1. A series of dynamic single crystals of [MII(en)3]SO4 (M = Ni, Mn, and Cd) shows tunable dielectric properties and anisotropic thermal expansion.
- Author
-
Wu, Cong, Gao, Kai-Ge, Yao, Zi-Shuo, and Tao, Jun
- Subjects
THERMAL expansion ,SINGLE crystals ,DIELECTRIC properties ,PHASE transitions ,THERMAL properties ,COORDINATION polymers ,TRANSITION metals - Abstract
A series of dynamic single crystals with a chemical formula of [M
II (en)3 ]SO4 (en = ethylene and MII = NiII , MnII , and CdII ) was synthesized. As the temperature decreases, these materials exhibit dielectric switching in the vicinity of the phase transition point accompanied by anisotropic thermal expansion in the cell parameters as a consequence of the order–disorder structural change of SO2− 4 in a cavity surrounded by five [MII (en)3 ]2+ complex cations. Because the variation of metal centers with different ionic radii changes the shape of the complex cation, which affects the distribution of hydrogen-bond interactions around the SO2− 4 , the dynamic motion of SO2− 4 is substantially tuned. Correspondingly, the dielectric properties and anisotropic thermal expansion of materials were largely shifted, especially in the single crystals of [MnII (en)3 ]SO4 , whose structural change is distinctly different from the crystals of Ni(II) and Cd(II). The detailed structural mechanism accounting for the different physical properties of these materials was discussed. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF