Reactions of HOSiMe2Ar with PtPPh3 complexes leading to Si-C bond activation or formation of a siloxoplatinum complex

PtI2(PPh3)(2) reacts with HOSiMe2(C6H4CF3-4) at 60 degreesC in the presence of AgBF4 to give a mixture of trans-PtI(C6H4CF3-4)(PPh3)(2) (1) and [Pt-2(mu -I)(2)(PPh3)(4)](BF4)(2) (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or NMR spectroscopy. The P-31{H-1}-NMR study of the reaction of AgBF4 with PtI2(PPh3)(2) in acetone-d(6) revealed the formation of trans-[PtI(PPh3)(2)(acetone)]BF4 (3) although isolation of the cationic complex was not feasible due to its facile conversion to 2. Addition of HOSiMe2(C6H4CF3-4) and Ag2O to a toluene Solution of trans-PtI(Ph)(PPh3)(2) causes replacement of the iodo ligand with the siloxo group to afford trans-[Pt(Ph) {OSiMe2(C6H4CF3-4)} (PPh3)(4)] (4). Crystallographic results of 4 show the coordination of the phenyl, siloxo, and PPh3 ligands to the square-planar Pt center with a large Pt-O-Si angle. Complex 4 does not decompose below 60 degreesC in a toluene solution, but reacts with CH2Cl2 and CHCl3 at room temperature to form trans-Pt-Cl(Ph)(PPh3)(2) (5). (C) 2001 Elsevier Science B.V. All rights reserved.