REACTIVITY OF MONOPHOSPHINE PLATINUM(0) C OMPLEXES WITH SO2

The addition reaction of (PPh3)Pt(ViSi) (ViSi = {eta2-H2C = CHSiMe2}2O ) (1) with SO2 gives within 30 min the red SO2 complex (PPh3)Pt(eta 2- H2C = CHSiMe2OSiMe2CH = CH2)(SO2) (2). A reaction time of 24 h with SO 2 leads to the elimination of the ViSi ligand, and the unstable monome ric intermediate (PPh3)Pt(SO2) cyclo-trimerizes to the stable cluster [Pt(PPh3)(SO2)]3 (3). 3 is also obtained within 30 min by the reaction of (PPh3)Pt(C2H4)2 (4) with SO2. The crystal structure of 3 has been determined; space group P2(1)/n, Z = 4, a = 1606.1(3), b = 1019.3(1), c = 3 624.6(5) pm, beta = 93.67-degrees, R/R(w) = 0.102/0.121.