研究者詳細 - 木村　憲喜

論文 - 木村　憲喜

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13C NMR spectra, 1H NMR relaxation and ESR measurements of Br2 doped {[Pt(en)2] [PtBr2(en)2]3(CuBr4)4 center dot 12H2O

N Kimura, H Aso, K Takizawa, T Ishii, H Miyasaka, K Sugiura, M Yamashita, R Ikeda (担当区分：筆頭著者,　責任著者 )

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 135 ( 1-3 ) 271 - 272 2003年04月 [査読有り]

We measured NMR and ESR in solid state of a Br2 doped halogen-bridged one-dimensional mixed-valence complex, {[Pt(en)2][PtBr2(en)2]}3(CuBr4)4.12H2O, which forms a double chain structure consisting of -Pt(II)-Br-Pt(IV)-Br- and -Cu(I)-Br-Cu(I)-Br-. 13C NMR measurements gave broad spectra explainable by marked effects from paramagnetic sites assignable to Pt(III) and/ or Cu(II) in the chain oxidized by bromine. Pt(III) sites are considered to form neutral solitons by referring to the electrical conductivity result.

DOI

Molecular motions in halogen-bridged one-dimensional Pt complexes, [PtII(en)2][PtIVX2(en)2](ClO4)4 (X = Cl, Br) studied by 2H and 1H NMR

N Kimura, T Hachisuka, Y Nakano, R Ikeda (担当区分：筆頭著者,　責任著者 )

ZEITSCHRIFT FUR NATURFORSCHUNG SECTION A-A JOURNAL OF PHYSICAL SCIENCES ( VERLAG Z NATURFORSCH ) 57 ( 6-7 ) 413 - 418 2002年06月 [査読有り]

2H and 1H NMR measurements were performed on crystalline [Pt(en)2][PtX2(en)2](ClO4)4 (X= Cl, Br), where the protonated and partially deuterated ethylenediamines (en's), NH2(CH2)2NH2, NH2(CD2)2NH2 and ND2(CH2)2ND2 were used as ligands. Measurements of 2H and 1H NMR spin-lattice relaxation times showed the presence of motions of en chelate rings at the temperatures near the phase transitions, whereas broad 2H NMR spectra and the reported X-ray diffraction data showed no marked motions. These results were consistently explained by introducing the en puckering motion between highly asymmetric potential wells with an energy difference of 10 - 13 kJ mol-1. This difference was shown to be much larger than 2 - 5 kJ mol-1, reported for the iodo-complex, [Pt(en)2][PtI2(en)2](ClO4)4.

Intrinsic localized vibrational modes in a highly nonlinear halogen-bridged metal

K Kisoda, N Kimura, H Harima, K Takenouchi, M Nakajima

JOURNAL OF LUMINESCENCE ( ELSEVIER SCIENCE BV ) 94 743 - 746 2001年12月 [査読有り]

Intrinsic localized vibrational modes in a halogen-bridged Pt complex were studied by Raman spectroscopy. We compared the peak frequency of the overtone of Pt-Cl stretch vibration between that excited by an Ar+ and that by a near infrared (NIR) lasers. The decrease in the overtone peak frequency of the NIR excitation were larger than that of the visible excitation. We interpreted that the charge transfer led to weaken the bond strength and that the anharmonicity of the system became weak. (C) 2001 Elsevier Science B.V. All rights reserved.

An unusual six-co-ordinate platinum(II) complex containing a neutral I2 ligand

R Makiura, Nagasawa, I, N Kimura, S Ishimaru, H Kitagawa, R Ikeda

CHEMICAL COMMUNICATIONS ( ROYAL SOC CHEMISTRY ) ( 17 ) 1642 - 1643 2001年09月 [査読有り]

Valence structure and magnetic interaction in MMX-type 1D complexes, A4[Pt2I(P2O5H2)4]center dot nH2O, studied by 31P solid NMR

