Physical and Chemical Characterisations, Optical Properties and Dielectric Studies of a New Organic–Inorganic Material: bis(4-amino-2-chloropyridinium) Tetrachloromercurate (II) Monohydrate

The synthesis, structural chemistry, spectroscopic studies, optical absorption and photoluminescence, density functional theory (DFT), thermal study (TGA–DSC) and dielectric measurement of the new hybrid bis(4-amino-2-chloropyridinium) tetrachloromercurate (II) monohydrate, (C 5 H 6 N 2 Cl) 2 [HgCl 4 ]•H 2 O, (abbreviated (CAP) 2 [HgCl 4 ]•H 2 O), were described and discussed in this research paper. The result of the crystallographic study at room temperature revealed that it crystallises in the centrosymmetric triclinic system. The 13 C NMR study demonstrated the presence of ten resonance signals, proving consistency with the X-ray structure, which corroborates the purity of the produced mixture. With a zero-dimensional lattice, this structure is stabilized through the presence of classical and non-classical C–H…Cl hydrogen bonds, and offset as well as π–π stacking interactions between identical antiparallel (aromatic-aromatic) CAPs. These interactions were further investigated through the use of Hirshfeld surface analysis. The theoretical results displayed a good convergence with the experimental results, using the time-dependent DFT (TD-DFT) approach. Moreover, the simulated spectrum satisfactorily coincided with the experimental UV–visible spectrum. Photoluminescence (PL) was characterized by two bands at 346 and 381 nm. The thermal properties were confirmed by TGA–DSC analysis. The studies conducted on electronic and dielectric properties unveiled that the conduction mechanism in this new salt was due to an H + proton hopping process.