Reactions of [Pt2(μ-S)2(PPh3)4] with Group 6 and 7 metal carbonyls; crystal structure of the apparently unsaturated heterometallic complex [Pt2Re(μ3-S)2(PPh3)4(CO)3]+

Reaction of [Pt2(μ-S)2(PPh3)4] (1) with a mixture containing [Re2(CO)10], Me3NO·2H2O and MeOH at room temperature affords an oxidative methoxylation complex, [Pt2Re2(μ-OMe)2(μ3-S)2(PPh3)4(CO)6] (2), and a PtRe heterometallic salt, [Pt2Re(μ3-S)2(PPh3)4(CO)3]+[Re3(μ3-OMe)(μ-OMe)3(CO)9]− (3a). The core of the cation of 3a comprises a {Pt2ReS2} trigonal bipyramidal ‘cluster’ with weak PtRe bonding interactions and an apparently unsaturated Re(I) atom. The [BF4]− salt of this cation, 3b, can be prepared by the reaction of 1 with [Re(CO)5(H2O)][BF4], and the Mn analogue, [Pt2Mn(μ3-S)2(PPh3)4(CO)3][BF4] (4), can be similarly synthesised using [Mn(FBF3)(CO)5]. Addition of 1 to [M(I)2(CO)3(NCMe)2] (M=Mo, W) is accompanied by iodide migration to give the salts [Pt2M(μ3-S)2I(PPh3)4(CO)4][M(I)3(CO)4] (M=Mo, 5; W, 6a). With [Mo(CO)4(NCMe)2], 1 undergoes reductive carbonylation and desulfurization to give [Pt2(μ-S)(PPh3)3(CO)] (7). The above reactions represent the first examples of 1 as a metalloligand towards carbonyl complexes of the less electron-rich transition metals, and demonstrate that addition reactions of 1 can be complicated by ligand dissociation, ligand migration, or reductive desulphurization. The crystal structures of compounds 3a and 3b were determined.