A dinuclear Cd^II cluster-based stable luminescent metal-organic framework for the consecutive and visual detection of H₂PO₄^- and OCN^-

Due to their hazard to biological systems, it is urgent to develop materials that can rapidly and sensitively detect the concentration of H2PO4- and OCN- ions. In this work, a new Cd-II-based luminescent metal-organic framework with the formula [Cd(BTDB)(2,6-BBIP)](n) (JXUST-47, H2BTDB = (benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid, 2,6-BBIP = 2,6-bis(benzimidazol-1-yl)pyridine) and sql topology was successfully synthesized using a mixed-ligand strategy. JXUST-47 shows good chemical and thermal stability. It also exhibits weak quenching and fluorescence blue shift for H2PO4- and red shift for OCN-, with the detection limits of 0.106 and 0.128 mM, respectively. In addition, considering the demand for H2PO4- and OCN(- )ion detection, by combining this with the functions of a smartphone, the chroma of photographs have been used to realize the consecutive visual detection of the concentration of these ions.