Partial molar volume as an important thermodynamic parameter. Application for uracil methyl derivatives

Quantum mechanical calculations of the solvation were performed for all 16 possible methylated uracil derivatives using the Polarizible Continuum Model (PCM) approach. The obtained results were found to reproduce the experimental data of hydration enthalpies. The decomposition of QM-derived Gibbs energy enabled to correlate the solute-solvent Gibbs energy interaction with the difference between partial molar volume and molecular volume. In aqueous medium, the change of the “effective” solute volume upon dissolution costs 1.8 kJ mol−1 per every 1 cm3 mol−1 of the difference between solute partial molar volume and molecular volume.