. Deuterium substitution of the hydroxyl grou...
Wataru Fujita
CrystEngComm   17 9193-9202   Jan 2015
© 2015 The Royal Society of Chemistry.Single crystals of layered copper hydroxides, 1-4, with aromatic sulfonate ions, p-toluenesulfonate, p-ethylbenzenesulfonate, 1-naphthalenesulfonate and 1,5-naphthalenedisulfonate, respectively, were convenien...
Rei Yoshida, Takeshi Kodama, Koichi Kikuchi, Shinobu Aoyagi, Wataru Fujita
Synthetic Metals   208 43-48   Dec 2014
© 2015 Elsevier B.V. All rights reserved.The crystal structure and magnetic properties of (BDTA)2(H3O)2[Fe(II)(CN)6] (1), a charge-transfer complex, were investigated. The charge transfer interaction works between BDTA+ and Fe(CN)64-in 1 from UV, ...
Shota Yoneyama, Takeshi Kodama, Koichi Kikuchi, Yutaka Fujii, Hikomitsu Kikuchi, Wataru Fujita
CrystEngComm   16 10385-10388   Dec 2014
© 2014 the Partner Organisations.A copper hydroxy salt, α-[Cu3(OH)2(CH3CO2)2(H2O)4](C6H5SO3)2, exhibited a distorted diamond chain magnetic network and paramagnetism with the dominance of the antiferromagnetic interactions down to 2 K.
Wataru Fujita
Dalton Transactions   44 903-907   Nov 2014
© 2014 The Royal Society of Chemistry.An organic radical cation salt, BBDTA·Au(CN)2, with a slipped π-stacking columnar structure and intercolumnar short contacts, shows ferromagnetic ordering at 8.2 K, the highest reported temperature among the B...
Kunio Awaga, Kunio Awaga, Kunio Awaga, Kenji Nomura, Kenji Nomura, Hideo Kishida, Wataru Fujita, Wataru Fujita, Wataru Fujita, Hirofumi Yoshikawa, Hirofumi Yoshikawa, Michio M. Matsushita, Michio M. Matsushita, Laigui Hu, Laigui Hu, Yoshiaki Shuku, Yoshiaki Shuku, Rie Suizu, Rie Suizu, Rie Suizu
Bulletin of the Chemical Society of Japan   87 234-249   Feb 2014
Heterocyclic thiazyl radicals possess unique chemical and physical properties as building blocks for molecule-based conductors and magnetic materials. They do not need protecting groups on their molecular skeletons, and the lack of such substituen...
Wataru Fujita, Koichi Kikuchi
European Journal of Inorganic Chemistry   93-100   Jan 2014
We investigate the crystal structure and magnetic properties of an organic radical cation salt, BBDTA·Cl, based on the monocation of benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazolyl (BBDTA) with one unpaired electron (spin quantum number S = 1/2) and a ch...
Shota Yoneyama, Takeshi Kodama, Koichi Kikuchi, Yohei Kawabata, Kentaro Kikuchi, Toshio Ono, Yuko Hosokoshi, Wataru Fujita
CrystEngComm   15 10193-10196   Dec 2013
A coordination polymer with a two-dimensional square planar lattice network, bis(glycolato)copper(ii), shows a large structural phase transition at around 220 K and ferromagnetic ordering at 1.1 K. © 2013 The Royal Society of Chemistry.
Akira Yamada, Ryuji Higashinaka, Ryoichi Miyazaki, Kengo Fushiya, Tatsuma D. Matsuda, Yuji Aoki, Wataru Fujita, Hisatomo Harima, Hideyuki Sato
Journal of the Physical Society of Japan   82    Dec 2013
The low-temperature properties of single crystals of SmTa 2Al20 have been studied by electrical resistivity, magnetization, and specific heat measurements. A λ-type peak structure, indicating a phase transition, was found in the specific heat at T...
Wataru Fujita, Koichi Kikuchi
Bulletin of the Chemical Society of Japan   86 921-926   Aug 2013
We have succeeded in preparing single crystals of the layered copper hydroxide [Cu7(OH)12(CH3CH2CO 2)2].(CH3CH2CO2H) 2.(H2O)6 (1) through hydrolysis of a copper propionate solution. X-ray structure analysis showed that this material did not have t...
Andrew C. Brooks, Andrew C. Brooks, Lee Martin, Peter Day, Elsa B. Lopes, Manuel Almeida, Koichi Kikuchi, Wataru Fujita, Kota Sasamori, Hiroki Aktusu, John D. Wallis
Dalton Transactions   42 6645-6654   Jul 2013
The novel radical cation salt (BEDT-TTF)3(sulfamate) 2·2H2O (BEDT-TTF = bis(ethylenedithio) tetrathiafulvalene) is semiconducting with donor stacks comprised of pairs of partially oxidized molecules and a single more highly oxidized molecule which...
Masayoshi Takase, Ayumi Inabe, Yuki Sugawara, Wataru Fujita, Tohru Nishinaga, Kotohiro Nomura
Organic Letters   15 3202-3205   Jul 2013
The expeditious synthesis of donor-acceptor segregated paracyclophanes has been achieved by a selective SNAr reaction of hexafluorobenzene with o-dipyrrolylbenzenes and subsequent cyclodehydrogenation. An orthogonally arranged D-A segregated struc...
