Studies on Cobalt(II), Nickel(II), Copper(II) and Zinc(II) Complexes Involving a Bidentate Schiff Base Ligand

Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base, derived by the condensation of indole-3-carboxaldehyde and beta-alanine, were synthesized and characterized by elemental analysis, conductance measurements, IR, electronic spectra, magnetic measurements and powder XRD. The analytical data show the composition of the metal complex to be ML2, where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. IR results demonstrate the bidentate binding of the Schiff base ligand involving azomethine nitrogen and carboxylato oxygen atom. The electronic spectral measurements indicate that Co(II) and Ni(II) complexes have pseudo tetrahedral geometry, while Cu(II) complex is square planar. The magnetic measurements show paramagnetic behaviour for Co(II), Ni(II) and Cu(II) complexes. The powder XRD studies show that Ni(II) and Zn(II) complexes are crystalline, while the Co(II) and Cu(II) complexes are amorphous. The crystallite size of the Zn(II) complex was found to be in the nanocrystalline regime. Antimicrobial studies indicate that the metal complexes are found to be more active than the ligand. Among the metal complexes, the Co(II) and Cu(II) complexes were more active compared to that Ni(II) and Zn(II) complexes.