DFT investigation of the antioxidant mechanisms of heavy Chalcogen (S, Se, Te) derivatives of Chrysin

Abstract

The present study investigates the primary antioxidant mechanisms of a series of complexes of heavy chalcogen derivatives of chrysin. Density Functional Theory (DFT) calculations were conducted utilizing the hybrid M05-2× functional and the range-separated LC-ωPBE functional. The 6–31 + G(d,p) basis set was utilized for the atoms H, C and O. Conversely, the Lanl2dz basis set, in conjunction with its associated effective core potential (ECP), was employed for the Te atom. Gas phase, nonpolar (benzene) and polar (water) solvents employing the SMD mode are discussed. In order to establish structure-activity relationships, global reactivity descriptors, frontier molecular orbitals, UV–visible spectra, charge-transfer parameters, spin density distributions and molecular electrostatic potential maps were analyzed. The thermodynamic parameters governing the HAT, SPLET, and SET-PT mechanisms were evaluated. The results of the study demonstrate an enhancement in radical stabilization upon chalcogen substitution, following the established trend S < Se < Te. HAT dominates in the gas phase, while SPLET is favored in polar media, with SET-PT remaining secondary. • Antioxidant mechanisms of heavy chalcogen chrysin derivatives were investigated using DFT (M05-2× and LC-ωPBE). • Solvent effects (gas, benzene, and water) were examined via the SMD model. • HAT dominates in the gas phase, while SPLET is favored in polar media. • Radical stabilization increases in the order S < Se < Te. • Chalcogen substitution significantly enhances the antioxidant activity of chrysin complexes.