Use of PM6 quantum-chemical calculations in studying the properties of antioxidants in the biological environment

• Published in: Russian journal of physical chemistry. B 2011-10, Vol.5 (5), p.836-845
• Main Authors: Volod’kin, A. A., Zaikov, G. E., Kurkovskaya, L. N., Burlakova, E. B.
• Format: Article
• Language: English
• Subjects: Chemical Physics of Biological Processes; Chemistry; Chemistry and Materials Science; Physical Chemistry
• ISSN: 1990-7931; 1990-7923
• DOI: 10.1134/S1990793111090235

The energies of formation, enthalpies, and entropies of the conformers of 1-(carboxy)-1-( N -methylamide)-2-(3′,5′-di- tert -butyl)-4-hydroxyphenyl)-propionic acid and sodium and potassium 1-(carboxy)-1-( N -methylamide)-2-(3′,5′-di- tert -butyl)-4-hydroxyphenyl)-propionates are calculated by quantum-chemical methods in the PM6 approximation. A doubling of signals in the 1 H NMR spectrum of the first conformer is observed, which merge into singlets when the compound is heated. Changes in the structure of the conformers and donor-acceptor complexes (solvates) occur with the preservation of the metal-ligand coordination bond. Calculations of the characteristics of 1-(carboxy)-1-( N -methylamide)-2-(3′,5′-di- tert -butyl)-4-hydroxyphenyl)-propionic acid and sodium and potassium 1-(carboxy)-1-( N -methylamide)-2-(3′,5′-di- tert -butyl)-4-hydroxyphenyl)-propionates in the PM6 approximation make it possible to predict the structure and properties of the solvated structures. The energies of homolysis of the H-O bond D (OH) are calculated, and a linear dependence of the antioxidant activity on D (OH) for the structures of the studied compounds is demonstrated. The results make it possible to predict the properties of antioxidants in the biological environment.