Synthesis, characterization and biological studies on some metal complexes with Schiff base ligand containing pyrazolone moiety

1:2 Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base ligand Indal-4-AAP, derived from indole-3-carboxaldehyde and 4-aminoantipyrine were synthesized and characterized by elemental analyses, mass, IR, electronic spectra, magnetic moment, molar conductance and cyclic voltammetry. The complexes were found to have the general formulae [ML2Cl2] (M = Co(II), Ni(II), Cu(II) and Zn(II)). The IR results demonstrate that the co-ordination sites are the azomethine nitrogen and carbonyl oxygen atoms of the Schiff base ligand. The electronic spectral and magnetic measurement data indicate that the complexes exhibit octahedral geometry around the metal center. The in vitro biological screening effects of the synthesized compounds were tested against various microbial species and the results show that the metal complexes are more biologically active than the ligand. The DNA cleavage activity of the ligand and its complexes was assayed on pUC18 DNA using gel electrophoresis. The result shows that Ni(II), Cu(II), and Zn(II) complexes have completely cleaved the DNA.