A room temperature reversible phase transition containing dielectric switching of a host–guest supramolecular metal–halide compound

Abstract

Following our recent findings on dielectric materials, we synthesized a new host–guest supramolecular metal–halide compound, [(2-AMPD)(18-crown-6)]CuCl₄ (1, 2-AMPD = 2-aminomethylpiperidinium). Systematic characterization techniques such as variable-temperature crystal structure analyses, differential scanning calorimetry (DSC) measurements, temperature-dependent dielectric measurements and powder X-ray diffraction (PXRD) measurements demonstrate that 1 undergoes a reversible phase transition at room temperature, accompanied by switchable dielectric responses and remarkable anisotropy along three different crystallographic axes. The structural phase transition mechanism is triggered by the order–disorder transition of the 18-crown-6 molecules. We believe that these findings might further promote the application of a host–guest inclusion compound in the field of switchable dielectric materials.