Reactions of the complexes Pt3(μ-CO)3L3 with SO2. Crystal structure of Pt3(μ-CO)3(PtBu2Ph)3·0.25(C4H8O)

Reactions of the complexes Pt3(μ-CO)3L3, where LPtBu3 (1a), PtBu2cPr (1b), PtBu2Ph (1c), PCy3 (1d) and PCy2Ph (1e), with SO2 have been examined. The complexes 1 may be divided into two classes: those complexes (1a, 1b and 1c) which fragment to yield a dimer Pt2(μ-SO2)(CO)2L2, where L=PtBu3 (2a), PtBu2CPr (2b), PtBu2Ph (2c), upon brief exposure to SO2 and those complexes (1d and 1e) which substitute CO ligands with SO2 ligands without a change in nuclearity to yield Pt3(μ-SO2)3L3, where L=PCy3 (3d) and PCy2Ph (3e). Traces of the complexes Pt3(μ-SO2)(μ-CO)2L3 (4) were observed after heating the complexes 2 under an SO2 atmosphere for 14 h. As formation of dimeric products appeared to be favoured by larger ligands L, a method of evaluating the non-bonding interactions between the ligands L and the cluster fragment Pt3(μ-CO)3 was used to evaluate the size to the phosphine ligands. The X-ray crystal structure of the complex Pt3(μ-CO)3(PtBu2Ph)3 (1c) is reported.