On the energetics of radical adduct formation of OH^• with phenol analogs and aniline

Theoretical studies on aniline, phenol, benzenethiol, benzeneselenol, and their corresponding adducts with hydroxyl radical in possible positions on a hydrocarbon ring are presented. Bond dissociation enthalpies, related to radical scavenging of primary antioxidants, were calculated using the M06–2X/6–311+G** method. Calculated data were compared with available experimental data. Preferable homolytic bond dissociation of the presented molecules with OH^• through functional groups X—OH followed by the m–OH ones has been confirmed. The highest antioxidant activity among the investigated positions is predicted for benzeneselenol. Also, the formation of non-covalent van der Waals structures has been shown as important in radical scavenging.