Inversion of methane on transition-metal complexes: A possible mechanism for inversion of stereochemistry

Kazunari Yoshizawa, Akiya Suzuki, Tokio Yamabe

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The inversion of methane bound to first-row transition-metal ions from Sc+ to Cu+ is systematically investigated using the B3LYP method, a hybrid density-functional-theory method of Becke and Lee, Yang, and Parr. The computed transition states for the methane inversion on the M+(CH4) complexes have a C(s) structure in which one pair of C-H bonds is about 1.2 Å in length and the other pair is about 1.1 Å. The barrier height for the methane inversion is significantly decreased from 109 kcal/mol for free methane to 43-48 kcal/mol on the late transition-metal complexes, Fe+(CH4), Co+(CH4), Ni+(CH4), and Cu+(CH4). Since each activation energy involves the binding energy of the complex (16 kcal/mol on the average), the actual barrier height should be lower by this quantity if measured from the dissociation limit. The inversion of methane can therefore occur at the transition-metal active center of catalysts or enzymes under ambient conditions through a thermally accessible transition state, and it would reasonably lead to inversion of stereochemistry at a carbon atom in catalytic reactions of hydrocarbons. We propose that a radical mechanism based on a planar carbon species may not be the sole source of the observed loss of stereochemistry in transition-metal-catalyzed hydrocarbon hydroxylations and other related reactions.

Original languageEnglish
Pages (from-to)5266-5273
Number of pages8
JournalJournal of the American Chemical Society
Volume121
Issue number22
DOIs
Publication statusPublished - Jun 9 1999
Externally publishedYes

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Stereochemistry
Coordination Complexes
Methane
Metal complexes
Transition metals
Metals
Hydrocarbons
Carbon
Hydroxylation
Binding energy
Density functional theory
Metal ions
Enzymes
Activation energy
Ions
Atoms
Catalysts

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Inversion of methane on transition-metal complexes : A possible mechanism for inversion of stereochemistry. / Yoshizawa, Kazunari; Suzuki, Akiya; Yamabe, Tokio.

In: Journal of the American Chemical Society, Vol. 121, No. 22, 09.06.1999, p. 5266-5273.

Research output: Contribution to journalArticle

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