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通过PM3方法研究氯自由基与吡啶分子加成反应的结果表明，生成不同产物2－氯吡啶、3－氯吡啶、4-氯吡啶的每一个反应通道都存在两个过渡态，生成2－氯吡啶反应路径主过渡态的能量及活化能最低，分别为-110 293．6和 139．2 kJ／mol，反应优先生成2－氯吡啶，与实验结果一致．生成2－氰吡啶反应过程（IRC）相关的键长、键级和原子净电荷变化表明，吡啶环反应部位C原子与Cl 加成形成C—Cl键主要与共轭双键断裂同步，而C—H键的断裂主要与共轭双键的重新形成同步．反应进程中氯原子净电荷从增加到减少的变化是氯原子诱导效应吸引电子和p－π共轭电荷平均分布等相互作用的结果．
The PM3 method was used to study the addition reaction of chlorine radical with pyridine. The results showed that there are two transition states in each reaction channel of 2-chloropyridine, 3-chloropyridine and 4-chloropyridine to form 2-chloro The energy and activation energy of the main transition state of the pyridine reaction pathway were the lowest, which were -110 293.6 and 139.2 kJ / mol, respectively. The reaction preferentially produced 2-chloropyridine, which was consistent with the experimental results. The bond length, bond-level and atomic net charge change related to the formation of 2-cyanopyridine reaction (IRC) indicated that the C-Cl bond formed by the addition of C atom to Cl in the pyridine ring was mainly in synchronicity with the cleavage of the conjugated double bond, The breaking of the H bond is mainly synchronized with the reformation of the conjugated double bond. The change of the net charge of chlorine atoms from increase to decrease in the reaction process is the result of the interaction between the attracting electrons and the average distribution of the conjugated charges of p-π.