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Molecule-based switchable dielectrics with distinct changes of dielectric constant, which enable conversion of electronic properties between different states under external stimuli, are technologically important. The crown-ether clathrate system is a highly promising class of molecule-based switchable dielectrics. Herein, by choosing yttrium nitrate to be assembled with a 15-crown-5 molecule, we synthesized a new crown-ether clathrate, namely [15-crown-5][Y(NO3)2(H2O)5][NO3] (1). One relatively small thermal anomaly peak was observed centered at 230 K (Ttr) for compound 1. Single-crystal structures obtained at various temperatures revealed its reversible phase transition to be driven by the synergistic effect of the dynamic changes of the counter [NO3]− anions from an ordered to disordered state and the relatively strong thermal vibrations of the 15-crown-5 molecules, along with the rearrangement of [Y(NO3)2(H2O)5]+ cations in the crystal. Meanwhile, compound 1 also displayed a bistable dielectric response characteristically found in different structural phases. This discovery confirmed the possibility of using compound 1 as a molecule-based dielectric switching material. [ABSTRACT FROM AUTHOR]

(HTz)[Ba(ClO4)3] (HTz=thiazolium cation, 1), a perchlorate‐based hybrid perovskite‐type single crystal undergoes sequential structural phase transitions at 143/154 K and 210/218 K. The perovskite‐type cage structure is composed of Ba2+ nodes and ClO4− linkers to form anionic cage Ba8(ClO4)12 in which the HTz resides. It is notable that the anionic framework incorporating HTz is a perovskite‐type structure with the (412 ⋅ 63) framework. Various‐temperature single‐crystal structure analyses reveal the stepwise changed dynamics of HTz, and the distortion of the anionic cage Ba8(ClO4)12 are the origin of the phase transitions. We tend to attribute the switchable dielectric constant behavior mainly to order‐disorder transition of the HTzs and the rearrangement of the Ba8(ClO4)12 framework. Furthermore, dielectric switching is recorded. Our findings may prompt investigations of new perchlorate‐based organic‐inorganic hybrid perovskites. [ABSTRACT FROM AUTHOR]

Low‐symmetric quasi‐spherical cations have been widely used in halogenometallate hybrids to increase the incidence of stimulus‐responsive crystal structures. In this paper, we successfully used triethylmethylammonium bromide and cadmium bromide for self‐assembly to obtain a A2BX4‐type hybrid compound [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3, 1) showing phase transition temperature (Tc) of 333 K above room temperature. Various‐temperature structures of 1 have been measured by X‐ray diffraction. We conclude, the phase transition property of 1 induced by thermal stimulation stems from the thermal ellipsoids of the [TEAMA]+ become strikingly larger with the increase of the temperature. The dynamics of the dipoles is the key to construct hybrid molecule‐based switchable dielectrics by motional changes of polar components at different phases. Furthermore, the dielectric properties have also been mentioned and discussed in great detail. [ABSTRACT FROM AUTHOR]

A series of multifunctional photoluminescent materials, [pyrrolidinium]2MnBr4 (1), [N‐methylpyrrolidinium]2MnBr4 (2), and [N‐methylpyrrolidinium]MnBr3 (3), were obtained by means of regulating diverse organic cations and different coordination modes of inorganic metal ions. Interestingly, compounds 1, 2, and 3 exhibit different dielectric switching and relaxation behavior in the process of structural transformations. Furthermore, compounds 1, 2, and 3 possess intriguing photoluminescence properties. When subjected to UV light, tetrahedrally coordinated compound 1 shows extraordinarily strong green light emission with a high quantum yield of 51.41 %. By changing the organic cation, compound 2 exhibits an unusual orange emission under ultraviolet excitation, which is different from that of conventional tetrahedrally coordinated manganese‐based compounds. By the regulation of coordination modes of inorganic metal ions, octahedrally coordinated compound 3 emits bright red light with a high quantum yield of 36.76 %. This finding may open a new approach toward designing multifunctional photoluminescent materials. [ABSTRACT FROM AUTHOR]

The ABX3-type inorganic–organic hybrid perovskite (H2dabco)[Na(BF4)3] (H2dabco = 1,4-diazabicyclo[2.2.2]octane cation, 1) undergoes a static-to-dynamic phase transition at 403/386 K (heating/cooling), respectively. Variable-temperature single crystal structure analysis reveals that the H2dabco cation and/or BF4− bridging ligand undergo disordering. Dielectric measurements show a typical switchable dielectric transition between high- and low- dielectric states during the phase transition. Notably, the reversibility of dielectric switching properties of 1 was also identified. These excellent switching characteristics of 1 make it a type of switchable dielectric material. [ABSTRACT FROM AUTHOR]

The title compound, catena-(1,2,3,6-tetrahydropyridine tris(μ2-chloro)-cadmium(II)), has a hexagonal perovskite-type structure with formula AMX3. It undergoes a reversible dielectric transition at about 197K. The transition was accompanied by significant dielectric anomaly, and was confirmed by DSC measurements. The variable-temperature single crystal X-ray diffraction analysis reveals that the transition is a process of the doubling of the cell volume from P21/m to P21/a. The transition is caused by the order-disorder change of the 1,2,3,6-tetrahydropyridinium cation. [ABSTRACT FROM AUTHOR]

