Sequential Phase Transitions with Switchable Dielectric Constant in a Metal-Free Ionic Crystal
Sequential Phase Transitions with Switchable Dielectric Constant in a Metal-Free Ionic Crystal
复制标题
无金属离子晶体中具有可切换介电常数的连续相变
DOI：
10.1002/ejic.201900182
复制
发表时间：
2019-05-26
影响因子：
2.3
通讯作者：
Ye, Heng-Yun
中科院分区：
文献类型：
--
作者：
Jing, Jing;Gao, Ji-Xing;Ye, Heng-Yun
An intriguing area for developing smart devices is metal-free materials. These materials have simple preparation, low processing temperature and environmentally-friendly processing of the crystal. Stimuli-responsive materials, which have been developed switchable property of dielectric constant in most inorganic-organic hybrid compounds, are rarely found in metal-free materials. Herein, a metal-free ionic crystal compound, [3R-(+)-3-AP][ClO4](2) (1, 3R-(+)-3-AP = 3R-(+)-3-aminopyrrolidine cation), was synthesized and characterized. The structure is featured by zero-dimensional supramolecular block structure built from the [3R-(+)-3-AP][ClO4](2) units. Compound 1 undergoes sequential reversible phase transitions at 350/373 K and 430/441 K, respectively. Variable-temperature single crystal structural analysis and dielectric constant measurements reveal changes of the crystal lattice dynamics, i.e., the twisting motion of the perchlorate anions and the dynamic changes of the [3R-(+)-3-AP] cations, are the origin of the phase transitions. This finding reveals that the amphidynamic metal-free crystal can evolve rich electrical properties once the dynamic components (especially the polar ones) undergo order-disorder transitions, such as temperature-responsive dielectric switching.
