Abstract:
The chiral transition of two stable conformations (amphoteric A_1 and neutral A_2) of α-Ala·Zn
2+ complex were investigated by means of M06 and MN15 method based on density functional theory. The study reveals that H of A_1 can migrated to realize chiral transition with oxygen, nitrogen, zinc, oxygen with nitrogen and oxygen with methyl carbon as the bridge, respectively. As for A_2, the chiral transition can be realized by H migration with oxygen as the bridge, and that can also be realized by various ways of A_1 chiral transition after opening the chelate ring to A_1 isomerism. The potential energy surface studies indicate that the chiral transition reaction of A_1 with Zn atom as a bridge to realize H migration has advantage, and the activation energy is 197.2 kJ·mol
−1. The chiral transition reaction with A_2 opening chelating ring to realize isomerization to A_1 and then using Zn atom as a bridge to realize H migration has advantage, and the activation energy is 228.7 kJ·mol
−1. The results show that Ala·Zn
2+ can maintain its chiral characteristics well.