Substituent effects on O-H and S-H bond dissociation enthalpies of disubstituted phenols and thiophenols

The O-H and S-H homolytic bond dissociation enthalpies of a set of disubstituted phenols and thiophenols (NH2, OH, CH3, Cl, CF3, and NO2) have been computed by a density functional theory procedure with the 6-311++G(d,p) basis set. A very good agreement between our results and available experimental ones is observed. The effect of substituents on structure, charges and BDEs are investigated and their correlation with Hammett parameters is studied. (c) 2007 Wiley Periodicals, Inc