Synthesis, characterization and antibacterial activities of novel mixed ligands (azo anils and oxalate ion) copper(II) complexes

Abstract

Three azo anils ligands; 4-[(4-nitrophenyl)diazenyl]-2-[(phenylimino)met-hyl]phenol (L1), 2-{[(2-methylphenyl)-imino]-methyl}-4-[(4-nitrophenyl)diazenyl]phenol (L2) and 2-[(naphthalen-1-ylimino)-methyl]-4-[(4-nitrophenyl)diazenyl]-phenol (L3) were synthesized and characterized using elemental analysis, FT/IR spectroscopy, ¹³C and ¹H NMR spectroscopy and UV-Vis spectroscopy. Similarly three mixed ligand complexes, {(L1)Cu(II)(OX)}, {(L2)Cu(II)(OX)} and  {(L3)Cu(II)(OX)} constituting of azo anils and oxalate ion were also synthesized and characterized using elemental analysis, atomic absorption spectroscopy, FT/IR spectroscopy and UV-Vis spectroscopy and square planner geometry was suggested for Cu(II) complexes. Antibacterial activities of free ligands (azo anils and oxalate) and Cu(II) complexes were determined. Gram positive (Bacillus subtilis and Staphylococcus aureus) and Gram negative (Enterobacter aerogenes and Escherichia coli) bacteria were used for antibacterial study. The results have shown that Cu(II) complexes have privileged antibacterial activities compared to free ligands. The enhancement in antibacterial activities of transition metal complexes compared to corresponding free ligands may be attributed to structural symmetry of transition metal. The order of antibacterial activities of transition metal complexes, {(L1)Cu(II)(OX)} ˃ {(L2)Cu(II)(OX)} ˃ {(L3)Cu(II)(OX)}.

KEY WORDS: Azo anils, Oxalate ion, Mixed ligands Cu(II) complexes, Spectroscopic study, Antibacterial activities

Bull. Chem. Soc. Ethiop. 2015, 29(3), 399-406.

DOI: http://dx.doi.org/10.4314/bcse.v29i3.7