氢分子消除体内羟基自由基的微观机理  

Microscopic Mechanism of the Reaction Between Hydroxyl Radical and Hydrogen Molecule

作　　者：孟祥军[1] 于静[1] 罗宝晶 张青[1] 魏金芳[1] 杨静[1] Meng Xiangjun;Yu Jing;Luo Baojing;Zhang Qing;Wei Jinfang;Yang Jing(Department of Chemistry,Tangshan Normal University,Tangshan 063000,China)

机构地区：[1]唐山师范学院化学系,河北唐山063000

出　　处：《南开大学学报（自然科学版）》2022年第2期87-93,共7页Acta Scientiarum Naturalium Universitatis Nankaiensis

基　　金：河北省高等教育教学改革研究与实践项目(2018GJJG491);唐山师范学院科研项目(2021B32)。

摘　　要：为了认识氢气生物学效应的分子机制,采用量子化学的M06-2X/6-311+G(d,p)和CCSD(t)/augcc-pVTZ方法模拟了人体条件下(310 K、液相)氢分子与羟基自由基的反应机理,计算发现该反应的吉布斯自由能变化值为-56.9 kJ/mol,活化自由能垒为20.9 kJ/mol,从热动力学角度氢分子均容易消除羟基自由基.然后从电子结构和轨道作用层面对氢分子清除·OH的微观机制进行了探讨,揭示了反应活化能的来源:氢分子的一个氢原子作用于·OH的氧原子形成复合物;复合物从反应物变为过渡态过程中,第5号α占据轨道在组成上失去了·OH片段4号轨道的贡献,导致能级显著升高,并且·OH片段向氢分子片段转移的电子数显著增加.In order to understand the molecular mechanism of biological effects for hydrogen, M06-2X/6-311+G(d,p) and CCSD(t)/aug-cc-pVTZ methods were used to simulate the conditions of human body(310 K, liquid phase) and investigate the reaction mechanism of hydrogen molecules with hydroxyl radicals.It was found that the variation value of Gibbs free energy and the barrier of activation free energy for the reaction were -56.9 kJ/mol and 20.9 kJ/mol, respectively. This indicates that the reaction is easy to proceed either from a thermodynamic or kinetic perspective. Besides, the microscopic mechanism of the reaction was discussed from the level of electronic structure and orbital interaction. The results show that the complex was formed by the action between the H atom of hydrogen molecule and the O atom of hydroxyl radicals, during the transition from reactant to transition state, the orbital energy level of the complex changed significantly and the number of electron transfer from the fragment OH to the fragment H;increased significantly too, which revealed the reason for higher energy of transition state.

关 键 词：氢气 生物学效应 活性氧化物 反应机理 轨道组成 

分 类 号：O641[理学—物理化学]