中文摘要：

基于密度泛函理论,在B3LYP/6-31＋g（d,p）水平上研究水环境下布洛芬分子的手性转变机理,确定水环境下布洛芬分子从S型向R型转变过程中的过渡态和中间体等极值点结构;在MP2/6-31＋＋g（d,p）水平上计算各稳定点和过渡态体系的单点能,并对体系能量进行零点振动能修正;绘制水环境下布洛芬分子手性转变反应路径上H转移和中间体异构过程的势能面.结果表明：水环境下布洛芬分子手性转变有两条路径,其H转移过程均可通过1个和2个水分子作为桥梁实现,最高能垒均来自于手性C的H向羰基O的转移过程,且均以2H2O为桥梁时能垒最低.

英文摘要：

The chiral shift mechanism of ibuprofen molecule in water was researched at the B3LYP/6-31＋g（d,p）level,which is based on density functional theory.In addition,the structures of transition states and intermediates during the shift process from S-type to R-type ibuprofen molecules were searched in water.At the MP2/6-31＋ ＋g（d,p）level,the single point energies of transition states and intermediates were calculated,as well as zero point vibrational energies of the whole system were amended to get a higher energy.Then the potential energy surfaces of hydrogen transfer and the heterogeneous processes of intermediates on the chiral transition path of ibuprofen molecules in water were drawn.The results show that there are two paths to achieve chiral transition of ibuprofen molecule in water.The process of hydrogen transfer can be achieved with single or two water molecules as bridge.The highest energy barriers of the two paths both come from the transfer processes of hydrogen on the chiral carbon transfers to the oxygen on the carbonyl.