New 2-methylimidazole–dicarboxylic acid molecular crystals: crystal structure and proton conductivity

Ławniczak, Paweł; Pogorzelec‐Glaser, Katarzyna; Pawlaczyk, Cz.; Pietraszko, A.; Szcześniak, Ł.

doi:10.1088/0953-8984/21/34/345403

Cited by 15 publications

(7 citation statements)

References 21 publications

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“…Results of structural and conductivity investigations for imidazole [19,20] and 2-methylimidazole [21] salts have been already published. Also, the details of experimental techniques are described there.…”

Section: 2mentioning

confidence: 99%

Anhydrous proton conductors for use as solid electrolytes

et al. 2010

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Anhydrous proton conductors in which proton transport proceeds via structure diffusion are interesting alternatives for membrane materials in hydrogen/air fuel cells. Understanding the mechanism of proton diffusion in candidate materials is necessary to improve their performance. We present the results of our studies of two classes of proton conductors in which conductivity does not rely on the presence of water molecules in their structure: crystalline hydrogen sulphates and selenates and new salts of nitrogen-containing heterocyclic molecules combined with a series of dicarboxylic acids. In the former group, superprotonic conductivity results from a high molecular dynamics of S/SeO 4 groups, which creates an excess of structurally equivalent positions for protons. Ferroelastic properties of the crystals determine their physical behaviour at high temperatures. In particular, ferroelasticity makes a smooth and reversible character of superionic phase transition possible. In the second group of materials, the heterocycles exhibit extensive specific interactions that result in a fluctuating network of H-bonds. Thus, the proton conduction in these materials depends on the number of protons, which can be involved in the diffusion and on the fluctuation rate of the hydrogen bond network.

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Section: 2mentioning

confidence: 99%

Anhydrous proton conductors for use as solid electrolytes

et al. 2010

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“…14 The pyrazole molecule, like other nitrogen-containing heterocycles (triazole, imidazole, benzimidazole), crystallizes in layer crystal structures held together by a hydrogen bond network, where protons can easily migrate through the crystal within the layers. [15][16][17][18][19][20][21][22] In the case of proton conductors, several proton diffusion mechanisms such as the Grotthuss process, the translocation mechanism, the vehicle mechanism, proton tunneling, and the solitonic mechanism have been proposed to explain the conducting properties. 23,24 The present study was carried out to provide detailed structural, electrical, and optical properties of this new proton conducting material.…”

Section: Introductionmentioning

confidence: 99%

Order–disorder phase transition in an anhydrous pyrazole-based proton conductor: the enhancement of electrical transport properties

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Pogorzelec‐Glaser

Pietraszko

et al. 2017

Phys. Chem. Chem. Phys.

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The crystal structure of 1H-pyrazol-2-ium hydrogen oxalate has been studied at 100 K. It consists of two-dimensional layers built with one-dimensional chains that contain pyrazolium and oxalate acids bonded by N-HO and O-HO hydrogen bonds. According to the X-ray data and the Quantum Theory of Atoms in Molecules, it was shown that weak and moderate hydrogen bonds are present in the crystal at room temperature. The thermal stability was studied with the DSC, TGA, and DTG methods: three endothermic peaks are observed at 384, 420, and 469 K. Conductivity measurements have been performed in the temperature range from 300 to 433 K. At 383 K the pyrazole-oxalic acid framework loses its rigidity and the crystal undergoes an ordered-disordered phase transition. At this temperature, the value of the activation energy of proton conductivity changes from 1.14 to 2.31 eV. The proton conduction pathways and the transport mechanism have been studied with theoretical methods.

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“…2 As the carboxylic acids are interesting for crystal engineering due to their ability in hydrogen bonding formation and the nitrogen containing heterocyclic bases are known to form similar hydrogen bond networks to water 3,4 we were interested in the relationship between crystal structure and proton conduction in salts of dicarboxylic acids with the heterocyclic bases. Previously we reported the results of our studies of imidazole (Im) salts of glutaric, malonic, adipic, suberic and sebacic acids, 5 the Im salt of succinic acid, 6 the Im salt of oxalic acid, 7 as well as the salts of 2-methylimidazole (MIm) salts of glutaric, suberic and azelaic acids, 8 1,2,4triazole with succinic acid 9 and recently on the benzimidazole (BIm) salt with azelaic acid. 10 Here we present the results of molecular and crystal structure, hydrogen bond network and proton conductivity studies of new salts of benzimidazole with two dicarboxylic acids: glutaric acid (GLU) containing five carbon atoms in the acid chain and pimelic (PIM) acid with seven carbon atoms in the chain.…”

Section: Introductionmentioning

confidence: 99%