METAL-ION INTERACTIONS WITH SOME ANTIBIOTIC DRUGS OF PENICILLIN FAMILY .4. EQUILIBRIUM STUDY ON THE COMPLEX-FORMATION OF COBALT(II), NICKEL(II) AND ZINC(II) WITH AMPICILLIN

Combined pH-metric And spectrophotometric study on the complex formation of M(2+) ions (M = Co, Ni and Zn) with ampicillin, (alpha-d-(-)nminobenzylpenicillin), ampH(+) at 37 degrees in aqueous solution at a fixed ionic strength, I = 0.1 M NaNO3, provided evidence of formation of complexes of the types : M(amp)(+), M(amp)(2), M(H(-1)amp), M(H(-1)(-)amp)(amp)(-) and M(H(-1)amp)(2)(2-). Ambidentate nature of the ligand and the possible mode of its coordination with the M(2+) ions st different pH values were elucidated.