Synthesis and characterization of methylbismuth(III) complexes containing dithio ligands: crystal and molecular structure of [MeBi{S2COMe}2] and transformation of [MeBi{S2COiPr}2] to Bi2S3

Reactions of sodium/potassium salts of xanthates, dithiocarbamates and dialkyldithiophosphates with methylbismuth dichloride have been carried out in 1:2 stiochiometric ratio in anhydrous benzene and products of the type [MeBi(S2COR)2] (R=Me, Et, Pri), [MeBi(S2CNR2)2] (R=Me, Et, 1/2C4H8N) and [MeBi{S2P(OR)2}2] (R=Me, Et, Pri) have been isolated. All of these complexes were characterized by elemental analyses and by IR and NMR (1H, 13C and 31P) spectra. The X-ray structure of [MeBi(S2COMe)2] indicates that the immediate environment around the central bismuth atom is distorted square pyramidal. However, inclusion of a significant Bi⋯S intermolecular bond results in pentagonal pyramidal geometry. Thermolysis of [MeBi(S2COiPr)2] in xylene indicates that it is a good precursor for preparation of Bi2S3 at low temperature.