Synthesis, characterization and bilogical activities of cu(ii) and hg(ii) complexes with a schiff base ligand synthesized from diethyl-2-amino-4-methylthiophene-3,5-dicarboxylate and 2,6-diaminopyridine

Abstract

Ethyl-4-amino-5-(((6-aminopyridin-2-yl)imino)(ethoxy)methyl)-2-methylthiophene-3-carboxylate was synthesized by the condensation of diethyl-2-amino-4-methylthiophene-3, 5-dicarboxylate and 2,6-diaminpyridine. The complex of Cu(II) and Hg(II) with this ligand was prepared by refluxing the mixture of the solutions of the sulphate salts of the metals and ligand in methanol. The resulting compounds were characterized using NMR, IR UV-Vis and molar conductance. The metal ions in complex are tricoordinated to the ligand through pyridine nitrogen, azomethine nitrogen and thiophene sulfur. The high conductance values of the complexes indicate that all the complexes were electrolytes. The antibacterial test indicates that the ligand was active against Staphylococcus aureus while it is inactive against Pseudomonas aeruginosa, Salmonella typhi and Escherichia coli. The Cu2+ and Hg2+complexes of the ligand exhibit higher antibacterial activities than the free ligand.