Synthesis, characterization and anti-bacterial activity of Schiff Base and its mixed ligand complexes of Cr (II) and Co (II) containing vanillin and 2-aminophenol

Abstract

Schiff Base are organic ligand that contained azomethine linkage (-HC=N-) which shows biological importance. Schiff Base from vanillin and 2-aminophenol was synthesized in 1:1 mole ratio. The complexes of Cr (II) and Co (II) from Schiff Base in 1:2 mole ratio metal-ligand (M-L) and the mixed ligand complexes from Schiff Base and 2-aminophenol in 1:1:1 mole ratio ligand-metal-ligand(L-M-L) were synthesized and characterized based on solubility, melting point, conductivity, Fourier transform infrared spectroscopy (FTIR) and ultraviolet (UV). The solubility result shows that, dimethyl sulfoxide(DMSO) dissolved all the complexes. The results obtained from melting point, conductivity indicated purity and non-electrolytic of the complexes respectively. In metal complexes, the infrared data showed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group and oxygen in phenolic group. In mixed ligand complexes, the infrared data revealed the ligands is coordinated to the metal ion through azomethine nitrogen, oxygen in methoxyl group, oxygen in phenolic group and nitrogen in amino group. The results showed a six coordinate octahedral geometry for these complexes. The ligands and the metal complexes were examined for their antibacterial activity using agar well diffusion method against Escherichia coli, Staphylococcus aureus, streptococcus pyrogens , Klebsiella pneumonia (gram - bacteria), and Bacillus sutilis, Staphylococcus aureus (gram + bacteria). In comparing the results, the complex of Co(HL¹)₂ has greater zone of inhibition against the tested organism than the free ligands as antibacterial agent.