Bond dissociation enthalpies in benzene derivatives and effect of substituents: an overview of density functional theory (B3LYP) based computational approach

Abstract

In this review, we have mainly focused on the recent computational studies on the bond dissociation enthalpies (BDE) of the X-H bonds of the para and meta substituted benzene derivatives (3Y-C₆H₄X-H and 4Y-C₆H₄X-H with X = O, S, Se, NH, PH, CH₂, SiH₂ and Y = H, F, Cl, CH₃, OCH₃, NH₂, CF₃, CN, NO₂). In addition, the remote substituent effects on the BDE(X-H), the radical stability and parent one have also been discussed in terms of the calculated ground State effect, radical effect and total effect. Model chemistry of ROB3LYP/6-311++G(d,p)//B3LYP/6-311 G(d,p) can reproduce the BDE values with the accuracy of 1.0-2.0 kcal/mol. The good linear correlations between Hammett constants and BDE values were discovered for both para and meta substitutions in phenols, thiophenols, benzeneselenols, anilines and phenylposphines with the R-squared lager than 0.94. In contrast, it does not occur in case of toluenes and phenylsilanes.