The prediction of pKa values for phenolic compounds by the DFT theory

Abstract

The acid dissociation constant is an important parameter that affects the physicochemical properties of molecules in solution. A set of 20 phenolic compounds were used to establish a model to predict  values of phenolic compounds. Calculations in aqueous medium were performed with a polarizable continuum solvent model (PCM) and three hybrid DFT functionals (B3LYP, PBE0, ωB97XD and M062X) with the basis set 6-311++G(d,p). The directly calculated value of  gives less accurate results with an average absolute error (MAE) of 1.74  units when using the ωB97XD functional and phenol as reference compound. In the case of using statistical correction, the accuracy of  is greatly improved. In the case of using statistical correction, the accuracy of  is greatly improved with the lowest MAE value of 0.14  units (M062X; ). The calculated results of  in this study have the same accuracy as the experimental measurements.The acid dissociation constant is an important parameter that affects the physicochemical properties of molecules in solution. A set of 20 phenolic compounds were used to establish a model to predict  values of phenolic compounds. Calculations in aqueous medium were performed with a polarizable continuum solvent model (PCM) and three hybrid DFT functionals (B3LYP, PBE0, ωB97XD and M062X) with the basis set 6-311++G(d,p). The directly calculated value of  gives less accurate results with an average absolute error (MAE) of 1.74  units when using the ωB97XD functional and phenol as reference compound. In the case of using statistical correction, the accuracy of  is greatly improved. In the case of using statistical correction, the accuracy of  is greatly improved with the lowest MAE value of 0.14  units (M062X; ). The calculated results of  in this study have the same accuracy as the experimental measurements.