A new multi-functional Cd(II)-organic framework as a platform for high selective fluorescence sensing and dye adsorption

Abstract

A new three-dimensional porous MOF: {[Cd4(L)2(H2O)6]·(H2O)13·[(H2N(Me)2]2}n was synthesized by solvothermal reaction of 2,4-di(2′,4′-dicarboxyphenyl) benzoic acid ligand with Cd(Ⅱ) metal ion. Cd-MOF has a unique Cd-O metal oxygen chain structure. Metal oxygen chains are connected by ligands to form a three-dimensional porous structure. The solid-state fluorescence spectrum of Cd-MOF shows that the maximum emission peak is at 408 nm. Further liquid fluorescence sensing studies show that the complex can effectively and selectively detect Fe3+, CrO42- and Cr2O72− in aqueous solution with detection limit of 1.77 × 10−4 M, 1.08 × 10−3 M and 1.86 × 10−4 M, respectively, and can be reused five times, so it is a potential fluorescence recognition probe material. The fluorescence quenching mechanism of the system was discussed in detail. At the same time, in the study of the adsorption of dye molecules, it is found that the Cd-MOF has good adsorption capacity for methyl green and methylene blue and can also be used as an excellent dye separation material to selectively adsorb and separate mixed anion and cationic dyes.