Basdogan Yasemin, Keith John A
Department of Chemical and Petroleum Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , USA . Email:
Chem Sci. 2018 May 30;9(24):5341-5346. doi: 10.1039/c8sc01424h. eCollection 2018 Jun 28.
We report a static quantum chemistry modeling treatment to study how solvent molecules affect chemical reaction mechanisms without dynamics simulations. This modeling scheme uses a global optimization procedure to identify low energy intermediate states with different numbers of explicit solvent molecules and then the growing string method to locate sequential transition states along a reaction pathway. Testing this approach on the acid-catalyzed Morita-Baylis-Hillman (MBH) reaction in methanol, we found a reaction mechanism that is consistent with both recent experiments and computationally intensive dynamics simulations with explicit solvation. In doing so, we explain unphysical pitfalls that obfuscate computational modeling that uses microsolvated reaction intermediates. This new paramedic approach can promisingly capture essential physical chemistry of the complicated and multistep MBH reaction mechanism, and the energy profiles found with this model appear reasonably insensitive to the level of theory used for energy calculations. Thus, it should be a useful and computationally cost-effective approach for modeling solvent mediated reaction mechanisms when dynamics simulations are not possible.
我们报告了一种静态量子化学建模方法，用于在不进行动力学模拟的情况下研究溶剂分子如何影响化学反应机理。该建模方案使用全局优化程序来识别具有不同数量显式溶剂分子的低能中间态，然后使用增长弦方法沿着反应路径定位连续的过渡态。在甲醇中酸催化的森田-贝利斯-希尔曼（MBH）反应上测试这种方法时，我们发现了一种与最近的实验以及使用显式溶剂化的计算密集型动力学模拟均一致的反应机理。在此过程中，我们解释了那些使使用微溶剂化反应中间体的计算建模变得模糊的非物理陷阱。这种新的辅助方法有望捕捉复杂多步MBH反应机理的基本物理化学性质，并且该模型得到的能量分布对用于能量计算的理论水平似乎相当不敏感。因此，当无法进行动力学模拟时，它应该是一种用于模拟溶剂介导反应机理的有用且计算成本效益高的方法。
