title: Well-Defined Cobalt(I) Dihydrogen Catalyst: Experimental Evidence for a Co(I)/Co(III) Redox Process in Olefin Hydrogenation.
abstract: The synthesis of a cobalt dihydrogen Co(I)-(H2) complex prepared from a Co(I)-(N2) precursor supported by a monoanionic pincer bis(carbene) ligand, (Mes)CCC ((Mes)CCC = bis(mesityl-benzimidazol-2-ylidene)phenyl), is described. This species is capable of H2/D2 scrambling and hydrogenating alkenes at room temperature. Stoichiometric addition of HCl to the Co(I)-(N2) cleanly affords the Co(III) hydridochloride complex, which, upon the addition of Cp2ZrHCl, evolves hydrogen gas and regenerates the Co(I)-(N2) complex. Furthermore, the catalytic olefin hydrogenation activity of the Co(I) species was studied by using multinuclear and parahydrogen (p-H2) induced polarization (PHIP) transfer NMR studies to elucidate catalytically relevant intermediates, as well as to establish the role of the Co(I)-(H2) in the Co(I)/Co(III) redox cycle.
authors: School of Chemical Sciences, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors: Kenan
authors: K
authors: Tokmic
authors: School of Chemical Sciences, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors: Charles R
authors: CR
authors: Markus
authors: School of Chemical Sciences, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors: Lingyang
authors: L
authors: Zhu
authors: School of Chemical Sciences, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors: Alison R
authors: AR
authors: Fout