Synthesis, Characterisation and Antimicrobial Activities of Copper(II) and Zinc(II) Complexes of Schiff Bases derived from Amino Acids and 1,10-Phenanthroline Mixed Ligands

Copper(II) and Zinc(II) complexes of Schiff bases and 1,10-phenanthroline mixed ligands have been synthesized in aqueous/methanolic solution. These complexes were characterised by elemental analyses, infrared and visible electronic spectroscopy. The results suggest a distorted octahedral coordination for Cu(II) and Zn(II) complexes in which the central metal ion is bonded to O-, N- and O- donor sites of the imino-N, phenoxyl-O and carboxyl-O groups respectively. Antimicrobial studies on the ligands and the metal complexes show that the ligands, salicylidene alanine (Sal-Al) and salicylidene histidine(Sal-His) are active against 3 out of the 8 tested organisms while the copper complex Cu(Sal-Ala)phen is active against 4 of the pathogens. The zinc complex Zn(Sal-Ala)phen is active against 7 of the pathogens. None of them is active against the fungus, candida albicans.