Abstract

The identification of metal complex–DNA interaction is of fundamental importance to understanding the molecular basis of therapeutic activity 1, 2. Metal complexes are well known to accelerate the drug action and the efficiency of a therapeutic agent can often be enhanced upon coordination with metal ions. The pharmacological activity has also been found to be highly dependent on the nature of the metal ion and the donor sequence of the ligands, as different ligands exhibit different biological properties 3, 4. In the present work a new Co (III) complexes of mixed ligands, 1, 10­phenenthroline (phen) and hydroxamic acid (L1 = AHA (acetohydroxamic acid), L2 = BHA (benzohydroxamic acid) and L3 = OHA (oxalohydroxamic acid) were synthesised and characterized by NMR, IR, UV­visible, mass spectrometer and elemental analysis. In the complexes, [Co(phen)2Ln]ClO4 (Ln = L1, L2, L3), the metal ion is coordinated by six atoms, one nitrogen and one oxygen atom from hydroxamic acid two oxygen atom from hydroxamic acid and 4N atom from co­ligand 1, 10­phenenthroline to form octahedral Co(III) complexes. All the metal complexes have been optimized by Gaussian 09 software. The interaction of these complexes with calf thymus DNA has been investigated by absorption spectroscopy, fluorescence spectroscopy and study of bacterial activity against Gram positive and Gram negative bacteria.