Theoretical study on kinetic isotope effects in the C-H bond activation of alkanes by iron-oxo complexes

研究成果: ジャーナルへの寄稿記事

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The C-H bond dissociation reactions of methane and ethane by the bare FeO+ complex, diiron and dicopper models of methane monooxygenase, and a compound I model of cytochrome P450 are discussed using density functional theory (DFT) calculations, with an emphasis on their kinetic isotope effects (KIEs). There are possible three types of transition states for the C-H bond dissociation. The first is an oxene insertion mechanism, in which a C-H bond is dissociated and C-O and O-H bonds are formed in a concerted manner via a three-centered transition state C···H···O-Fe which directly leads to a product alcohol. The second is a direct abstraction mechanism in which a linear transition state C···H···O-Fe leads to the dissociation into an Fe-OH intermediate and an alkyl radical species. The third mechanism involves a four-centered transition state C···H···O-Fe in its initial stages, which leads to a reaction intermediate involving OH and CH3 ligands. DFT computations demonstrate that the second and third types of transition states are likely to occur in the activation of a C-H bond, The four-centered H atom abstraction can preferentially occur when the metal active center of catalysts and enzymes is coordinatively unsaturated (five-coordinate), whereas the direct abstraction should occur when the metal active center is six-coordinate. KIE values calculated with transition state theory are significantly dependent on temperature, substituents, and ways of abstraction.

元の言語英語
ページ(範囲)251-259
ページ数9
ジャーナルCoordination Chemistry Reviews
226
発行部数1-2
DOI
出版物ステータス出版済み - 3 19 2002

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Alkanes
Isotopes
isotope effect
Paraffins
alkanes
Iron
Chemical activation
methane monooxygenase
activation
iron
Kinetics
Density functional theory
kinetics
Methane
Metals
Reaction intermediates
Ethane
dissociation
Cytochrome P-450 Enzyme System
Alcohols

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

これを引用

Theoretical study on kinetic isotope effects in the C-H bond activation of alkanes by iron-oxo complexes. / Yoshizawa, Kazunari.

:: Coordination Chemistry Reviews, 巻 226, 番号 1-2, 19.03.2002, p. 251-259.

研究成果: ジャーナルへの寄稿記事

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