Synthesis, characterization and biological studies of some homodinuclear complexes of zinc with second-generation quinolone drug and neutral bidentate ligands

The novel homodinuclear zinc(II) complexes with the quinolone antibacterial drugs ciprofloxacine and neutral bidentate ligands have been synthesized and characterized by elemental analysis, TG analyses and various spectroscopic techniques. The metal ion exhibits octahedral geometry with two water molecule in the inner sphere cavity environment. The interaction of complexes with DNA was determined using absorption titration, viscosity measurements and electrophoresis technique. The intrinsic binding constants (Kb) of complexes were determined, which were ranging from 1.0 × 104 to 3.5 × 104 per mole. Suggesting that complexes bind more strongly to DNA. Effect on viscosity has also been checked to authenticate the binding of metal complexes with DNA. An antimicrobial activity of all the ligands and metal complexes has been examined by minimum inhibitory concentration method (MIC).

One of the most critical tests to determine the binding mode in the solution state, in the absence of crystallographic structural data, is viscosity measurement. A classical intercalation mode similar to complex [Ru(phen)2(DPPZ)]2− is reflected by the increase in viscosity of DNA on successive increases in the [M]/[DNA] ratio.Figure optionsDownload as PowerPoint slide