A porous anionic zinc(ii) metal-organic framework for gas adsorption, selective uptake of dyes and sensing of Fe3+ by Tb3+ ion encapsulation

A three-dimensional (3D) metal-organic framework [(CH3)(2)NH2][Zn-2(DMTDC)(2)(3-mtz)]center dot 4DMF center dot 3H(2)O (Zn-MOF) has been solvothermally synthesized by using mixed ligands of 3-methyl-1,2,4-triazole (3-Hmtz) and a thiophene-functionalized dicarboxylate ligand, 3,4-dimethylthieno[2,3-b]thiophene-2,5-dicarboxylic acid (H2DMTDC). Zn-MOF exhibits a uninodal 6-connected pcu alpha-Po topology structure and possesses an anionic framework with large 1D-trapezoidal channels. Gas adsorption studies reveal that the activated Zn-MOF-a displays selective adsorption of CO2 over N-2 at 273 K and 298 K as well as a high isosteric heat of CO2 adsorption. Moreover, Zn-MOF shows selective adsorption of the cationic dyes over the anionic and neutral dyes, and can be used as a fast-response and sensitive probe for the detection of Fe3+ by fluorescence quenching after encapsulation of Tb3+ into the pores by postsynthetic cation exchange.

Automated summary

In this study, a three-dimensional metal-organic framework with large channels was successfully synthesized, showing selective adsorption of CO2 and cationic dyes. Additionally, Zn-MOF can be used as a fluorescence quencher for detecting Fe3+ with high sensitivity.