SolvateIt : A Tool for Solvating Molecules. A Case Study of Phloroglucinol in Solution

The explicit first solvation shell remains a pivotal challenge in quantum chemical studies of solution-phase systems. A surface coverage-based protocol to construct explicit solvation environment is presented, in which the number and arrangement of solvent molecules emerge from the percentage of Solvent Accessible Surface (SAS) surrounding the solute rather than being user-defined. This strategy is implemented in a computational tool to ensure reproducibility. Phloroglucinol (PG) in ethanol is analyzed to validate this approach, comparing in vacuum, implicit solvent, and explicit ethanol systems corresponding to 10%, 25%, 50%, and 90% SAS coverage. Density Functional Theory calculations within a QM/QM methodology reveal that full first-shell improves the prediction of solvent-perturbed properties. In particular, the dipole moment obtained with 90% SAS coverage deviates by only 0.7% from the experimental value. Explicit solvation is shown to strongly influence geometry, electrostatic potential and intermolecular interactions, highlighting the importance of physically motivated solvation shell construction.