摘要
用量子化学ONIOM(B3LYP/6-311++G(3df,3pd):UFF)//ONIOM(B3LYP/6-31+G(d,p):UFF)方法,研究了α-Ala限域在SWCNT(12,6)与水复合环境的手性转变.分子结构计算表明:反应物S型α-Ala在SWCNT(12,6)和水的复合环境与单体相比,氢转移需要断的O—H键长都略长,氢转移的H与其要转到的目标原子O的距离均短很多.中间体在SWCNT(12,6)和水的复合环境下与单体相比,涉及到氢转移的C—H键略长;涉及到氢转移的H和O的距离都短.反应通道研究发现:α-Ala在SWCNT(12,6)与水复合环境下,手性转变反应有4条路径,每条路径上的氢转移都能以1个或2个水分子为媒介实现.势能面计算发现:各反应路径上的最高能垒均来自氢从手性碳向羰基氧转移的过渡态.最高能垒的最小值在氨基先异构接着羧基氢转移的路径,并以2H2O为氢转移媒介,能垒为100.3kJ·mol-1.比α-Ala在SWCNT(9,9)与水复合环境手性转变过程最高能垒的最低值154.3kJ·mol-1明显降低.结果表明:对于α-Ala的手性转变反应,螺手性SWCNT是比扶椅型SWCNT更好的纳米反应器.
Using the quantum chemistry ONIOM（B3LYP/6-311＋＋G（3df,3pd）：UFF）∥ONIOM（B3LYP/6-31＋ G（d,p）：UFF）method,the chiral transition mechanism ofα-alanine confined in the chiral helicity SWCNT（12,6）/water complex environment is studied.The research on the molecular structure shows that,compared s-typeα-Ala in the SWCNT（12,6）/water complex environment with monomer molecules,the bond lengths between oxygen and hydrogen involving hydrogen transfer are slightly increased.However,the distance between oxygen and hydrogen is significantly shorten under the same condition.Compared the intermediate in the SWCNT（12,6）/water complex environment with monomer molecules,the bond lengths between carbon and hydrogen involving hydrogen transfer are slightly increased and the distance between oxygen and hydrogen is significantly shorten.The research on the reaction channels ofα-Ala chiral shift shows that,there are four reaction paths in SWCNT（12,6）.Whats more,the process of the hydrogen transfer are all realized by the way which makes one or two water molecules as bridge.The research on the potential energy surfaces of chiral reaction shows that,the maximum energy barriers of every path are always coming from transition state where hydrogen transfers from chiral carbon to carbonyl.The minimum of maximum energy barriers is 100.3kJ·mol-1 in this process Amino heterogeneous first then hydrogen transfers inside the carboxyl which using two water molecules as bridge.Corresponding to chiral transition ofα-Ala in the SWCNT（9,9）/water complex environment,the minimum of maximum energy barriers is 154.3 kJ· mol-1 which obviously reduced.The results show that chiral helicity SWCNT is better nanoreactor than armchair SWCNT forα-Ala.
出处
《复旦学报（自然科学版）》
CAS
CSCD
北大核心
2015年第3期261-276,共16页
Journal of Fudan University：Natural Science
基金
吉林省科技发展计划资助项目(20130101131JC)
国家自然科学基金资助项目(11004076)
关键词
碳纳米管
Α-丙氨酸
手性转变
ONIOM方法
密度泛函
过渡态
carbon nanotubes
a-alanine
chiral transition
ONIOM （our own n-layered integrated molecule orbitand molecule.mechanics） method
density functional theory
transition state
