Structural study, intermolecular interactions in view of X-ray and Hirshfeld surface analysis, DSC characterization, and electrical properties of bis-(4-benzylpyridinium) tetrabromozincate

Abstract

The synthesis and crystal structure of the bis-(4-benzylpyridinium) tetrabromozincate(II) “(4-BP)2[ZnBr4]” salt are reported in the present paper. After an X-ray investigation, it has been shown that the title compound belongs to the centrosymmetric monoclinic system at 296 K, in the space group P21/n with the following lattice parameters a = 15.0764(8) A, b = 22.5575(12) A, c = 16.0739(9) A, and β = 93.887(3)°. The FT-IR and Raman spectra confirm the presence of both cationic and anionic parts. The crystal packing is governed by an extensive network: N–H…Br, (N: pyridinium), C–H…Br hydrogen bonds, π…π, and C–H…π stacking between identical 4-BP (aromatic–aromatic), in which they may be effective in the stabilization of the crystal structure. Moreover, Hirshfeld surface analysis was used for visually analyzing intermolecular interactions in crystal structures. The phase transitions at T = 323 K have been confirmed by the differential scanning calorimetry. The electrical technique was measured in the 209 Hz–5-MHz frequency range and 298–393-K temperature intervals. The evolution of the dielectric constant as a function of frequency and temperature proved the presence of a first-order phase transition at 323 K.