A multifunctional [CdI4]2−·[H2Bimb]2+ complex to probe high performance photocatalytic degradation of methyl violet and fluorescent detection of Cr2O72− and Hg2+ ions

Abstract

A new organic–inorganic complex, [CdI₄]²⁻·[H₂Bimb]²⁺ (KA@S) (Bimb = 1,4-bis[(1H-imidazol-1-yl)methyl]benzene), has been synthesized at ambient temperature and characterized using single-crystal X-ray diffraction (SC-XRD), elemental analysis, variable temperature powder X-ray diffraction (VT-PXRD), Fourier transform infrared (FT-IR) spectroscopy and thermal stability analysis. SC-XRD analyses reveal that KA@S has anionic and cationic moieties, [CdI₄]²⁻ and [H₂Bimb]²⁺, respectively. C–H⋯I and N–H⋯I interactions, in addition to strong N–H⋯N and N–H⋯O hydrogen bonds and parallel displaced π⋯π stacking interactions, are instrumental towards the extended 1D chain, 2D layer and 3D supramolecular network of KA@S. Promising photocatalytic degradation efficiencies for the dyes MV (96.5%), Rh6G (94.4%), RB (93.5%), CR (91.2%) and CV (89.2%) under sunlight irradiation in 80 minutes were observed among the 13 screened harmful dyes. The detection limits for dyes were found to be 0.39 ppm (MV), 0.57 ppm (Rh6G), 0.58 ppm (RB), 0.88 ppm (CR) and 1.02 ppm (CV). It was found that KA@S is an excellent luminescent sensor for Cr₂O₇²⁻ anions and Hg²⁺ metal ions in aqueous solution at the ppm level among various probed cations and anions. The minimum detection limit (LOD) of 2.62 × 10⁻⁶ M (0.77 ppm) for Cr₂O₇²⁻ and 4.81 × 10⁻⁷ M (0.096 ppm) for Hg²⁺ metal ions were observed.