Synthesis and study of platinum silylene complexes of the type (<i>R</i>₃P)₂Pt=SiMes₂ (Mes = 2,4,6-trimethylphenyl)

The synthesis and characterization of neutral platinum silylene complexes (R 3 P) 2 Pt=SiMes 2 (R = i-Pr (1) or cyclohexyl (2), Mes = 2,4,6-trimethylphenyl) is reported. The dimesitylsilylene ligand in 2 is displaced by a number of ligands including phosphines, alkenes, alkynes, and O 2 . Complex 2 reacts with ROH substrates (R = H, Me, Et) to give (Cy 3 P) 2 Pt and Mes 2 Si(OR)(H) and with H 2 to give trans-(Cy 3 P) 2 Pt(H)SiHMes 2 (3). Reaction of H 2 SiMes 2 with (Cy 3 P) 2 Pt gave cis-(Cy 3 P) 2 Pt(H)SiHMes 2 (4). EXSY NMR experiments of 4 reveal that exchange of silicon and platinum hydrides occurs via reductive elimination – oxidative addition and not via a silylene intermediate.Key words: silylene, EXSY, platinum, hydride.