C-C versus C-H activation and versus agostic C-C interaction controlled by electron density at the metal center

Mark Gandelman, Linda J.W. Shimon, David Milstein

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58 Citations (Scopus)


Based on the PCN ligand 2, a remarkable degree of control over C-C versus C-H bond activation and versus formation of an agostic C-C complex was demonstrated by choice of cationic [Rh(CO)n(C2H 4)2-n] (n=0, 1, 2) precursors. Whereas reaction of 2 with [Rh(C2H4)2(solv)n]BF4 results in exclusive C-C bond activation to yield product 5, reaction with the dicarbonyl precursor [Rh(CO)2(solv)n]BF4 leads to formation of the C-H activated complex 9. The latter process is promoted by intramolecular deprotonation of the C-H bond by the hemilabile amine arm of the PCN ligand. The mixed monocarbonyl monoethylene Rh species [Rh(CO)(C 2H4)]BF4 reacts with the PCN ligand 2 to give an agostic complex 7. The C-C activated complex 5 is easily converted to the C-H activated one (9) by reaction with CO; the reaction proceeds by a unique sequence of 1,2-metal-to-carbon methyl shift, agostic interaction, and C-H activation processes. Similarly, the C-C agostic complex 7 is converted to the same C-H activated product 9 by treatment with CO.

Original languageEnglish
Pages (from-to)4295-4300
Number of pages6
JournalChemistry - A European Journal
Issue number18
Publication statusPublished - Sep 22 2003



  • Agostic interactions
  • C-C activation
  • C-H activation
  • Carbonyl ligands
  • Dearomatization
  • Tridentate ligands

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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