Masayoshi Takase, Tomoyuki Narita, Wataru Fujita, Motoko S. Asano, Tohru Nishinaga, Hiroaki Benten, Kenji Yoza, Klaus Müllen
Journal of the American Chemical Society   135 8031-8040   May 2013
A novel pyrrole-fused azacoronene family was synthesized via oxidative cyclodehydrogenation of the corresponding hexaarylbenzenes as the key step, and the crystal structures of tetraazacoronene 3b and triazacoronene 4a were elucidated. The photoph...
Kota Sasamori, Kazuyuki Takahashi, Takeshi Kodama, Wataru Fujita, Koichi Kikuchi, Jun Ichi Yamada
Journal of the Physical Society of Japan   82    May 2013
The pressure-induced organic superconductor β-(BDA-TTP) 2FeCl4 [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)- 1,3,4,6-tetrathiapentalene], which shows a metal-insulator (MI) transition at TMI = 113K under ambient pressure, has been found by X-ray stud...
Tadamitsu Nakamura, Kota Sasamori, Takeshi Kodama, Koichi Kikuchi, Wataru Fujita
Chemistry - An Asian Journal   8 348-350   Feb 2013
1, 3, 2, 4, 5, go! A new dithiolene ligand, 1,3,2-dithiazole-4-thione-5- thiolate (dttt-), which is a stable and diamagnetic monoanion, was prepared. Its tris(dithiolene) complex Cr(dttt)3×CS2 is octahedral and forms a dimer through intermolecular...
Wataru Fujita, Koichi Kikuchi, Wasuke Mori
Chemistry - An Asian Journal   7 2830-2835   Dec 2012
We prepared single crystals of basic copper formate Cu2(OH) 3HCO2 (1) by hydrolysis of formate anions in an aqueous solution of copper formate. X-ray structure analysis showed that this material has a two-dimensional triangular lattice network wit...
Koichi Kikuchi, Takayuki Isono, Masayuki Kojima, Haruo Yoshimoto, Takeshi Kodama, Wataru Fujita, Keiichi Yokogawa, Harukazu Yoshino, Keizo Murata, Takayuki Kaihatsu, Hiroki Akutsu, Jun Ichi Yamada
Journal of the American Chemical Society   133 19590-19593   Dec 2011
Dependence of the superconducting transition temperature (Tc) and critial superconducting pressure (Pc) of the pressure-induced superconductor β-(BDA-TTP)2I3 [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] on the orientation ...
Wilhelm L. Hemme, Wataru Fujita, Kunio Awaga, Hellmut Eckert
Solid State Nuclear Magnetic Resonance   39 106-115   May 2011
The radical cations 2-(3-N-butylpyridinium)-4,4,5,5-tetramethyl-4,5- dihydro-1H-imidazol-1-oxyl-3-N-oxide (m-BuPYNN) and 4-(ethylammonium)-2,2,6,6- tetramethylpiperidin-1-oxide (EATEP) are successfully intercalated into the layered host structure ...
Wataru Fujita, Kazuyuki Takahashi, Hayao Kobayashi
Crystal Growth and Design   11 575-582   Feb 2011
The magnetostructural correlation was investigated in three organic radical cation salts based on the monocation of benzo[1, 2-d:4, 5-d']bis[1, 3, 2]dithiazolyl (BBDTA), which is an S = 1/2 system, and the tetrahedral diamagnetic monoanions, TlBr4...
Tohru Nishinaga, Masaki Tateno, Mika Fujii, Wataru Fujita, Masayoshi Takase, Masahiko Iyoda
Organic Letters   12 5374-5377   Dec 2010
Combined DFT calculations and UV-vis-NIR, ESR, and SQUID measurements revealed that the ground-state electronic structure of a linear π-conjugated oligomer dication composed of two pyrrole and six or seven thiophene rings and methylthio end-cappin...
Ken Ichi Suzuki, Takeshi Kodama, Koichi Kikuchi, Wataru Fujita
Chemistry Letters   39 1096-1098   Sep 2010
A new molecule-based magnet, α-(benzo[1,2-d:4,5-d′]bis-[1,3,2] dithiazole (BBDTA))2ReBr6, comprised a one-dimensional network composed of an alternative alignment of BBDTA+ (S =1/2) and ReBr62- (S =3/2) and an S= 1/2 regular chain network of the o...
Taku Matsushita, Nobuko Hamaguchi, Kengo Shimizu, Nobuo Wada, Wataru Fujita, Wataru Fujita, Kunio Awaga, Akira Yamaguchi, Akira Yamaguchi, Hidehiko Ishimoto
Journal of the Physical Society of Japan   79    Sep 2010
The organic Heisenberg antiferromagnet m-MPYNN·BF 4 has a two-dimensional Kagomé lattice of S = 1 dimers with a small trigonal distortion. This antiferromagnet indicates a nonmagnetic ground state with a gap of 0.2 K in zero...
Masaki Mito, Seiichiro Kawagoe, Hiroyuki Deguchi, Seishi Takagi, Wataru Fujita, Kunio Awaga, Ryusuke Kondo, Seiichi Kagoshima
Journal of the Physical Society of Japan   78    Dec 2009
We investigated the effects of hydrostatic pressure and uniaxial strain on the spin-Peierls (SP) transition of an organic radical magnet, benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazole(BBDTA) · InCl4. It has a one-dimensional coordination polymer structu...
