Synthesis, antimicrobial, DNA-binding and photonuclease studies of cobalt(III) and nickel(II) Schiff base complexes.

New metal complexes of the type M(nih)(L)(n)·xH(2)O and M(nih)(2)·xH(2)O (where M=Co(III) or Ni(II), L=1,10-phenanthroline (phen)/or 2,2' bipyridine (bpy), nih=2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone, n=2 or 1 and x=3 or 2) have been synthesized and characterized by elemental analysis, magnetic, IR and (1)H NMR spectral data. The electronic and magnetic moment 2.97-3.07 B.M. data infers octahedral geometry for all the complexes. The IR data reveals that Schiff base (nih) form coordination bond with the metal ion through azomethine-nitrogen, phenolic-oxygen and carbonyl-oxygen in a tridentate fashion. In addition, DNA-binding properties of these six metal complexes were investigated using absorption spectroscopy, viscosity measurements and thermal denaturation methods. The results indicated that the nickel(II) complex strongly bind with calf-thymus DNA with intrinsic DNA binding constant K(b) value of 4.9×10(4) M(-1) for (3), 4.2×10(4) M(-1) for (4), presumably via an intercalation mechanism compared to cobalt(III) complex with K(b) value of 4.6×10(4) M(-1) (1) and 4.1×10(4) M(-1) (2). The DNA Photoclevage experiment shows that, the complexes act as effective DNA cleavage agent.