Faculty Profiles - SUZUKI Takayoshi

Papers - SUZUKI Takayoshi

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鉄(VI)の八面体型錯体！

鈴木孝義

化学 62 ( 1 ) 61 - 62 2007

Sulfur-bonded 2-methylthiopyridine (2-MeSpy) complex of iridium(III). Crystal structure of [Cp*IrI2-(2-MeSpy-kappa S)] (Cp* = eta(5)-C5Me5)

Yusuke Sekioka, Takayoshi Suzuki

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 79 ( 12 ) 1897 - 1899 2006.12

Language：English Publishing type：Research paper (scientific journal) Publisher：CHEMICAL SOC JAPAN

A reaction of [Cp*lr(2-Spy)(N-3)] (Cp* = pentarnethylcyclopentadienyl; 2-Spy = 2-pyridinethiolate) with two equivalents of methyl iodide afforded the diiodo complex bearing 2-MeSpy, [Cp*lrl(2)(2-MeSpy)] (3). From X-ray crystallography and IR spectroscopy, the S atom of 2-MeSpy is coordinated to the metal ion in the solid state. In CD2Cl2, complex 3 exhibited a dissociation equilibrium of 2-MeSpy similar to the corresponding thioanisole complex of [Cp*lrl(2)(MeSPh)].

DOI： 10.1246/bcsj.79.1897

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cis-Bis[(3-aminopropyl)dimethyl-phosphine-kappa N-2,P]palladium(II) dichloride methanol solvate

Takayoshi Suzuki, Atsushi Hasegawa, Hiroshi Yamaguchi, Kazuo Kashiwabara, Hideo D. Takagi

ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 62 M461 - M463 2006.10

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

In the title compound, cis-[Pd(C5H14NP)(2)]Cl-2.CH4O, the coordination geometry around the Pd-II center is distorted square planar, with a cis-P2N2 configuration of the two chelating (3-amino-prop-yl)dimethyl-phosphine (pdmp) ligands. The six-membered pdmp chelate rings adopt chair conformations, and pairing of the chairs designates the complex cation as a (C-s)-chair(2) conformer. The distances between the Pd-II center and the Cl- anions are greater than 4.5 angstrom, indicating no obvious inter-action.

DOI： 10.1107/S0108270106023596

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(5,16-Dimethyl-2,6,13,17-tetraazatricyclo-[14,4,0(1,18),0(7,12)]docosane-kappa N-4) dinitrato-copper(II) trihydrate

Jong-Ha Choi, Takayoshi Suzuki, Sumio Kaizaki

ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62 M2383 - M2385 2006.9

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

In the title compound, [Cu(NO3)(2)(C20H40N4)] center dot 3H(2)O, the Cu atom lies on a crystallographic inversion centre and has a distorted octahedral geometry, with four N atoms of the macrocyclic ligand in the equatorial positions and two O atoms of the axial nitrate ligands. The long axial Cu-O bond of 2.746 (2) angstrom may result from the Jahn-Teller effect. The macrocyclic ligand adopts the most stable trans-III configuration with the two six-membered rings in chair form and two five-membered rings in a gauche form.

DOI： 10.1007/S1600536806034234

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Novel configurational structures of sodium tetrakis(3-heptafluorobutylryl-(+)-camphorato) Ln(III) complexes with a trapped Na+ by Na+center dot center dot center dot FC interactions in the solid state and in solution

Dai Shirotani, Takayoshi Suzuki, Sumio Kaizaki

INORGANIC CHEMISTRY 45 ( 16 ) 6111 - 6113 2006.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

For newly prepared sodium tetrakis( 3-heptafluorobutylryl-( +)-camphorato) Ln( III) complexes, the X-ray crystal analysis revealed an unprecedented pseudo-achiral dodecahedron ( DD-8 ( D-2d)), whereas in CHCl3 solution, the exciton CD and F-19 NMR spectra showed a novel chiral Delta-SAPR-8 ( C-4) configuration which is stereospecifically formed by a trapped Na+ ion with Na+center dot center dot center dot FC ( fluorocarbon) interactions.

