Zhang Jun, Zhang Zhen, Yang Yi Isaac, Liu Sirui, Yang Lijiang, Gao Yi Qin
Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering and Biodynamic Optical Imaging Center, Peking University, Beijing 100871, China.
ACS Cent Sci. 2017 May 24;3(5):407-414. doi: 10.1021/acscentsci.7b00037. Epub 2017 Apr 15.
Efficient sampling in both configuration and trajectory spaces, combined with mechanism analyses via data mining, allows a systematic investigation of the thermodynamics, kinetics, and molecular-detailed dynamics of chemical reactions in solution. Through a Bayesian learning algorithm, the reaction coordinate(s) of a (retro-)Claisen rearrangement in bulk water was variationally optimized. The bond formation/breakage was found to couple with intramolecular charge separation and dipole change, and significant dynamic solvent effects manifest, leading to the "in-water" acceleration of Claisen rearrangement. In addition, the vibrational modes of the reactant and the solvation states are significantly coupled to the reaction dynamics, leading to heterogeneous and oscillatory reaction paths. The calculated reaction rate is well interpreted by the Kramers' theory with a diffusion term accounting for solvent-solute interactions. These findings demonstrated that the reaction mechanisms can be complicated in homogeneous solutions since the solvent-solute interactions can profoundly influence the reaction dynamics and the energy transfer process.
在构型空间和轨迹空间中进行高效采样，并结合通过数据挖掘进行的机理分析，能够对溶液中化学反应的热力学、动力学和分子详细动力学进行系统研究。通过贝叶斯学习算法，对大量水中（逆）克莱森重排的反应坐标进行了变分优化。发现键的形成/断裂与分子内电荷分离和偶极变化相关联，并且表现出显著的动态溶剂效应，导致克莱森重排在“水中”加速。此外，反应物的振动模式和溶剂化状态与反应动力学显著耦合，导致反应路径的不均匀性和振荡性。计算得到的反应速率可以用包含溶剂 - 溶质相互作用扩散项的克莱默斯理论很好地解释。这些发现表明，由于溶剂 - 溶质相互作用会深刻影响反应动力学和能量转移过程，因此在均相溶液中反应机理可能很复杂。
