Ab Initio Study of Chiral Discrimination in the Glycidol Dimer
Ab Initio Study of Chiral Discrimination in the Glycidol Dimer
复制标题
缩水甘油二聚体手性辨别的从头算研究
DOI：
10.1021/acs.jpca.0c07764
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Patkowski, Konrad
中科院分区：
文献类型：
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作者：
Hemmati, Reza;Patkowski, Konrad
手性辨别，手性分子表现出不同的弱分子间相互作用比其镜像的能力，研究了二聚体的氧化二胺乙醇（甘油）。为此，采用高水平从头计算方法研究了甘二醇的同手性和异手性二聚体的手性识别效应。共研究了14种二聚体结构，其中7种是同手性的，7种是异手性的，它们都具有两个O - h···O氢键。这些结构是用二阶Møller-Plesset摄动理论（MP2）确定的，使用auguc -cc- pvtz基集，并验证了它们属于实际的局部最小值。基准相互作用能值的计算使用了从aug-cc-pVQZ和aug-cc-pV5Z基中外推的MP2，并在aug-cc-pVTZ基中进行了更高水平的校正。整体最小结构是一个同手性结构，由两个氢键组成一个由8个重原子组成的环。类似的异手性结构的结合能要小0.6 kcal/mol左右。最大的非对映异构体能差约为1.0 kcal/mol。通过对称适应微动理论（SAPT）和官能团SAPT （F-SAPT）差异分析，进一步深入了解了手性区分的起源，以研究从非手性环氧乙烷二聚体到手性甘二醇二聚体的两个- H/ -CH2OH取代的直接和间接影响。最后但并非最不重要的是，计算和分析了相对于非相互作用的甘二醇分子的所有构象的谐波频移，以深入了解手性区分的起源。研究发现，最大的频移与氢键对O-H伸展模式的影响、同时包含两个氢键的环的稳定性以及甘二醇分子的两个非等效极小值之间的跃迁有关。
Chiral discrimination, the ability of a chiral molecule to exhibit different weak intermolecular interactions than its mirror image, is investigated for dimers of oxiranemethanol (glycidol). In this regard, high-level ab initio calculations were performed to study the chiral recognition effects in the homochiral and heterochiral dimers of glycidol. Fourteen dimer structures, seven homochiral and seven heterochiral, were studied: they all feature two intermolecular O–H···O hydrogen bonds. These structures have been determined with the second-order Møller–Plesset perturbation theory (MP2) using the aug-cc-pVTZ basis set and verified to pertain to actual local minima. The benchmark interaction energy values were computed using MP2 extrapolated from the aug-cc-pVQZ and aug-cc-pV5Z bases with a higher-level correction from a coupled-cluster calculation in the aug-cc-pVTZ basis. The global minimum structure is a homochiral one, with the two hydrogen bonds forming a part of a ring with eight heavy atoms. A similar heterochiral structure has a binding energy smaller by about 0.6 kcal/mol. The largest diastereomeric energy difference is about 1.0 kcal/mol. Further insight into the origins of chiral discrimination was provided by symmetry-adapted perturbation theory (SAPT) and a functional-group SAPT (F-SAPT) difference analysis to investigate the direct and indirect effects of two −H/–CH2OH substitutions leading from an achiral ethylene oxide dimer to the chiral glycidol dimer. Last but not least, harmonic frequency shifts relative to a noninteracting glycidol molecule were calculated and analyzed for all conformations to get insight into the origins of chiral discrimination. It is found that the largest frequency shifts are related to the effect of hydrogen bonding on the O–H stretch mode, the stability of the ring involving both hydrogen bonds, and the transition between two nonequivalent minima of the glycidol molecule.