Solvent-induced reversible high-temperature phase transition in crown ether clathrates†
Abstract
Crown-ether coordination compounds and derivatives have been extensively studied in dynamic responsive materials due to their rich structures and properties. However, it is still challenging to design crown ether clathrate phase-transition materials with high phase-transition temperatures (Tr). To overcome this obstacle that limits their application range, here, we obtained [(F2CHCH2NH3)-(18-crown-6)][PF6] (1) and [(F2CHCH2NH3)-(18-crown-6)][PF6]·CH3CN (1·ACN) by regulating different solvents. Due to the solvent-induced effect, compound 1·ACN exhibits dielectric response properties; however, compound 1 does not undergo any phase transition. As was revealed by our experimental results, the reversible phase transition at 349 K is induced by the order–disorder change of the [PF6]− octahedral anion. In short, the solvent-induced effect in this study not only realized the generation of phase transition but also increased the phase-transition temperature of the crown ether clathrates, which can provide a useful tool for the design of interesting crown ether clathrates with high phase-transition temperatures.