Synthesis, Spectral and Antimicrobial Activity of Some Mixed Ligand Cu(II) Complexes of Schiff Base 2-[(3-Hydroxy Phenylimino)Methyl]-4-Nitrophenol with Some Amino Acids

The mixed ligand complexes of Cu(II) with 2-[(3-hydroxy phenylimino)methyl]-4-nitrophenol (HPIMNP) as primary ligand and amino acid (valine, alanine or glutamine) as secondary ligand have been synthesised and characterised. The complexes were characterised by elemental analysis, conductivity measurement, ¹H NMR, IR and ultraviolet–visible (UV–vis) spectral studies. Schiff base acts as bidentate ligand coordinating through deprotonated phenolic oxygen and azomethine N-atom. The conductivity studies of the complexes in Dimethyl sulphoxide at 10⁻³ M concentration indicate their non-electrolyte nature. From analytical and spectral data, the stoichiometry of these complexes is found to be 1:1:1 and exhibited octahedral geometry. Tube dilution method has been used to study the antimicrobial activity of Schiff base and its mixed ligand complexes. It was found that the mixed ligand complexes have higher anti-microbial activity than the Schiff base.