水与扶手椅型SWCNT复合环境下α-Ala分子的手性转变机理

采用组合量子化学ONIOM方法,基于氨基作为氢迁移桥梁,考察单壁碳纳米管(SWCNT)与水复合环境下α-丙氨酸分子(α-Ala)的手性转变机理.结果表明:基于氨基作为氢迁移桥梁的手性转变反应有a和b两个通道,其中通道a最具优势;水与扶手椅型SWCNT复合环境对氢迁移反应具有较好的催化作用;在SWCNT(8,8)的限域环境下,3个水分子构成的链使主反应通道的决速步骤能垒从裸反应的266.1kJ/mol降至117.8kJ/mol.表明SWCNT(8,8)与水构成的复合环境可作为实现α-Ala手性转变的理想纳米反应器,生命体内α-Ala分子可在类似的纳米环境实现旋光异构.

Chiral Transition Mechanism of α-Ala Molecule under Complex Environment of Armchair SWCNT and Water

We investigated chiral transition mechanism of α-Ala molecule under complex environment of single walled carbon nanotubes and water based on amidogen as H transfer bridge by using the method of quantum chemistry ONIOM. The results show that there are two shift reaction channels a and b based on amidogen as a bridge of hydrogen transfer process in chiral transformation. The channel a is the most advantage way. Armchair SWCNT/water complex environment providea preferable catalytic effect for hydrogen transfer reaction. Under the confined environment of SWCNT(8,8), compared with the primary reaction, the rate determining step energy barrier drops from 266.1 kJ/mol of naked reaction to 117.8 kJ/mol using chain of three water molecules. Thus the SWCNT (8,8)/watercomplex can used as an ideal nano reactor of implementation α-Ala chiral shift, and α-Ala molecule will also make this optical isomerism reacion reality in a similar nano environment in organisms.