High-pressure and temperature dependence of the spontaneous resolution of 1,1'-binaphthyl enantiomers.

High pressure increases the temperature of the spontaneous resolution of 1,1'-binaphthyl conformational enantiomers in the crystalline state, which confirms that the enantiomers and racemates are stabilized in the molecular environments in compressed structures. The established pressure-temperature (p-T) preference diagram for the racemate-enantiomer spontaneous crystallization corresponds to a boundary between solid phases, as it is consistent with the Clausius-Clapeyron equation, however, the hysteresis of such a solid-state transformation extends to very high pressure, to 3 GPa, at least according to this study. High-pressure X-ray diffraction study on single crystals of 1,1'-binaphthyl racemate and enantiomer reveals their monotonic compression and structural changes up to 3 GPa. It also reveals the increasing role of intermolecular interactions for stabilizing the structures, despite the exceptionally large density difference between the racemate (1.277 g cm-1) and enantiomers (1.183 g cm-1).