Wilhelm L. Hemme, Wataru Fujita, Kunio Awaga, Hellmut Eckert
Journal of Solid State Chemistry   182 3330-3341   Dec 2009
The radical cation 2-(3-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-N-oxide (abbreviated as m-MPYNN) is successfully intercalated into the layered host structure CdPS3. The reaction proceeds via an ion exchange reactio...
Wilhelm L. Hemme, Wataru Fujita, Kunio Awaga, Hellmut Eckert
Dalton Transactions   7995-8004   Sep 2009
2-(3- and 4-N-methylpyridinium)-4,4,5,5-tetramethyl-4,5-dihydro-1H- imidazol-1-oxyl 3-N-oxide (abbreviated as m- and p-MPYNN), the butyl derivative (m- and p-BuPYNN), 4-(N-ethylammonium)-2,2,5,5-tetramethylpiperidin-1-oxyl (ETEP) and N,N,N′,N′-Tet...
Wataru Fujita, Koichi Kikuchi
Chemistry - An Asian Journal   4 400-405   Mar 2009
We investigate the preparation, crystal growth, crystal structure, and magnetic properties of the three polymorphs (α, β, and γ) of an organic magnet, BBDTA(=benzo[1,2-d:4,5-d'] bis[1,3,2]dithiazole)-GaBr 4, which is an S-1/2 system. In the a phas...
Masaki Mito, Masatsugu Fujino, Yuki Komorida, Hiroyuki Deguchi, Seishi Takagi, Wataru Fujita, Kunio Awaga
Journal of the Physical Society of Japan   77    Dec 2008
A thiazyl-based ferromagnet, the γ-phase of BBDTA (i.e., benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazole)·GaCl4, has a high ferromagnetic ordering temperature of 7.0 K in organic radical ferromagnets. In this system, pressurization generated more compact ...
Wataru Fujita, Koichi Kikuchi, Kunio Awaga
Angewandte Chemie - International Edition   47 9480-9483   Nov 2008
(Graph Presented) A magnetic coordination polymer, BBDTA·InBr 4, undergoes a spin-Peierls-like phase transition at 250 K. X-ray crystal analysis illustrates that the lattice dimerization accompanies elongation and contraction of the In - N coordin...
Kunio Awaga, Yoshikatsu Umezono, Wataru Fujita, Hirofumi Yoshikawa, HengBo Cui, Hayao Kobayashi, Sarah S. Staniland, Neil Robertson
Inorganica Chimica Acta   361 3761-3770   Oct 2008
We have examined the crystal structures and the electrical and magnetic properties of the molecular compounds of a thiazyl radical, 1,3,2-benzodithiazolyl (abbreviated as BDTA). BDTA was found to be a useful building block for molecular conductors...
Kai Iketaki, Kaname Kanai, Wataru Fujita, Kunio Awaga, Jun'ya Tsutsumi, Hiroyuki Yoshida, Naoki Sato, Martin Knupfer, Yukio Ouchi, Kazuhiko Seki, Kazuhiko Seki
Chemical Physics Letters   451 58-62   Jan 2008
The adsorption of 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) on a gold surface has been studied using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS) under ultrahigh vacuum conditions. TTTA was deposited on...
Kentaro Okamoto, Toshiyuki Tanaka, Wataru Fujita, Kunio Awaga, Tamotsu Inabe
Physical Review B - Condensed Matter and Materials Physics   76    Aug 2007
We here examine the electrical and magnetic properties of the isostructural NT3·M Cl4 (NT=naphtho [2,1- d: 6,5- d′] bis([1,2,3] dithiazole and M=Ga and Fe). The crystal structure of NT3·M Cl4 consists of one-dimensional π -stacking chains of NT wi...
Yasuhiro Ito, Wataru Fujita, Toshiya Okazaki, Toshiya Okazaki, Toshiki Sugai, Kunio Awaga, Eiji Nishibori, Masaki Takata, Makoto Sakata, Hisanori Shinohara
ChemPhysChem   8 1019-1024   May 2007
Magnetic properties of solvent-free crystals of the endohedral Sc@C 82 are investigated by SQUID and X-ray powder diffraction. We find that the crystal is a paramagnet and the magnetic susceptibility decreases from 150 K with evidence of antiferro...
X. M. Ren, S. Nishihara, T. Akutagawa, T. Akutagawa, S. Noro, S. Noro, T. Nakamura, T. Nakamura, W. Fujita, K. Awaga
Chemical Physics Letters   439 318-322   May 2007
Two quasi-1D molecular magnets, [RBzPy][Ni(mnt)2] (RBzPy+ = 1-(4′-nitrobenzyl)pyridinium (1) and 1-(4′-brominobenzyl)pyridinium (2); mnt2- = maleonitriledithiolate), are isostructural and possess a spin-Peierls-like transition at Tc ≈ 184 K for 1 ...
Kengo Shimizu, Tomotaka Gotohda, Taku Matsushita, Nobuo Wada, Wataru Fujita, Kunio Awaga, Yasuhiro Saiga, Dai S. Hirashima
Journal of Magnetism and Magnetic Materials   310 1479-1481   Mar 2007
An organic magnet β - BBDTA · GaBr4 shows a ferromagnetic transition at TC = 0.42 K that is a typical long-range ordering of the Heisenberg S = frac(1, 2) ferromagnetic chains with intra-chain interaction of 2 JF = 8.7 K, induced by only a ferroma...
