摘要:
用量子力学与分子力学组合的ONIOM方法,考察布洛芬(Ibu)分子限域在螺旋手性单壁碳纳米管(SWCN T)内的手性转变机理.结果表明:螺旋手性单壁碳纳米管的直径越小,限域在其孔道内的布洛芬分子形变越明显;布洛芬分子在SWCNT(6,4)和SWCNT(7,4)内的旋光异构只有一个反应通道,在SWCN T(8,5)内的旋光异构有两个反应通道;布洛芬分子限域在SWCNT(6,4),SWCNT(7,4)和SWCNT(8,5)内时,旋光异构反应决速步骤的内禀能垒分别为247.95,273.83,292.24 kJ/mol,总包能垒分别为278.96,291.91,325.88 kJ/mol.可见S-Ibu的旋光异构易在较小孔径的螺旋手性SWCNT内实现,SWCN T(6,4)可以作为布洛芬分子旋光异构的纳米反应器.%We investigated the chiral transition mechanism of the ibuprofen molecules confined in the helically chiral SWCNT by using the ONIOM methods of combination of quantum mechanics and molecular mechanics . The results show that the deformation of ibuprofen molecules in the confinement region is more and more obvious with the decrease of chirality SWCNT diameter .There is only one reaction channel for the optical isomerism of ibuprofen molecules in SWCNT (6 ,4) and SWCNT (7 ,4) ,and there are two reaction channels for the optical isomerism in SWCNT (8 ,5) .When the ibuprofen molecules are confined in SWCNT (6 ,4) ,SWCNT(7 ,4) and SWCNT(8 ,5) ,the energy barriers of rate-determining step for the optical isomerism reaction are 247.95 , 273.83 , 292.24 kJ/mol ,respectively ,while the total energy barrier are 278 .96 ,291 .91 ,325 .88 kJ/mol .The optical isomerism of S-Ibu molecule is easy to be achieved in the smaller pore size of the helically chiral SWCNT ,and SWCNT (6 ,4) can be used as a nanoreactor for optical isomerism of ibuprofen molecules .