Copper, cobalt and platinum complexes with dithiothiophene-based ligands

The preparation and characterisation of new thiophenedithiolate complexes of Cu, Co and Pt with the ligands alpha-tpdt and tpdt (alpha-tpdt = 2,3-thiophenedithiolate, tpdt = 3,4-thiophenedithiolate) is reported. The Co and Pt complexes present regular square-planar coordination geometry and low oxidation potentials when compared with complexes with simpler ligands, but their monoanionic state is found to be rather unstable. The Co(tpdt)(2) complex can be isolated both in the monoanionic and dianionic states as a stable compound but the Co(alpha-tpdt)(2) and the Pt complexes can be obtained only in the dianionic state, while their monoanionic state is unstable. The Co and Pt complexes can, however, be easily oxidised to the neutral state, giving a fine-powdered microcrystalline material without high electrical conductivity. With Cu only a less frequent geometry based on a tetrametallic Cut cluster and three ligands is observed as [CU4(alpha-tpdt)(3)](2-) and [CU4(tpdt)(3)](2-).((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).