DOI： 10.1021/ic0606633

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trans-Bis(O-ethylxanthato)bis(triphenylphosphine)ruthenium(III) hexafluorophosphate monohydrate

Y Ohuchi, K Noda, T Suzuki, K Kashiwabara, HD Takagi

ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62 M1077 - M1078 2006.5

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL PUBLISHING

In the monoclinic crystal structure of the title compound, trans-[ Ru( C3H5OS2)(2)( C18H15P)(2)] PF6 center dot H2O, the structure of the Ru-III complex cation is very similar to that in the orthorhombic crystal of the nonhydrated complex [ Noda, Ohuchi, Hashimoto, Fujiki, Itoh, Iwatsuki, Noda, Suzuki, Kashiwabara & Takagi ( 2006), Inorg. Chem. 45, 1349 - 1355]. In the present crystal structure, the P-Ru-P bond axes of the complex cations are aligned parallel to the [ 101] direction.

DOI： 10.1107/S1600536806013420

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Monodentate, didentate chelating, and bridging 1,8-naphthyridine complexes of pentamethylcyclopentadienyliridium(III): Syntheses and structures in the solid states and in solution

T Suzuki

INORGANICA CHIMICA ACTA 359 ( 8 ) 2431 - 2438 2006.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

A series of new iridium(III) complexes containing pentamethylcyclopentadienyl (Cp* = eta(5)-C5Me5) and 1,8-naphthyridine (napy) have been prepared. X-ray crystallography revealed that napy acted as a monodentate, a didentate chelating, and a bridging ligand in complexes of [Cp*IrCl2(napy)] (1), [Cp*IrCl(napy)]PF6 (2), and [(Cp*IrC])(2)(H)(napy)]PF6 (4), respectively. The crystal structure of [Cp*Ir(napy)(2)]-(PF6)(2) (3) has also been determined; the dicationic complex bore both monodentate and chelating napy ligands. Dinuclear Cp*Ir-III complex bridged by napy was only isolable if two Ir-III centers were supported by a hydride (H-) bridge. In complexes 2 and 3, the four-membered chelate rings formed by napy exhibited a large steric strain; in the rings the N-Ir-N bond angles were only 60.5(2)-61.0(4)degrees and the Ir-N-C angles were 94.7(8)-96.7(8)degrees. The bridging coordination of napy in complex 4 also afforded a large strain, i.e., the Ir-III centers were displaced by 0.84(3) angstrom from the napy plane, due to the steric interaction between two Cp*IrCl moieties. The monodentate napy complex I in CDCl3 or CD2Cl2 at ambient temperature showed a rapid coordination-site exchange reaction, which gave two N sites of napy equivalent; at temperatures below -40 degrees C, the H-1 NMR spectra corresponded to the molecular structure of [Cp*IrCl2(napy-KN)]. The analogous diazido complex of [Cp*Ir(N-3)(2)(napy)] (5) has also been prepared, and the crystal structure has been determined. In contrast to the dichloro complex 1, the diazido complex 5 exhibited a dissociation equilibrium of coordinated napy in solution. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ica.2006.02.033

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Syntheses, structural determinations of [Ru(ROCS2)(2)(PPh3)(2)](+/0) pairs, and kinetic analyses of thermal reactions involving transient trans-[Ru(PrOCS2)(2)(PPh3)(2)] species (ROCS2- = ethyl- or isopropylldithiocarbonate and PPh3 = triphenylphosphine)

K Noda, Y Ohuchi, A Hashimoto, M Fujiki, S Itoh, S Iwatsuki, T Noda, T Suzuki, K Kashiwabara, HD Takagi

