Dihydrido(pentamethylcyclopentadienyl) bis(triethylsilyl)iridium(v) and related triphenylsilyl-rhodium(v) and -iridium(v) complexes

Reaction of [{(C5Me5)lr),CI,], (1 b), with triethylsilane gave [(C5Me5)lr(H),CI(SiEt3)],(4b), which, under more drastic conditions, reacted further to give [(C,Me5)lr(H),(SiEt3)2], (5b). Complex (4b) was also formed by reaction of SiEt3H with the di-p-hydrido-complex [{ (C5Me5)lr)2(H)2C12] ; this is an example of the highly unusual oxidative addition lr(iii) to Ir(v) (d6 to d4). Reaction of (1 b) with triphenylsilane gave [(C5Me5)Ir( H)2CI(SiPh3) J , analogous to (4b). By contrast, [((C5Me5)Rh)2C14J reacted with triphenylsilane to give [(C5Me,)Rh(H)2(SiPh3)2] and [(C,Me,) Rh(H),(SiPh,)(SiPh,Cl)]. These reactions are compared and mechanistic schemes for the formation of the various products are proposed, based upon sequences of oxidative addition and reductive elimination reactions.