Abstract

SYNTHESIS, CHARACTERIZATION, AND ANTIBACTERIAL ACTIVITY OF METAL COMPLEXES OF 4-METHYL-N'-(4-NITROBENZYLIDENE) BENZOHYDRAZIDE

Emmanuel Olusola Malumi*, Afamefuna Elvis Okoronkwo, Bodunde Joseph Owolabi and Victor Olusegun Oyetayo and Emmanuel Gurgur

ABSTRACT

A series of 4-methyl-N'-(4-nitrobenzylidene) benzohydrazide metal complexes obtained from p-toluic acid hydrazide and p-nitro benzaldehyde were synthesized, characterized and screened for antibacterial activity. The ligand, 4-methyl-N'-(4-nitrobenzylidene) benzohydrazide and its metal complexes were characterized by melting point and decomposition temperature, elemental analysis, solubility, conductivity measurement, atomic absorption spectroscopy, Nuclear Magnetic Resonance (NMR) spectroscopy, magnetic susceptibility measurement, electronic and infrared spectroscopies, TGA/DTG and TOF-Mass spectroscopy. The results of the spectroscopic studies revealed that the ligand function as bidentate ligand, condensing through Oxygen atom of the carbonyl group and Nitrogen atom of the azomethine group in the complexes. All metal complexes were paramagnetic except for Zn (II) complex was diamagnetic as expected. Furthermore, the elemental analysis, TOF-mass spectroscopy and conductivity measurement revealed a 1:2 metal to ligand confirmation and formulated masses of the complexes that were electrolytic in nature except for Cu (II) that was covalent. NMR spectrum further confirmed the structure of the ligand. The TGA/DTG of the ligand showed that the ligand was relatively stable. The antibacterial activities of the compounds against four isolates of microbes that is Eschericha Coli (E. Coli), Klebsiella pneumoniea (K.pneumoniea), Staptococcus pyogenes (s.pyogenes) salmonella typhi (S.typi) were studied. The results of the antibacterial activity of the compounds revealed that the positive control was active against all bacterial strains while metal complexes showed higher activities against the bacterial strains except for S.typhi (which bio-metalated the compounds) than the ligand that showed no activity.

Keywords: Schiff bases, Metal complexes, Antibacterial activity, Hydrazone derivatives, Thermal decomposition, Japp-Klingemann reaction.