Reactions of a Neutral Silylene Ruthenium Complex with Heterocumulenes: C═O Hydrosilylation of Isocyanates vs C═S Bond Cleavage of Isothiocyanate

Abstract

Reactions of the neutral silylene ruthenium complex Cp*(CO)(H)Ru═Si(H){C(SiMe3)3} (2) with heterocumulenes were investigated. Treatment of 2 with ArNCO (Ar = Mes, Ph; Mes = 2,4,6-trimethylphenyl) resulted in hydrosilylation of ArNCO selectively at the C═O bond at room temperature to give the five-membered chelate complexes Cp*(CO)Ru[κ2N,Si-N(Ar)═C(H)OSi(H){C(SiMe3)3}] (3a, Ar = Mes; 3b, Ar = Ph). In contrast, the reaction of 2 with MesNCS led to cleavage of the C═S double bond to give the isocyanide complex Cp*(CO)Ru(CNMes){SSiH2C(SiMe3)3} (4). The structures of both types of products were unambiguously determined by X-ray crystallography.