Construction of Two-Dimensional Potential Energy Surfaces of Reactions with Post-Transition-State Bifurcations
Construction of Two-Dimensional Potential Energy Surfaces of Reactions with Post-Transition-State Bifurcations
复制标题
具有后过渡态分岔的反应的二维势能面的构建
DOI：
10.1021/acs.jctc.0c00172
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发表时间：
2020-07-14
影响因子：
5.5
通讯作者：
Hsu, Chao-Ping
中科院分区：
文献类型：
--
作者：
Chuang, Hsiao-Han;Tantillo, Dean J.;Hsu, Chao-Ping
过渡态后分叉反应包括初始的双峰过渡态结构，随后是一个导致两种可能产物的不稳定区域。ptsb存在于许多有机、有机金属和生物合成反应中，但分析这些反应的选择性的起源是具有挑战性的，很大程度上是因为所涉及的势能表面的复杂性，这使得基于单一内在反应坐标（IRC；质量加权坐标中最陡下降路径）的分析成为可能。虽然可以使用分子动力学模拟来预测选择性，但将这些计算结果与势能表面的形貌联系起来是困难的。在本工作中，描述了一种生成PTSBs二维势能面的方法。第一个维度从第一个过渡态结构的IRC开始，然后是到达第二个过渡态结构的修改反应坐标，它将两个分岔反应路径的产物相互转换。第二个过渡状态结构的IRC构成了第二个维度。此外，描述了一种将Born-Oppenheimer分子动力学模拟的轨迹映射到这些表面上的方法。这两种方法都用有机化学领域的代表性例子加以说明。5种不对称情况下的2d - ps在第一过渡态结构后具有明显的倾斜形貌，倾斜方向与先前动态模拟观察到的选择性具有良好的相关性。我们的方法不是通过化学直觉来选择反应坐标，而是提供了一种构建具有过渡后分岔反应的二维势能面的一般方法。
Reactions with post-transition-state bifurcations (PTSBs) involve initial ambimodal transition-state structures followed by an unstable region leading to two possible products. PTSBs are seen in many organic, organometallic, and biosynthetic reactions, but analyzing the origins of selectivity for these reactions is challenging, in large part due to the complex nature of the potential energy surfaces involved, which precludes analyses based on single intrinsic reaction coordinate (IRC; steepest-descent path in mass-weighted coordinate). While selectivity can be predicted using molecular dynamics simulation, connecting results from such calculations to the topography of potential energy surfaces is difficult. In the present work, a method for generating two-dimensional potential energy surfaces for PTSBs is described. The first dimension starts with the IRC for the first transition-state structure, followed by a modified reaction coordinate that reaches the second transition-state structure, which interconverts the two products of a bifurcating reaction path. The IRC for the second transition-state structure constitutes the second dimension. In addition, a method for mapping trajectories from Born-Oppenheimer molecular dynamics simulations onto these surfaces is described. Both approaches are illustrated with representative examples from the field of organic chemistry. The 2D-PESs for five asymmetric cases tested have clear tilted topography after the first transition-state structure, and the tilted direction correlates well with the selectivity observed from previous dynamic simulation. Instead of selecting reaction coordinates by chemical intuition, our method provides a general means to construct two-dimensional potential energy surfaces for reactions with post-transition-state bifurcations.