A Two-Coordinate Nickel Imido Complex That Effects C−H Amination

An exceptionally low coordinate nickel imido complex, (IPr*)NiN(dmp) (2) (dmp = 2,6-dimesitylphenyl), has been prepared by the elimination of N2 from a bulky aryl azide in its reaction with (IPr*)Ni(η6-C7H8) (1). The solid-state structure of 2 features two-coordinate nickel with a linear C−Ni−N core and a short Ni−N distance, both indicative of multiple-bond character. Computational studies using density functional theory showed a NiN bond dominated by Ni(dπ)−N(pπ) interactions, resulting in two nearly degenerate singly occupied molecular orbitals (SOMOs) that are Ni−N π* in character. Reaction of 2 with CO resulted in nitrene-group transfer to form (dmp)NCO and (IPr*)Ni(CO)3 (3). Net C−H insertion was observed in the reaction of 2 with ethene, forming the vinylamine (dmp)NH(CHCH2) (5) via an azanickelacyclobutane intermediate, (IPr*)Ni{N,C:κ2-N(dmp)CH2CH2} (4).