The synthesis and reactivity of a new trimetallic complex Ti(NP)4Ni2 (NP = 2-diphenylphosphinopyrrolide) (3) is reported. Single-crystal X-ray diffraction and X-ray absorption studies point to a unique bonding motif: a d10-d10, Ni0-Ni0 bond stabilized by a proximal d0 TiIV metal center. The coordination chemistry of 3 with a variety of L (L = isocyanide and alkyne) donors has also been explored. In the case of isocyanide coordination, the Ni-Ni bond is broken, while diphenylacetylene binding results in a symmetric butterfly μ2-κ2-alkyne bridge across the Ni-Ni moiety. Finally, complex 3 is capable of the 4-electron cleavage of the N=N double bond in benzo[c]cinnoline, the first example of N=N bond cleavage by Ni. The resulting product, 7, has been characterized structurally and spectroscopically, and the mechanistic implications are discussed in the context of metal-metal cooperativity.
Bibliographical noteFunding Information:
Financial support was provided by the Inorganometallic Catalyst Design Center, an EFRC funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (Grant DE-SC0012702 to I.A.T.) and the National Science Foundation (NSF) (Grant CHE-1454455 to K.M.L.). I.A.T. and K.M.L. gratefully acknowledge the Alfred P. Sloan Foundation for support. P.L.D. acknowledges a UMN Doctoral Dissertation Fellowship for funding. Equipment for the University of Minnesota Chemistry Department NMR facility was supported through a grant from the National Institutes of Health (S10OD011952) with matching funds from the University of Minnesota. XAS data were obtained at SSRL, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the Department of Energy’s Office of Biological and Environmental Research, and by NIH/NIGMS (including Grant P41GM103393).
Copyright © 2019 American Chemical Society.