Solvation Free Energies for Aqueous and Nonaqueous Solutions Computed Using PM7 Atomic Charges

[Image: see text] We describe a simple and accurate method, ESE-PM7, for calculating solvation free energies ΔG(solv)(°) in aqueous and nonaqueous solutions. The method is based on a noniterative COSMO algorithm. Molecular geometries and atomic charges calculated using the semiempirical method PM7 are used to calculate ΔG(solv)(°). The method has been tested on 92 different solvents and 988 solutes. The mean absolute errors (MAEs) in ΔG(solv)(°) in aqueous solutions estimated by the ESE-PM7 approach are found to be 1.62 kcal/mol for 389 neutral solutes and 3.06 kcal/mol for 139 ions. The MAEs for neutral molecules in organic solvents are 0.97, 0.74, and 0.51 kcal/mol in polar protic, polar aprotic, and nonpolar solvents, respectively. The developed method can be employed to quickly screen ΔG(solv)(°) values of extended molecular systems including pharmaceutical and biological molecules.