Exclusive C−Si Bond Formation upon Reaction of a Platinum(II) Alkyl with Silanes

An unusual, highly selective C−Si coupling reaction takes place upon treating the platinum(II) alkyl complex cis -(DIPPIDH)(DIPPID)PtMe ( 2 ) (DIPPIDH = α 2 -( d i i so p ropyl p hosphino) i so d urene, 1 ) with HSiR 3 (R 3 = Et 3, EtMe 2, Me 2 Ph), leading to formation of MeSiR 3 and the hydrido complex trans- (DIPPIDH)(DIPPID)PtH ( 5 ). The overall process involves activation of a Si−H bond, reverse-cyclometalation of the phosphine ligand DIPPIDH ( 1 ), and C−Si elimination. The resulting thermally stable platinum(II) hydride complex 5 was independently prepared by thermolysis of a platinum(II) dihydride, trans -(DIPPIDH) 2 PtH 2 ( 6 ), which was obtained by reaction of 2 with H 2 . In the absence of silane, the cis complex 2 isomerizes thermally to trans -(DIPPIDH)(DIPPID)PtMe ( 3 ), which does not react productively with silanes. Our results indicate that opening of the metallacycle of 2 by benzylic C−H formation is kinetically preferred over formation of CH 4 or CH 3 SiR 3 .