C-H Activation by Isolable Cationic Bis(phosphine) Cobalt(III) Metallacycles

William G. Whitehurst, Junho Kim, Stefan G. Koenig, Paul J. Chirik

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6 Scopus citations


Five- and six-coordinate cationic bis(phosphine) cobalt(III) metallacycle complexes were synthesized with the general structures, [(depe)Co(cycloneophyl)(L)(L′)][BArF4] (depe = 1,2-bis(diethylphosphino)ethane; cycloneophyl = [κ-C:C-(CH2C(Me)2)C6H4]; L/L′ = pyridine, pivalonitrile, or the vacant site, BAr4F= B[(3,5-(CF3)2)C6H3]4). Each of these compounds promoted facile directed C(sp2)-H activation with exclusive selectivity for ortho-alkylated products, consistent with the selectivity of reported cobalt-catalyzed arene-alkene-alkyne coupling reactions. The direct observation of C-H activation by cobalt(III) metallacycles provided experimental support for the intermediacy of these compounds in this class of catalytic C-H functionalization reaction. Deuterium labeling and kinetic studies provided insight into the nature of C-H bond cleavage and C-C bond reductive elimination from isolable cobalt(III) precursors.

Original languageEnglish (US)
Pages (from-to)19186-19195
Number of pages10
JournalJournal of the American Chemical Society
Issue number41
StatePublished - Oct 19 2022

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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