Stability studies in relation to IR data of some schiff base complexes of transition metals and their biological and pharmacological studies

Abstract

Schiff bases derived from salicylaldehyde and 2-substituted anilines and their Cu(II), Ni(II) and Co(II) complexes have been synthesized and characterized by their elemental analysis, TGA, IR and electronic spectral studies, molar conductance and magnetic susceptibility measurements. The mode of bonding between Cu(II), Ni(II) and Co(Il) and Schiff bases has been studied by IR spectrophotometry. The shift in the band positions of the groups involved in coordination has been utilized to estimate the metal- nitrogen bond lengths. The results obtained are in good agreement with the values of metal-nitrogen modes and ligand-field splitting energy (10 Dq). The antimicrobial activities of the synthesized ligands and their metal complexes have been determined on Gram-positive ( Staphylococcus aureus), Gram- negative ( Escherichia coli) bacteria and on fungi like Aspergillus niger, Aspergillus nidulense and Candida albicans. The antimicrobial activity of the organic ligands increased several folds on chelation as compared to the ligand molecule alone. However, their anti-inflammatory activity showed a different pattern; the activity of some ligands was more than their respective metal chelates. It is interesting to note that only cobalt complexes exhibited anti-inflammatory activity.