Mode-Specific SN2 Reaction Dynamics

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• 作者：Yan Wang ; Hongwei Song ; István Szabó ; Gábor Czakó ; Hua Guo ; Minghui Yang
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：September 1, 2016
• 年：2016
• 卷：7
• 期：17
• 页码：3322-3327
• 全文大小：400K
• 年卷期：0
• ISSN：1948-7185

文摘

Despite its importance in chemistry, the microscopic dynamics of bimolecular nucleophilic substitution (S<sub>Nsub>2) reactions is still not completely elucidated. In this publication, the dynamics of a prototypical S<sub>Nsub>2 reaction (F<sup>–sup> + CH<sub>3sub>Cl → CH<sub>3sub>F + Cl<sup>–sup>) is investigated using a high-dimensional quantum mechanical model on an accurate potential energy surface (PES) and further analyzed by quasi-classical trajectories on the same PES. While the indirect mechanism dominates at low collision energies, the direct mechanism makes a significant contribution. The reactivity is found to depend on the specific reactant vibrational mode excitation. The mode specificity, which is more prevalent in the direct reaction, is rationalized by a transition-state-based model.