| Co-Investigator(Kenkyū-buntansha) |
SUGIURA Yukio Kyoto University, Institute for Chemical Research, Professor, 化学研究所, 教授 (40025698)
TAKANO Mikio Kyoto University, Institute for Chemical Research, Professor, 化学研究所, 教授 (70068138)
TANAKA Tsunehiro Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (70201621)
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| Research Abstract |
In the project for development of new monooxygnase- and dioxygenase-like catalytic reactions in the multicomponent system of nonheme iron complexes/molecular oxyen/electron transfer, we were successful to develop new reactions in the oxygenation of aromatics, alkanes, and alkenes catalyzed by Fe(III), Fe(II) and Mn(II) complexes. In the monooxygenase functional model systems, we have developed a new system using catecholateiron(III) comlex as the iron center and hydroquinones as the electron and proton donors. This gave characteristic results in the monooxygenation of alkanes, alkenes, and aromatics. In the functional model reactions for α-keto acid-dependent dioxygenases, new oxygenations were developed in the selective epoxidation of alkenes such as cyclooctene and norbornene, hydroxylation or carbonylation of alkanes such as adamantane and cyclohexane. Selective oxygenations of catechols by iron(III) complexes has been extensively studied. Besides the selective intradiol oxygenation by Fe(III), we have developed a new reaction by Mn(II) complex. This is the first model system for the manganese-dependent catechol dioxygenases. As an intermediate, we have isolated a Mn(II)-semiquinonate complex as a new type of complex. The structure of the complex was clarified by X-ray crystallographif analysis, ESI-Mass, ESR, IR, UV-VIS spectra. What is the most interesting is that the complex maitains the electronic structure of Mn(II)-semiquinonate configuration. This is a very important information for the mechanism of catechol dioxygenases.
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