Koshiro Toriumi

Bio: Koshiro Toriumi is an academic researcher from University of Hyogo. The author has contributed to research in topics: Crystal structure & Nickel. The author has an hindex of 32, co-authored 150 publications receiving 4370 citations. Previous affiliations of Koshiro Toriumi include Hiroshima University & Kyoto University.

A new model for dioxygen binding in hemocyanin. Synthesis, characterization, and molecular structure of the .mu.-.eta.2:.eta.2 peroxo dinuclear copper(II) complexes, [Cu(HB(3,5-R2pz)3)]2(O2) (R = isopropyl and Ph)

Abstract: The synthesis and characterization of μ-η 2 :η 2 peroxo dinuclear copper(II) complexes which to oxyhemocyanin (or oxytyrosinase) in their physicochemical properties are presented. The low-temperature reaction of a di-μ-hydroxo copper(II) complex [Cu(HB(3,5-i-Pr 2 pz) 3 )] 2 (OH) 2 (8) with H 2 O 2 gave a μ-peroxo complex [Cu(HB(3,5-i-Pr 2 pz) 3 )] 2 (O 2 ) (6)

.mu.-.eta.2:.eta.2-Peroxo binuclear copper complex, [Cu(HB(3,5-(Me2CH)2pz)3)]2(O2)

Abstract: In this communication, we report the crystal structure of the analogous complex [Cu(HB-(3,5-iPr 2 pz) 3 )] 2 (O 2 ) (2), which contains the novel coordination mode of the peroxide ion, μ-η 2 :η 2

Crystal Structures of [VO(sal-L-ala)(OCH3)(CH3OH)] (sal-L-ala=N-salicylidene-L-alaninate) and {[VO(sal-L-ala)]2O}2·2CH2Cl2, and the Catalytic Activity of These and Related Complexes on Asymmetric Oxidation of Methyl Phenyl Sulfide with t-Butyl Hydroperoxide

Abstract: A reddish brown oxovanadium(V) complex, [VVO(sal-L-ala)(OCH3)(CH3OH)] (2a, sal-L-ala=N-salicylidene-L-alaninate) was formed by dissolving [VIVO(sal-L-ala)(H2O)] (1a) in methanol. Treatment of 2a with wet dichloromethane yielded deep blue crystals of {[VVO(sal-L-ala)]2O}2·2CH2Cl2 (3a). The structures of 2a and 3a have been determined by X-ray analyses. Crystal data are: [VO(sal-L-ala)(OCH3)(CH3OH)] (2a), monoclinic, C2, a=19.621(6), b=6.734(1), c=12.059(4) A, β=117.72(2)° and Z=4. {[VO(sal-L-ala)]2O}2·2CH2Cl2 (3a), orthorhombic, P212121, a=19.938(4), b=23.854(5), c=11.526(2) A, and Z=4. In 2a, the tridentate sal-L-ala ligand and a methoxide ion occupy the basal positions, and form distorted octahedral geometry around the vanadium(V) ion together with one methanol molecule (V–O distance: 2.384(4) A) and the oxide ion of oxovanadium(V). The tetranuclear complex (3a) consists of two μ-oxo dinuclear vanadium(V) complexes, and each vanadium(V) ion has a distorted octahedral coordination. The Schiff base coordin...

Polymer photovoltaic cells : enhanced efficiencies via a network of internal donor-acceptor heterojunctions

Abstract: The carrier collection efficiency (ηc) and energy conversion efficiency (ηe) of polymer photovoltaic cells were improved by blending of the semiconducting polymer with C60 or its functionalized derivatives. Composite films of poly(2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and fullerenes exhibit ηc of about 29 percent of electrons per photon and ηe of about 2.9 percent, efficiencies that are better by more than two orders of magnitude than those that have been achieved with devices made with pure MEH-PPV. The efficient charge separation results from photoinduced electron transfer from the MEH-PPV (as donor) to C60 (as acceptor); the high collection efficiency results from a bicontinuous network of internal donor-acceptor heterojunctions.

First-principles calculations of the electronic structure and spectra of strongly correlated systems: the LDA+ U method

Abstract: The generalization of the Local Density Approximation (LDA) method for the systems with strong Coulomb correlations is presented which gives a correct description of the Mott insulators. The LDA+U method is based on the model hamiltonian approach and allows to take into account the non-sphericity of the Coulomb and exchange interactions. parameters. Orbital-dependent LDA+U potential gives correct orbital polarization and corresponding Jahn-Teller distortion. To calculate the spectra of the strongly correlated systems the impurity Anderson model should be solved with a many-electron trial wave function. All parameters of the many-electron hamiltonian are taken from LDA+U calculations. The method was applied to NiO and has shown good agreement with experimental photoemission spectra and with the oxygen Kα X-ray emission spectrum.

Multicopper Oxidases and Oxygenases

Abstract: Copper is an essential trace element in living systems, present in the parts per million concentration range. It is a key cofactor in a diverse array of biological oxidation-reduction reactions. These involve either outer-sphere electron transfer, as in the blue copper proteins and the Cu{sub A} site of cytochrome oxidase and nitrous oxide redutase, or inner-sphere electron transfer in the binding, activation, and reduction of dioxygen, superoxide, nitrite, and nitrous oxide. Copper sites have historically been divided into three classes based on their spectroscopic features, which reflect the geometric and electronic structure of the active site: type 1 (T1) or blue copper, type 2 (T2) or normal copper, and type 3 (T3) or coupled binuclear copper centers. 428 refs.