N Kimura, S Ishimaru, T Kawashima, S Miya, T Manabe, M Yamashita, R Ikeda (担当区分：筆頭著者,　責任著者 )

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 120 ( 1-3 ) 779 - 780 2001年03月 [査読有り]

31P MAS-NMR spectra and spin-lattice relaxation time T1 in solid were measured on A4[Pt2I(P2O5H2)4]. nH2O (A: Cs, Rb, K, Na and Li). Continuous spectrum changes in both line and splitting widths were observed with changing the cation size and the number of crystalline water. Complexes with A: Cs (n=0) and Rb (n=2) afforded two kinds of 31P resonance lines with chemical shifts close to those in the Pt3+ and Pt2+ monomer complexes indicating a mixed valence structure. On the other hand, complexes with A: Na (n=2) and Li (n=4) yielded a broad single line suggesting the formation of paramagnetic Pt sites with an averaged valence of Pt2.5+. An analogous continuous change was observed in 31P T1 in consistent with the above analysis. The observed spectra and T1 depending on the cation size and the H2O number suggest valence fluctuation due to spin jumps in and between Pt-Pt units sensitively influenced by crystal packings and hydrogen bonding.

Metal valence structures in 1-D mixed-metal complexes [Ni1-xPdxX(chxn)2]X2 studied by solid NMR

N Kimura, M Kano, T Manabe, M Yamashita, R Ikeda (担当区分：筆頭著者 )

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 120 ( 1-3 ) 777 - 778 2001年03月 [査読有り]

13C magic-angle-spinning NMR spectra in solid were measured in mixed-metal 1-D complexes [Ni1-xPdxX(chxn)2]X2 (X: Cl, Br; 0.0 less than or equal tox less than or equal to1.0) where the antiferromagnetically coupled paramagnetic -X-Ni3+-X-Ni3+- chains are formed at x=0.0, while the mixed-valence -X-Pd2+-X-Pd4+- state is made at x=1.0. Upon increasing x from 0.0, 13C spectra in the C-alpha position in the chxn ligand was broadened and shifted from original Pd2+ and Pd4+ positions indicating the fluctuation of Pd valency in mixed states. A marked spectrum broadening observed in C-beta is also attributable to the effect from the partial mixing of paramagnetic Pd3+ sites in consistent with reported ESR results.

Molecular motions and phase transitions in halogen-bridged one-dimensional complexes [Pt(en)2][PtX2(en)2](ClO4)4 (X : I, Br)

N Kimura, T Hachisuka, Y Nakano, R Ikeda (担当区分：筆頭著者,　責任著者 )

PHYSICAL CHEMISTRY CHEMICAL PHYSICS ( ROYAL SOC CHEMISTRY ) 3 ( 9 ) 1778 - 1781 2001年 [査読有り]

1H and 2H NMR and thermal measurements were performed on crystalline [Pt(en)2][PtI2(en)2](ClO4)4 in which protonated and partially deuterated ethylenediamines H2N(CH2)2NH2, D2N(CH2)2ND2 and H2N(CD2)2NH2 were used as the ligand "en''. A metastable crystalline phase of [Pt(en)(2)][PtBr2(en)2](ClO4)4 with conformational disorder of the en chelate rings was shown to have a different phase transition at ca. 380 K to the stable crystalline form of the ordered structure. NMR spectra and relaxation times showed that the distribution of the en conformation is not static but dynamic in both I and Br complexes where a puckering motion of en chelate rings was shown to take place between asymmetric potential wells.

