Selective Adsorption of Dyes and Fe 3+ Sensing via Tb 3+ Incorporation in an Anionic Cadmium-Organic Framework.

A three-dimensional (3D) anionic cadmium-organic framework, namely [(CH 3 ) 2 NH 2 ][Cd 1.5 (DMTDC) 2 ] ⋅ 2DMA ⋅ 0.5H 2 O (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 (H 2 DMTDC). 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, Tb 3+ -loaded Cd-MOF serves as a fast-response fluorescence sensor for the sensitive detection of Fe 3+ ions with a low limit of detection (8.90×10 -7  M) through fluorescence quenching.