Front Cover: High Quality of a Perchlorate-Based Hybrid Perovskite-Type Cage-Like Single Crystal - Evidence of Temperature-Induced Distinct Dielectric Transition (Eur. J. Inorg. Organic-inorganic hybrid composites, Perovskite phases, Phase transitions, Structure elucidation, Switchable dielectric constants Keywords: Organic-inorganic hybrid composites; Perovskite phases; Phase transitions; Structure elucidation; Switchable dielectric constants EN Organic-inorganic hybrid composites Perovskite phases Phase transitions Structure elucidation Switchable dielectric constants 4406 4406 1 11/24/21 20211122 NES 211122 B The Front Cover b shows the first three-dimensional Ba-based ABX SB 3 sb type organic-inorganic hybrid perovskite compound (HTZ)[Ba(ClO SB 4 sb ) SB 3 sb ] (HTZ = thiazolium cation) with Ba SP 2+ sp nodes and ClO SB 4 sb SP - sp linkers. [Extracted from the article]

Stimuli-responsive materials with coexisting nonlinear optical (NLO) and dielectric properties are technologically important, which enable simultaneous conversion of optoelectronic properties between different states under external stimuli. By rationally screening guest cations (C6H5NF2)+ in the crown-ether inclusion system, we synthesized a crown-ether supramolecular compound [(C6H5NF2)(18-crown-6)][PF6] (1). Differential scanning calorimetry (DSC) showed that 1 undergoes a reversible phase transition above room temperatures (305 K/292 K), with a thermal hysteresis of 13 K. Temperature-dependent dielectric and NLO measurements show that the compound exhibits two distinct switching response behaviors. Structural analysis indicates that the order–disorder change of the host molecule 18-crown-6 and the guest organic cation during the phase transition induces the dielectric and NLO switching behavior of the compound. [ABSTRACT FROM AUTHOR]

Low‐symmetric quasi‐spherical cations have been widely used in halogenometallate hybrids to increase the incidence of stimulus‐responsive crystal structures. In this paper, we successfully used triethylmethylammonium bromide and cadmium bromide for self‐assembly to obtain a A2BX4‐type hybrid compound [TEAMA]2[CdBr4] (TEAMA=(CH3CH2)3NCH3, 1) showing phase transition temperature (Tc) of 333 K above room temperature. Various‐temperature structures of 1 have been measured by X‐ray diffraction. We conclude, the phase transition property of 1 induced by thermal stimulation stems from the thermal ellipsoids of the [TEAMA]+ become strikingly larger with the increase of the temperature. The dynamics of the dipoles is the key to construct hybrid molecule‐based switchable dielectrics by motional changes of polar components at different phases. Furthermore, the dielectric properties have also been mentioned and discussed in great detail. [ABSTRACT FROM AUTHOR]

A new Zn-halide hybrid crystal based on pyrrolidine-derivative exhibits reversible phase transition at around 330 K/320 K (heating/cooling). [Display omitted] • (HNBNMP) 2 (ZnCl 4) (HNBNMP = N-bromomethyl-N-methylpyrrolidinium cation, compound 1), shows a reversible phase transition at 330/320 K (heating/cooling) through differential scanning calorimetry (DSC). • Variable-temperature single-crystal structural analysis and powder X-ray diffraction patterns verify the structural phase transition. • Variable-temperature dielectric measurements show the dielectric switching behavior indicating the potential application in the dielectric functional materials. We have successfully synthesized compound 1 (HNBNMP) 2 (ZnCl 4) (HNBNMP = N-bromomethyl-N-methylpyrrolidinium cation) through the slow evaporation method at room temperature. Several studies (differential scanning calorimetry measurements, single crystal structural analysis, variable-temperature powder X-ray diffraction and dielectric measurements) show that compound 1 has a reversible structural phase transition at around 330 K/320 K (heating/cooling), respectively. Variable-temperature powder X-ray diffraction patterns further demonstrate that compound 1 undergoes a phase transition. Meanwhile, the unique phase transition behavior was also confirmed by its remarkable dielectric and thermal anomalies around the phase transition point. The step-like dielectric switching in compound 1 can be mainly ascribed to the motional changes of polar components between room-temperature and high-temperature phases. This finding should stimulate further synthesis for switchable functional materials. [ABSTRACT FROM AUTHOR]

Abstract: The two compounds Cr2(2-TPY)4(HO)2 1 and Cr(2-TPY)2(H2O)Cl 2 have been synthesized and characterized by single-crystal X-ray crystallography, elemental analysis and IR, (2-TPY=2-(1 H-tetrazol-5-yl)pyridine). Moreover, their temperature-dependence dielectric constant (ε) measurements of powder and single-crystal samples were performed. The ε of single-crystal sample is twice the ε of powder sample. However, the dielectric loss value (tanδ) of the crystal is relatively small and only half of the tanδ of powder sample. These characteristics were attributed to the higher density level and ordered arrangement of the crystal lattice. [Copyright &y& Elsevier]

Abstract: The fern-like 1D coordination polymer, [K(2-PTA)(H2O)] n (1), which is constructed by an inorganic skeleton chain [KO2] n with organic 2-PTA wings on both sides, has been synthesized and characterized by single crystal X-ray crystallography and dielectric constant (ε) measurement (2-PTA=2-(5-(pyridin-2-yl)-2H-tetrazol-2-yl) acetic acid). The ε of temperature dependence maintains unchanged, and ε of frequency dependence shows a significant decline, which is attributed to the highly ordered polarization mechanism. [Copyright &y& Elsevier]