Exclusive C-C oxidative addition in a rhodium thiophosphoryl pincer complex and computational evidence for an ν 3-C-C-H agostic intermediate

Michael Montag, Irena Efremenko, Yael Diskin-Posner, Yehoshoa Ben-David, Jan M.L. Martin, David Milstein

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22 Citations (Scopus)

Abstract

The room-temperature reaction between the Rh(I) precursor [Rh(COE) 2(acetone) 2]BF 4 (COE = cyclooctene) and a new thiophosphoryl-based SCS pincer ligand leads to oxidative addition of an sp 2-sp 3 C-C bond as the only observed outcome, despite the presence of accessible sp 3 C-H bonds. A DFT study reveals that the chemistry of the SCS system is controlled by π repulsion between occupied rhodium d orbitals and the lone-pair electrons on the two sulfur atoms. This repulsion gives rise to the thermodynamic selectivity for C-C over C-H cleavage, as it is attributed to the higher electronegativity of a methyl versus hydride ligand, thereby allowing more effective release of excessive π electron density. It is also demonstrated that the observed C-C and unobserved C-H cleavage pathways originate from a common intermediate that features a novel ν 3-C-C-H agostic interaction. The COE ligand is shown to play an important role by greatly stabilizing this intermediate, making it the only available entry point to both reaction pathways.

Original languageEnglish
Pages (from-to)505-512
Number of pages8
JournalOrganometallics
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 9 2012

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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