Dye functionalized lanthanide metal–organic framework as a multifunctional luminescent hybrid material for visual sensing of biomarker 2-methoxyaceticacid and sulfide anion

Based on the anionic Slug-47 [Gd(bpdc)2-] [NH2(CH3)2+], a multifunctional fluorescent material with ultra-high stability has been fabricated successfully. Firstly, Eu0.04Tb39.96Gd60 with white light emission is prepared by adjusting the doping ratio of Eu3+ ions and Tb3+ ions. Then, the dye acriflavine (ACF) is further introduced into the framework of Eu@ Slug-47 (1) via cation exchange to obtain ACF@1, which can be used as a ratio fluorescence sensor to detect 2-methoxyaceticacid (Maa), a toxic metabolite of glycol monomethyl ether, with the limit of detection (LOD) as low as 0.27 μg/mL. It is impressive that the emissions of ACF and biphenyl-4,4'-dicarboxylicacid ligands are gradually enhanced with the gradual weakening of the emission of Eu3+ ions during the detection of Maa. Under the superposition of three different colors, the sensing process undergoes a distinct color change from red to white and then to blue. These rich and colorful colors provide conditions for accurate visual detection of Maa. In addition, the material can also respond well to the pollutant S2- ions and the LOD can reach 11.3 μmol /L. It is worth mentioning that the available quenching effect can be observed even if Maa and S2- ions are detected in urine and tap water respectively, indicating that the multifunctional material has a brilliant application prospect. Finally, the quenching mechanism of Maa, S2- ions toward ACF@1 is discussed in detail.