Complexes of nalidixic acid with some vital metal ions: Synthesis, chemical structure elucidation, and antimicrobial evaluation

Complexes of nalidixic acid with Ca(II), Mg(II), Zn(II), Fe(III), and VO(II) ions, have been synthesized and characterized by means of microanalysis, conductance, IR, NMR and UV-Vis spectroscopy and thermogravimetric (TGA/DTG and DTA) measurements. The ligand coordinates in a bidentate mode via one carboxylate oxygen atom and the oxygen atom of the pyridine carbonyl group. The kinetic thermodynamic parameters such as: activation energy E*, Delta H*, Delta S*, and Delta G* have been estimated using Coats and Redfern as well as Horowitz-Metzger equations. Antimicrobial activity of the obtained complexes against some kinds of bacteria and fungi has been evaluated.