title: Supramolecular bola-like ferroelectric: 4-methoxyanilinium tetrafluoroborate-18-crown-6.
abstract: Molecular motion is one of the structural foundations for the development of functional molecular materials such as artificial motors and molecular ferroelectrics. Herein, we show that pendulum-like motion of the terminal group of a molecule causes a ferroelectric phase transition. Complex 4-methoxyanilinium tetrafluoroborate-18-crown-6 ([C(7)H(10)NO(18-crown-6)](+)[BF(4)](-), 1) shows a second-order ferroelectric phase transition at 127 K, together with an abrupt dielectric anomaly, Debye-type relaxation behavior, and the symmetry breaking confirmed by temperature dependence of second harmonic generation effect. The origin of the polarization is due to the order-disorder transition of the pendulum-like motions of the terminal para-methyl group of the 4-methoxyanilinium guest cation; that is, the freezing of pendulum motion at low temperature forces significant orientational motions of the guest molecules and thus induces the formation of the ferroelectric phase. The supramolecular bola-like ferroelectric is distinct from the precedent ferroelectrics and will open a new avenue for the design of polar functional materials.
authors: Ordered Matter Science Research Center, Southeast University, Nanjing 211189, China.
authors: Da-Wei
authors: DW
authors: Fu
authors: Wen
authors: W
authors: Zhang
authors: Hong-Ling
authors: HL
authors: Cai
authors: Yi
authors: Y
authors: Zhang
authors: Jia-Zhen
authors: JZ
authors: Ge
authors: Ren-Gen
authors: RG
authors: Xiong
authors: Songping D
authors: SD
authors: Huang