Polarization effects for hydrogen-bonded complexes of substituted phenols with water and chloride ion
Polarization effects for hydrogen-bonded complexes of substituted phenols with water and chloride ion
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DOI：
10.1021/ct7001754
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发表时间：
2007-11-01
影响因子：
5.5
通讯作者：
Alexandrova, Anastassia N.
中科院分区：
文献类型：
--
作者：
Jorgensen, William L.;Jensen, Kasper P.;Alexandrova, Anastassia N.
氢键强度的变化进行了研究9对位取代苯酚（XPhOH）与水分子和氯离子的配合物。用从头算HF/6-311+G（d，p）和MP2/6-311+G（d，p）//HF/6- 311 +G（d，p）方法计算了分子的结构，并与OPLS/CM 1A和OPLS-AA力场的计算结果进行了比较.在OPLS-AA模型中，苯酚羟基上的部分电荷不受帕拉取代基选择的影响，而在OPLS/CM 1A方法中使用CM 1A电荷确实提供了电荷重新分配。从头计算揭示了2.0千卡/摩尔范围内的氢键强度的XPhOH…OH 2络合物的顺序为X = NO 2> CN > CF 3> Cl > F > H > OH > CH 3> NH 2。用OPLS-AA不能很好地再现该模式，其还将变化压缩到0.7 kcal/mol。然而，OPLS/CM 1A的结果是在良好的雅阁符合从头计算结果的顺序和范围，2.3千卡/摩尔。当然，以XPhOH为受体时，氢键较弱，X的顺序在很大程度上颠倒，范围缩小到约100。1.0千卡/摩尔氯离子络合物的取代基效应要大得多，范围为11千卡/摩尔。为了定量处理如此强的离子与分子相互作用，证明了完全可极化的力场的必要性。
Variations in hydrogen-bond strengths are investigated for complexes of nine parasubstituted phenols (XPhOH) with a water molecule and chloride ion. Results from ab initio HF/6-311+G(d, p) and MP2/6-311+G(d, p)//HF/6-311+G(d, p) calculations are compared with those from the OPLS-AA and OPLS/CM1A force fields. In the OPLS-AA model, the partial charges on the hydroxyl group of phenol are not affected by the choice of para substituent, while the use of CM1A charges in the OPLS/CM1A approach does provide charge redistribution. The ab initio calculations reveal a 2.0-kcal/mol range in hydrogen-bond strengths for the XPhOH... OH2 complexes in the order X = NO2 > CN > CF3 > Cl > F > H > OH > CH3 > NH2. The pattern is not well-reproduced with OPLS-AA, which also compresses the variation to 0.7 kcal/mol. However, the OPLS/CM1A results are in good accord with the ab initio findings for both the ordering and range, 2.3 kcal/mol. The hydrogen bonding is, of course, weaker with XPhOH as acceptor, the order for X is largely inverted, and the range is reduced to ca. 1.0 kcal/mol. The substituent effects are found to be much greater for the chloride ion complexes with a range of 11 kcal/mol. For quantitative treatment of such strong ion-molecule interactions the need for fully polarizable force fields is demonstrated.