title: CMIRS Solvation Model for Methanol: Parametrization, Testing, and Comparison with SMD, SM8, and COSMO-RS.
abstract: 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, pKaof acids and protonated bases, and the activation free-energy barriers of SN2 and SNAr reactions in methanol. A comparison was performed with other continuum models, such as SMD, SM8, and COSMO-RS. For a prediction of pKaand 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 pKaof 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.
authors.affiliation: Departamento de Ciências Naturais, Universidade Federal de São João del-Rei , 36301-160 São João del-Rei, Minas Gerais, Brazil.
authors.forename: Natalia M
authors.initials: NM
authors.lastname: Silva
authors.affiliation: Polymer Processing & Engineering, BASF SE , Carl-Bosch-Str. 38, 67056 Ludwigshafen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Deglmann
authors.affiliation: Departamento de Ciências Naturais, Universidade Federal de São João del-Rei , 36301-160 São João del-Rei, Minas Gerais, Brazil.
authors.forename: Josefredo R
authors.identifier: 0000-0002-2944-5332
authors.initials: JR
authors.lastname: Pliego