Structural analysis of phenyl-germanium, -tin, and -lead dithiocarboxylates [(RCSS)xMPh4−x, M=Ge, Sn, Pb; x=1–3]: affinity between thiocarbonyl sulfur and Group 14 elements

A series of RCSSGePh3, (RCSS)2GePh2, (RCSS)3SnPh, and (RCSS)2PbPh2 were synthesized, and the structures of some p-tolyl derivatives [RCSSMPh3 (R=4-CH3C6H4, M=Ge: 1d, Sn: 3d, Pb: 6d) and (4-CH3C6H4CSS)2SnPh2 (4d)] and a o-tolyl derivative [(2-CH3C6H4CSS)3SnPh: (5c)] were analyzed by X-ray. The results indicate intramolecular non-bonded interactions between the thiocarbonyl sulfur and the central Group 14 element metals. The mono dithiocarboxylates (1d, 3d, and 6d) exhibit a distorted tetrahedral structure around the central Group 14 elements. Diphenyltin bis(dithiocarboxylate) (4d) is shown to take a distorted octahedron or skewed trapezoidal bipyramid, where the two dithiocarboxylate groups are bound to the Sn atom as an anisobidentate ligand, and the tin tris(dithiocarboxylate) (5c) exhibits a seven-coordinated pentagonal bipyramid. The distance between the thiocarbonyl sulfur and the Sn atom in 4-CH3C6H4CSSMPh3 (M=Ge, Sn, Pb) is shorter than those in the corresponding germanium and lead derivatives. Based on these distances, the affinity of Group 14 elements for sulfur atoms is deduced to decrease in the order Sn>Pb≥Ge>Si>C.