Synthesis, Infra-red, CP/MAS-NMR characterization, structural study and electrical properties of the bis(4-amino-2-chloropyridinium) tetrachlorozincate (II) monohydrate

Single crystals of the new ionic salt bis(4-amino-2-chloropyridinium) tetrachlorozincate (II) monohydrate, (C5H6N2Cl)2 ZnCl4⋅H2O, were grown by slow evaporation from aqueous solution at room temperature. The compound was characterized by IR, thermal analysis (TGA-DSC), single crystal X-ray diffraction, CP/MAS-NMR and impedance spectroscopy. The structure (4-amino-2-chloropyridinium)2 ZnCl4·H2O, [(CAP)2ZnCl4·H2O], consists of isolated H2O, isolated [ZnCl4]2− tetrahedral anions and 4-amino-2-chloropyridinium [C5H6N2Cl] + cations, CAP, which are connected together via N–H⋯Cl, N–H⋯O ((N: pyridinium) and (N: amine)), O–H⋯Cl and C–H⋯Cl hydrogen bonds. Cation–cation, offset-face-to-face interactions (π−π stacking) between identical antiparallel CAP (aromatic–aromatic), in which they may be effective in the stabilization of the crystal structure. Solid state CP/MAS-NMR spectra showed five isotropic resonances, 13C, confirming the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for a single crystal, revealed that the conduction in the material was due to a hopping process. This work aims to reveal the thermal properties of a new zinc (II) based organic–inorganic hybrid and the conductivity properties that these compounds exhibit.