Arrested 1,2-Hydrogen Migration from Silicon to Nickel upon Oxidation of a Three-Coordinate Ni(I) Silyl Complex

Reaction of the dimeric Ni(I) chloride complex [(dtbpe)NiCl]2 (1) with dimesitylsilyl potassium affords the three-coordinate Ni(I) silyl complex (dtbpe)Ni(SiHMes2) (2). Alternatively, 2 can be prepared by an oxidative-addition reaction of Mes2Si(H)OTf (Tf = CF3SO3) with the nickel(0) complex [(dtbpe)Ni]2(μ-C6H6) (3), with (dtbpe)Ni(OTf) (4) formed as an easily separable byproduct. The one-electron oxidation of 2 by ferrocenium affords diamagnetic [(dtbpe)Ni(μ-H)SiMes2][BArF4] (5), a Ni(II) complex formed by partial 1,2-H migration from silicon to nickel and featuring an unusual 3-center, 2-electron bonding motif between Ni, Si, and the bridging H. Complex 5 was also obtained from Mes2SiH2 activation by the neopentyl complex salt [(dtbpe)Ni(CH2CMe3)][BArF4] (6) with elimination of neopentane.