SYNTHESIS, PHYSICOCHEMICAL AND ANTIMICROBIAL EVALUATION OF A TETRADENTATE SCHIFF BASE LIGAND WITH Hg(II), Pb(II), Mn(II), Cd(II), Fe(III) AND Cr(III) METAL COMPLEXES

Abstract

Schiff base ligand derived from the condensation of 2-hydroxybenzaldehyde with ethylenediamine was synthesized and characterized by elemental analysis, M.pt, IR and 1 HNMR. The elemental analysis revealed a 1:2 molar ratio (amine:aldehyde) for the ligand. The complexes formed from the ligand were characterized by elemental analysis, M.pt, solubility, conductivity, IR and electronic spectra. The complexes showed various colours ranging from yellow, brown and golden. The ligand melted at 210 o C whereas the complexes melted in the range 200-270 o C. This high melting point indicates thermal stability of the compounds. The molar conductivities of the complexes (15.00-40.20 Scm 2 mol-1) indicates that they are non-electrolytes in the organic solvents used for the investigation. The comparison of the IR spectra of the Schiff-base and its metal complexes showed that the Schiff base acted as tetradentate ligand. The electronic spectral data indicated d-d transitions in the visible region in some of the complexes. Some metal-ligand charge transfer (MLCT) or vice versa were also observed around 28,600 cm-1 in the complexes. Antimicrobial results revealed that [Hg(HL)Cl] complex appeared to have promising antimicrobial effect on S. pyogenes when compared to the other complexes.