双水协同作用下苯丙氨酸分子的手性转变机制

摘要

基于密度泛函理论的B3LYP方法,在6-311+G(2df)基组水平上考察双水协同作用下苯丙氨酸分子的手性转变过程.通过寻找反应过程中过渡态和中间体的极值点结构,绘制双水协同作用下完整的苯丙氨酸分子手性转变路径反应势能面,并分析各极值点的几何和电子结构特性.结果表明:双水协同作用下S型苯丙氨酸分子手性C上的H原子以羧基上的O原子为桥,转移至手性C原子的另一侧,实现从S型到R型苯丙氨酸分子的手性转变;双水协同作用下该路径有4个中间体和5个过渡态,最大反应能垒为173.8081 kJ/mol,来源于第二个过渡态TS2-S-Phe&2 H 2 O-2.%Using the method of density functional theory B3LYP,we investigated the chiral transition process of the phenylalanine molecule under the cooperative action of dual-H 2 O at the level of 6-311+G(2df ).We drew a complete reaction potential energy surface for chiral transition path of phenylalanine molecule by finding the structures of the extreme value points including the transition states and intermediates,and analyzed the geometric and electronic structure properties of extreme value points.The results show that the H atom on the chiral C atom of S-phenylalanine molecule can transfer to the other side of the C atom via the O atoms of carboxyl atoms as a bridge,and achieve the chiral transition of phenylalanine molecule from S-type to R-type. On this path there are four intermediates and five transition states.The maximum reaction energy barrier is 173.8081 kJ/mol, which comes from the second transition state TS2-S-Phe&2 H 2 O-2.