Sequential Phase Transitions Near Room Temperature in a Metal-Crown Ether Compound SbBr₃(15-Crown-5)

Abstract

A molecular metal–crown ether coordination compound, SbBr3(15‐crown‐5) (1), has been discovered to undergo an isostructural phase transition at 233.1 K (T1) and another symmetry‐breaking one at 294.5 K (T2), accompanied by thermal and dielectric anomalies, which were confirmed by differential scanning calorimetry (DSC) measurements, dielectric measurements, variable‐temperature structural analyses and Raman spectra. The crystal structures determined at 173, 238, and 318 K were solved in P212121, P212121, Pnma, respectively. Structural analyses reveal that both the changes of the crown ether conformation and the displacements of the Sb cation and Br anion lead to the sequential and reversible phase transitions.

Reversible Structural Phase Transition and Dielectric Switches Induced by Disordering‐Ordering Motion of Tetrachloroferrate (III) Anions

“…Research on reversible phase transitions behaviors in solid state molecules have been attracted much interest recently, since they are promised with widely application on molecular ferroelectric, dielectric switches, temperature controlling switches and NLO (non‐linear optical) materials etc …”