Abstrait

Synthesis, characterization, redox and biological screening studies of amino acids ternary complexes of nickel(II)with isonitrosoacetophenone

N.Tidjani-Rahmouni, S.Djebbar, O.Benali-Baitich*

Mixed ligand complexes havingmolecular formulaeNi(INAP)L (H2O)2where INAP= isonitrosoacetophenone and L= amino acid such as L-Histidine, LPhenylalanine and L-Tryptophan have been synthesized. Characterization of these complexes was carried out by elemental analyses, UV-Vis, IR and 1H NMR spectroscopy. Molar conductance of the complexes in DMSO solution at 10-3 M concentration indicate their non-electrolyte nature. The IR spectra support the binding of the ligands with two N and two O donor sites to the metal (II) ion giving an arrangement of N2O2donor groups. The magnetic and spectral data indicate an octahedral geometry for all the complexes. Electrochemical studies of the complexes have been investigated by cyclic voltammetry which shows that the chelated structure and electron donating effects of the ligands substituents are among the factors influencing the redox potentials of the complexes. The antioxidant activity which is related to redox properties was evaluated for Nickel complexes by the means DPPH assay. The antimicrobial activitywas investigated against Gram-positive: streptococcus pyogenes, staphylococcus aureus and bacillus subtilis and Gram-negative: Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and one yeast: Candida albicans. The Nickel complexes were found to be more active against Gram-positive than Gramnegative bacteria.