Some divalent transition metal complexes were synthesized by the reaction of the chlorides of Co(II), Fe(II), Mn(II) and Ni(II) with Schiff bases derived from the reaction of 4-methoxybenzaldehyde with p-anisidine in methanolic solution. The Schiff base [L] was obtained as grey colored crystals with a melting point of 153ºC. The metal(II) complexes [ML] obtained were all colored and decomposed at the range of 171-177 ºC. Molar conductivity measurements for the complexes carried out using DMSO were found to be at the range of 1.19-16.07Ω–1mol–1cm2. The small values could be an indication for non-electrolytic nature of the complexes. From the values of the magnetic moment (4.40–5.85 B.M), all the complexes were found to be paramagnetic and soluble in most common solvents. The infra-red spectral analysis indicates complexation has taken place due to metal-nitrogen bands at the range, 632–645cm-1 for [ML]. The metal-ligands ratio in all the complexes was 1:2 as obtained from the Job’s method of continuous variation. The percentage composition of the metals and their corresponding ligands were found gravimetrically and the results obtained were in good agreement with the calculated values. The ligands and their corresponding complexes were screened in-vitro for their antimicrobial activity against Escherichia coli, Aspergillus fumigatus, Salmonella typhi, Staphylococcus aureus, Aspergillus flavus and Mucor species using the paper-discs diffusion method. Inhibition properties of the compounds showed that the complexes have higher antimicrobial activities than the ligands which could be attributed to chelation.
Keywords: Complexes, Imine, antimicrobial activity and chelation., ligands, paramagnetic
