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

Following our recent findings on dielectric materials, we synthesized a new host-guest supramolecular metal-halide compound, [(2-AMPD)(18-crown-6)]CuCl (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.