Synthesis, Characterization and Antimicrobial Studies of Ampicillin Complexes

The complexes obtained were characterized by solubility in methanol, acetone, ethanol and distilled water in which only the cobalt complex is soluble in hot acetone and methanol. Melting points of the complexes were 270°C and 251°C for the Cu and Co complexes, respectively. The copper complex was found to have a lower conductance (5.46 x 10-6 Ω-1 mol-1 cm2) than the cobalt complex (5.58 x10-6 Ω-1 mol-1 cm2). Infrared spectroscopic analysis shows a hypsochromic shift in ν(C=O) band of the spectra from 1396.79 cm-1 for the ampicillin ligand to 1268.55 cm-1 and 1156.61 cm-1 for the complexes of copper and cobalt, respectively, while insignificant shifts for the ν(C-N), ν(C=N) and ν(N-H) bands were noted. These band shifts indicate that the coordination occurs through carbonyl oxygen of the complexes. Investigation of antimicrobial activity was also carried out on gram negative and positive microorganisms of Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia. The complexes were found to be active on Escherichia coli showing a high zone of inhibition, followed by the Klebsiella isolates, and insignificant action on Staphylococcus aureus. Based on the inhibition zone findings, the synthesized complexes exhibit higher activities for these microorganisms than the parent ligand.