摘要
在MP2/6-311++G(2df,pd)//B3LYP/6-31+G(d,p)双理论水平,采用自洽反应场(SCRF)理论的smd模型方法,对标题反应进行了研究。反应通道研究表明:水环境下缬氨酸的旋光异构可以在3个通道a、b和c实现,分别是质子以水分子簇为媒介以氨基氮、羰基氧和羧基为桥梁,从α-碳的一侧迁移到另一侧;水分子辅助羟自由基抽氢致缬氨酸损伤发生在a通道。势能面计算表明:2个和3个水分子簇作氢迁移媒介时,水分子簇对旋光异构反应的氢迁移过程有极好的催化作用,使反应能垒相对裸反应大幅降低,水溶剂效应在a通道有较好的助催化作用,对b和c通道影响不大。水分子辅助羟自由基抽氢致缬氨酸损伤气相反应能垒较低,水溶剂效应对此反应有较大的阻碍作用。
The mechanism of optical isomerization of valine molecules with dual-hydrogen amino and carboxyl groups and the damage induced by hydroxyl radicals in water environment by using MP/6 -311 ＋＋ G （2df, pd） // B3LYP/6 -31 ＋ G （d, p） dual-theory and SMD model method for self consistent reaction field （SCRF） theory. The study of reaction channels showed that there were three channels a, b and c in the optical isomer reaction of valine in water environment. Using water cluster as medium, the protons transfered from one side of the a-carbon to the amino group, O atom of carbonyl group and carboxyl group as bridges. The hydrogen abstraction which damaged the valine molecules happened in channel a, and the water molecules were assistants.The potential energy surface calculation showed that when two or three water clusters were transport medium , they acted a good catalytic action on the process of hydrogen-transfer of Optical I-somerization, and reduced the barrier of reaction vs naked reaction. Water solution effect had good catalytic activity in channel a, but catalytic activities were not obvious in channel b and c. The reaction barrier of hydrogen abstraction reaction which damaged the valine molecules with water molecules as assistants was low. The water solution effect has a big impediment effect on this reaction.
作者
赵宇
汤振宇
吴怡
张育凯
杨晓翠
王佐成
ZHAO Yu;TANG Zhenyu;WU Yi;ZHANG Yukai;YANG Xiaocui;WANG Zuocheng(College of Computer Science,Baicheng Normal University,Baicheng 137000,China;College of Physics,Baicheng Normal University,Baicheng 137000,China)
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第3期96-107,共12页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
吉林省科技发展计划自然科学基金(20130101308JC)
关键词
旋光异构
缬氨酸
密度泛函理论
过渡态
微扰论
溶剂效应
羟自由基
损伤
optical isomerization
valine
density functional theory
transition state
perturbation theory
solvent effect
hydroxyl radical
damage
