Transition Metal Schiff Base Complexes with N, S and O Donors - Synthesis, Characterisation and Antimicrobial Studies

The Schiff base complexes of Thiophene-2-carboxaldehyde and L-histidine with Co(II), Ni(II), Cu(II) and Zn(II) were synthesized and characterized by elemental analysis, molar conductance, IR, UV-Vis, magnetic moment, CV, and thermal analyses (TG and DTA). All the complexes were found to be non-electrolytic in nature. FTIR spectra show that the Schiff base ligand is bound to the metal ions in a tridentate manner involving thiophene sulphur, azomethine nitrogen and carboxylato oxygen atoms. The fourth position in the coordination sphere is occupied by the chloride ion. The geometrical structures of Co(II),Ni(II) and Zn(II) complexes are found to be tetrahedral whereas Cu(II) complexes are square planar. The antimicrobial results show that the metal complexes were found to be more active than the ligand. The complexes showed increased nuclease activity in the presence of an oxidant when compared to the ligand.