Some New Four Coordinated Hg(II) Complexes: Synthesis, Characterization, Electrochemical Behavior, Antibacterial/Antifungal Properties, and Theoretical Investigation

Abstract

Five mercury(II) complexes of a recently synthesized bidentate Schiff base ligand were prepared. All mercury(II) coordination compounds were characterized perfectly with the aid of elemental analysis, FTIR, 1H NMR, 13C NMR, UV-Visible, and molar conductance. Morphology of mercury bromide particles as typical one in the view point of shape and size were qualified by SEM. Electrochemical behaviors of Hg(II) complexes as compared with ligand were evaluated by using cyclic voltammetry method. The results showed a similar redox behavior for coordinated ligand in complexes with respect to free ligand. Antibacterial/antifungal properties of the compounds were checked against three Gram-negative bacteria Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 9027), Salmonella spp., and two Gram-positive bacteria Staphylococcus aureus (ATCC 6538) and Coryne- bacterium renale, and three fungal strains (Aspergillus niger, Penicillium chrysogenum, and Candida albicans). The results revealed acceptable antibacterial/antifungal activities for most of the compounds. HgL(N3)2 showed remarkable activity against Penicillium chrysogenum. Furthermore theoretical investigation of ligand and mercury complexes was performed by Gaussian 98 at the UB3LYP/LANL2MB level of theory. Some structural and energetic data such as bond length, bond angle, torsional angle, dipole moment of compounds, Gibbs free energy, and enthalpy and entropy of complex formation were evaluated.