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 [Pt-2(mu-S)(2)(PPh3)(4)] (1) with a mixture containing [Re-2(CO)(10)], Me3NO . 2H(2)O and MeOH at room temperature affords an oxidative methoxylation complex, [Pt2Re2(mu-OMe)(2)(mu(3)-S)(2)(PPh3)(4)(CO)(6)] (2), and a Pt-Re heterometallic salt, [Pt2Re(mu(3)-S)(2)(PPh3)(4)(CO)(3)](+) [Re-3(mu(3)-OMe)(mu-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(mu(3)-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(mu(3)-S)(2)(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 [Pt-2(mu-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. (C) 2000 Elsevier Science S.A. All rights reserved.