Synthesis, spectroscopic and biological studies of Cobalt(II), Nickel(II) and Iron(III) mixed antibiotic metal complexes

Complexes of Co(II), Ni(II) and Fe(III) with ampicillin and amoxicillin as ligands have been synthesized in aqueous solution and characterized by physical, IR and electronic spectra. The elemental data obtained agreed with the general formula [M(A)(C)].3H2O, where A= amoxicillin, C= ampicillin and M= metal ion. The IR spectra shows that the ligands coordinated to the metal ions through v(C=O), v(COO) and v(N-H) respectively due to their structural similarities. Electronic spectral data further revealed the probable geometry of Co(II) and Fe(III) complexes to be octahedral, while that of Zn(II) complex is tetrahedral. All the complexes and the ligands were screened for their biological activity on some selected bacterial species which includes:- Staphylococcus aurous, Streptococcus pyogene, Bacillus subtilis, Escherichia coli, Salmonella shigela, Klebsiella pneumoniae and Pseudomonas aeuroginosa. The results of biological activity indicated that the Co(II) and Ni(II) complexes have increased activity while Fe(III) had decreased activity. The complexes are also soluble in polar solvents.