INORGANIC CHEMISTRY 45 ( 3 ) 1349 - 1355 2006.2

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Controlled-potential electrochemical oxidation of cis-[Ru(ROCS2)(2)(PPh3)(2)] (R = Et, Pr-i) yielded corresponding Ru(III) complexes, and the crystal structures of cis-[Ru(ROCS2)(2)(PPh3)(2)] and trans-[Ru(ROCS2)(2)(PPh3)(2)](PF6) were determined. Both pairs of complexes exhibited almost identical coordination structures. The Ru-P distances in trans-[Ru-III(ROCS2)(2)(PPh3)(2)](PF6) [2.436(3)-2.443(3) angstrom] were significantly longer than those in cis-[Ru-II(ROCS2)(2)(PPh3)(2)] [2.306(1)-2.315(2) angstrom]: the smaller ionic radius of Ru(III) than that of Ru(II) stabilizes the trans conformation for the Ru(III) complex due to the steric requirement of bulky phosphine ligands while mutual trans influence by the phosphine ligands induces significant elongation of the Ru-III-P bonds. Cyclic voltammograms of the cis-[Ru(ROCS2)(2)(PPh3)(2)] and trans-[Ru(ROCS2)(2)(PPh3)(2)](+) Complexes in dichloromethane solution exhibited typical dual redox signals corresponding to the cis-[Ru(ROCS2)(2)(PPh3)(2)](+/0) (ca. +0.15 and +0.10 V vs ferrocenium/ferrocene couple for R = Et and Pr-i, respectively) and to trans-[Ru(ROCS2)(2)(PPh3)(2)](+/0) (-0.05 and -0.15 V vs ferrocenium/ferrocene for R = Et and Pr-i, respectively) couples. Analyses on the basis of the Nicholson and Shain's method revealed that the thermal disappearance rate of transient trans-[Ru(ROCS2)(2)(PPh3)(2)] was dependent on the concentration of PPh3 in the bulk: the rate constant for the intramolecular isomerization reaction of trans-[Ru((PrOCS2)-Pr-i)(2)(PPh3)(2)] was determined as 0.338 +/- 0.004 s(-1) at 298.3 K (Delta H* = 41.8 +/- 1.5 kJ mol(-1) and Delta S* = -114 +/- J mol(-1) K-1), while the dissociation rate constant of coordinated PPh3 from the trans-[Ru((PrOCS2)-Pr-i)(2)(PPh3)(2)] species was estimated as 0.113 +/- 0.008 s(-1) at 298.3 K (Delta H* = 97.6 +/- 0.8 kJ mol(-1) and Delta S* = 64 +/- 3 J mol(-1) K-1), by monitoring the EC reaction (electrode reaction followed by chemical processes) at different concentrations of PPh3 in the bulk. It was found that the trans to cis isomerization reaction takes place via the partial dissociation of (PrOCS2-)-Pr-i from Ru(II), contrary to the previous claim that it takes place by the twist mechanism.

DOI： 10.1021/ic0514871

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Synthesis, structure and magnetic properties of pyrazolate-bridged dinuclear complexes [{M(NCS)(4-Phpy)}(2)(mu-bpypz)(2)](M=Co2+ and Fe2+)

K Yoneda, K Nakano, J Fujioka, K Yamada, T Suzuki, A Fuyuhiro, S Kawata, S Kaizaki

POLYHEDRON 24 ( 16-17 ) 2437 - 2442 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

The synthesis and magnetic characterization of pyrazolato-bridged dinuclear complexes [{M(NCS)(4-Phpy)}(2)(mu-bpypz)(2)] (Hbpypz=3,5-bis(2-pyridyl)-pyrazole; 4-Phpy=4-phenylpyridine; M=CO2+ (1) and Fe2+ (2)) are described together with the X-ray crystal analysis of the cobalt complex. The structure of 1 shows that the desired coordination has been achieved with the cobalt atoms being coordinated to two bpypz to form the dimer. The X-ray diffraction patterns show 1 and 2 to be isomorphous at room temperature. 2 displays it single spin-crossover transition between the [HS-HS] and [LS-LS] states with T-c = 150 K. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.poly.2005.03.047

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Structure and reactivity of a pyridine-1-imido-2-thiolato complex of iridium(III), Cp*Ir(1-N-2-Spy), generated by photolysis of the (azido)(pyridine-2-thiolato) complex, Cp*Ir(2-Spy)(N-3)

Y Sekioka, S Kaizaki, JM Mayer, T Suzuki

INORGANIC CHEMISTRY 44 ( 23 ) 8173 - 8175 2005.11

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Photolysis of the (azido)(pyrdine-2-thiolato)iridium(III) complex Cp*lr(2-Spy)(N-3) (1) gave a pyridine-1-imido-2-thiolato complex, Cp*lr(1-N-2-Spy) (2), in which one of the nitrogen atoms of the azide ligand has been inserted into the lr-N(py) bond (Cp* = eta(5)-C5Me5). Complex 2 reacted quantitatively with methyl iodide to give the N-methylated product, [Cp*lr(1-NMe-2-Spy)]l (3). X-ray crystallography revealed that both 2 and 3 have similar two-legged piano stool structures with planar 1-N-2-Spy(2-) or 1-NMe-2(-)Spyligands, which form iridacyclopentadienyl-like rings by moderate S(p pi)/N(p pi) to lr(d pi) pi donation.

