Bracher Christoph E, Allen Connor J, Singleton Daniel A
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, Texas 77842, United States.
J Am Chem Soc. 2024 Sep 25;146(38):25907-25911. doi: 10.1021/jacs.4c09306. Epub 2024 Sep 16.
The understanding of selectivity in reactions exhibiting nonstatistical dynamics is impeded by the limitations of trajectory studies with regard to nuclear quantum effects, especially tunneling. We described here the use of ring-polymer molecular dynamics (RPMD) to account for an unusual regiochemical isotope effect on the regioselectivity of hydroborations of alkenes with BH/BD. RPMD is able to account for the experimental observation, while statistical approaches and classical trajectories fail. The combination of experiment and RPMD trajectories suggests that tunneling in the initial collision of reactants is the major source of the nonstatistical selectivity.
在具有非统计动力学的反应中，由于轨迹研究在核量子效应（尤其是隧穿）方面存在局限性，使得对选择性的理解受到阻碍。我们在此描述了使用环聚体分子动力学（RPMD）来解释烯烃与BH/BD硼氢化反应区域选择性上一种不寻常的区域化学同位素效应。RPMD能够解释实验观察结果，而统计方法和经典轨迹则无法做到。实验与RPMD轨迹的结合表明，反应物初始碰撞中的隧穿是非统计选择性的主要来源。
