水液相下两性α-丙氨酸Ca(Ⅱ)配合物旋光异构的理论研究  

Theoretical study on the optical isomerism of amphotericα-alanine Ca(Ⅱ)complex in water-liquid phase environment

作　　者：刘芳[1] 张雪娇 刘军[3] 闫红彦[3] 姜春旭 王佐成[1] LIU Fang;ZHANG Xue-jiao;LIU Jun;YAN Hong-yan;JIANG Chun-xu;WANG Zuo-cheng(College of Physics,Baicheng Normal University,Baicheng 137000,Jilin,China;Communication College,Baicheng Normal University,Baicheng 137000,Jilin,China;College of Computer Science,Baicheng Normal University,Baicheng 137000,Jilin,China)

机构地区：[1]白城师范学院物理学院,吉林白城137000 [2]白城师范学院传媒学院,吉林白城137000 [3]白城师范学院计算机学院,吉林白城137000

出　　处：《云南大学学报（自然科学版）》2021年第2期358-368,共11页Journal of Yunnan University(Natural Sciences Edition)

基　　金：吉林省教育厅科学研究规划项目(JJKH20200002KJ);吉林省科技发展计划自然科学基金(20160101308JC).

摘　　要：采用密度泛函理论的M06-2X方法,结合自洽反应场理论的SMD模型方法,研究了水液相下两性α-丙氨酸与二价钙配合物(S-Ala·Ca^(2+))的旋光异构.研究发现:S-Ala·Ca^(2+)的旋光异构有a、b和c 3个通道,a是α-氢迁移到羰基氧后,质子再从质子化氨基迁移到α-碳;b是质子只以羰基氧为桥迁移;c是质子从质子化氨基迁移到羰基氧后,再以氨基氮为桥迁移.势能面计算表明,隐性溶剂效应下,c通道具有优势,决速步内禀能垒是232.8 kJ·mol^(−1);a和b通道是劣势通道,决速步内禀能垒均是268.6 kJ·mol^(−1).显性溶剂效应下,a和b通道略具优势,决速步内禀能垒在141.3~145.0 kJ·mol^(−1)之间;c通道略具劣势,决速步内禀能垒在153.1~161.0 kJ·mol^(−1)之间.结果表明,水液相下丙氨酸钙配合物很难消旋,用于生命体补充钙和丙氨酸具有较好的安全性.The optical isomerism of the amphotericα-alanine and Ca^(2+)complexes(S-Ala·Ca^(2+))in water-liquid phase environment is researched by using density functional theory-based M06-2X methods combined with the SMD model method based on self consistent reaction field(SCRF)theory.The study shows that there are three channels a,b and c in the optical isomerism reaction of S-Ala·Ca^(2+).In channel a,the proton transfers toα-C from protonation amino afterα-H is transferred to carbonyl oxygen.In channel b,the proton is transferred merely using carbonyl oxygen as a bridge.In channel c,the proton is transferred to carbonyl oxygen from protonation amin and then transfers with amino nitrogen as a bridge.Calculations of potential energy surface shows that the channel c has advantages under the effect of recessive solvent and the inherent energy barrier of the rate-determining step is 232.8 kJ·mol^(−1);a and b are inferior channels and their inherent energy barrier of the rate-determining step is 268.6 kJ·mol^(−1).Channel a and b are at a slight advantage with the explicit solvent effect and the inherent energy barrier of the rate-determining step is between 141.3 and 145.0 kJ·mol^(−1);channel c has a slight disadvantage with the inherent energy barrier of the rate-determining step is between 153.1 and 161.0 kJ·mol^(−1).The results show thatα-alanine Ca(Ⅱ)complex is hard to racemize in water-liquid phase environment.It has good safety to be used for life supplementing calcium and alanine.

关 键 词：Α-丙氨酸 钙离子 旋光异构 密度泛函理论 自洽反应场理论 过渡态 能垒 

分 类 号：O641.12[理学—物理化学]