Ofloxacin metal complexes: Synthesis, characterization, analytical properties, and DNA binding studies

The present work comprises the synthesis of ofloxacin (OFL) complexes with various transition metals. Two types of complexes [Cu(OFL)Cl₂].H ₂O, [Pt(OFL)CI₂].3H₂O, [Zn(OFL) ₂]2CI.4H₂O, [Ru(OFL)₂ClH₂O]2CI. 4H₂O, and [Fe(OFL)₂Cl]2CI.5H₂O were obtained. The complexes were characterized by different physicochemical, spectroscopic, and elemental analysis. The thermal decomposition behaviors of metal complexes were investigated in nitrogen atmosphere using TG and DTA techniques. Results suggest that OFL interacts with the metals as a monoanionic bidentate ligand. These complexes were also tested for their antibacterial activity against nine different microorganisms, and the results were compared with the parent drug. The electrochemical properties of all complexes have been investigated by cyclic voltammetry using glassy carbon electrode. The oxidation/reduction of metal complexes was irreversible/reversible and exhibited diffusion controlled process depending on pH. The dependence of intensities of currents and potentials on pH, concentration, scan rate, nature of the buffer was investigated. The oxidation/reduction mechanism was proposed and discussed. The DNA binding activity of the complexes was evaluated by examining their ability to bind to calf-thymus DNA (CT DNA) with UV spectroscopy. UV studies of the interaction of the OFL and complexes with DNA have shown that these compounds can bind to CT DNA. The binding constants of the OFL and complexes with CT DNA have also been calculated.