Synthesis, characterization and antimicrobial activities of leucine-acetylacetone Schiff base and its Mn(II), Ni(II) and Cu(II) complexes

Abstract

A Schiff-base derived from leucine and acetylacetone, and its Cu(II), Ni(II) and Mn(II) complexes were synthesized and analyzed based on their melting point/decomposition temperature, solubility, molar conductance, magnetic and infrared analyses. Physical and analytical data suggested that the Schiff base acted as tridentate ligand towards metal ion via azomethine-N, deprotonated-O of carboxylic group and enolic-O group of acetylacetone. All the c mplexes have lower molar conductance values (6.4-17.7Ω^-1cm²mol^-1), indicating that they are non-electrolyte. The magnetic moment values showed that all the metal ions in the complexes are paramagnetic. The synthesized ligand and its respective metal complexes were screened for their antibacterial activity against Staphylococcus aureus (Gram-positive), Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Klebsiella pneumonia (Gram-negative) and antifungal activity against Candida albicans, Fusarium solani and Aspergillus fumigatus. The results of these studies revealed that the compound (ligand) and its metal complexes showed significant antibacterial and antifungal strength at high concentrations.

Keywords: Schiff base, acetylacetone, leucine, antimicrobial activity, Synthesis