Structural characterization, dielectric properties, optical and theoretical DFT study of (C8H14N2)(BF4)2·H2O compound

The new organic salt m -xylylenediaminium bis (tetrafluoroborate) monohydrate was prepared from a mixture of an aqueous solution of tetrafluoroborate acid and m -xylylenediamine. Crystals were grown by slow evaporation method and characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group P 2 1 / c , with a = 5.4839(2), b = 10.9453(3), c = 23.0760(6) Å, β = 95.105(1)°, V = 1379.59(14) Å 3 and Z = 4. The intermolecular interactions were identified by Hirshfeld Surfaces analysis and their associated 2D fingerprint plots. Photoluminescence and UV–Vis absorption were carried out to identify optical properties and determine the energy gap. Dielectric and conduction mechanism were studied at different frequencies, in the temperature range of 303–390 K. A comparison of the optimized structure at the B3LYP/6-311++G(2 d ,2 p ) level, using the density functional theory, was made with the experimentally determined structure. Comprehensive experimental and theoretical structural studies were carried out by FT-IR. Molecular electrostatic potentials were also studied and discussed. Graphic abstract