Stoichiometric and catalytic behavior of cationic silyl and silylene complexes

Reactions of Ir(III) silyl and silylene complexes with a variety of unsaturated substrates were investigated. The reactivity of these complexes toward small molecules was also examined, and this led to the discovery of a nitrile carbon-carbon bond cleavage under mild conditions. Both silyl and silylene complexes of Ir(III) are precatalysts for catalytic hydrosilylation of ketones, and the mechanism of this reaction is discussed. In the course of studying the catalytic reaction mechanism, analogous new ruthenium silylene complexes of the form [Cp*(PMe3)(2)Ru(SiR2)][B(C6F5)(4)] (Cp* = eta(5)-C5Me5, R = Pr-i, SPh) were prepared. A comparison of [Cp*(PMe3)Ir(SiPh2)(H)][B(C6F5)(4)] and the known Lewis acid hydrosilylation catalyst B(C6F5)(3) is also made.