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A novel organic–inorganic ABX3 perovskite-type material with specific hydrogen bonding interactions, N,N-dimethylethanolammonium trichlorocadmate ([DMEA]CdCl3), has been synthesized as a phase transition material. It is notable that the DMEA cations are arranged to form one-dimensional chains connected by hydrogen bonds at room temperature, which are very sparse in other perovskite-type compounds. The strong intermolecular interactions have made the phase transition temperature of the material reach up to 429 K, as confirmed by differential scanning calorimetry measurements, variable-temperature structural analyses, and dielectric measurements. The origin of the symmetry-breaking phase transition is associated with the motion or reorientation of the DMEA cations, accompanied by the crystal structures from orthorhombic Pnma to monoclinic P21/c with the temperature decreases. The finding of [DMEA]CdCl3 with unprecedented hydrogen bonding interactions has opened a new avenue to design novel phase transition materials with higher transition temperatures. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid materials with a high-temperature phase transition have been widely applied as a kind of smart material. In this work, a new organic–inorganic 2H-perovskite compound, namely [Me3NCH2CH3]CdCl3 (1), is reported with a high temperature dielectric transition showing excellent reversibility and sustainability. 1 has an ABX3 hybrid perovskite structure, where A is a [Me3NCH2CH3]+ cation, B is a divalent metal atom, and X is a halogen atom. Differential scanning calorimetry (DSC) and dielectric measurements were applied for further characterization. Variable temperature single-crystal X-ray diffraction revealed that 1 crystallizes in the orthorhombic Pbca space group (No. 61) at 293 K and hexagonal P63/mmc space group (No. 194) at 363 K. The structural phase transition is primarily attributed to an ordered–disordered type resulting from the [Me3NCH2CH3]+ cations. Organic–inorganic perovskite compounds, as a result of a long exploration history and forward-looking prospects, can deepen research into molecular materials and their physical properties can be effectively optimized in the next-generation of temperature-responsive electrical switches. [ABSTRACT FROM AUTHOR]

• A new organic-inorganic hybrid material (TEACCl) 2 CuBr 4 was designed and constructed. • A switchable dielectric property can be observed. A reversible phase change was verified by differential scanning calorimetry, single crystal structure determination and dielectric measurement. For organic-inorganic hybrid material, a change of dielectric constant always occurs in phase transition, which can be further controlled by temperature, light, pressure and etc. The design of organic-inorganic hybrid material with a significant dielectric change remains a challenge. Herein, an organic-inorganic hybrid material (TEACCl) 2 CuBr 4 (TEACCl = (CH 3 CH 2) 3 NCH 2 Cl+) with a distinct dielectric transition at 315.8 K was designed and constructed. Differential scanning calorimetry (DSC) test proved that there exists a reversible phase change at 315.8 K. Thermogravimetric (TG) measurement proved that it remained stable up to 505 K, exhibiting excellent stability. In addition, the single crystal structure, intermolecular interaction analysis and ultraviolet-vis spectral were discussed in this article. [ABSTRACT FROM AUTHOR]

Two new organic ionic plastic crystals (OIPCs), [TMBM] [ClO4] (1) and [TMBM] [BF4] (2) (TMBM = trimethylbromomethyl ammonium), were successfully synthesized. Systematic characterization via differential scanning calorimetry (DSC), variable-temperature single-crystal X-ray diffraction, variable-temperature powder X-ray diffraction (PXRD) and dielectric measurements demonstrated that 1 and 2 undergo reversible high-temperature sequential phase transitions accompanied by distinct stepwise switchable dielectric anomalies (1 at 358 K and 388 K and 2 at 346 K and 379 K). The structural relatively ordered-disordered transitions of ClO4−, BF4− and [TMBM]+ contributed to the switching of the dielectric constant from the low-dielectric state to the high-dielectric state. Thus, OIPCs consisting of spherical ammonia cations and inorganic acid anions are proven to be promising in the search for high-temperature multi-step switchable dielectric materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new organic-inorganic hybrid material TEACCl·FeCl 4 with an order-disorder phase change. • Enthalpy change of phase transition is high. • A switchable dielectric property can be observed. A new organic-inorganic hybrid material TEACCl·FeCl 4 (1 , TEACCl+ = Et 3 NCH 2 Cl+) with a phase change at 264.3 K was synthesized. 1 was characterized by thermogravimetric, differential scanning calorimetry, single crystal structure determination, dielectric measurement, infrared spectra and ultraviolet-vis spectral measurement. It is worth noting that a reversible phase change appeared near 264.3 K, which is verified by differential scanning calorimetry, single crystal structure determination and dielectric measurement. The corresponding enthalpy change of phase transition equals to 8.17 J·mol−1·K−1 on the heating process and −8.83 J·mol−1·K−1 on the cooling process, indicating 1 can be used as a heat storage material. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid materials with a high-temperature phase transition have been widely applied as a kind of smart material. In this work, a new organic–inorganic 2H-perovskite compound, namely [Me3NCH2CH3]CdCl3 (1), is reported with a high temperature dielectric transition showing excellent reversibility and sustainability. 1 has an ABX3 hybrid perovskite structure, where A is a [Me3NCH2CH3]+ cation, B is a divalent metal atom, and X is a halogen atom. Differential scanning calorimetry (DSC) and dielectric measurements were applied for further characterization. Variable temperature single-crystal X-ray diffraction revealed that 1 crystallizes in the orthorhombic Pbca space group (No. 61) at 293 K and hexagonal P63/mmc space group (No. 194) at 363 K. The structural phase transition is primarily attributed to an ordered–disordered type resulting from the [Me3NCH2CH3]+ cations. Organic–inorganic perovskite compounds, as a result of a long exploration history and forward-looking prospects, can deepen research into molecular materials and their physical properties can be effectively optimized in the next-generation of temperature-responsive electrical switches. [ABSTRACT FROM AUTHOR]

Two new organic ionic plastic crystals (OIPCs), [TMBM] [ClO4] (1) and [TMBM] [BF4] (2) (TMBM = trimethylbromomethyl ammonium), were successfully synthesized. Systematic characterization via differential scanning calorimetry (DSC), variable-temperature single-crystal X-ray diffraction, variable-temperature powder X-ray diffraction (PXRD) and dielectric measurements demonstrated that 1 and 2 undergo reversible high-temperature sequential phase transitions accompanied by distinct stepwise switchable dielectric anomalies (1 at 358 K and 388 K and 2 at 346 K and 379 K). The structural relatively ordered-disordered transitions of ClO4−, BF4− and [TMBM]+ contributed to the switching of the dielectric constant from the low-dielectric state to the high-dielectric state. Thus, OIPCs consisting of spherical ammonia cations and inorganic acid anions are proven to be promising in the search for high-temperature multi-step switchable dielectric materials. [ABSTRACT FROM AUTHOR]