Synthesis, characterisation and antibacterial study of copper(ii) complexes of new benzylacetone-benzoylhydrazone and its para-nitro and para-hydroxy substituted analogues

Three new ligands viz, benzylacetone-enzoylhydrazone [babh (L1)], para-hydroxy-benzylacetone-benzoylhydrazone [p-OH-babh (L2 )] and para-nitrobenzylacetone-benzoylhydrazone [p-NO2 -babh (L3 )], were synthesised by condensation of hydrazides with benzylacetone. The ligands were each reacted with copper(II) salts (chloride, nitrate, acetate and sulphate) to form complexes with the general formulae ML2X2 (X = Cl , NO3 , AcO- and SO4 ). The compounds were characterised using 1H NMR, Infrared and UV-Visible spectroscopy, as 4 well as CHN elemental analyser and magnetic susceptibility measurements. Antibacterial activity of the ligands and synthesised complexes were investigated using the agar diffusion method against two Gram-positive (Staphylococcus aureus NCTC 6571 and Bacillus cereus ATCC 11778) and three Gram- negative (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 10145, Klebsiella pneumonia ATCC 13048) bacterial strains. However, the observed antimicrobial strength of the synthesized compounds was rather low.