A d10 Ni–(H2) Adduct as an Intermediate in H[BOND]H Oxidative Addition across a Ni[BOND]B Bond

Authors

  • Dr. W. Hill Harman,

    1. Division of Chemistry and Chemical Engineering, California Institute of Technology (USA)
    2. Current address: Department of Chemistry, University of California, Riverside, CA 92521 (USA)
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  • Dr. Tzu-Pin Lin,

    1. Division of Chemistry and Chemical Engineering, California Institute of Technology (USA)
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  • Prof. Dr. Jonas C. Peters

    Corresponding author
    1. Division of Chemistry and Chemical Engineering, California Institute of Technology (USA)
    • Division of Chemistry and Chemical Engineering, California Institute of Technology (USA)

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  • This research was supported by the NSF Center for Chemical Innovation: Solar Fuels (grant CHE-0802907) and by the Gordon and Betty Moore Foundation. We thank Prof. Christopher C. Cummins and Dr. Smith Nielsen for insightful discussions.

Abstract

Bifunctional E[BOND]H activation offers a promising approach for the design of two-electron-reduction catalysts with late first-row metals, such as Ni. To this end, we have been pursuing H2 activation reactions at late-metal boratranes and herein describe a diphosphine–borane-supported Ni—(H2) complex, [(PhDPBiPr)Ni(H2)], which has been characterized in solution. 1H NMR spectroscopy confirms the presence of an intact H2 ligand. A range of data, including electronic-structure calculations, suggests a d10 configuration for [(PhDPBiPr)Ni(H2)] as most appropriate. Such a configuration is highly unusual among transition-metal H2 adducts. The nonclassical H2 adduct is an intermediate in the complete activation of H2 across the Ni[BOND]B interaction. Reaction-coordinate analysis suggests synergistic activation of the H2 ligand by both the Ni and B centers of the nickel boratrane subunit, thus highlighting an important role of the borane ligand both in stabilizing the d10 Ni—(H2) interaction and in the H—H cleavage step.

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