Calculation of Solvation Free Energies with DCOSMO-RS

The
concept of dielectric continuum models has turned out to be
very fruitful for the qualitative description of solvation effects
in quantum chemical calculations, although from a theoretical perspective
its basis is questionable, at least if applied to polar solvents,
because the electrostatic nearest neighbor interactions in polar solvents
are much too strong to be described by macroscopic dielectric continuum
theory. On the basis of this insight, the Conductorlike Screening
Model for Realistic Solvation (COSMO-RS) had been developed, which
gives a thermodynamically consistent, quantitative description of
solvation effects in polar and nonpolar solvents, even in mixtures
and at variable temperature, starting from quantum chemical calculations
of solute and solvent molecules embedded in a virtual conductor (COSMO).
Though COSMO-RS usually only requires quantum chemical calculations
in the conductor and thus does not allow for studying of the concrete
solvent influence on the solute electron density, the direct COSMO-RS
(DCOSMO-RS) has been introduced, which uses the σ-potential,
i.e., a solvent specific response function provided by COSMO-RS, as
a replacement of the conductor or dielectric response employed in
continuum solvation models. In this article we describe the current
status of DCOSMO-RS and demonstrate the performance of the DCOSMO-RS
approach for the prediction of free energies of solvation.