Antimony and bismuth dithiocarboxylates: Synthesis, characterization, crystal structures of [Sb(S2Ctol)3] and [Bi(S2CPh)3] and their transformation to polycrystalline M2S3 (M = Sb, Bi)

Antimony and bismuth dithiocarboxylates of the type [M(S₂CAr)₃] (M = Sb, Bi; Ar = C₆H₅ (Ph), 4-MeC₆H₄ (tol)) have been synthesized. These complexes were characterized by elemental analysis, IR, UV-Vis, and ¹H NMR spectroscopy. X-ray crystal structural analyses of [Sb(S₂Ctol)₃] and [Bi(S₂CPh)₃] showed that the dithiocarboxylates are asymmetrically chelated to metal atom. The latter acquires a distorted pentagonal pyramidal geometry as a consequence of the presence of a stereochemically active lone pair of electrons. Pyrolysis of these complexes either in a furnace or in refluxing diphenylether gave M₂S₃ as characterized by their XRD pattern and EDAX analysis.