Mixed bismuth(III) complexes with sulfur donor ligands: Studies on synthetic, structural, thermal and biological properties

Mixed bismuth(III) bis( O -alkyldithiocarbonato- S , S ′) complexes with dialkyldithiocarbamates have been obtained by two-step one-pot synthesis. These complexes have been characterized by physicochemical (molecular mass determination, melting point and elemental analysis), spectral (UV–Visible, FTIR, far-IR, 1 H and 13 C NMR), thermal and powder X-ray diffraction studies. It has been observed that both the dithiolato ligands are coordinated via an anisobidentate mode to the central metal atom. Powder XRD analysis indicates that all the complexes are in nanoranged crystallite size (3.1–8.8 nm) and have adopted monoclinic crystal system. Bismuth sulfide (Bi 2 S 3 ) nanoparticles have been obtained upon thermal decomposition of these complexes. The preparation of bismuth sulfide (Bi 2 S 3 ) nanoparticles was further confirmed by the help of EDAX analysis of the thermal degradation product. All the synthesized complexes exhibited greater antimicrobial activity than standard antibacterial drug chloramphenicol and antifungal drug terbinafine.