Magnesium Glycinate and Tyrosinate: Structure Calculations and IR Spectra by the DFT Method

Abstract Structural dynamic models of magnesium glycinate and magnesium tyrosinate complexes were simulated by the method of density-functional theory (DFT) using the B3LYP functional in the 6-31G(d,p) and 6-31G basis sets. The molecular geometric parameters and frequencies of normal vibrations within the harmonic approximation in the IR spectra of the developed models were calculated. Magnesium(II) complexes with glycine and tyrosine were synthesized from aqueous solutions of the corresponding salts of magnesium chloride and the amino acid. The content of amino acids in the synthesized compounds was determined by formol titration using the Sørensen method. The content of magnesium(II) ions is determined by complexometric titration. The IR spectra of the synthesized compounds were recorded in the range of 500–4000 cm–1. The calculated and experimental IR spectra of the synthesized magnesium(II) complexes with glycine and tyrosine were compared in order to validate their structures. Data on the coordination of calcium and magnesium ion complexes with amino acids contributes to understanding the structure of these poorly studied complexes and improving methods for obtaining these complex compounds with a predetermined composition and structure.