Insight into Channel-Type Ionic Crystals Based on Cholic Acid for Chiral Phase Transition Materials

Herein, we presented a new channel-type ionic crystal based on cholic acid (CA), n-pentylamine cholate (CA-PA), which possesses 11 chiral carbon atoms. Compared with the CA 2-fluoroaniline (CA-2-FBA) and CA 4-fluoroaniline (CA-4-FBA) clathrates, flexible long-chain PA cations are prone to dynamic disorders. As expected, differential scanning calorimetry (DSC) and dielectric measurements demonstrate that CA-PA exhibits a reversible phase transition at 285.3/270.8 K. Variable-temperature single-crystal structure and Hirshfeld surface analyses show that phase transition is indeed caused by the disorder-order transitions of flexible PA cations situated in the channel space. This finding will pave a new way to explore chiral phase transition materials, and even provide inspiration for the design of bioferroelectrics.