Role of anions (sulphate, nitrate, oxalate and acetate) on the antibacterial properties of cobalt(II), copper(II), nickel(II) and zinc(II) complexes with ONO, NNO and SNO donor pyrazinoylhydrazine-derived ligands

Some biologically active complexes of cobalt(II), copper(II), nickel(II) an d zinc(II) with pyrazinoylhydrazine-derived ONO, NNO and SNO donor Schiff-b ase ligands having the same metal ion but different anions such as sulphate , nitrate, oxalate and acetate have been synthesised and characterised on t he basis of their physical spectral and analytical data. In order to evalua te the role of anions on their antibacterial properties, these ligands and their synthesised metal complexes with various anions have been screened ag ainst bacterial species Escherichia coli. Pseudomonas aeruginosa, Staphyloc occus aureus, and Klebsiella pneumonge. The title studies have proved a def inative role of anions in increasing the antibacterial properties.