Vibrational and Electronic Spectroscopic Characterizations of Amino Acid-Metal Complexes

Abstract

For vibrational and electronic spectroscopic characterizations of a-amino acid mineral chelates, nine water-soluble a-amino acids of Ala, Asn, Gin, His, Ile, Lys, Pro, Thr, and Val were used to prepare metal complexes with Fe(II), Fe(III), Cu(II), and Zn(II) ions. The alpha-amino acid-metal complexes were characterized by FT-IR and UV-Vis spectrometers to determine the complex formation. The vibrational energy changes of the ammonium and carboxylate groups by FT-IR spectroscopy were characteristic features in the amino acid-metal complex formation. The electronic transition energy changes determined by UV-Vis spectrometer were also characteristic to the Fe(II), Fe(III), and Cu(II) complexes. The amino acid-Zn(II) complexes did not show these changes, because there was no absorption band due to d-d transitions.