Noncovalent Interactions and Physicochemical Properties of an 8‐Hydroxyquinolinium‐Bromoferrate (III) Hybrid Material: Experimental and Computational Approaches

Abstract A novel organic‐inorganic ferrate (III) hybrid compound, bis(8‐hydroxyquinolinium) tetrabromoferrate (III) bromide [(8‐HQ)₂FeBr₄]Br, was synthesized at room temperature via the slow evaporation method. Single‐crystal X‐ray crystallography, coupled with Hirshfeld surface analysis, revealed that the noncovalent hybrid assembly is governed by classical (O─H···Br and N─H···Br) and unconventional (C─H···Br) hydrogen bonding, as well as π‐stacking interactions. Notably, a unique Anion···π interaction between the [FeBr₄]⁻ anion and the hydroxyquinoline heterocycle was observed. Furthermore, a multi‐approach quantum mechanical method with dispersion‐corrected DFT (ωB97X‐D/aug‐cc‐pVTZ) was employed to analyze all identified noncovalent interactions, providing insights into their strength and nature. In addition, vibrational characteristics and optical properties were investigated using Infrared and Raman spectroscopies, as well as UV–visible and photoluminescence (PL) techniques. Finally, frontier molecular orbital (FMO) and Mulliken charge analyses were performed to determine the electronic features of the compound. A strong agreement was found between the experimental and theoretical findings.