Synthesis, Characterization and Antimicrobial Studies Of A Schiff Base Derived From 1,8 Diaminonaphthalene And 2-Hydroxy-1-Naphthaldehyde With Its Metal Complexes

The metal complexes of Mn(II), Hg(II), Pb(II), Cd(II), Fe(III) and Cr(III) have been synthesized from a Schiff base ligand (HL) derived from the condensation of 2-hydroxy-1naphthaldehyde with 1,8 diaminonaphthalene. The compounds were characterized by elemental analysis, M.pt, IR and I HNMR. The elemental analysis revealed a 1:2 molar ratio (amine:aldehyde) for the ligand (HL) and 1:1 molar ratio (M:L) for the complexes. The IR spectra showed the azomethine (>C=N) bond around 1624 cm -1 in the ligand. This was shifted to higher frequencies in the complexes. The doublet signals in the range 10.08-10.82 ppm in the I HNMR of the ligand is assigned to the azomethine proton (>C=N) group. The multiplet signals in the range 6.30-8.90 ppm, indicated aromatic proton. The synthesized compounds were assayed for antibacterial activity against some pathogenic bacteria such as Gram positive: Staphylococcus aureus, Streptococcus pyogenes) and two Gram negative (Escherichia coli, Klebsiella pnuemonae) and two fungi (Aspergillus niger and Candida albicans) using filter paper disc agar diffusion method.