Gonçalves Paulo F B, Stassen Hubert
Grupo de Química Teórica, Instituto de Química, Universidade Federal do Rio Grande do Sul, 91540-000 Porto Alegre, RS, Brazil.
J Comput Chem. 2003 Nov 15;24(14):1758-65. doi: 10.1002/jcc.10294.
Using molecular dynamics simulation, we present new results for the free energy of solvation for solvents with low dielectric constants (CCl(4), CHCl(3), benzene). The solvation free energy is computed as the sum of three contributions originated at the cavitation of the solute by the solvent, the solute-solvent repulsion and dispersion interactions, and the electrostatic solvation of the solute. The cavitational contribution has been obtained from the Claverie-Pierotti model applied to excluded volumes obtained from distances for nearest neighbor configurations between the solute's atoms and a spherical solvent description. An electrostatic continuum model has been adapted for the computation of the electrostatic free energy of solvation, whereas the van der Waals contribution has been calculated directly from the intermolecular interactions defined by the force fields applied to the simulations. For each solvent, a large set of solute molecules containing most of the chemically interesting functionalities has been treated. The simulated solvation free energies are in very good agreement with experimental data, although a small systematical overestimation of the free energy of solvation indicates a failure of the spherical approach to the solvent molecules in the case of benzene.
通过分子动力学模拟，我们给出了低介电常数溶剂（四氯化碳、氯仿、苯）溶剂化自由能的新结果。溶剂化自由能计算为溶剂使溶质空化、溶质 - 溶剂排斥和色散相互作用以及溶质静电溶剂化这三种贡献的总和。空化贡献是通过将Claverie - Pierotti模型应用于从溶质原子与球形溶剂描述的最近邻构型距离获得的排斥体积得到的。一种静电连续介质模型已被用于计算静电溶剂化自由能，而范德华贡献则直接从应用于模拟的力场定义的分子间相互作用计算得出。对于每种溶剂，已经处理了一大组包含大多数化学上有趣官能团的溶质分子。模拟的溶剂化自由能与实验数据非常吻合，尽管溶剂化自由能存在小的系统性高估，这表明在苯的情况下，将溶剂分子视为球形的方法存在不足。
