Synthesis and characterization of complexes formed by Fe(III), Cr(III), Co(II), Cu(II), Cd(II), and Ag(I) ions with the drug captopril and the amino acid glycine

The capability of Fe(III), Cr(III), Co(II), Cu(II), Cd(II), and Ag(I) ions to form stable mixed-ligand complexes was examined. The ligands are the antihypertensive drug captopril (L1) and the glycine amino acid (L2). The characterization data suggest that Fe(III), Cr(III), Co(II), Cu(II), and Cd(II) ions react with the L1 and L2 ligands in a ratio of 1:1:1 (metal ion: L1:L2), whereas the Ag(I) ions interacted with the ligands in a 2:1:1 ratio (metal ion: L1: L2). Results suggest that the L1 ligand capture the metal ions using the S atom of the mercpto (SH) group and the O atom of the amide (C=O) group, whereas the L2 ligand captures the metal ions using the O and N atoms of the carboxylate and amino groups, respectively. The XRD analysis demonstrated that Fe(III), Cr(III), Co(II) and Cu(II) complexes had well-defined and well-crystallized morphology, whereas the Cd(II) and Ag(I) complexes mainly possessed an amorphous structure. The microscopic characterizations indicate that the particles of Fe(III), Cr(III), Co(II), and Cu(II) complexes had rod-like shaped morphology with well-defined and clear shapes. The morphology of Cd(II) and Ag(I) complexes did not form short or long rods but rather contained particles in small aggregated shapes. KEY WORDS: Drug captopril, Mixed-ligand complex, Glycine, Metal ion, Thermal decomposition Bull. Chem. Soc. Ethiop. 2025, 39(6), 1137-1152. DOI: https://dx.doi.org/10.4314/bcse.v39i6.9