Crystal structure, spectroscopic study, photoluminescent properties and DFT calculations of the 2-guanidinobenzimidazolium dichloride and dibromide monohydrate salts

A New Zn(II) Metal Hybrid Material of 5-Nitrobenzimidazolium Organic Cation (C7H6N3O2)2[ZnCl4]: Elaboration, Structure, Hirshfeld Surface, Spectroscopic, Molecular Docking Analysis, Electric and Dielectric Properties

The slow solvent evaporation approach was used to create a single crystal of (C₇H₆N₃O₂)₂[ZnCl₄] at room temperature. Our compound has been investigated by single-crystal XRD which declares that the complex crystallizes in the monoclinic crystallographic system with the P2₁/c as a space group. The molecular arrangement of the compound can be described by slightly distorted tetrahedral ZnCl₄^2- anionic entities and 5-nitrobenzimidazolium as cations, linked together by different non-covalent interaction types (H-bonds, Cl…Cl, π…π and C-H…π). Hirshfeld's surface study allows us to identify that the dominant contacts in the crystal building are H…Cl/Cl…H contacts (37.3%). FT-IR method was used to identify the different groups in (C₇H₆N₃O₂)₂[ZnCl₄]. Furthermore, impedance spectroscopy analysis in 393 ≤ T ≤ 438 K shows that the temperature dependence of DC conductivity follows Arrhenius' law. The frequency-temperature dependence of AC conductivity for the studied sample shows one region (E_a = 2.75 eV). In order to determine modes of interactions of compound with double stranded DNA, molecular docking simulations were performed at molecular level.

Spectroscopic and structural studies, thermal characterization, optical proprieties and theoretical investigation of 2-aminobenzimidazolium tetrachlorocobaltate(II)

In this study we present the crystal structure, spectroscopic and thermal behavior, Hirshfeld surface analysis, and DFT calculations of a new organic-inorganic hybrid compound (C₇H₈N₃)₂[CoCl₄]. This compound crystallizes in the centrosymmetric space group P1¯. Single-crystal X-ray diffraction analysis indicates that structure consists of a succession of mixed layers formed by organic cations and inorganic anions parallel to the (001) plane and propagate according to the c-axis. Layers further are assembled into a 3D supramolecular architecture through N-H^…Cl hydrogen bonds and π^…π interactions. The peak positions of the experimental PXRD pattern are in agreement with the simulated ones from the crystal structure, indicating phase purity of the title compound. The presence of the different functional groups and the nature of their vibrations were identified by ATR-FTIR and FT-Raman spectroscopies. The tetrahedral environment of Co²⁺ was confirmed by UV-visible spectroscopy, where the spectrum shows three weak absorption bands in the visible range due to d-d electronic transitions ⁴A₂(F) → ⁴T₂(F), ⁴A₂(F) → ⁴T₁(F) and ⁴A₂(F) → ⁴T₁(P) typical of Co(II) coordination compounds. The direct and indirect optical band gap values were determined by Tauc method. The optimized structure and calculated vibrational frequencies were obtained by density functional theory (DFT) using B3LYP functional. TGA and DSC coupled to mass spectrometry (MS) experiments under argon atmosphere in the temperature range (25-950 °C) were carried out in order to determine the thermal stability of the title compound.