Electron spin carriers in halogen-bridged 1-D complexes with non-degenerate CDW ground state

N Kimura, H Suzuki, T Kawashima, T Manabe, M Yamashita, R Ikeda (担当区分：筆頭著者 )

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 103 ( 1-3 ) 2604 - 2605 1999年06月 [査読有り]

We measured temperature dependences of ESR spectra and 1H NMR spin-lattice relaxation time T1 on recently prepared mixed-valence hetero-metal complexes [Pd(en)2][PtX2(en)2](ClO4)4 (en: ethylenediamine; X: Cl, Br) which consist of a 1-D structure of -X-Pd-II-X-Pt-II-X-Pd-II-X-Pt-IV-X- chain giving a non-degenerated electronic ground state. The observed low-concentration of paramagnetic MIII sites and also long 1H NMR T1 compared with those in home-metal complexes [MII(en)2][(MIVX2(en)2](ClO4)4 ( M: Pt, Pd; X: Cl, Br) having the degenerated ground state, can be explained well by the hindrance of the formation of domain-wall type spin solitons in the hetero-metal complexes. This result supports our previous conclusion of the neutral soliton formation in the home-metal halogen-bridged complexes.

Spin solitons in halogen-bridged one-dimensional mixed-valence complexes, [MII(en)2][(MIVBr2(en)2](ClO4)4 (M : Pt, Pd) studied by 1H NMR and EPR

N Kimura, S Ishimaru, R Ikeda, M Yamashita (担当区分：筆頭著者 )

JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS ( ROYAL SOC CHEMISTRY ) 94 ( 24 ) 3659 - 3663 1998年12月 [査読有り]

Temperature and Larmor frequency dependences of 1H NMR spin-lattice relaxation time (T1) in 1-D mixed-valence complexes [M(en)(2)][MBr2(en)2](ClO4)4 (M: Pt, Pd; en: ethylenediamine) were observed in the ranges 90-330 K and 15-60 MHz. EPR spectra observed for the Pd complex showed the presence of paramagnetic Pd-III sites of a temperature independent concentration of 10(-4) per Pd site, and a motional narrowing upon heating attributable to thermally activated motions of these sites. The NMR T1 data giving an omega(1/2) frequency dependence in the range 100-150 K were successfully analysed by applying the Devreux's treatment of rapidly 1-D diffusing electron spins. Comparing the present results with the electrical conductivity data, the diffusing paramagnetic spins could be explained by kink-type neutral solitons analogous to the spin soliton model reported for trans-polyacetylene. Diffusion rates of 10(12)-10(13) and 10(13)-10(14) rad s(-1) were estimated in Pt and Pd complexes, respectively, below ca. 150 K. This diffusion in the present 1-D structure complexes was shown to be much easier than that in [Pd(chxn)2][PdBr2(chxn)2]Br4 (chxn: 1R,2R-cyclohexanediamine) with 2-D hydrogen bond networks.

Spin solitons in a halogen-bridged 1-D Pt complex

N Kimura, S Ishimaru, H Okamoto, M Yamashita, R Ikeda (担当区分：筆頭著者 )

SYNTHETIC METALS ( ELSEVIER SCIENCE SA LAUSANNE ) 86 ( 1-3 ) 2151 - 2152 1997年02月 [査読有り]

Temperature and Larmor frequency dependences of 1H NMR relaxation time T1 were measured in a 1-D halogen-bridged complex [Pt(en)2][PtX2(en)2](ClO4)4 in ranges of 90-300 K and 15-60 MHz, respectively. The observed main and long T1 component was explainable by the magnetic dipolar relaxation due to electron spins diffusing along the 1-D chain containing paramagnetic Pt-III sites with a concentration of 10(-4) in molar ratio. These spins attributed to neutral spin solitons were shown to diffuse more rapidly than those in [Pd(chxn)2][PdBr2(chxn)2]Br4 forming 2-D H-bond networks.

Solid state 1H NMR in one dimensional neutral complex: [PtCl2(en)][PtCl4(en)]

Ashutosh Ghosh, Noriyoshi Kimura, Shin'ichi Ishimaru, Ryuichi Ikeda, Akiko Takano, Norimichi Kojima

SOLID STATE COMMUNICATIONS ( Elsevier Ltd ) 104 ( 8 ) 469 - 472 1997年 [査読有り]

The 1H NMR spin-lattice relaxation time T1 of [PtCl2(en)][PtCl4(en)] (en = ethylenediamine) has been measured from 110 to 330 K at Larmor frequencies 25.1 and 54.0 MHz. A BPP-type frequency dependency of T1 due to magnetic dipolar interactions was observed above ca. 200 K and could be attributed to the puckering motion of the ethylenediamine chelate rings. The DTA and X-ray powder diffraction measurements showed that onset of this puckering motion is associated with a second or higher order phase transition located at ca. 210 K. The nonexponential recovery of 1H magnetization observed in the low-temperature range was well explained by almost fixed paramagnetic Pt(III) sites of a low concentration formed along the 1-D chain. © 1997 Published by Elsevier Science Ltd.

