SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES OF HYDROXYTRIAZENES AND THEIR COPPER (II) COMPLEXES

Abstract

Bacterial pathogens that are resistant to current antibacterial drugs pose serious clinical challenges including high treatment costs, increased mortalities and opportunistic infections during surgical operations and in immunocompromised patients. There is therefore an urgent need to develop novel antibiotics to counter threats posed by resistant bacterial pathogens. In this study, hydroxytriazene ligands and their copper (II) complexes were synthesized by the coupling of aryl hydroxylamines and diazonium salts of aromatic amines. The synthesized compounds were characterized by micro-elemental analysis, Fourier Transform Infrared (FT-IR) spectroscopy, Ultraviolet-Visible (UV-Vis) spectroscopy, Proton-Nuclear Magnetic Resonance (¹H-NMR) spectroscopy and molar conductivity measurements. The target hydroxytriazene ligands and their copper (II) complexes were obtained in high yields and purity. The synthesized complexes were non-electrolytes and exhibited a 1:2 metal to ligand stoichiometry.The synthesized compounds were all inactive against Pseudomonas putida, Salmonella enteriditis, Klebsiella pneumoniae,enteropathogenic Escherichia coli, enteroaggregative Escherichia coli, and enterohaemorrhagic Escherichia coli. Ligands (L₁-L₅) were active against Vibrio cholera (25-50 μg/ml) and Proteus mirabilis (12.5-25 μg/ml).  Complexes Cu-L₁and Cu-L₂ were active against Vibrio cholerae(50 μg/ml) while complexes Cu-L₁ to Cu-L₄were active against Proteus mirabilis (12.5-25 μg/ml). The synthesized compounds are promising antibacterial agents for both Gram-positive and Gram-negative bacterial strains.