Study on structural, optical, thermal and electrical properties of a new centrosymmetric compound (Qx-H)4Bi2Cl10

Due to their wide field uses, the organic–inorganic hybrid materials are subject to several researches. In this respect, these compounds exhibit multiple transitions depending upon the preparation process. In this research paper, the new-centrosymmetric (Qx-H)4Bi2Cl10 compound, where Qx-H+ = [C8H7N2]+ (i.e., quinoxalinium) was successfully synthesized by the slow evaporation method at room temperature. The title compound crystallizes in the triclinic system P 1¯ space group with cell parameters: a = 8.422(2) Å, b = 11.698(3) Å, c = 12.321(3) Å, α = 64.923(2) °, β = 83.502(4) °, γ = 71.983(4) ° and V = 1045.3(4) A3, Z = 2 at 293 K. The crystal structure is made up of discrete binuclear [Bi2Cl10]4- anions and Qx-H+ cations. The crystal packing is governed by strong NH∙∙∙Cl hydrogen bonds and π-π stacking interactions to build a three-dimensional network. Intermolecular interactions seen in the grown single crystal are studied by Hirshfeld surface and 2‐D fingerprint plot. The IR absorption spectroscopy at room temperature (4000 – 400 cm−1) ensures the presence of organic part. The optical absorption of the title compound corroborated the semiconductor nature with a band gap around 2.97 eV. Differential thermal analysis (DTA) shows an endothermic peak at 383± (5) K upon heating which is notably ascribed to a structural phase transition since no decomposition of the title compound was proven by thermogravimetric analysis. The investigation of complex impedance spectra illustrates that the electrical and dielectric properties are heavily dependent on temperature and frequency, suggesting a relaxation phenomenon and a semiconductor-type behavior. The AC conductivity obeys the Jonscher's law. The investigations of both complex impedance and conductivity revealed the NTCR character of the (Qx-H)4Bi2Cl10 compound. The temperature dependences of the real ε′ and imaginary ε″ components of the dielectric primitivity demonstrated the presence of a relaxing process at high temperatures, which is assigned to the reorientational motion of the cationic parts.