Structural characterisation, Hirshfeld surfaces, DSC, periodic DFT modeling, vibrational and optical study of heptylenediammonium pentachlorobismuthate H3N(CH2)7NH3BiCl5

Abstract

A perspective hybrid material, NH3(CH2)7NH3BiCl5, was extensively characterized by structural, DSC, spectroscopic (FT-IR, FT-Raman, and UV-fluorescence) and theoretical (periodic DFT/GGA/PBE) methods. The structural features, noncovalent interactions between molecules in the crystal and electronic structure were examined and discussed in relation to the phase transitions, vibrational characteristics and optical properties. The compound crystallizes at 296 ​K in orthorhombic system (Pbcn space group, Z ​= ​8). The Cl⋯H/H⋯Cl intermolecular contacts act as the major contributor (77.2%) in the crystal. The compound was stable from the ambient temperature to 503 ​K, and it underwent one-reversible phase transition of second order type near 498 ​K, at heating. Characteristic bands in FT-IR (400-4000 ​cm-1) and FT-Raman (50-3500 ​cm-1) spectra were interpreted based on factor group analysis and calculated vibrational spectrum. The UV-fluorescence excitation at 396 ​nm and the visible region emission at 483 ​nm, which are of Cl(3p) ↔ Bi(6p) electron transition character, suggest potential applications as UV-filters and blue photoluminescent emmiters.