Synthesis, characterization, antimicrobial and theoretical investigation of a new mercury bromide complexes

Mercury is an extremely toxic element that is naturally present in the environment and also as a result of human activities. Analysis of biosystems with mercury ion becomes a problem of particular importance in view of the established toxic influence of this metal, associated with Cd and Pb to the group of the most toxic environmental pollutants. Recently, an increase in the concentration of this metal in living organisms has been observed. Its toxicity derives from the fact that it is rapidly localized intracellularly, mainly in the liver, and then bound to metallothionein forming a complex that is slowly transferred to the bloodstream to be deposited in the kidneys. This metal competes with Zn and blocks active sites of metal–enzymes and as a relatively soft acid it can dislodge Zn(II) in cysteine-coordinated zinc compounds or Ca(II) ions in bone cells. Therefore, investigation of possibility of its coordination to various ligand especially nitrogen donor ligand can be useful for following its pathway in biological system[1-3]. In this work we report synthesis and characterization of some new zinc halide complexes formulated as HgLBr2 (L= Schiff base ligand). The Schiff base ligand was prepared by a condensation of chlorobenzaldehyde and 2-aminoethylethylenedianie in 2:1 molar ration in ethanol for 3h at room temperature. The zinc complexes were synthesized by direct reaction of the ligand and zinc salt in 1:1 molar ratio in ethanol. Furthermore the ligand and its complexes have been screened for their antibacterial and antifungal activities and the data reveal that the complexes have higher activity than the free ligand. Finally, optimized structures, molecular parameters and vibrational frequencies were calculated at the B3LYP/LANL2DZ level of theory.