水液相下α-丙氨酸Co(Ⅱ)旋光异构的密度泛函理论研究  

Density Functional Theory Study on the Optical Isomerism ofα-Alanine Co(Ⅱ)in Water-Liquid Phase Environment

作　　者：彭国强[1] 刘芳[2] 张雪娇[2] 雷泽平 郝成欣[1] 佟华[2] 丛建民 王佐成[2] PENG Guoqiang;LIU Fang;ZHANG Xuejiao;LEI Zeping;HAO Chengxin;TONG Hua;CONG Jianmin;WANG Zuocheng(Department of Basie Medicine,Baicheng Medical Collge,Baicheng 137000,Jilin,China;Theretical Computing Center,Baicheng Normal University,Baicheng 137000,Jilin,China;College of Life Science.Baicheng Normal University,Baicheng 137000.Jilin,China)

机构地区：[1]白城医学高等专科学校基础医学部,吉林白城137000 [2]白城师范学院理论计算中心,吉林白城137000 [3]白城师范学院生命科学学院,吉林白城137000

出　　处：《武汉大学学报（理学版）》2022年第4期444-454,共11页Journal of Wuhan University:Natural 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);吉林省科技发展计划自然科学基金(20130101131JC)。

摘　　要：采用密度泛函理论的M06和MN15方法,结合自洽反应场理论的SMD模型方法,研究了两性及中性α-丙氨酸(α-Ala_1和α-Ala_2)与Co^(2+)配合物在水液相下的旋光异构。α-Ala_1·Co^(2+)可在4个通道(a、b、c和d)实现旋光异构:a通道是质子以羧基底部的氧为桥迁移;b通道是α-氢迁移至羧基底部的氧后,质子在纸面内从氨基向α-碳迁移;c通道是质子以羧基上部的氧为桥迁移;d通道是α-氢迁移至羧基上部的氧后,质子在纸面内从氨基向α-碳迁移。α-Ala_2·Co^(2+)的旋光异构有2个通道(a和b):a通道是其异构成α-Ala_1·Co^(2+)后,再按α-Ala_1·Co^(2+)异构的方式进一步异构;b通道是质子以羰基氧和甲基碳为桥迁移。势能面计算表明:α-Ala_1·Co^(2+)在a和b通道的旋光异构具有优势,隐性溶剂效应下决速步能垒为283.1 kJ/mol,显性溶剂效应下该能垒降至120.3 kJ/mol;α-Ala_2·Co^(2+)在a通道的旋光异构具有优势,决速步能垒与α-Ala_1·Co^(2+)在a和b通道旋光异构的能垒相同。结果表明,水液相下α-丙氨酸Co(Ⅱ)很难发生旋光异构。The optical isomerism of amphoteric and neutralα-alanine(α-Ala_1 andα-Ala_2)and Cocomplexes was studied in water-liquid phase environment by means of M06 and MN15 methods based on density functional theory and SMD model method of self consistent reaction field theory.The study shows that the optical isomerization ofα-Ala_1·Cohas four channels a,b,c and d.In channel a,the proton transfers with the oxygen at the bottom of the carboxyl group as a bridge.In channel b,the proton transfers toα-C from amino group inside the paper afterα-H is transferred to the oxygen at the bottom of the carboxyl group.In channel c,the proton transfers with the oxygen on the upper part of the carboxyl group as a bridge.In channel d,the proton transfers toα-C from amino group inside the paper afterα-H is transferred to the oxygen on the upper part of the carboxyl group.The optical isomerization ofα-Ala_2·Co^(2+)has two channels a and b.In channel a,α-Ala_2·Co^(2+)isomerizes toα-Ala_1·Co^(2+)followed by the isomerization ofα-Ala_1·Co^(2+).In channel b,the protons transfer with carbonyl oxygen and methyl carbon as bridges.The potential energy surface shows that the optical isomerization ofα-Ala_1·Co^(2+)in channel a and b has the most advantage.Under the recessive solvent effect,the energy barrier of the rate-determining step is 283.1 k J/mol.The energy barrier drops to 120.3 k J/mol under the effect of explicit solvent.The optical isomerization ofα-Ala_2·Co^(2+)in channel a has the most advantage.The energy barrier of the rate-determining step is the same as that ofα-Ala_1·Co^(2+)in channel a and b.The results show thatα-alanine Co(Ⅱ)is difficult to racemize in water-liquid phase.

关 键 词：丙氨酸 二价钴离子(Co(Ⅱ)) 密度泛函理论 SMD模型 旋光异构 能垒 

分 类 号：O641.12[理学—物理化学]