Transition metal silyl complexes.: Part 63. Influence of the phosphane ligands and the metal complex geometry on the silyl group exchange between L2Pt(SiMe2Ph)2 (L2=R2PCH2CH2PR2 or 2PR3) and HSiR′3

The exchange of the silyl ligands upon reaction of [(κ2-P,P)-R2PCH2CH2PR2]Pt(SiMe2Ph)2 (R=Ph, Me, cyclohexyl) with HSi(OMe)3 or 1,2-bis(dimethylsilyl)benzene was investigated by NMR spectroscopy. The exchange rate is considerably lower than in the complexes cis-(R3P)2Pt(SiMe2Ph)2, and decreases in the order R=Ph>Me>cyclohexyl. No exchange was observed in the analogous reactions of trans-(R3P)2Pt(SiMe2Ph)2. The isomerization of cis-(PhMe2P)2Pt(SiMe2Ph)2 into trans-(PhMe2P)2Pt(SiMe2Ph)2 is catalyzed by di- and oligosilanes.