Facile preparation and crystallographic characterization of a new zero-dimensional antimony (III)-based organic-inorganic material with white light emission properties

Zero-dimensional materials based on antimony(III) chloride have attracted considerable attention as broadband emitters. These 0D compounds exhibit structural adaptability, adopting either octahedral or square-pyramidal geometries, which significantly influence their emissive properties. In this context, a novel organic-inorganic hybrid material, (Qx-H)₄Sb₂Cl₁₀ (Qx-H⁺: quinoxalinium), was synthesized and thoroughly characterized using X-ray diffraction at 100 K, Hirshfeld surface analysis, vibrational spectroscopy, and optical studies. The compound crystallizes in the triclinic P$\overline{1}$ space group, and its crystal structure reveals unusual Sb···Cl interactions in the solid state, leading to the conversion of individual [SbCl₅]²⁻ polyhedra into discrete binuclear [Sb₂Cl₁₀]⁴⁻ units. The three-dimensional (3D) supramolecular framework of (Qx-H)₄Sb₂Cl₁₀ is stabilized by multiple secondary interactions, including N–H···Cl hydrogen bonds and π···π stacking interactions. Additionally, 2D fingerprint plots and Hirshfeld surface analyses were employed to identify the key intermolecular interactions governing the crystal packing. A vibrational analysis was carried out using Raman and infrared spectroscopy. The optical properties were investigated by UV–Visible spectroscopy, revealing a band gap of 3.99 eV. Density Functional Theory (DFT) calculations at the CAM-B3LYP/Lanl2dz level were performed to gain theoretical insights into the electronic structure, particularly the absorption spectrum and the HOMO–LUMO gap. Furthermore, the nonlinear optical (NLO) properties were examined to evaluate the dipole moment, linear polarizability, and second hyperpolarizability. Notably, the compound exhibits significant white light emission upon excitation at 375 nm. The correlated color temperature (CCT) was measured at 6623 K, indicative of a "cool" white light emission.