Kunio Awaga, Toshiyuki Tanaka, Takahiro Shirai, Yoshikatsu Umezono, Wataru Fujita
Comptes Rendus Chimie   10 52-59   Jan 2007
We examined the crystal structures and magnetic properties of heterocyclic thiazyl radicals and their molecular compounds. 1,3,5-Trithia-2,4,6-triazapentalenyl (TTTA) exhibited a room-temperature bistability between a paramagnetic high-temperature...
Kengo Shimizu, Tomotaka Gotohda, Taku Matsushita, Nobuo Wada, Wataru Fujita, Kunio Awaga, Yasuhiro Saiga, Dai S. Hirashima
Physical Review B - Condensed Matter and Materials Physics   74    Dec 2006
We have observed the magnetic susceptibility and the specific heat of the β phase of an organic magnet BBDTA•Ga Br4 which consists of antiferromagnetic chains and ferromagnetic chains. At low temperatures, the antiferromagnetic chains do not contr...
K. Awaga, W. Fujita, T. Tanaka, H. Matsuzaki, H. Okamoto
Carbon Based Magnetism   189-200   Dec 2006
This chapter elaborates magnetic bistability in molecule-based magnetic materials. The heterocyclic thiazyl radicals possess unique chemical and physical properties. They are chemically stable in contrast to the instability of the most organic rad...
Kunio Awaga, Toshiyuki Tanaka, Takahiro Shirai, Masato Fujimori, Yosuke Suzuki, Hirofumi Yoshikawa, Wataru Fujita
Bulletin of the Chemical Society of Japan   79 25-34   Nov 2006
The crystal structures and magnetic properties of heterocyclic thiazyl radicals and related materials have been examined. TTTA (=1,3,5-trithia-2,4,6- triazapentalenyl) exhibited a first-order phase transition between a paramagnetic high-temperatur...
Kentaro Okamoto, Toshiyuki Tanaka, Wataru Fujita, Kunio Awaga, Tamotsu Inabe
Angewandte Chemie - International Edition   45 4516-4518   Jul 2006
(Graph Presented) Resistance is useful: A thiazyl-radical salt, [NT] 3[GaCl4] (see structural diagram), exhibits negative resistance (see graph) in a charge-ordered state of the square columnar network of NT molecules. As the negative-resistance e...
X. M. Ren, X. M. Ren, S. Nishihara, T. Akutagawa, T. Akutagawa, S. Noro, S. Noro, T. Nakamura, T. Nakamura, W. Fujita, K. Awaga, Z. P. Ni, J. L. Xie, Q. J. Meng, R. K. Kremer
Dalton Transactions   1988-1994   Jun 2006
The syntheses, structural characterizations and magnetic behaviors of three new complexes, 1-(3′,4′,5′-trifluorobenzyl)pyridinium [M(mnt)2]- [M = Ni (1), Pd (2) or Pt (3)], are reported. These complexes are isomorphous and their prominent structur...
Sarah S. Staniland, Sarah S. Staniland, Wataru Fujita, Yoshikatsu Umezono, Kunio Awaga, Stephen Crawford, Simon Parsons, Neil Robertson
Molecular Crystals and Liquid Crystals   452 123-135   May 2006
Three new [dithiazolylium]x[M(tdas)2] salts are reported (tdas = 1,2,5-thiadiazole-3, 4-dithiole). Single-crystal X-ray structures have been obtained for [BDTA]2[Fe(tdas)2Cl] (1) and [BDTA]2[Ni(tdas)2] (2) (BDTA = benzo-1,3,2- dithiazolyl). These ...
Wataru Fujita, Kunio Awaga, Ryusuke Kondo, Seiichi Kagoshima
Journal of the American Chemical Society   128 6016-6017   May 2006
We have studied the crystal structure and magnetic properties of the organic radical cation salt, BBDTA·InCl4. This material formed a one-dimensional coordination polymer. Magnetic measurements indicated the spin-Peierls transition-like behavior a...
X. M. Ren, X. M. Ren, S. Nishihara, T. Akutagawa, T. Akutagawa, S. Noro, S. Noro, T. Nakamura, T. Nakamura, W. Fujita, K. Awaga
Chemical Physics Letters   418 423-427   Feb 2006
Two new molecular magnets, based on [M(mnt)2]- [M = Pt (1) or Ni (2)], were prepared and characterized structurally and magnetically. The [M(mnt)2]- anions form the columnar stack in 1 and 2. Both compounds are expected to be ideal quasi-1D magnet...
Yoshikatsu Umezono, Wataru Fujita, Kunio Awaga
Journal of the American Chemical Society   128 1084-1085   Feb 2006
The crystal structure of a charge-transfer salt, (BDTA)2[Co(mnt)2], where BDTA is 1,3,2-benzodithiazolyl and mnt is maleonitriledithiolate, consisted of an alternating stacking column of a head-to-head BDTA+ dimer and a planar [Co(mnt)2]2- dianion...
Masaki Mito, Masatsugu Fujino, Hiroyuki Deguchi, Seishi Takagi, Wataru Fujita, Kunio Awaga
Polyhedron   24 2501-2504   Nov 2005
A radical cation salt, BBDTA (= benzo[1,2-d:4,5-d′]bis[1,3,2] dithiazole)·GaCl4, has three polymorphs, labeled α, β and γ. The γ-phase shows a ferromagnetic ordering at 7.0 K, and this Curie temperature (TC) is eminently high, in contrast to those...
