Synthesis, characterization, electrochemical properties and antibacterial activity of some transition metal complexes with 2-[N-(2'-hydroxy-1'-naphthylidene)-amino]-3-carboxyethyl-4,5-dimethylthiophene

摘要

A potentially tridentate Schiff base has been prepared by condensing 2-amino-3-carboxyethyl-4,5-dimethylthiophene with 2-hydroxy-1-naphthaldehyde under well defined condition. The ligand is versatile in forming a series of metal complexes with transition metal ions such as manganese(II), iron(II), cobalt(u), nickel(II), copper(II) and zinc(Il). The ligand and the metal complexes have been characterized on the basis of elemental analyses, molar conductance values, magnetic susceptibility data, NMR, UV-Visible, IR and EPR spectral studies wherever possible and applicable. The spectral studies reveal that the Schiff base behaves as monobasic tridentate, coordinating to the metal ion through azomethine nitrogen, ester carbonyl oxygen and the naphtholate oxygen after deprotonation. Analytical data reveal that nickel(II), copper(II) and zinc(II) complexes possess 1 : 1 metal-ligand ratios while manganese(II), iron(II) and cobalt(II) complexes exhibit 1 : 2 ratios. Molar conductance values support the non-electrolytic nature of the complexes. The electrochemical behaviour of the copper(II) complex has been investigated by cyclic voltammetry. The ligand and the metal complexes have been subjected to antibacterial studies and it has been observed that the complexes are more potent bactericides than the ligands.