Structural studies of metal complexes with sulphur-containing bidentate ligands. Part 2. Evidence for a metal–metal bond from the molecular structures of bis(phenyldithioacetato)-nickel(II) and -palladium(II)
The molecular structures of the title complexes consist of binuclear bridged units of composition [M2(S2CCH2Ph)4] in which each metal atom is co-ordinated to four sulphur and to the other metal atoms in a square-pyramidal geometry. Other evidence for a metal–metal bond is obtained from a comparison of the metal–sulphur distances and those in nickel and palladium square-planar complexes with comparable–S– and –M– angles. The crystal structures have been solved from X-ray data by the heavy-atom technique and refined by anisotropic least squares to final R values of 0.06 (Ni) and 0.05 (Pd). The two complexes are isostructural and isomorphous, both crystallizing in space group Iba2, with Z= 4 in unit cells of dimensions a= 9.232(3), b= 29.420(7), c= 12.097(3)Å, and a= 9.334(5), b= 29.592(5), c= 12.023(5)Å. respectively.