K. Iketaki, K. Kanai, K. Tsuboi, W. Fujita, K. Awaga, M. Knupfer, Y. Ouchi, K. Seki, K. Seki
Synthetic Metals   153 457-460   Sep 2005
Thin films of 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA) were prepared on gold surfaces by "dry" and "wet" processes and were investigated by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and surface plasmo...
Wataru Fujita, Kunio Awaga
Journal of the Chemical Society, Chemical Communications   739-740   Dec 1995
The organic radical cations, 2-(3- and 4-N-methylpyridinium)-4,4,5,5- tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-N-oxide, are intercalated into saponite clay {Na0.46[Si3.54Al0.46Mg 3O10(OH)2]·nH2O} by means of cation exchange, and display Curie ...
Wataru Fujita, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals   271 123-128   Sep 1995
The N-alkylpyridinium nitronyl nitroxide cations were intercalated into saponite clay (Na0.46[Si3.54Al0.46Mg3O10(OH)2].nH2O) by means of the cation exchange. Up to 70 % of the sodium ions were replaced by the organic radicals. The organic radical-...
J. Y. Jin, W. Fujita, N. Teramae, H. Haraguchi
Journal of Applied Polymer Science: Applied Polymer Symposium   241-250   Dec 1993
When an electrochemically roughened silver electrode was immersed in an electrolytic solution containing aniline monomer, it was found that the aniline molecule adsorbed on the electrode surface could be polymerized even at a lower positive potent...

Misc

 
Nobuko Hamaguchi, Taku Matsushita, Nobuo Wada, Wataru Fujita, Kunio Awaga
AIP Conference Proceedings   850 1097-1098   Dec 2006
We have studied the specific heat of an organic compound m-MPYNNBF 4-(1/3)(acetone) in magnetic fields. This compound is a spin-1 Kagomé Heisenberg antiferromagnet and has a non-magnetic ground state with a spin gap of 0.25-0.45 K in zero field. W...
X. M. Ren, X. M. Ren, T. Akutagawa, T. Akutagawa, S. Nishihara, T. Nakamura, T. Nakamura, W. Fujita, K. Awaga
Journal of Physical Chemistry B   109 16610-16615   Sep 2005
Crystal structures and magnetic properties were determined for two novel compounds, [1-(4′-iodobenzyl)-pyridinium][M(mnt)2] (mnt 2- = maleonitriledithiolate; M = Ni (1) or Cu (2)). At room temperature, single crystals of 1 and 2 were isostructural...
Tomotaka Gotohda, Yoshikazu Kugimiya, Nobuko Hamaguchi, Taku Matsushita, Nobuo Wada, Wataru Fujita, Kunio Awaga
Journal of Physics and Chemistry of Solids   66 1446-1449   Aug 2005
We have observed the magnetic susceptibility and the magnetization of an organic S=1 Heisenberg magnet m-EPYNN·BF4·1/3(ethanol) which has a slightly distorted two-dimensional Kagomé lattice and antiferromagnetic interactions. In contrast to the no...
Sarah S. Staniland, Wataru Fujita, Yoshikatsu Umezono, Kunio Awaga, Stewart J. Clark, HengBo Cui, Hayao Kobayashi, Neil Robertson
Chemical Communications   3204-3206   Jul 2005
A new molecular conducting material, [BDTA][Ni(dmit)2] 2, with a novel multiband electronic structure has been prepared by simple mixing of precursor salts of the components. © The Royal Society of Chemistry 2005.
Yoshikatsu Umezono, Wataru Fujita, Kunio Awaga
Chemical Physics Letters   409 139-143   Jun 2005
The crystal structure of a charge transfer salt, (BDTA)[Ni(mnt) 2], where BDTA is 1,3,2-benzodithiazolyl and mnt is maleonitriledithiolate, was found to consist of alternating stacking columns of S = 0 BDTA+ and S = 1/2 [Ni(mnt)2]-. Magnetic and t...
Sarah S. Staniland, Wataru Fujita, Yoshikatsu Umezono, Kunio Awaga, Philip J. Camp, Stewart J. Clark, Neil Robertson
Inorganic Chemistry   44 546-551   Feb 2005
[BDTA]2[Cu(mnt)2] (BDTA = benzo-1,3,2-dithiazolyl, mnt = maleonitriledithiolate) was crystallized in the space group P1 with an inversion center on Cu giving a stacked structure with each metal complex anion sandwiched by two cations. Short interm...
T. Tanaka, W. Fujita, K. Awaga
Chemical Physics Letters   393 150-152   Jul 2004
We studied the pressure effects on l,3,5-trithia-2,4,6-triazapentalenyl (TTTA), which exhibits paramagnetic-diamagnetic bistability in the range between Tc↓=230 K and Tc↑=305 K at ambient pressure. The bistable temperature range shifted toward hig...
T. Kambe, K. Oshima, W. Fujita, K. Awaga
Journal of Magnetism and Magnetic Materials   272-276    May 2004
We carefully examined ESR and magnetic susceptibility around Ts = 128.7K, at which the structural phase transition takes place, of m-MPYNN BF4 1/3 acetone. Both the ESR parameters and the magnetic susceptibility have a clear anomaly around Ts. The...
