南京大学学报（自然科学版）Issue(1)：206-216,11.DOI:10.13232/j.cnki.jnju.2015.01.028
α-丙氨酸分子在扶手椅型SWBNNT（9,9）内的手性转变机制
The chiral shift mechanism ofα-alanine inside single-walled armchair SWBNNT(9,9)
摘要
Abstract
Methods of combined quantum chemistry ONIOM(Our own N-layered Integrated molecule Orbit and molecule Mechanics)are widely used to study the chemical reaction system associated with nanotubes.This work will study the system which is divided into two layers.The inner layer isα-alanine,using the B3LYP method based on density functional theory,and basis set selection 6-31++G(d,p).The outer layer,a single arm boron nitride nanotubes SWBNNT(9,9)is processed by using molecular mechanics UFF(universal force field)force field,and then the molecular structure and the hiral transition reaction mechanism ofα-alanine confined in SWBNNT(9,9)are studied.Besides,the stable point and transition state of chiral shift reaction process have been optimized.By analyzing the imaginary frequency vibration mode of transition states and intrinsic reaction coordinate (IRC ) calculation for the transition states,the reliability of the transition state has been determined.In order to obtain relatively high levels of energy of the system,we depict potential energy surface of the relatively exact chirality process of transformation and calculate a single point energy of each Inclusion on the ONIOM(B3LYP/6-311++G (3df,3pd):UFF)level.Then we draw the potential energy surface of the reaction process to correct the total system energy of zero-point vibrational energy.The analysis to molecular structure shows that compared with the monomerα-alanine,the bond lengths of skeleton C-N are shorten in different degree whenα-alanine is confined in SWBNNT (9,9).At the same time,the bond angles of skeleton carbons and the dihedral angles of skeleton C-N increase slightly.The study of reaction channel of chiral shift shows that there are two roughly same reaction with channels of chiral shift ofα-alanine in SWBNNT(9,9),and only the reaction channel of collaborative transfer hydrogen in carbonyl and methyl without monomer.The calculation of potential energy surface in chiral shift reaction shows that compared with the monomerα-alanine chiral transformation,whenα-alanine is limited in SWBNNT(9,9),the energy barrier of outboard hydrogen which transfers from chiral carbon directly to oxygen in carbonyl reduces from 326.5 kJ·mol-1 to 319.7 kJ·mol-1 .The energy barriers of hydrogen transfer inside the carboxyl and hydrogen in chiral carbon transfer from outboard to carbonyl respectively decrease from 198.0 kJ·mol-1 and 320.3 kJ·mol-1 to 135.5 kJ·mol-1 and 302.7 kJ·mol-1 .The results show that the energy barriers of different hydrogen transfer decrease in different degree,whenα-alanine is limited in SWBNNT(9,9).关键词
氮化硼纳米管/α-丙氨酸/手性转变/密度泛函理论/过渡态/ONIOM方法Key words
boron nitride nanotubes/α-alanine/chiral transition/density functional theory/transitionstate/ONIOM method分类
化学化工引用本文复制引用
王佐成,梅泽民,吕洋..α-丙氨酸分子在扶手椅型SWBNNT（9,9）内的手性转变机制[J].南京大学学报（自然科学版）,2015,(1):206-216,11.基金项目
吉林省科技发展计划(20130101131JC),国家自然科学基金(11004076),白城师范学院科技计划重点项目(2013第A2号) （20130101131JC）
