Cinoxacin complexes with divalent metal ions. Spectroscopiccharacterization. Crystal structure of a new dinuclear Cd(II) complexhaving two chelate-bridging carboxylate groups. Antibacterial studies

摘要

Several cinoxacin (HCx) complexes with divalent metal ions have been prepared and characterized by spectroscopic techniques. The crystal structure of [Cd-2(Cx)(4)(H2O)(2)] . 10H(2)O has been determined by X-ray diffraction, The complex is triclinic, space group P (1) over bar with unit-cell dimensions: a = 10.412(2), b = 11.119(2), c = 13.143(6)Angstrom, alpha = 76.78(4)degrees, beta = 74.59(3)degrees, gamma = 77.12(3)degrees, V= 1406.0(8) Angstrom(3). In this complex each cadmium atom is heptacoordinated; the metal environment is formed by two O-keto and two O-carbox atoms from two different cinoxacinate monoanions, two carboxylate oxygen atoms from a third cinoxacinate ligand and by one water oxygen atom on the seventh position, Two of the cinoxacinate ions act as tridentate chelate and bridging ligands and the other one as a bidentate chelate ligand. In the bridging monoanions the carboxylate group is behaving as a chelate ligand, All the complexes were screened for their activity against several bacteria, showing activity similar to that of cinoxacin. Additionally, the number of bacteria killed after 3 h of incubation with cinoxacin, [Cu(Cx)(2)] . 2H(2)O and [Co(Cx)(3)]Na . 10H(2)O complexes was determined against E. coli ATCC 25922; the copper compound presents paradoxical effect which has been described and related to the mechanism of action of quinolones. (