Dimethylplatinum complexes of polydentate alkene–sulfur and –selenium ligands

Abstract

Interaction of [PtMe₂(SMe₂)₂] with 1 equivalent of 5-selenanona-1,8-diene produces a monomeric complex containing the ligand chelating through one alkene moiety and the selenium atom. The unco-ordinated alkene moiety undergoes exchange with the co-ordinated alkene moiety which has been studied by dynamic NMR spectroscopy. Interaction of the same platinum(II) precursor with 0.5 mol equivalent of the dialkenyl chalcogenoether ligands E(CH₂CH₂CHCH₂)₂(E = S or Se) produced the novel dinuclear complexes [Pt₂Me₄{µ-E(CH₂CH₂CHCH₂)₂}] both of which have been characterised by X-ray crystallography and shown to be isostructural. The unit cells are of dimensions a= 10.850(2), b= 11.289(7) and c= 12.415(1)(E = S) and a= 11.056(1), b= 11.251(1) and c= 12.546(2)Å, (E = Se). In each case the two metals are bridged by a tetrahedrally co-ordinated chalcogen atom, with one alkenyl group chelating to each platinum atom. The platinum–chalcogen distances are Pt–S 2.354(8) and Pt–Se 2.457(5)Å.