Assembly of zeolite-like anionic indium-organic frameworks based on flexible tetra-carboxylate ligands for organic dyes separation

Zeolite-like metal-organic frameworks (ZMOFs) have attracted a great attention because of their special performances in adsorption and separation. It is still of significant to synthesize new ZMOFs with attractive structural features. In this work, two new anionic MOFs, namely [(Me2)NH2]·[In(TCM)]·4DMF (JOU-13), and [(Me2)NH2]·[In(TCM)]·DMF (JOU-14), have been successfully synthesized based on [In(COO)4]- units and flexible tetra-carboxylate ligand (H4TCM = Tetrakis(4-carboxyphenoxymethyl)methane). The structures of JOU-13 and JOU-14 were well characterized by single-crystal X-ray diffraction. It is shown that JOU-13 represents a rare example of interpenetrating framework with gis topology, while JOU-14 is a (4,4)-connected dia topological structure. Notably, JOU-13, owning to its porous and anionic skeleton, exhibits outstanding performance in selectively adsorbing and separating cationic dye methylene blue, displaying reversible capabilities in dye adsorption and release. This work provides valuable clues for preparing new anionic zeolite-like MOFs with special properties.