DOI： 10.1021/ic051097z

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Preparation, crystal structures and spectroscopic properties of novel [(MCl3-n)-Cl-III (P)3(+n)]n(+) (M = Co, Rh; n=0, 1, 2 or 3) series of complexes containing tripodal tridentate phosphine, 1,1,1-tris(dimethylphosphinomethyl)ethane

T Suzuki, T Tsukuda, M Kiki, S Kaizaki, K Isobe, HD Takagi, K Kashiwabara

INORGANICA CHIMICA ACTA 358 ( 8 ) 2501 - 2512 2005.5

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

Cobalt(III) and rhodium(III) complexes of the series of [(MCl3)-Cl-III - (P)(3) + n](n+) (M = Co or Rh; n = 0, 1, 2 or 3) have been prepared with the use of 1,1,1-tris(dimethylphosphinomethyl)ethane (tdmme) and mono- or didentate phosphines. The single-crystal X-ray analyses of both series of complexes revealed that the M-P and M-Cl bond lengths were dependent primarily on the strong trans influence of the phosphines, and secondarily on the steric congestion around the metal center resulting from the coordination of several phosphine groups. In fact, the M-P(tdmme) bonds became longer in the order Of [MCl3(tdmme)] < [MCl2(tdmme)(PMe3)](+) < [MCI(tdmme)(dmpe)](2+) (dmpe = 1,2-bis(dimethylphosphino)ethane) < [M(tdmme)(2)](3+) for both Co-III and Rh-III series of complexes, while the M-CI bond lengths were shortened in this order (except for [M(tdmme)(2)](3+)). Such a steric congestion around the metal center can also account for the structural and spectroscopic characteristics of the series of complexes, [MCI(tdmme)(dmpm, dmpe or dmpp)](2+) (dmpm = bis(dimethylphosphino)methane, dmpp = 1,3-bis(dimethylphosphino)propane). The X-ray analysis for [CoCl(tdmme)(dmpm or dmpe)](BF4)(2) showed that all Co-P bonds in the dmpm complex were shorter by 0.03-0.04 angstrom than those in the dmpe complex. Furthermore, the first d-d transition energy of the Co-III complexes and the (1)J(Rh-P(tdmme)) coupling constants observed for the Rh-III complexes indicated an unusual order in the coordination bond strengths of the didentate diphosphines, i.e., dmpm > dmpe > dmpp. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ica.2005.02.008

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Synthesis, structure and magnetic properties of lanthanide(III) complexes with new imidazole-substituted imino nitroxide radical

T Tsukuda, T Suzuki, S Kaizaki

INORGANICA CHIMICA ACTA 358 ( 4 ) 1253 - 1257 2005.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

Synthesis, characterization and magnetic properties of new lanthanide-radical complexes, [Ln(III)(hfac)(3)(IM2imH)] (Ln = Gd, Tb; IM2imH=2-(2-pyridyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy), are described. The molecular structure of the [Tb(hfaC)(3)(IM2imH)] has been determined by the X-ray diffraction. The magnetic susceptibility data for [Gd(hfaC)(3)(IM2imH)] show that the Gd-IM2imH magnetic interaction is antiferromagnetic with an exchange coupling constant J = -2.59 cm(-1) in contrast to the ferromagnetic interaction in most of Gd(III) complexes containing paramagnetic center, which will be examined in connection with planarity of the IM2imH chelate. (c) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ica.2004.11.001

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Azido(2,2 '-bipyridine)(eta(5)-pentamethylcyclopentadienyl)iridium(III) hexafluorophosphate

T Suzuki

ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61 M488 - M490 2005.3

Language：English Publishing type：Research paper (scientific journal) Publisher：BLACKWELL MUNKSGAARD

In the title compound, [Ir(C10H15)(N-3)(C10H8N2)]PF6, the linear azide ligand adopts an end-on terminal coordination mode with a relatively long Ir-N bond of 2.230 (6) Angstrom. The azide is asymmetric in an unusual way: the azide N-N bond adjacent to the azide Ir-N bond [1.025 (12) Angstrom] is significantly shorter than the terminal azide N-N bond [1.282 (15) Angstrom], while the azide Ir-N-N bond angle is 116.4 (6)degrees.

