预测发生亲电取代反应的活性位点具有重要的理论和实际意义.目前已提出了许多基于反应物自身电子结构的预测方法.本文选择14个单取代苯和8个双取代苯作为测试集,对14种预测方法的可靠性进行了详细的比较分析.结果表明,福井函数、平均局部离子化能等体现局部电子软度的方法特别适合含有邻对位定位基的单取代苯和双取代苯体系,但对于含有单个间位定位基的体系,这类方法往往预测失败.基于静电效应的预测方法整体表现明显不如体现局部软度的方法,但更适合含有单个问位定位基的体系.对所有体系预测能力最稳健的是双描述符,因此可以作为普适性的预测方法.
Predicting the reactivity of electrophilic substitution at different sites is of theoretical and practical significance, and many prediction methods based on the electronic structure of reactants have been proposed. We compared the reliability of 14 prediction methods, using 14 monosubstituted and 8 disubstituted benzenes as test sets. Methods reflecting local electronic softness, such as the Fukui function and average local ionization energy, are well-suited to monosubstituted benzenes with ortho-para directing groups and disubstituted benzenes. However, these methods often fail for systems containing a single meta directing group. Methods reflecting electrostatic effects perform worse overall than those reflecting local softness, but are better suited to systems containing a single meta directing group. Dual descriptor is the most overall robust method, and can be regarded as a universal prediction method.