CMIRS Solvation Model for Methanol: Parametrization, Testing, and Comparison with SMD, SM8, and COSMO-RS

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• 作者：Natalia M. Silva ; Peter Deglmann ; Josefredo R. Pliego Jr.
• 刊名：Journal of Physical Chemistry B
• 出版年：2016
• 出版时间：December 15, 2016
• 年：2016
• 卷：120
• 期：49
• 页码：12660-12668
• 全文大小：477K
• ISSN：1520-5207

文摘

The new continuum solvation model, composite method for implicit representation of solvent (CMIRS), proposed by Pomogaeva and Chipman and implemented in GAMESS was parametrized for methanol solvent, with the aim of using it for ionic reactions in solution. The model was tested for predicting single-ion solvation free energy, pK<sub>asub> of acids and protonated bases, and the activation free-energy barriers of S<sub>Nsub>2 and S<sub>Nsub>Ar reactions in methanol. A comparison was performed with other continuum models, such as SMD, SM8, and COSMO-RS. For a prediction of pK<sub>asub> and free-energy barriers, the order of performance was CMIRS > COSMO-RS > SMD > SM8. In particular, the CMIRS model is much superior to the other continuum models for predicting pK<sub>asub> of acids (without empirical corrections) and is able to evenly describe hard ions like methoxide and charge-dispersed ions like 2,4,6-trinitrophenol. On the basis of our results, we suggest that the field-extremum contribution, present in CMIRS, should be included in continuum solvation models, which can result in substantial improvement in the modeling of ionic reactions in solution.