Reversible phase transition triggered by order–disorder transformations and distortions in dipropylammonium d-(+)-10-camphorsulfonate

Abstract

Dipropylammonium D-(+)-10-camphorsulfonate (compound 1) was constructed from a mono-component rotator–stator type dipropylammonium cation and D-(+)-10-camphorsulfonate anion and undergoes a phase transition at 205 K. Differential scanning calorimetry curves of 1 present a pair of peaks, which indicate reversible and first-order phase transition characters. Continuous changes in the dielectric constants, but with a slight anomaly near the phase transition point further confirm the occurrence of a phase transition. Single crystal X-ray diffractions illustrate that 1 crystallizes in the polar space group P2₁ at 130 K and 293 K. Closer inspections reveal that the partially disorder–order transformations of one propyl group in the dipropylammonium cation, as well as a distinct distortion of the terminal ethyl group, induced the structural phase transition. We believe that all these findings would spur the exploration of new structural phase transition compounds.