Metal complexes of the third generation quinolone antibacterial drug sparfloxacin: preparation, structure, and microbial evaluation

The interactions of yttrium chloride, zirconium chloride, and uranium nitrate with sparfloxacin (SPAR) in ethanol, methanol, and acetone were studied. The isolated solid complexes were characterized by elemental analysis, infrared, 1H-NMR and electronic spectra, and thermogravimetric analysis. The results support the formation of {[}Y(SPAR)2Cl2]Cl 12H2O, {[}ZrO(SPAR)2Cl]Cl 15H2O, and {[}UO2(SPAR)3](NO3)2 5H2O. Infrared spectra of the isolated solid complexes indicate that SPAR is bidentate through the ring carbonyl oxygen and one oxygen of carboxylate. The calculated bond length and force constant, F(U=O), in the uranyl complex are 1.747 angstrom and 655.29 Nm-1, respectively. The antimicrobial activities of the ligand and metal complexes have been tested against bacteria Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa) and fungi Penicillium rotatum (P. rotatum) and Trichoderma sp., showing that the complexes exhibit higher antibacterial activity than SPAR.