Wataru Fujita, Kunio Awaga
Chemical Physics Letters   388 186-189   Apr 2004
Three polymorphs, labeled α (plates), β (needles), and γ (blocks), of BBDTA(=benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazole) ·GaCl4 were obtained as a mixture of three polymorphs, by recrystallization at -23°C. The γ-phase showed the ferromagnetic orderi...
Takashi Kambe, Yoshio Nogami, Kokichi Oshima, Wataru Fujita, Kunio Awaga
Journal of the Physical Society of Japan   73 796-799   Apr 2004
We found for the first time a structural phase transition in two-dimensional kagomé antiferromagnet m-N-methylpyridinium α-nitronyl nitroxide (m-MPYNN)·BF4·1/3 (acetone). As, below Ts = 128.7 K, the intense satellite reflections are clearly observ...
Tsunehisa Okuno, Kazunori Kuwamoto, Wataru Fujita, Kunio Awaga, Warô Nakanishi
Polyhedron   22 2311-2315   Jul 2003
Novel NiII(tdas)2 complexes, (m- or p-MPYNN)2Ni(tdas)2 (MPYNN = N-methylpyridinium α-nitronyl nitroxide and tdas = 1,2,5-thiadiazole-3,4-dithiolate), were prepared. The Ni(tdas)2 anions are located on the lattice points and at the lattice center i...
H. Matsuzaki, W. Fujita, K. Awaga, H. Okamoto
Physical Review Letters   91    Jul 2003
A PIPT from a diamagnetic LT phase to a paramagnetic HT phase with a drastic color change for the organic radical crystal TTTA at both room temperature and 11 K using nanosecond laser pulses was demonstrated. Suppression of the SP instability by a...
Yutaka Fujii, Takao Goto, Wataru Fujita, Kunio Awaga
Physica B: Condensed Matter   329-333 973-974   May 2003
The organic radical salt m-MPYNN·BF4 is characterized as a spin-1 kagomé antiferromagnet and has been suggested to have a singlet ground state with a finite spin gap. 1H-NMR measurements for this salt have been carried out in the temperature range...
W. Fujita, K. Awaga
Synthetic Metals   137 1263-1265   Apr 2003
We report unique magnetic properties of three kinds of heterocyclic thiazyl radicals, (i) TTTA (=1,3,5-trithia-2,4,6-triazapentalenyl) showed room-temperature magnetic bistability realized by a first-order phase transition between a paramagnetic h...
S. Ohira, K. Awaga, W. Fujita, I. Watanabe, K. Nagamine, K. Nagamine
Physica B: Condensed Matter   326 568-571   Feb 2003
The magnetic properties of p-NPNN·Cu(hfac)2 (p-NPNN= p-nitrophenyl nitronylnitroxide, hfac= hexafluoroacetylacetonat) were studied by muon spin relaxation (μSR). From an AC susceptibility measurement, the system is suggested to exhibit an antiferr...
Pierre Rabu, Marc Drillon, Kunio Awaga, Wataru Fujita, Taketoshi Sekine
Magnetism: Molecules to Materials   2-5 357-395   Jan 2003
Yutaka Fujii, Takao Goto, Wataru Fujita, Kunio Awaga
Progress of Theoretical Physics   68-71   Dec 2002
1H-NMR measurements for an organic radical antiferromagnet, m-MPYNN·BF4, have been carried out in the temperature range down to 0.05 K and under the magnetic fields up to 70 kOe. The gapped magnetic state is found above about 10 kOe where the spin...
Wataru Fujita, Kunio Awaga, Masashi Takahashi, Masuo Takeda, Tomoyuki Yamazaki
Chemical Physics Letters   362 97-102   Aug 2002
An organic/inorganic hybrid system, (benzo[1,2-d:4,5-d′]bis[1,3,2]dithiazole (= BBDTA)) · FeCl4 · CH3COCH3, is shown to exhibit a drastic change in magnetism after evaporation of the volatile crystal solvent, acetone. The solvated material, with a...
W. Fujita, K. Awaga
Chemical Physics Letters   357 385-388   May 2002
The crystals of the organic cation radical salt, BBDTA (benzo[1,2-d:4,5-d']bis[1,3,2]dithiazole)·GaCl4 · CH3CN, was found to consist of a ladder-type structure of BBDTA, coordinated by the crystal solvent, CH3CN. While this material exhibited diam...
Wataru Fujita, Kunio Awaga, Yasuhiro Nakazawa, Kazuya Saito, Michio Sorai
Chemical Physics Letters   352 348-352   Feb 2002
We examined the magnetic and thermal properties of a stable thiazyl radical 1,3,2-benzodithiazolyl, BDTA. While the diamagnetic room-temperature phase had been known for BDTA, we found a new phase transition to a paramagnetic solid phase at 346 K ...
Wataru Fujita, Kunio Agwa, Hiroyuki Matsuzaki, Hiroshi Okamoto
Physical Review B - Condensed Matter and Materials Physics   65 644341-644349   Feb 2002
An organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), exhibits a first-order phase transition between a paramagnetic high-temperature (HT) phase and a diamagnetic low-temperature (LT) phase, with a surprisingly wide thermal hysteresis l...
Wataru Fujita, Kunio Awaga, Kunio Awaga
Synthetic Metals   122 569-572   Aug 2001
We report the intercalation of a stable organic radical, 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidine-1-oxyl anion (PROXYL-) into the layered copper hydroxides, Cu2(OH)3 (CH3CO2)·H2O, by means of the anion exchange. The powder X-ray diffractions re...
