Reference data for prolinol-water clusters

The dataset reports experimental fits for prolinol and its hydrated complexes with one to three water molecules, obtained from broadband rotational spectra using the SPFIT/SPCAT programs. Bare prolinol adopts two low-energy conformations stabilized by an intramolecular O–H···N hydrogen bond. Upon complexation with a single water molecule, four prolinol–H₂O isomers are identified, comprising both addition and insertion structures that preserve the original conformations. For complexes with two and three water molecules, prolinol is stabilized in its highest-energy conformations by an intramolecular N–H···O hydrogen bond. These results reveal how stepwise hydration induces significant structural rearrangements and provide insights into the role of water in shaping the conformational preferences of flexible chiral molecules. Isotopologues of selected complexes, either in natural abundance or prepared under isotopic enrichment conditions, are also included.