An order-disorder ferroelectric host-guest inclusion compound.
The host-guest complex [(DIPA)([18]crown-6)](ClO4) (1; DIPA=2,6-diisopropylanilinium) was constructed and found to undergo a sequence of phase transitions (Ibam-Pbcn-Pna21) at T1=278 K and T2=132 K, respectively. Systematic characterizations, such as differential scanning calorimetry, heat capacity, temperature-dependent dielectric constant, and P-E hysteresis loop, reveal that the centrosymmetric-to-polar phase transition at T2 is a paraelectric-to-ferroelectric transition. The symmetry breaking was also confirmed by temperature-dependent second-harmonic generation effect and X-ray powder diffraction. The ferroelectric mechanism is attributable to the linear motion of the perchlorate counterions accompanied by the order-disorder transition of the [18]crown-6 molecules and the anions.
Ordered Matter Science Research Center, Southeast University, Nanjing 211189 (P.R. China).
Yi
Y
Zhang
Heng-Yun
HY
Ye
Da-Wei
DW
Fu
Ren-Gen
RG
Xiong
dielectric constant; ferroelectrics; host-guest compounds; order-disorder; phase transitions