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

M Ameen,A Naseer,S R Gilani,I Shoukat,S D Ali

doi:10.4314/bcse.v29i3.7

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

Highlights

Schiff bases are gaining a centre of attention for biochemist due to their medicinal properties and are being used in medicinal products [1]
We are reporting antibacterial activities of three newly synthesized azo anils ligands and their three mixed ligands complexes with Cu(II) complexes using oxalate ion as second ligand
Electronic spectra regarding mixed ligands complexes of copper(II) exhibited two absorption bands at 288 nm and 330 nm which were corresponded to d-d and 2B1g 2Eg, transitions and square planner geometry was suggested for Cu(II) complexes as reported earlier [24]

Summary

Introduction

Schiff bases are gaining a centre of attention for biochemist due to their medicinal properties and are being used in medicinal products [1]. Reddish brown solid; yield: 75%; m.p. 205-207 oC; UV-Vis (DMSO) λmax/nm: 292 and 337; FT/IR (KBr, cm−1): 3270-3370 (-OH stretching of phenolic proton), 3640-3740 (H2O, stretching of coordinated water), 3053 (C-H, stretching of aromatic hydrogen), 1660 (-C=N, stretching of azomethine group), 1608 (-C=C-, stretching of aromatic ring), 1435 (-N=N-, stretching of azo group), 1257 (C-O, stretching of aromatic carbon and phenolic oxygen); 1H NMR (DMSO-d6) /ppm: 12.50 (S, 1H), 8.50 (S, 1H), 8.40 (S, 2H), 8.0 (S, 2H), 7.80 (S, 2H), 7.50 (S, 2H), 7.20 (S, 1H), 7.25 (S, 2H), 6.95 (S, 1H); 13C NMR (DMSO-d6) /ppm: 163.20 (C-10), 160.0 (C-5), 152.40 (C-14), 151.50 (C-6), 150.40 (C-15), 129.20 (C-22), 126.10 (C-13) ,125.50 (C-4), 124.50 (C-12), 123.40 (C-23), 118.50 (C-8), 113.2 (C-3).

Results

Conclusion