An H-Substituted Rhodium Silylene.

Abstract

Divergent reactivity of organometallic rhodium(I) complexes, which led to the isolation of neutral rhodium silylenes, is described. Addition of PhRSiH2 (R=H, Ph) to the rhodium cyclooctene complex (iPr NNN)Rh(COE) (1-COE; iPr NNN=2,5-[iPr2 P=N(4-iPrC6 H4 )]2 N(C6 H2 )- , COE=cyclooctene) resulted in the oxidative addition of an Si-H bond, providing rhodium(III) silyl hydride complexes (iPr NNN)Rh(H)SiHRPh (R=H, 2-SiH2 Ph; Ph, 2-SiHPh2 ). When the carbonyl complex (iPr NNN)Rh(CO) (1-CO) was treated with hydrosilanes, base-stabilized rhodium(I) silylenes κ2 -N,N-(iPr NNN)(CO)Rh=SiRPh (R=H, 3-SiHPh; Ph, 3-SiPh2 ) were isolated and characterized using multinuclear NMR spectroscopy and X-ray crystallography. Both silylene species feature short Rh-Si bonds [2.262(1) Å, 3-SiHPh; 2.2702(7) Å, 3-SiPh2 ] that agree well with the DFT-computed structures. The overall reaction led to a change in the iPr NNN ligand bonding mode (κ3 →κ2 ) and loss of H2 from PhSiRH2 , as corroborated by deuterium labelling experiments.