Synthesis and solid-state structural characterisation of Pt(II,IV) bromide complexes containing bidentate organothiomethylpyridine heteroleptic ligands

A convenient synthetic method for the preparation of organothiomethylpyridine ligands 2-(RSCH2)C5H4N (R = Ph (L-1), Me (L-2)), 2-MeS-6-Me-C5H3N (L-3), and 2-MeS-4-Me-C5H3N (L-4) via the initial lithiation of substituted 2-picolines followed by the nucleophilic reaction with a diorgany1disulfide is described. The complexes [PtBr2L] (L = L-1-L-4) have been prepared in good to high yields as yellow solids with low solubility in organic solvents. The solid state structures of the complexes have been determined, showing the spatial arrangement of the complexes to depend significantly upon varying substituents within the ligand. The complexes undergo oxidation by bromine to form the tetravalent complexes [PtBr4(L)] (L = L-1-L-4). The solid state structures of [PtBr4(L-2)] and [PtBr4(L-4)] have been determined, and shown to be monomeric with the ligand chelating the platinum centre. (c) 2006 Elsevier Ltd. All rights reserved.