ANTIBIOTIC ACTIVITY OF NEW SPECIES OF SCHIFF BASE METAL COMPLEXES

Bacterial resistance is a growing challenge facing drug design scientists to find new medications or update commonly used antibiotics. The objective of this study was to synthesize, structure and highlight biological features of new species of metal-organic complexes [(MCl2)(2)Li] {M = Ni, Cu, Li = N,N'-1,4-Phenylenebis(methanylylidene)bis(ethane-1,2-diamine)} and [(NiCl2)(2)L-2]. The Schiff base ligands were prepared in an excellent yeilds by adding terephthalaldehyde to 1,2-ethane-diamine or 1,4-butane-diamine. Three binuclear Schiff base metal complexes were synthesized in a simple one-pot reaction by reacting the corresponding metal chloride (NiCl2 and CuCl2) salts with the Schiff base ligands {L-1 = N,N'-(1,4 phenylenebis(methanylylidene)bis(1,2-diethylamine)) and L-2 = N,N'-(1,4 phenylenebis(methanylylidene)bis(butane-1,4-diamine))}. The obtained Schiff base metal complexes were analytically, characterized by a set of spectroscopic techniques such as FT-IR spectroscopy, H-1 NMR spectra, and mass spectra. The structures characterization studies suggest that Schiff base ligands behave as N bidentate ligands for nickel and copper metal centers, which are known to act as Lewis acids. The biological activity of the Schiff base of nickel(II) and copper(II) complexes was tested by using the broth dilution method. The complexes showed antibacterial activity against all gram-negative and gram-positive bacteria (Enterobacter cloacae G-, Citrobacter G-, Pseudomonas G-, Klebsiella G-, Staphylococcus G+, and Streptococcus G+) that used in the trials. It is concluded that Schiff base metal complexes are a good candidate for the antibacterial drug because of its good activity against gram-negative and gram-positive strains demonstrated in the present study, as well as in other studies in the literature.