扶手椅型单壁碳纳米管的尺寸对布洛芬分子手性转变的限域影响  

The Confined Affect of the Size of Armchair Single-Walled Carbon Nanotubes(SWCNT)on the Chiral Transition of Ibuprofen Molecule

作　　者：王佐成[1] 梅泽民[2] 吕洋[3] 邹晓威[4] 

机构地区：[1]白城师范学院物理学院,白城137000 [2]白城师范学院化学学院,白城137000 [3]白城师范学院网络管理中心,白城137000 [4]海口经济学院数理教研部,海口570100

出　　处：《复旦学报（自然科学版）》2015年第2期234-244,共11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)

摘　　要：用量子力学和分子力学相结合的ONIOM(B3LYP/6-31+g(d,p)∶UFF)方法,研究SWCNT((8,8),(7,7),(6,6))内的布洛芬(IBU)分子结构和手性转变机理,在ONIOM(B3LYP/6-311++g(2df,pd)∶UFF)水平计算单点能.分子结构研究表明:与单体IBU分子相比,受限于SWCNT(6,6)时,羧基C与它的两个O的键长,羧基C与手性C的键长明显减小,导致手性C和羰基O以及羧基两个O的间距明显缩短.随着管径的增加,IBU分子结构变化变得不明显.手性转变反应通道研究表明:在SWCNT(8,8)内存在两个反应通道,一是手性碳上的氢直接以羰基氧为桥梁转移到手性碳的另一侧;二是氢先在羧基内转移,从羟基转移到羰基,而后手性碳上的氢再以羰基氧为桥梁转移到手性碳的另一侧.在SWCNT(7,7)和SWCNT(6,6)内只存在第二通道.反应势能面计算发现:IBU分子在SWCNT(6,6)内,羧基内氢转移和氢从手性碳转移到羰基的能垒明显降低,从单体的143.9和306.4kJ·mol-1分别降到123.3和246.3kJ·mol-1;在SWCNT(7,7)内降低的幅度次之,在SWCNT(8,8)内降低幅度很小.结果表明:IBU限域在SWCNT内时的氢转移反应能垒随管径减小而降低.The structure and the chiral shifting mechanism of Ibuprofen（IBU） molecular within SWCNT（8,8）, （7,7） ,（6,6） are researched, using the ONIOM（B3LYP/6-31 q-g（d, p） ： UFF） method which combines quantummechanics and molecular mechanics. What＇s more, the energies of single-points are calculated at the ONIOM（B3LYP/6-311-l-q-g（2df, pd） ： UFF） level. The research on the molecular structure shows that, compared withthe monomer IBU molecules, the bond lengths between carbon on carboxyl and its two oxygen atoms aresignificantly reduced, which is the same between carbon on carboxyt and chiral carbon. Therefore, the distancebetween chiral carbon and oxygen on carbonyl, as well as the two oxygen atoms on carboxyl is significantly shortenwhen limited in SWCNT（6,6）. Then the causes further make the energy barriers reduced, include the processesthat hydrogen transfers inside carboxyl, and hydrogen transfers between chiral carbon and carbonyl. However,the change of molecular structure is not obvious along with the increase of the diameter. The research on thereaction channels of chiral shift shows that, there are two reaction paths in SWCNT（8,8）. The first path is theprocess that the hydrogen on chiral carbon directly transfers to the other side which makes the carbonyl oxygen asbridge. The second path is the process that hydrogen transfers inside the carboxyl first, then the hydrogen onchiral carbon directly transfers to the other side which makes the carbonyl oxygen as bridge. There is only thesecond path existing in SWCNT（7,7） and SWCNT（6,6）. The research on the potential energy surfaces of chiralreaction shows that, compared with monomer IBU, the energy barrier of hydrogen transfer is significantly reducedwhen IBU molecules is inside SWCNT（6,6）, no matter the transfer happens inside the earboxyl or from chiralcarbon to carbonyl. The energy barriers of two paths respectively reduce from 143. 9 and 306. 4 kJ ·mol-1 inmonomer to 123.3 and 246. 3 kJ · mol-1 in SWCNT（6,6�

关 键 词：碳纳米管 布洛芬 手性转变 密度泛函理论 过度态 ONIOM 

分 类 号：O641.12[理学—物理化学]