Synthesis, characterization and antimicrobial study of dithiocarbamate and schiff base ligands and their cu (ii) and zn (ii) complexes

Abstract

Chemistry of transition metal complexes with Schiff base and dithiocarbamate mixed ligands are much interest in bioinorganic chemistry. They have many applications including as catalyst and medicine. Due to the increase in resistance of pathogenic microorganism to the available antibiotics, efforts are being made to develop chemotherapeutic agents. Thus, the aim of this study is to synthesize, characterize and evaluate antimicrobial activities of Zn (II) diphenyl dithiocarbamate and Cu (II) complex containing Schiff base of 1,10-phenanthroline and diphenyl dithiocarbamate. Meanwhile, the sodium diphenyl dithiocarbamate ligand was synthesized by the reaction of CS2 with diphenylamine in the presence of NaOH. The mixed ligand Cu (II) complex was synthesized by reaction of CuCl2.2H2O with sodium diphenyl dithiocarbamate and 1, 10-phenanthroline. Also Zn (II) complex was synthesized by reaction of ZnCl2.6H2O with diphenyl dithiocarbamate. The synthesized ligand and its metal complex was characterized by melting point, chloride test, conductivity measurement, CHNS elemental analysis, AAS, FT-IR, UVVisible spectroscopy and NMR spectroscopy. The data obtained from this instruments confirm that bidentate nitrogen group of 1, 10-phenanthroline coordinate to copper ion (N→M), Sulfur group of diphenyl dithiocarbamate coordinated to copper ion (S→M) and coordination of water molecules through oxygen atoms (O→M). These data also indicate bidentate sulfur group of diphenyl dithiocarbamate coordinated to zinc ion. The result of molar conductivity shows 1:1 electrolytic nature of Cu (II) complex and non-electrolytic nature of Zn (II) complex. These data show octahedral geometry of Zn (II) complex and distorted octahedral geometry in the case of the Cu (II) complex. All the synthesized compounds were screened for their antibacterial and antifungal activity against bacterial and fungal strains. From the bioassay result, both metal complexes are potent against all bacterial strain. Cu (II) complex and Zn (II) complex appeared to display strong to inhibitory effect (25-29 mm) and (23-29 mm) respectively.