Dioxygen Activation by Iron Complexes: The Catalytic Role of Intersystem Crossing Dynamics for a Heme-Related Model
Dioxygen Activation by Iron Complexes: The Catalytic Role of Intersystem Crossing Dynamics for a Heme-Related Model
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铁络合物活化分子氧：系统间交叉动力学对血红素相关模型的催化作用
DOI：
10.1021/acs.jpcc.7b11462
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发表时间：
2018-01
期刊：
影响因子：
--
通讯作者：
Gao Jun
中科院分区：
文献类型：
--
作者：
Du Likai;Liu Fang;Li Yanwei;Yang Zhongyue;Zhang Qingzhu;Zhu Chaoyuan;Gao Jun
含有血红素、非血红素铁或铜活性位点的酶在二氧结合和底物氧化激活中起重要作用。这一初级催化步骤的定量建模在概念上的挑战来自于：(1)由自旋轨道耦合介导的三重态双氧分子（3O2）自旋翻转事件的内在电子非绝热性；(2)由于双氧结合过程的高放热性，可能存在散热通道。本文从非绝热轨迹表面跳跃动力学的角度直接研究了还原血红素模型的自旋禁止双氧结合动力学，包括耦合的单重态、三重态和五重态。这项工作揭示了这一元素反应的复杂性，并且过氧化铁的结合/解离动力学对解释随后的H原子提取反应步骤很重要。此外，我们确定了通过传统的静态几何计算无法观察到的非绝热动力效应。
Enzymes containing heme, nonheme iron, or copper active sites play an essential role in the dioxygen binding and activation for substrate oxidation. The conceptual challenges to the quantitative modeling of this primary catalytic step arise from (1) instrinsic electronic nonadiabaticity of the spin flip events of the triplet dioxygen molecule (3O2), mediated by spin–orbit coupling and (2) possible heat dissipation channels, due to the high exothermicity of dioxygen binding processes. Herein, the spin-forbidden dioxygen binding dynamics of a reduced heme model was directly investigated in terms of the nonadiabatic trajectory surface-hopping dynamics, involving the coupled singlet, triplet and quintet states. This work reveals the complexity of this elemental reaction, and the binding/dissociation dynamics of iron peroxo species is important to interpret the subsequent H atom abstraction reaction step. Furthermore, we identify nonadiabatic dynamical effects that could not be observed through traditional calculations of static geometries.