W. Fujita, K. Awaga, K. Awaga
Polyhedron   20 1517-1519   May 2001
We studied the magnetic properties of a heterocyclic thiazyl radical, TTTA (1,3,5-trithia-2,4,6-triazapentalenyl). The temperature dependence of the paramagnetic susceptibility of TTTA indicates a first-order phase transition between a paramagneti...
Wataru Fujita, Kunio Awaga, Kunio Awaga
Synthetic Metals   121 1767-1769   Mar 2001
A large first-order magnetic phase transition in an organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl is described, that occurs with a wide thermal hysteresis loop over the temperature range from 230 to 305 K. The high-temperature phase is par...
W. Fujita, K. Awaga
Journal of Solid State Chemistry   159 451-454   Jan 2001
Magnetic bistability is attracting much interest as a useful function of molecule-based magnetic materials. We report room-temperature magnetic bistability in the crystal of an organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (abbreviated as ...
Tomoyuki Akutagawa, Tomoyuki Akutagawa, Tomoyuki Akutagawa, Nobuhiro Takamatsu, Kozo Shitagami, Tatsuo Hasegawa, Tatsuo Hasegawa, Takayoshi Nakamura, Takayoshi Nakamura, Takayoshi Nakamura, Tamotsu Inabe, Wataru Fujita, Kunio Awaga, Kunio Awaga
Journal of Materials Chemistry   11 2118-2124   Jan 2001
Calcium ion (Ca2+) and crown ethers, 12-crown-4, 15-crown-5, 1-aza-18-crown-6 (A18-crown-6) and 1,10-diaza-18-crown-6 (DA18-crown-6), were assembled into divalent supramolecular cation (SC2+) structures in the monovalent [Ni(dmit)2]- salts (dmit2-...
Neil Robertson, Simon Parsons, Kunio Awaga, Wataru Fujita
CrystEngComm   2 121-124   Dec 2000
Slow interdiffusion of acetonitrile solutions of [TBA][Ni(bdt)2] (bdt = 1,2-denzenedithiol) and [MPYNN][I] (MPYNN = 4,4,5,5-tetramethyl-2-(1- methyl-4-pyridinio)-3-oxide-4,5-dihydro-1H-1-imidazolyloxyl) resulted in two sets of crystals suitable fo...
Wataru Fujita, Yusuke Torigoe, Kunio Awaga, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   345    Dec 2000
A large first order magnetic phase transition in an organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl is described, that occurs with a wide thermal hysteresis loop over the temperature range from 230 to 305 K. The high-temperature phase is par...
Wataru Fujita, Kunio Awaga, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   341 389-393   Dec 2000
The effects of high pressure up to 1 GPa were investigated on a layered copper hydroxides, Cu 2(OH) 3(n-C 7H 15CO 2), which exhibits weak ferromagnetism of T N = 22 K at the ambient pressure. With an increase in pressure, the magnetization gradual...
Nobuhiro Takamatsu, Tomoyuki Akutagawa, Tomoyuki Akutagawa, Tomoyuki Akutagawa, Tatsuo Hasegawa, Tatsuo Hasegawa, Takayoshi Nakamura, Takayoshi Nakamura, Tamotsu Inabe, Wataru Fujita, Kunio Awaga, Kunio Awaga
Inorganic Chemistry   39 870-871   Mar 2000
Mixed-stack structures of monovalent [Ni(dmit)2]- and planar M+(4,13-diaza-18-crown-6) (M+ = K+ or Rb+) supramolecular cation were obtained in the isostructural M+(4,13-diaza-18-crown-6)[Ni(dmit)2] salts. The mixed-stack structure decreases the ef...
Mihai A. Gîrţu, Mihai A. Gîrţu, Charles M. Wynn, Charles M. Wynn, Wataru Fujita, Kunio Awaga, Arthur J. Epstein
Physical Review B - Condensed Matter and Materials Physics   61 4117-4130   Feb 2000
We report results of extensive magnetic studies of three triangular quantum Heisenberg antiferromagnets (TQHAF's) with weak additional Dzyaloshinskii-Moriya interaction, Cu2(OH)3(CmH2m+1COO), m = 7, 9, and 11. Fits of the dc susceptibility data to...
Nobuhiro Takamatsu, Tomoyuki Akutagawa, Tomoyuki Akutagawa, Tatsuo Hasegawa, Tatsuo Hasegawa, Takayoshi Nakamura, Tamotsu Inabe, Wataru Fujita, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   343    Jan 2000
Supramolecular cations (SC+) of K+, Rb+, or NH4+(crown ether) were incorporated into the monovalent [Ni(dmit)2]- salts. The K+ and Rb+(DA18-crown-6) units had a planar disk-shaped SC+ structure, while the [NH4+(150-crown-5)2]2 was the barrel type ...
Wataru Fujita, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   334 597-604   Dec 1999
A reversible structural transformation of the basic copper hydroxides Cu2(OH)3[8-((p-(phenylazo)phenyl)oxy)octanoate] occurs as a result of soaking in hot methanol and acetonitrile. X-ray diffraction patterns indicate that the organic layer in the...
