TY - JOUR
T1 - Well-Defined Cobalt(I) Dihydrogen Catalyst
T2 - Experimental Evidence for a Co(I)/Co(III) Redox Process in Olefin Hydrogenation
AU - Tokmic, Kenan
AU - Markus, Charles R.
AU - Zhu, Lingyang
AU - Fout, Alison R.
N1 - Funding Information:
The authors thank Dr. Jeffery A. Bertke for assisting with crystallography and the NSF for financial support with a CAREER award (1351961) to A.R.F. C.R.M. has been supported in part by an NSF award (CHE 12-13811) and a NASA award (NNX13AE62G) to PI Prof. Benjamin J. McCall. We also thank Prof. McCall for the use of the p-H2 generator.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/9/14
Y1 - 2016/9/14
N2 - The synthesis of a cobalt dihydrogen CoI-(H2) complex prepared from a CoI-(N2) precursor supported by a monoanionic pincer bis(carbene) ligand, MesCCC (MesCCC = 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 CoI-(N2) cleanly affords the CoIII hydridochloride complex, which, upon the addition of Cp2ZrHCl, evolves hydrogen gas and regenerates the CoI-(N2) complex. Furthermore, the catalytic olefin hydrogenation activity of the CoI 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 CoI-(H2) in the CoI/CoIII redox cycle.
AB - The synthesis of a cobalt dihydrogen CoI-(H2) complex prepared from a CoI-(N2) precursor supported by a monoanionic pincer bis(carbene) ligand, MesCCC (MesCCC = 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 CoI-(N2) cleanly affords the CoIII hydridochloride complex, which, upon the addition of Cp2ZrHCl, evolves hydrogen gas and regenerates the CoI-(N2) complex. Furthermore, the catalytic olefin hydrogenation activity of the CoI 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 CoI-(H2) in the CoI/CoIII redox cycle.
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U2 - 10.1021/jacs.6b07066
DO - 10.1021/jacs.6b07066
M3 - Article
C2 - 27569420
AN - SCOPUS:84987811468
SN - 0002-7863
VL - 138
SP - 11907
EP - 11913
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 36
ER -