【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-Ala（丙氨酸）与Mg²⁺配合物的旋光异构.研究发现:α-Ala·Mg²⁺的旋光异构反应有3个通道a、b和c,a是质子分别以羰基氧和氨基氮为桥迁移;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:隐性水溶剂效应作用下α-Ala·Mg²⁺旋光异构的c通道具有优势,决速步能垒是218.1kJ·mol^-1,a和b通道处于劣势,具有共同的决速步能垒297.1kJ·mol^-1.水分子（簇）的作用使c通道的决速步能垒降到143.0kJ·mol^-1,a和b通道的决速步能垒降到148.7kJ·mol^-1.结果表明:水液相环境下α-Ala·Mg²⁺可以较好地保持其手性特征,α-丙氨酸二价镁盐用于生命体镁和丙氨酸同补具有很好的安全性.更多还原

【Abstract】 The optical isomerization of the amphotericα-alanine and Mg²⁺complexes in water-liquid phase environment has been studied using the M06-2 Xmethod combined with the Slovation Model Density（SMD）model method based on self consistent reaction field theory.The study shows that theα-Ala·Mg²⁺optical isomerization reaction has three channels a,b and c.The proton is transferred with carbonyl oxygen and amino nitrogen respectively as the bridge in channel a;and that is only transferred with carbonyl oxygen as the bridge in b.In channel c,the proton is transferred with amino nitrogen as a bridge after the transition that from protonated amino to carbonyl oxygen.The potential energy surface shows that the channel c of theα-Ala·Mg²⁺optical isomerization has the most advantage under the effect of recessive solvent and the energy barrier of the rate-determining step is218.1 kJ·mol^-1,channel a and b are at a disadvantage,they have the common energy barrier of the ratedetermining step is 297.1 kJ·mol^-1.The effect of water molecule（cluster）reduced the energy barrier of ratedetermining step of the channel c to 143.0 kJ·mol^-1,the energy barrier is reduced to 148.7 kJ·mol^-1 in a and b.The results shows thatα-Ala·Mg²⁺can retain its chirality well in the water-liquid environment,and it’s excellently safe that the supplement of magnesium and alanine for life simultaneously throughα-alanine divalent magnesium salt.更多还原