Mihai A. Gîrtu, Charles M. Wynn, Wataru Fujita, Kunio Awaga, Arthur J. Epstein, Arthur J. Epstein
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   334 703-712   Dec 1999
We report magnetic studies of a family of triangular quantum Heisenberg antiferromagnets (TQHAFs) with weak additional Dzyaloshinskii-Moriya interaction. CU2(OH)3(CmH2m+1COO), m = 7, 9 and 11. The three compounds have nearly identical magnetic pro...
Wataru Fujita, Kunio Awaga, Kunio Awaga
Science   286 261-262   Oct 1999
A large first-order magnetic phase transition in an organic radical 1,3,5-trithia-2,4,6-triazapentalenyl, is described. The transition occurs with a wide thermal hysteresis loop over the temperature range 230 to 305 kelvin. The high-temperature ph...
Wataru Fujita, Kunio Awaga, Kunio Awaga, Toshihiko Yokoyama
Applied Clay Science   15 281-303   Sep 1999
Physical and chemical properties of organic/inorganic hybrid nanocomposites are attractive, because they are potential materials yielding new functionality, such as a cooperative phenomenon, multi-functional property and so on. Layered copper hydr...
M. A. Gîrţu, C. M. Wynn, W. Fujita, K. Awaga, A. J. Epstein, A. J. Epstein
Journal of Applied Physics   83 7378-7380   Dec 1998
We report magnetic properties of a new class of hybrid organic/inorganic layered materials, Cu2(OH)3(CmH 2m+1COO), m=7, 9, and 11. The frequency dependence of the linear ac susceptibility and the irreversibility in the field-cooled/zero-field-cool...
Wataru Fujita, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   314 331-336   Dec 1998
The copper hydroxy layered hybrids, Cu2(OH)3X, where X = p-(phenylazo)-benzoate 1 and X = 8-((p-(phenylazo)phenyl)oxy)octanoate 2, were prepared. The material 1 is paramagnetic with an antiferromagnetic interaction above 3 K, while 2 becomes a wea...
Kunio Awaga, Taketoshi Sekine, Masaki Okawa, Wataru Fujita, Stephen M. Holmes, Gregory S. Girolami
Chemical Physics Letters   293 352-356   Sep 1998
The effects of high pressure, up to 1 GPa, on a Mn-based Prussian blue ferrimagnet, Mn3II[MnIII(CN)6] 2·12H2O·1.7(CH3OH) with TN=29 K, were studied. The transition temperature gradually increases with an increase in pressure and becomes ~40 K at 1...
M. A. Gîrţu, C. M. Wynn, W. Fujita, K. Awaga, A. J. Epstein, A. J. Epstein
Physical Review B - Condensed Matter and Materials Physics   57    May 1998
We present magnetic studies of three triangular quantum Heisenberg antifer romagnets (TQHAF's) with weak additional Dzyaloshinskii-Moriya interaction, Cu2(OH)3(CmH2m + 1COO), m = 7, 9, and 11. Fits of the dc susceptibility data to high-temperature...
Wataru Fujita, Kunio Awaga
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   314    May 1998
The copper hydroxy layered hybrids, Cu2(OH)3X, where X = p-(phenylazo)-benzoate 1 and X = 8-((phenylazo)phenyl)oxy)octanoate 2, were prepared. The material 1 is paramagnetic with an antiferromagnetic interaction above 3 K, while 2 becomes a weak f...
Takeshi Origuchi, Wataru Fujita, Akira Yamaguchi, Tsunehisa Okuno, Kunio Awaga, Hideo Yano, Nobuo Wada
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   296 281-292   Dec 1997
The complex p-NPNN·Cu(hfac)2 (p-NPNN =p-nitrophenyl nitronylnitroxide and hfac=hexafluoroacetylacetonate) crystallizes into the triclinic P1̄ space group [a=12.515(3) Å, b=12.540(2) Å, c=11.610(3) Å, α=106.18(2)°, β=119.15(2)°, γ=91.14(2)°, V=1501...
Wataru Fujita, Kunio Awaga, Toshihiko Yokoyama
Inorganic Chemistry   36 196-199   Dec 1997
The local structures of the two-dimensional organic/inorganic hybrid nanocomposites. Cu2(OH)3(n-CmH2m+1-COO) (m = 0, 1, 7, 8, 9), have been investigated, together with Cu2(OH)3NO3, by means of Cu K-edge EXAFS spectroscopy at 20 K. The axial and eq...
W. Fujita, K. Awaga
Journal of the American Chemical Society   119 4563-4564   Jan 1997
Kunio Awaga, Wataru Fujita, Taketoshi Sekine, Tsunehisa Okuno
Molecular Crystals and Liquid Crystals Science and Technology Section A: Molecular Crystals and Liquid Crystals   285-286 1-8   Dec 1996
(i) The magnetic properties of the series of a layered material, Cu2(OH)3(n-CmH2m+1COO), are found to show an anomalous change, depending on the alkyl-chain length: the m=0 and 1 materials are metamagnetic while the m=7-9 materials become weak fer...
Wataru Fujita, Kunio Awaga
Inorganic Chemistry   35 1915-1917   Dec 1996
Magnetic properties of the layered materials Cu2(OH)3(n-CmH2m+1COO) (m = 0, 1,7, 8, and 9) have been examined. X-ray powder diffraction patterns indicate that the interlayer distance increases in the order of m. The interlayer distances of the m =...

Conference Activities & Talks

 
Fujita Wataru, Kikuchi Koichi
Meeting abstracts of the Physical Society of Japan   25 Aug 2008