Metal complexes of moxifloxacin–imidazole mixed ligands: Characterization and biological studies

Solid complexes [M(MOX)(HIm)Clx]·nH2O, [M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cr(III)] and [Ag(MOX)(HIm)·2.5H2O]; MOX = moxifloxacin, HIm = imidazole were prepared and characterized using elemental analyses, IR spectroscopy, conductance measurements, UV–Vis spectra, ESR of the copper complex, magnetic moments measurements, 1H and 13C NMR for the nickel (II) complex and thermal analyses. The results indicate that moxifloxacin reacts as a bidentate ligand and is bound to the metal ions through the pyridone oxygen and one carboxylic oxygen, except for the silver (I) complex where the metal ion is chelated to the hydro pyridinium nitrogen. The activation energies, ΔE∗; entropies ΔS∗; enthalpies ΔH∗ and order of reactions have been derived from differential thermogravimetric (DTA) curves, using Horowitz–Metzeger method. The mixed ligands complexes were evaluated for their antibacterial activity against two bacterial species, namely Staphylococcus aureus (S. aureus), Escherichia coli (E. coli). Antifungal screening was studied against two species (Aspergillus flavus and Condida albicans). The complexes under investigation were found to possess better antibacterial agents than uncomplexed Moxifloxacin and have antifungal activity as well.