Selective Adsorption of Dyes and Fe³⁺ Sensing via Tb³⁺ Incorporation in an Anionic Cadmium‐Organic Framework

Abstract

A three‐dimensional (3D) anionic cadmium‐organic framework, namely [(CH3)2NH2][Cd1.5(DMTDC)2] ⋅ 2DMA ⋅ 0.5H2O (Cd‐MOF; DMA=N,N‐dimethylacetamide), was successfully synthesized under solvothermal conditions by using a linear thienothiophene‐containing dicarboxylate ligand, 3,4‐dimethylthieno [2,3‐b]‐thiophene‐2,5‐dicar‐boxylic acid (H2DMTDC). Single‐crystal X‐ray diffraction analysis reveals that Cd‐MOF exhibits a 3D anionic framework with pcu α‐Po topology, featuring rectangle and rhombus‐shaped channels along b‐ and c‐ axis direction. Cd‐MOF demonstrates selective adsorption of cationic dyes over anionic and neutral dyes. Additionally, Tb3+‐loaded Cd‐MOF serves as a fast‐response fluorescence sensor for the sensitive detection of Fe3+ ions with a low limit of detection (8.90×10−7 M) through fluorescence quenching.