Design, synthesis, and structural elucidation of tin(IV)-based metal-organic hybrids: Hirshfeld surface analysis of bis(4-cyanopyridinium) hexahalostannate(IV)

Abstract

The research focuses on the synthesis and characterization of two hybrid materials: bis(4-cyanopyridinium) hexachlorostannate(IV) and hexabromostannate(IV). The compounds were synthesized by reacting 4-cyanopyridinium halides with tin halides, yielding crystalline materials. Infrared spectroscopy revealed key functional groups, including cyano, aromatic, and C–H stretches, while UV-DRS analysis showed distinct band gaps (4.10 eV for the chlorostannate and 2.94 eV for the bromostannate). Photoluminescence studies indicated promising emission properties for optoelectronic applications. SEM/EDS analyses provided insights into surface morphology and elemental composition, and X-ray diffraction confirmed the high crystallinity of both compounds. Single-crystal X-ray analysis revealed isostructural monoclinic arrangements with octahedral geometries for the anions, with π-π stacking and hydrogen bonding contributing to structural stability. Bond valence sum calculations for SnCl₆²⁻ and SnBr₆²⁻ anions gave values of 3.95 and 3.97, respectively. Hirshfeld surface analysis highlighted significant intermolecular interactions crucial for molecular packing and crystal cohesion.