A Novel Organic-inorganic Hybrid Phase Transition Compound with Switchable Dielectric Property

A novel organic-inorganic hybrid phase transition compound [（C3H7）2 dabco]CoBr4 with switchable dielectric property is synthesized, and the phase transition behavior was measured by DSC measurements. The DSC curves display a pair of endothermic and exothermic peaks at 230 and 212 K, confirming a reversible first-order phase transition by the calculation of entropy change and the 18 K thermal hysteresis. The structural change from P42/m at room-temperature to P42 at 100 K accompanied by a deletion of mirror plane m was determined by variable temperature single-crystal X-ray diffractions. Furthermore, switchable step-like dielectric anomalies can be observed around 230 K by the real part of dielectric constant curves. The 10-fold difference of ε' between high ε' and low ε' states make compound 1 a potential candidate for sensor and detection devices at appropriate temperature and frequencies.