Synthesis, antimicrobial activities of metal (ii) complexes from salicylaldehyde and valine Schiff base

Complexes formed from the interaction of Fe(II), Co(II), Cu(II), and Zn(II) with Schiff base derived from salicylaldehyde and valine have been synthesized and characterized on the basis of melting point/decomposition temperature, solubility, molar conductance, UV spectroscopy and infrared spectral analysis. The Schiff base melted at a temperature of 208oC while the synthesized metal (II) complexes decomposed at a temperature range of 220-241°C. All the complexes were found to be soluble in water and DMSO but insoluble in acetonitrile, ether and hexane. Octahedral geometry around these metal ions has been proposed on the basis of magnetic and spectral studies. The synthesized Schiff base as well as the complexes were tested against the bacterial strains comprising Staphylococcus aureus (Gram positive), Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis and Klebsiella pneumonia (Gram negative) and two fungal species; Aspergillus fumigatus and mucor species. A comparative study of inhibition values of the Schiff base and its complexes indicated that the complexes exhibited higher antimicrobial activity than the free ligand.