DOI： 10.1107/S1600536805003727

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Syntheses, structural analyses and redox kinetics of four-coordinate [CuL2](2+) and five-coordinate [CuL2(solvent)](2+) complexes (L=6,6 '-dimethyl-2,2 '-bipyridine or 2,9-dimethyl-1,10-phenanthroline): completely gated reduction reaction of [Cu(dmp)(2)](2+) in nitromethane

S Itoh, N Kishikawa, T Suzuki, HD Takagi

DALTON TRANSACTIONS ( 6 ) 1066 - 1078 2005

Language：English Publishing type：Research paper (scientific journal) Publisher：ROYAL SOC CHEMISTRY

[Cu(2,9-dimethyl-1,10-phenanthroline)2](2+) and [Cu(6,6'-dimethyl-2,2'-bipyridine)(2)](2+/+) complexes with no coordinated solvent molecule were synthesized and the crystal structures were analyzed: the coordination geometry around the Cu(I) center was in the D-2d symmetry while a D-2 structure was observed for the four-coordinate Cu(II) complexes. Coordination of a water or an acetonitrile molecule was found in the trigonal plane of the five-coordinate Cu(II) complex in the Tbp (trigonal bipyramidal) structure. Spectrophotometric analyses revealed that the D-2 structure of the Cu(II) complex was retained in nitromethane, although a five-coordinate Tbp species (green in color), was readily formed upon dissolution of the solid (reddish brown) in acetonitrile. The electron self-exchange reaction between D-2d-Cu(I) and D-2-Cu(II), observed by the NMR method, was very rapid with k(ex) = (1.1 +/- 0.2) x 10(5) kg mol(-1) s(-1) at 25degreesC(DeltaH* = 15.6 +/- 1.3 kJ mol(-1) and DeltaS* = 96 +/- 4 J mol(-1) K-1), which was more than 10 times larger than that reported for the self-exchange reaction between D-2d-Cu(I) and Tbp-Cu(II) in acetonitrile. The cross reduction reactions of D-2-Cu(II) by ferrocene and decamethylferrocene in nitromethane exhibited a completely gated behavior, while the oxidation reaction of D-2d-Cu(I) by [Ni(1,4,7-triazacyclononane)(2)](3+) in nitromethane estimated an identically large self-exchange rate constant to that directly obtained by the NMR method. The electron self-exchange rate constant estimated from the oxidation cross reaction in 50% v/v acetonitrile nitromethane mixture was 10 times smaller than that observed in pure nitromethane. On the basis of the Principle of the Least Motion (PLM) and the Symmetry Rules, it was concluded that gated behaviors observed for the reduction reactions of the five-coordinate Cu(II) polypyridine complexes are related to the high-energy C-2v --> D-2d conformational change around Cu(II), and that the electron self-exchange reactions of the Cu(II)/(I) couples are always adiabatic through the C-2v structures for both Cu(II) and Cu(I) since the conformational changes between D-2d, D-2 and C-2v structures for Cu(I) as well as the conformational change between Tbp and C-2v structures for Cu(II) are symmetry-allowed. The completely gated behavior observed for the reduction reactions of D-2-Cu(II) species in nitromethane was attributed to the very slow conformational change from the ground-state D-2 to the entatic D-2d structure that is symmetry-forbidden for d(9) metal complexes: the very slow back reaction, the forbidden conformational change from entatic to the ground-state D-2 structure, ensures that the rate of the reduction reaction is independent of the concentration of the reducing reagent.

DOI： 10.1039/b415057k

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Anomalous diamagnetic behaviour of the H-1 NMR spectra of a coordinated imino nitroxide radical in diamagnetic and paramagnetic lanthanide(III) complexes

Tsukuda, T., Ogita, M., Suzuki, T., Kaizaki, S.

European Journal of Inorganic Chemistry ( 22 ) 2004