AN INVESTIGATION OF THE Cu(II) COMPLEXES OF CERTAIN CEPHALOSPORIN ANTIBIOTICS: SPECTRAL, THERMAL, AND PHOTOCHEMICAL STUDIES

摘要

The following Cu(II) complexes of some cephalosporin antibiotics were synthesized and characterized: (Cu(ATB)Cl)-xH_2O, (Cu(ATB)_2) centre dot xH_2O and (Cu(ATB)_2) centre dot xH_2O, where HATB = cephalexin, cephapirin, cefamandole, cefuroxime or cefotaxime, H_2ATB = ceftazidime and x = 1-4. The stoichio-metries and structures of the complexes were deduced from their elemental analyses, IR and electronic spectra and thermal decomposition. Thermal stabilities of the complexes were discussed and kinetic parameters were calculated using the Coats-Redfern and Horowitz-Metzger equations. The photochemical behaviour of the complexes was investigated. Upon irradiation, the Cu(II) complex of cefamandole underwent two competitive processes, one is photodegradation, the other is intramolecular hydrogen abstraction, as indicated from the spectral changes. The remaining studied Cu(II) complexes behave similar to their corresponding free antibiotics.