Direct Dynamics Trajectories Demonstrate Dynamic Matching and Nonstatistical Radical Pair Intermediates during Fe-Oxo-Mediated C–H Functionalization Reactions
Direct Dynamics Trajectories Demonstrate Dynamic Matching and Nonstatistical Radical Pair Intermediates during Fe-Oxo-Mediated C–H Functionalization Reactions
复制标题
直接动力学轨迹展示了 Fe-Oxo 介导的 C–H 功能化反应过程中的动态匹配和非统计自由基对中间体
DOI：
10.1021/jacs.3c01196
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发表时间：
2023
影响因子：
15
通讯作者：
Ess, Daniel H.
中科院分区：
文献类型：
--
作者：
Joy, Jyothish;Ess, Daniel H.
通常提出的非血红素Fe-氧代络合物和烷烃C-H键之间的反应机制涉及氢原子转移（HAT）反应步骤，其中自由基对中间体然后具有竞争性自由基反弹、解离或去饱和途径。在这里，我们报告基于密度泛函理论的准经典直接动力学轨迹，检查后HAT反应动力学。轨迹表明，自由基对中间体可以是一个非统计型中间体没有完整的内部振动再分配和后HAT的选择性通常是由动力学效应。快速反弹轨迹发生通过动态匹配之间的旋转运动的新形成的Fe-OH键和碰撞的烷烃自由基，所有这一切都发生通过一个非同步的动态协调的过程，绕过自由基对中间结构。对于自由基对解离，轨迹进行到自由基对中间体非常短的时间，然后完全解离。这些轨迹提供了一个新的观点和模型，以了解非血红素铁氧介导的C-H官能化反应的内在反应途径的选择性。
The generally proposed mechanism for the reaction between non-heme Fe-oxo complexes and alkane C–H bonds involves a hydrogen atom transfer (HAT) reaction step with a radical pair intermediate that then has competitive radical rebound, dissociation, or desaturation pathways. Here, we report density functional theory-based quasiclassical direct dynamics trajectories that examine post-HAT reaction dynamics. Trajectories revealed that the radical pair intermediate can be a nonstatistical type intermediate without complete internal vibrational redistribution and post-HAT selectivity is generally determined by dynamic effects. Fast rebound trajectories occur through dynamic matching between the rotational motion of the newly formed Fe–OH bond and collision with the alkane radical, and all of this occurs through a nonsynchronous dynamically concerted process that circumvents the radical pair intermediate structure. For radical pair dissociation, trajectories proceeded to the radical pair intermediate for a very brief time, followed by complete dissociation. These trajectories provide a new viewpoint and model to understand the inherent reaction pathway selectivity for non-heme Fe-oxo-mediated C–H functionalization reactions.