2000 Fiscal Year Final Research Report Summary
Summary of Molecular Methodology and Reaction Control of Oxygen Active Species
Project/Area Number |
11228204
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Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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Allocation Type | Single-year Grants |
Review Section |
Science and Engineering
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Research Institution | Osaka University |
Principal Investigator |
FUKUZUMI Shunichi Osaka University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (40144430)
|
Co-Investigator(Kenkyū-buntansha) |
MORO-OKA Yoshihiko Tokiwa University, Faculty of Community Development, Professor, コミュニティー振興学部, 教授 (70016731)
|
Project Period (FY) |
1999 – 2003
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Keywords | Active Oxygen Complexes / Electron Transfer / SOD / Monooxygenase / Cytochrome / X-ray Crystal Structure / Metalloproteins / Hemerythrin / Oxygenation |
Research Abstract |
This research project aims at exploring the structures and reactivity of active oxygen-metal complexes to develop clean energy conversion systems as well as highly efficient and selective oxidation processes. The research team is divided into four groups to study (1) electron transfer properties of active oxygen complexes, (2) synthesis and structures of active oxygen complexes, (3) reactivity control of active oxygen complexes, and (4) catalytic functions of active oxygen complexes. In order to facilitate cooperative researches among four groups, two meetings and one symposium which is open to public were held last year. Fukuzumi and Morooka acting as presiding group members evaluated the research achievement of each group and made appropriate suggestions to facilitate the research activity of each group. The main results in this fiscal year are following. (1) Catalytic reactivity of a series metal ions in superoxide formation has been evaluated quantitatively for the first time. SOD m
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odels having the highest catalytic reactivity have been successfully prepared and characterized. The catalytic function of dioxygen has aslo been found for the first time in electron transfer reactions. (2) High-valent bis (μ-oxo) Cu (III)_2, Ni (III)_2, and (μ-oxo or hydroxo)(μ-peroxo) Fe_2 (III) complexes were successfully prepared as functional models for dioxygen activating metalloproteins such as methane monooxygenase (MMO). The 4-electron oxidation of the two oxo groups in the bis (μ-oxo) Cu (III)_2 complex has been shown to occur to produce O^2 and copper (I) complex by bubbling N_2 gas. (3) Chemical models both for cytochrome P450 and for cytochrome c oxidase having a Fe/Cu dinuclear complex have successfully been characterized by spectroscopic methods. The first example of hemoproteins reconstituted with artificial prosthetic groups has also been obtained. Novel diiron (II) complexes showing a reversible dioxygen-binding as a functional model of hemerythrin have been synthesized and characterized. The mononuclear iron (III) complexes with a hydroperoxide and alkylperoxide have been isolated for the first time. (4) Nickel and cobalt alkylperoxo complexes with a Tp^R ligand are prepared and fully characterized. Oxygenation of phenols to catechols by a (μ-η^2 : η^2-peroxo) dicopper (II) complex and aliphatic hydroxylation by a bis (μ-oxo) dicopper (III) complex have been found to proceed quantitatively. Structure and reactivity of nickel-active oxygen intermediates have been elucidated to provide important insight into the roles of metal ions in dioxygen activation. Less
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Research Products
(51 results)