Solvation enthalpies of neutral solutes in water and octanol (original) (raw)

The balance between electrostatic and nonelectrostatic enthalpic contributions to the free energy of solvation of a series of neutral solutes in water and n-octanol is examined by means of continuum solvation calculations based on the Miertus-Scrocco-Tomasi (MST) method. The experimental data indicate that the solvation enthalpy of hydrocarbons is very similar in water and n-octanol, and that the enthalpic contribution measured for polar compounds is larger in water than in n-octanol. According to MST calculations, the different magnitude of the solvation enthalpy found for polar compounds in the two solvents can be largely attributed to the electrostatic contribution. Moreover, the results point out that there is close resemblance between the non-electrostatic components for both hydrocarbons and polar compounds in the two solvents. Finally, the results show the power of current continuum models like MST to dissect the total free energy of solvation in entropic and enthalpic contributions and suggest that new refinements of continuum solvation models should include not only the fitting to solvation free energies, but also their enthalpic components.