Synthesis, characterization and interaction with DNA of mononuclear metal complexes with oxolinic acid

Abstract

Seven new neutral mononuclear metal complexes of VO 2+, Mn 2+, Fe 3+, Co 2+, Ni 2+, Zn 2+ and Cd 2+ with the quinolone antibacterial agent oxolinic acid (=Hoxo) have been prepared and characterized with physicochemical and spectroscopic techniques. In all the complexes, oxolinic acid acts as a bidentate deprotonated ligand bound to the metal through the pyridone oxygen and one carboxylate oxygen. The metals in all the complexes are six-coordinate with slightly distorted octahedral geometry. The lowest energy model structures of the complexes Fe(oxo) 3, VO(oxo) 2(H 2O) and Mn(oxo) 2(H 2O) 2 have been determined with molecular modeling calculations. The ability of all the complexes to bind to calf-thymus DNA has been investigated with diverse spectroscopic techniques.