Synthesis and reactivity of dinuclear Cp*Ru tert-butylamido and cyclometallated Bis(trimethylsilyl)amido complexes

Treatment of [Cp*Ru(mu(3)-Cl)](4) with 4 equiv of (LiNHBu)-Bu-t in THF produces the dimeric tert-butylamido complex [Cp*Ru(mu-(NHBu)-Bu-t)](2) (1b) in 85% yield. Complex 1b reacts with Ph2S=CH2 and (CNBu)-Bu-t to give the imido methylene complex (Cp*Ru)(2)(mu-(NBu)-Bu-t)(mu-CH2) (2b) and the bis(amido) bis(isocyanide) complex [Cp*Ru((CNBu)-Bu-t)(mu-(NHBu)-Bu-t)](2) (3b), respectively. The reaction of [Cp*Ru(mu(3)-Cl)](4) with 4 equiv of NaN(SiMe3)(2) proceeds via double C-H activation of a SiMe group to give the cyclometallated silylamido complex (Cp*Ru)(2)(mu-H)(mu-HCSiMe2NSiMe3) (4) in 91% yield. Single-crystal X-ray analysis and low-temperature H-1 and C-13 NMR spectroscopy for 4 reveal the amido-carbene formulation of the cyclometallated ligand. Variable-temperature NMR analysis for 4 reveals a rapid exchange of the hydride and carbene protons and indicates a reversible C-H reductive coupling between the silylcarbene and the hydride moieties, which has been reasonably modeled by DFT calculations. (C) 2015 Elsevier B.V. All rights reserved.