DOI

Electron-spin dynamics in the new halogen-bridged one-dimensional complex, NI2(CH3CS2)4I studied by 1H NMR

R Ikeda, N Kimura, H Ohki, T Furuta, M Yamashita

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 71 ( 1-3 ) 1907 - 1908 1995年04月 [査読有り]

We measured temperature and Larmor frequency(omega) dependences of the 1H NMR spin-lattice relaxation time T1 in solid Ni2(CH3CS2)4I which contains the one-dimensional(1-D) chain of -Ni-Ni-I-Ni-Ni-I- with no Peierls distortion. Almost temperature independent T1 values of ca. 180 ms observed at omega = 40.98 MHz and in the range of 90-300 K are attributable to the relaxation due to the fluctuation of antiferromagnetically coupled unpaired electron spin formed at each -X-Ni-Ni- unit in consistent with the 1-D Mott-Hubbard type structure. T1 in this temperature range showed the Larmor frequency dependence of omega(1/2) explainable by rapid spin diffusion along the 1-D chain. Applying the Devreux's treatment on the low-dimensional spin dynamics, the diffusion rate and activation energy for the 1-D hopping of electron spins were evaluated.

Structural control of quasi-one-dimensional halogen-bridged nickel-complexes

K Inoue, M Yamashita, T Furuta, A Ichikawa, T Ohishi, H Okamoto, N Kimura, H Ohki, R Ikeda, S Bandow, K Toriumi, T Mitani, H Kitagawa, H Miyamae

SYNTHETIC METALS ( ELSEVIER SCIENCE SA ) 71 ( 1-3 ) 1913 - 1914 1995年04月 [査読有り]

Valence structure of one-dimensional halogen bridged-Pt-Pt-X-Pt-Pt-X-type complexes studied by 31P solid NMR

N Kimura, H Ohki, R Ikeda, M Yamashita (担当区分：筆頭著者 )

CHEMICAL PHYSICS LETTERS ( ELSEVIER SCIENCE BV ) 220 ( 1-2 ) 40 - 45 1994年03月 [査読有り]

31P MAS NMR spectra in the solid state were measured on halogen-bridged one-dimensional complexes (NH4)4[Pt2X(pop)4] (pop: P2O3H-2-; X: Cl, Br, I) together with the corresponding binuclear Pt(II) and Pt(III) monomer complexes containing [Pt2(pop)4]4- and [Pt2X2(pop)4]4- (X: Cl, Br, I) ions, respectively. The polymer complexes afforded two kinds of P-31 resonance lines with chemical shifts of 20-40 and 50-70 ppm, values which are close to those in the monomer Pt(II) and Pt(III) complexes, respectively. From the analysis of spectra and spin-lattice relaxation data, a mixed-valence - Pt(II)-Pt(II)-X-Pt(III)-Pt(III)-X-type chain structure was concluded for the polymer complexes.

Control of charge instabilities in quasi-one-dimensional halogen-bridged nickel compounds

M Yamashita, K Inoue, T Furuta, A Ichikawa, H Okamoto, N Kimura, H Ohki, R Ikeda, H Kitagawa, S Bandow, K Toriumi, T Mitani, T Ohishi, H Miyamae

MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY SECTION A-MOLECULAR CRYSTALS AND LIQUID CRYSTALS ( GORDON BREACH SCI PUBL LTD ) 256 179 - 186 1994年 [査読有り]

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