Reactions of HOSiMe2Ar with PtPPh3 complexes leading to SiC bond activation or formation of a siloxoplatinum complex

PtI2(PPh3)2 reacts with HOSiMe2(C6H4CF3-4) at 60°C in the presence of AgBF4 to give a mixture of trans-PtI(C6H4CF3-4)(PPh3)2 (1) and [Pt2(μ-I)2(PPh3)4](BF4)2 (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or NMR spectroscopy. The 31P{1H}-NMR study of the reaction of AgBF4 with PtI2(PPh3)2 in acetone-d6 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)2] (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°C in a toluene solution, but reacts with CH2Cl2 and CHCl3 at room temperature to form trans-PtCl(Ph)(PPh3)2 (5).