Department of Chemical and Process Engineering, University of Strathclyde, 75 Montrose Street, Glasgow, G1 1XJ, United Kingdom.
J Comput Chem. 2017 Mar 5;38(6):359-369. doi: 10.1002/jcc.24689.
Existing united-atom models for non-polar hydrocarbons lead to systematic deviations in predicted solvation free energies in hydrophobic solvents. In this article, an improved set of parameters is proposed for alkane molecules that corrects this systematic deviation and accurately predicts solvation free energies in hydrophobic media, while simultaneously providing a very good description of pure liquid densities. The model is then extended to alkenes and alkynes, again yielding very accurate predictions of solvation free energies and densities for these classes of compounds. For alkynes in particular, this work represents the first attempt at a systematic parameterization using the united-atom approach. Averaging over all 95 solute/solvent pairs tested, the mean signed deviation from experimental data is very close to zero, indicating no systematic error in the predictions. The fact that predictions are robust even for relatively large molecules suggests that the new model may be applicable to solvation of non-polar macromolecules without accumulation of errors. The root mean squared deviation of the simulations is only 0.6 kJ/mol, which is lower than the estimated uncertainty in the experimental measurements. This excellent performance constitutes a solid basis on which a more general model can be parameterized to describe solvation in both polar and non-polar environments. © 2016 Wiley Periodicals, Inc.
现有的非极性碳氢化合物的统一原子模型导致在疏水溶剂中预测的溶剂化自由能存在系统偏差。在本文中，提出了一组改进的烷烃分子参数，该参数可纠正这种系统偏差，并准确预测疏水性介质中的溶剂化自由能，同时很好地描述纯液体的密度。然后将该模型扩展到烯烃和炔烃，再次对这些化合物类别的溶剂化自由能和密度进行了非常准确的预测。特别是对于炔烃，这是首次使用统一原子方法进行系统参数化的尝试。对于测试的所有 95 个溶质/溶剂对进行平均，与实验数据的平均符号偏差非常接近零，表明预测中没有系统误差。即使对于相对较大的分子，预测仍然稳健，这表明新模型可能适用于非极性大分子的溶剂化，而不会累积误差。模拟的均方根偏差仅为 0.6 kJ/mol，低于实验测量的估计不确定性。这种出色的性能为更一般的模型提供了可靠的基础，以便在极性和非极性环境中描述溶剂化。©2016 年 Wiley 期刊，公司。
