Synthesis and characterization of copper(II) and zinc(II) complexes of chelating ligands derived from 2,6-diacetylpyridine and phenylalanine/tyrosine/histidine/histamine and 2-(2-aminoethyl)-pyridine

Abstract

The copper(II) and zinc(II) complexes of Schiff base ligands L1 and L2 derived from the condensation of 2,6-diacetylpyridine with 2 mol of phenylalanine methyl ester or tyrosine ethyl ester have been prepared. The IR spectral data indicate that the ester group undergoes hydrolysis in the formation of the Zn(II) complexes more readily than that of the Cu(II). The 1H and 13C NMR spectra of the Zn(II) complexes of L1 and L2 as well as those derived from condensation of 2,6-diacetylpyridine and histidine methyl ester (L3), histamine (L4) and 2-(2-aminoethyl)-pyridine (L5) were examined. Differences in IR spectral properties as well as in chemical shifts of similar 1H and 13C nuclei in these five types of complexes have been attributed to significant Zn(II)-carboxylate oxygen interactions in complexes of L1 and L2. © 1988 Pergamon Press plc.