Performance of SM8 on a Test To Predict Small-Molecule Solvation Free Energies.
June 29th, 2008 | by admin |Performance of SM8 on a Test To Predict Small-Molecule Solvation Free Energies.
The SM8 quantum mechanical aqueous continuum solvation model is applied to a 17-molecule test set proposed by Nicholls et al. ( J. Med. Chem. 2008, 51, 769) to predict free energies of solvation. With the M06-2X density functional, the 6-31G(d) basis set, and CM4M charge model, the root-mean-square error (RMSE) of SM8 is 1.08 kcal mol (-1) for aqueous geometries and 1.14 kcal mol (-1) for gas-phase geometries. These errors compare favorably with optimal explicit and continuum models reported by Nicholls et al., having RMSEs of 1.33 and 1.87 kcal mol (-1), respectively. Other models examined by these workers had RMSEs of 1.5-2.6 kcal mol (-1). We also explore the use of other density functionals and charge models with SM8 and the RMSE increases to 1.21 kcal mol (-1) for mPW1/CM4 with gas-phase geometries, to 1.50 kcal mol (-1) for M06-2X/CM4 with gas-phase geometries, and to 1.27-1.64 kcal mol (-1) with three different models at B3LYP gas-phase geometries.
Chamberlin AC, Cramer CJ, Truhlar DG.
cramer@umn.edu, truhlar@umn.edu.