The C6H4(NH3)2(NO3)2 assembly investigations: Crystal structure, optical properties and impedance spectroscopy, electrical relaxation with Ac conductivity studies

Abstract

The assembly involving ([C6H4(NH3)2]2+/(NO3)–) hybrid as building units has been conceived to carefully produce hybrid-supramlecules with H- bonded nitrogen, which is expected to replace conventional optical materials. Successfully obtained, a new hybrid compound, C6H4(NH3)2(NO3)2 by hydrothermal methods and characterized using single-crystal X-ray diffraction method, Hirshfeld surface analysis, IR / CP MAS- NMR spectroscopy and UV–vis spectrophotometry. Electrical properties and ac conductivity of the title compound has been reported in the temperature and frequency range from 303 to 413 K and 1–106 Hz, respectively. The impedance and electrical modulus spectral data and the frequency and temperature correlation analysis of the Nyquist plots has shown that the grains and grain boundaries contribute to the electrical properties of the prepared materials.The single crystals were obtained by a hydrothermal method. It was found to crystallize in the monoclinic system P21/c with the following lattice parameters: a = 12.6966(17) Å; b = 7.9444(11) Å c = 10.3904(14) Å; β = 105.68(0) and Z = 4. The structural analysis shows that the presence of a layer arrangement perpendicular to the c-axis: planes of [C6H4(NH3)2]2+ cations alternated with planes of two anionic group (NO3)– anions. The cohesion of the molecular arrangement is ensured by hydrogen bonding C–H…O and N– H…O. Hirshfeld Surface analysis of intermolecular interactions confirmed that the hydrogen bonds: C/H, H/C, H/O/H/O and H/H contacts, play a dominant role in the crystal structure of the investigated compounds. Infrared and MAS NMR spectroscopic measurements were carried out to confirm the results obtained by X-ray diffraction. In optical studies, data analysis revealed the existence of optical direct with the band gap energy equal to 5.03 eV.The ac electrical conductivity is investigated at the frequency and temperature. The two semicircles observed in the complex impedance clearly show the contribution of the grain interior and grain boundaries to the electrical response of the material. The equivalent circuit based on the Z-View-software is proposed and the conduction mechanisms are determined. Dielectric data are analyzed using complex electrical modulus M* at various temperatures. The variation of the dielectric parameters (ε’’) is found .Moreover, the temperature dependence study of frequency exponent n (T) is investigated to explain the conduction mechanism in the different range of temperature and frequency.