Synthesis, structural characterization of supramolecular cocrystals of bis(3-hydroxy-1-methylpyridin-1-ium iodide)-18-crown-6

A new supramolecular cocrystal of bis(3-hydroxy-1-methylpyridin-1-ium iodide)-18-crown-6 (I) has been synthesized successfully from 3-hydroxypyridine, methyl iodide and 18-crown-6 (18C6). The cocrystal was characterized by FT-IR, UV-DRS and PL spectroscopy, single crystal and powder X-ray diffraction (XRD) analysis, SEM and EDS analysis, and thermogravimetric analysis. The bulk phase purity of the compound is confirmed by powder XRD analysis, whereas single-crystal XRD confirms that it packs in a monoclinic system with centrosymmetric space group (P21/c). Single crystal XRD shows that the asymmetric unit is C6H12O3, [C6H8NO]+[I]¯. The presence of C–H⋯O, C–H⋯I and O–H⋯I intermolecular contacts helps to achieve crystal cohesion. The direct band gap energy has been estimated to be 3.21 eV using diffuse reflectance spectral measurements. Thermogravimetric analysis was employed to determine the compound’s thermal behaviour concerning temperature. EDS and SEM investigations were used to examine the elemental composition and surface morphology of the compound.