Synthesis, Characterization and Antimicrobial Studies of Metal(II) Complexes with A Schiff Base Derived From 2, 4-Dihydroxybenzophenone with Ethylenediamine

Metal complexes of Mn(II), Cu(II) and Ni(II) with a Schiff base ligand (HL) derived from condensation of 2, 4-dihydroxybenzophenone with ethylenediamine were synthesized in an alcoholic medium. The complexes were characterized on the basis of melting point, conductivity, solubility, IR and UV/Visible spectral studies. The in vitro antibacterial activities of the complexes were tested against different strains of bacteria such as Gram positive (Staphylococcus aureus, Streptococcus pyogenes), Gram negative (Escherichia coli, Salmonella typhi) and fungus Candida albicans. The complexes were formed in moderate yields (29–41%) and they are of various colours and have sharp melting points. The complexes were either soluble or slightly soluble in most of the polar solvents used. The IR spectra revealed that the complexes coordinated through azomethine nitrogen and phenolic oxygen of the ligands. Further conclusive evidence of the coordination of the Schiff base with the metal ions was shown by the appearance of new bands due to v(M-N) and v(M-O) in the metal complexes. The UV/visible electronic spectra further revealed that the Mn(II), Cu(II) and Ni(II) complexes are octahedral. Measured molar conductance (5.80 x 10⁻³-44.30 x 10⁻³ Scm²mol⁻¹) showed that the complexes are non-electrolytes. The results of the anti-microbial study showed that the complexes had more potent activities than their free ligand.