Spectroscopic and Structural Study of a New Conducting Pyrazolium Salt

Abstract

The increase in conductivity with temperature in 1H-pyrazol-2-ium 2,6-dicarboxybenzoate monohydrate was analyzed, and the influence of the mobility of the water was discussed in this study. The electric properties of the salt were studied using the impedance spectroscopy method. WB97XD/6-311++G(d,p) calculations were performed, and the quantum theory of atoms in molecules (QTAiM) approach and the Hirshfeld surface method were applied to analyze the hydrogen bond interaction. It was found that temperature influences the spectroscopic properties of pyrazolium salt, particularly the carbonyl and hydroxyl frequencies. The influence of water molecules, connected by three-center hydrogen bonds with co-planar tetrameters, on the formation of structural defects is also discussed in this report.

Effect of Azole Counterions on Thermal and Transport Properties of the Hydrated Salts of Hemimelitic Acid

“…At 363 K, intensities of the carbonyl bands ν C=O at 1737 and 1715 cm −1 decreased, and at the same time, a band from the water vibration ν O−H at 1640 cm −1 appeared. It was observed previously 26 Electrical conductivity analysis was performed using impedance spectroscopy (see the Supporting Information). Obtained fitting parameter α takes values for crystalline 44 Changes in the parameter strongly manifest between the grain boundary contribution of pyrazolium salt, and other contributions are visible in the presentation of the scaled imaginary part of impedance versus scaled frequency (see Figure 6a).…”

“…In PyrHem•H 2 O, activation energies equal 5.05, 2.68, and 1.23 eV. 26 An activation energy of 5.05 eV at 323−347 K indicates the very high stiffness of the sample. At 347−354 K, it decreases to 2.68 eV but is still high for a proton conductor.…”

“…The PyrHem•H 2 O was studied previously in our group. 26 In the second part of this study, an analysis of the HBs network of the hydrated hemimelitate salts ImiHem•H 2 O and PyrHem• H 2 O was carried out to find an interplay between the hydrogen bond motifs and the basicity of the heterocyclic rings.…”

Proton tautomerism in 5-dimethylaminomethylidene-4-(o-,m-,p-hydroxyphenyl)amino-1,3-thiazol-2(5H)-ones: synthesis, crystal structure and spectroscopic studies

“…Intermolecular interactions of compounds 1-3 were analyzed using the quantum theory of atoms in molecules (QTAiM) (Matta & Boyd, 2007). This approach distinguishes different intermolecular interactions and provides insight into their nature (Zie ˛ba et al, 2019(Zie ˛ba et al, , 2021. Using the QTAiM approach, the following parameters were determined: electron density ( BCP ), the Laplacian of the electron density (Á BCP ), potential electron energy density (V BCP ), kinetic electron energy density (G BCP ), the total electron energy density (H BCP ) and the energy of the hydrogen bond (E HB ) at a critical point (Bader, 1994).…”

“…The intermolecular interactions in the investigated compounds 1-3 can also be analyzed using Hirshfeld surfaces (Hirshfeld, 1977;Zie ˛ba et al, 2019) and fingerprint plots (McKinnon et al, 2004;Zie ˛ba et al, 2021). The Hirshfeld surface (McKinnon et al, 2004) of a molecule in a crystal is constructed by partitioning space in the crystal into regions where the electron distribution of a sum of spherical atoms for the molecule (the promolecule) dominates the corresponding sum over the crystal (the procrystal).…”