New model for calculation of solvation free energies: Correction of self-consistent reaction field continuum dielectric theory for short-range hydrogen-bonding effects
New model for calculation of solvation free energies: Correction of self-consistent reaction field continuum dielectric theory for short-range hydrogen-bonding effects
复制标题
DOI：
10.1021/jp953087x
复制
发表时间：
1996-07-11
影响因子：
--
通讯作者：
Honig, B
中科院分区：
文献类型：
--
作者：
Marten, B;Kim, K;Honig, B
我们提出了自一致反应场（SCRF）计算，利用相关从头算量子力学，为一个大的数据库的分子溶质的水溶剂化自由能，我们确定了一个子集的化学官能团，有系统的偏差在理论和实验的比较；此外，对于一个已经被广泛研究的情况，甲基化胺，类似的偏差出现在使用几种常用分子力学势函数的显式溶剂自由能微扰计算中。通过对溶质与水分子的氢键能进行高水平从头算量子化学计算，我们对理论与实验之间的分歧得到了一致的解释，即氢键能在某些情况下与经典静电相互作用能相关性较差。我们发现，溶质的氢键能偏离参考分子（SCRF计算和实验之间有很好的一致性）是对该溶质在SCRF计算中产生的误差的一个很好的预测因子。我们建立了一个新的SCRF模型，其中基于溶剂可及性对这些化学官能团进行了短期经验修正；这将整个数据库计算的溶剂化自由能的平均误差降低了2倍，降至0.37 kcal/mol。这些结果对显式溶剂势函数和介质连续介质模型的准确性具有重要意义。最后，我们还确定了在溶剂化自由能中观察到的差异不能用对氢键结果来解释的情况，并提出了这里可能特定于介电连续统理论的问题。
We present self-consistent reaction field (SCRF) calculations, utilizing correlated ab initio quantum mechanics, of aqueous solvation free energies for a large data base of molecular solutes, We identify a subset of chemical functional groups for which there are systematic deviations in the comparison of theory and experiment; furthermore, for one case which has been extensively investigated, methylated amines, similar deviations appear in explicit solvent free energy perturbation calculations employing several commonly used molecular mechanics potential functions. By carrying out high-level ab initio quantum chemical calculations of hydrogen-bonding energies of the solutes to a water molecule, we arrive at a coherent explanation of the disagreements between theory and experiment, namely, that hydrogen-bonding energies are in some cases poorly correlated with classical electrostatic interaction energies. We show that the deviation in hydrogen-bonding energies of a solute from a reference molecule (for which there is good agreement between the SCRF calculations and experiment) is an excellent predictor of the errors made for that solute in the SCRF calculations, A new SCRF model is developed in which short-range empirical corrections, based upon solvent accessibility, are made for these chemical functional groups; this reduces the mean error of the calculated solvation free energies for the entire data base by a factor of similar to 2, to 0.37 kcal/mol. These results have significant implications for the accuracy of explicit solvent potential functions as well as dielectric continuum models. Finally, we also identify cases where the observed discrepancies in solvation free energies cannot be explained by pair hydrogen-bonding results and suggest problems here that may be specific to dielectric continuum theory.