2021, Vol.94, No.7


We examined various combinations of semiempirical and polarizable continuum methods and found that SMD/PM7 provides the highest accuracy in calculating LogPo/w. The correlation between the experimental and calculated LogPo/w is approximately R2 = 0.74. However, this result is not sufficiently accurate for achieving a practical prediction. To clarify the details of the calculation results, a linear fitting was conducted for each functional group and each atom. The results showed a large variation, indicating a large error. We then conducted a multiple regression analysis using the number of atoms in the molecule, the number of multiple bonds, the ring structure, and the indicator for aromatic nature as explanatory variables and the experimental value of LogPo/w as the objective variable; finally, we incorporated a correction to the calculated value of LogPo/w. We showed that the accuracy was significantly improved to approximately R2 = 0.95 when adopting the difference in solvation energy, along with four additional explanatory variables.