LAUSR

Two novel phase transition materials, [C9H20N2][Na(BF4)3] (1) and [C9H20N2][(PF6)2] (2), were synthesized based on 1-isopropyl-1,4-diazabicyclo[2.2.2]octan-1-ium with sodium tetrafluoroborate and hexafluorophosphoric acid, respectively. Differential scanning calorimetry measurements detected that 1 and 2 underwent reversible phase transitions, which were confirmed by dielectric measurements. Single crystal X-ray diffraction data suggested that compound 1 changed from a high temperature phase with a space group of P63 to a low temperature one with a space group of P21/c, and that compound 2 transformed from the space group of Pbca at room temperature to P21/c at low temperature. Formation of hydrogen bonds and distortion of 1,4-diazabicyclo[2.2.2]octane rings may drive the transitions.