Molecular and Supramolecular Structures of 1‐Phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H 2 L) and its Complexes with Diphenyllead(IV) Chloride and Acetate

Reaction of 1‐phenyl‐4‐phenylacetyl‐2‐thiosemicarbazide (H 2 L) with diphenyllead(IV) dichloride and acetate afforded the complexes [PbPh 2 Cl 2 (H 2 L) 2 ] and [PbPh 2 L]. The ligand and the complexes were characterized by elemental analyses, 1 H and 13 C NMR spectroscopy and X‐ray crystallography. In the asymmetric unit of crystals of the ligand there are four independent molecules of H 2 L and four molecules of water, which associate in the lattice as two independent sheets. The complex [PbPh 2 Cl 2 (H 2 L) 2 ]·4MeOH has slightly distorted all‐ trans octahedral geometry around the lead atom, and the fact that the ligand is S‐bound rather than O‐bound suggests that PbPh 2 Cl 2 behaves as a “soft” Lewis acid. Hydrogen bonds involving NH groups, Cl atoms and MeOH molecules form a three‐dimensional supramolecular structure. In [PbPh 2 L]·Me 2 CO, the L 2− anion bridges between two metal centres, binding to one strongly via the N and S atoms and weakly via the O atom, and to the other via the O atom, thus creating polymeric chains along the b axis. The double deprotonation and metallation of H 2 L induce significant changes in its configuration and lengthen the C‐S and C‐O bonds, suggesting an evolution of the dianion towards a thiol‐enol form.