水液相环境下α-丙氨酸Mn(Ⅱ)配合物旋光异构的理论研究  

Theoretical study on the optical isomerization ofα-alanine Mn(Ⅱ)complex in water-liquid phase environment

作　　者：刘军 姜春旭 刘芳[2] 高峰[2] 张雪娇[2] 雷泽萍 佟华[2] 王佐成[2] LIU Jun;JIANG Chunxu;LIU Fang;GAO Feng;ZHANG Xuejiao;LEI Zeping;TONG Hua;WANG Zuocheng(College of Computer Science,Baicheng Normal University,Baicheng 137000,Jilin Province,China;Theoretical Calculation Center,Baicheng Normal University,Baicheng 137000,Jilin Province,China)

机构地区：[1]白城师范学院计算机科学学院,吉林白城137000 [2]白城师范学院理论计算中心,吉林白城137000

出　　处：《浙江大学学报（理学版）》2021年第6期700-710,共11页Journal of Zhejiang University（Science Edition）

基　　金：吉林省教育厅科学研究规划项目(JJKH20210010KJ);全国大学生创新项目(202110206019);吉林省科技厅自然科学基金项目(20160101308JC).

摘　　要：采用密度泛函理论的明尼苏达泛函2006(M06)和明尼苏达泛函2015(MN15)方法,结合自洽场理论的溶质全电子密度溶剂化(solvation model based on desity,SMD)模型,研究了水液相下两性α-丙氨酸二价锰配合物(Mn(Ⅱ))的旋光异构。研究结果表明,S-Ala·Mn^(2+)(S-Mn(Ⅱ))可在a、b、c和d 4个通道旋光异构,a通道H以O为桥迁移,b通道H以O和N顺次为桥迁移,c通道H以N为桥迁移,d通道H以Mn(Ⅱ)为桥迁移。势能面计算结果表明,c通道最具优势,决速步能垒为220.8 kJ·mol^(-1);a和b通道同为亚优势通道,决速步能垒为254.8 kJ·mol^(-1);d通道为劣势通道,决速步能垒为293.3 kJ·mol^(-1)。在水分子(簇)作用下,c通道决速步能垒降至155.1 kJ·mol^(-1);a和b通道决速步能垒降至165.8 kJ·mol^(-1);d通道仍为劣势通道,且S-A·Mn无法在该通道旋光异构。水液相下S-A·Mn很难消旋,Mn(Ⅱ)用于生命体补充二价锰和α-丙氨酸具有较好的安全性。The optical isomerism of amphotericα-alanine Mn(Ⅱ)(A·Mn)complex was studied in water-liquid phase environment by means of M06 and MN15 methods based on density functional theory and SMD model of self consistent reaction field theory.The study reveals that S-Mn(Ⅱ)can be optically isomerized in channels a,b,c and d.The proton was transferred with carbonyl oxygen as the bridge in channel a,and that was transferred with carbonyl oxygen and amino nitrogen in turn as the bridge in channel b,and that that was transferred with amino nitrogen as the bridge in channel c,while hydride ion was transferred with Mn as the bridge in channel d.The potential energy surface shows that channel c has the most advantage and the energy barrier of the rate-determining step is 220.8 kJ·mol^(-1),channel a and b are both sub-dominant channels and the energy barrier of the rate-determining step are 254.8 kJ·mol^(-1),d is the inferior channel and the energy barrier is 293.3 kJ·mol^(-1).Furthermore,under the action of water molecule(cluster),the energy barrier of the rate-determining step is reduced to 155.1 kJ·mol^(-1) in channel c,and reduced to 160.3 kJ·mol^(-1) in channel a and b,while channel d is still the inferior channel in which the optical isomerization of S-A·Mn cannot take place.The results show that S-A·Mn is difficult to be racemized in water-liquid phase,and A·Mn is safe to supplement bivalent manganese andα-alanine in life.

关 键 词：丙氨酸 二价锰 密度泛函理论 溶剂效应 旋光异构 过渡态 能垒 

分 类 号：O641.12[理学—物理化学]