Density Functional Theory (B3LYP) Study of Substituent Effects on O–H Bond Dissociation Enthalpies of trans-Resveratrol Derivatives and the Role of Intramolecular Hydrogen Bonds

In this paper, 23 substituents with various electron-donating and electron-withdrawing characters were placed in available positions of trans-resveratrol in order to study their effect on the three O-H bond dissociation enthalpies (BDEs) via density functional theory (DFT) with Becke three-parameter exchange and Lee-Yang-Parr correlation (B3LYP). It has been found that the mutual positions of substituents and OH groups affect investigated BDEs substantially. Formation of strong intramolecular hydrogen bonds and suitable spin density distributions in several radicals result in low BDEs. Calculated BDEs have been correlated with Hammett constants, selected geometry parameters, and charge on phenoxy radical oxygen q(O). Found dependences are satisfactorily linear.