Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Thermal Dielectric Switch Triggered by Blooming-Flower Structural Phase Transition in Ionic Crystal without Metal

Due to having excellent properties of sensitive switchable physical and/or chemical response, simple preparation, and environmentally friendly processing, bistable switches (electric switching between “on” and “off” bistable states) have gradually developed into an ideal class of highly smart materials. However, most of them contain metals, especially heavy metals, which are highly toxic to the environment, and metal-free switch materials are rarely reported. Based on this issue, we successfully designed and synthesized organic ion crystals and realized thermal dielectric switching characteristics. Differential scanning calorimetry and dielectric measurements show that the large-size crystal (F-TEDA)­(BF₄)₂ (<b>1</b>) can be regarded as an sensitive dielectric bistable switching between high (switch on) and low (switch off) dielectric states. Variable-temperature single crystal structure reveals one-half of the BF₄^– anions in the crystal undergoes order–disorder transition around 200 K, similar to the transition between flower buds and blooming flowers. This flower-style transition of BF₍₁₎₄^–/BF_(0.5)8^– triggered the rapid switching performance; those properties establish the basis of their applications in excellent temperature-responsive electrical switches, especially lightweight devices

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Reversible Phase Transition of 1,4-Diazoniabicyclo[2.2.2]octane-1-acetate-4-acetic Acid Chloride Trihydrate

1,4-Diazoniabicyclo­[2.2.2]­octane-1-acetate-4-acetic acid forms a complex (<b>1</b>) with chloride ion and water molecule in the ratio 1:1:3. Differential scanning calorimetry (DSC) measurement shows a pair of reversible peaks at 210.7 K (heating) and 180.3 K (cooling) with a large heat hysteresis about 30.4 K, indicating this compound undergoes a reversible structural phase transition. Dielectric measurement further confirms the phase transition. The DSC and dielectric measurements results of its deuterated compound (<b>2</b>) exhibit obvious change compared to those of <b>1</b>. The crystal structures of these two compounds, determined at 153 and 298 K, are all monoclinic in <i>P</i>2₁/<i>n</i>, suggesting the phase transition is isosymmetric. Structural analysis reveals that the changes of the relative location of water molecules and chloride ions affect the formation of different modes of hydrogen-bonded anionic chains, leading to the reversible structural phase transition

Highly Efficient Red-Light Emission in An Organic–Inorganic Hybrid Ferroelectric: (Pyrrolidinium)MnCl₃

Luminescence of ferroelectric materials is one important property for technological applications, such as low-energy electron excitation. However, the vast majority of doped inorganic ferroelectric materials have low luminescent efficiency. The past decade has envisaged much progress in the design of both ferroelectric and luminescent organic–inorganic hybrid complexes for optoelectronic applications. The combination of ferroelectricity and luminescence within organic–inorganic hybrids would lead to a new type of luminescent ferroelectric multifunctional materials. We herein report a hybrid molecular ferroelectric, (pyrrolidinium)­MnCl₃, which exhibits excellent ferroelectricity with a saturation polarization of 5.5 μC/cm² as well as intense red luminescence with high quantum yield of 56% under a UV excitation. This finding may extend the application of organic–inorganic hybrid compounds to the field of ferroelectric luminescence and/or multifunctional devices

Temperature-Triggered Reversible Dielectric and Nonlinear Optical Switch Based on the One-Dimensional Organic–Inorganic Hybrid Phase Transition Compound [C₆H₁₁NH₃]₂CdCl₄

The one-dimensional organic–inorganic hybrid compound bis­(cyclohexylammonium) tetrachlorocadmate­(II) (<b>1</b>), in which the adjacent infinite [CdCl₄]_<i>n</i>^– chains are connected to each other though Cd···Cl weak interactions to form perovskite-type layers of corner-sharing CdCl₆ octahedra separated by cyclohexylammonium cation bilayers, was synthesized. It undergoes two successive structural phase transitions, at 215 and 367 K, which were confirmed by systematic characterizations including differential scanning calorimetry (DSC) measurements, variable-temperature structural analyses, and dielectric and second harmonic generation (SHG) measurements. A precise structural analysis discloses that the phase transition at 215 K is induced by the disorder–order transition of cyclohexylammonium cations, while the phase transition at 367 K derives from changes in the relative location of Cd atoms. Emphatically, both the dielectric constant and SHG intensity of <b>1</b> show a striking change between low and high states at around 367 K, which reveals that <b>1</b> might be considered as a potential dielectric and nonlinear optical (NLO) switch with high-temperature response characterization, excellent reversibility, and obvious change of states