Anthracene-Modified Metal–Organic Framework with fof Topology for Highly Efficient Adsorption and Separation of Organic Dyes

A novel anthracene-modified metal–organic framework, [Cu2(ADEDA)(H2O)2]·4DMF (compound 1) (H4ADEDA = 5,5′-(anthracene-9,10-diylbis(ethyne-2,1-diyl))diisophthalic acid), has been successfully synthesized under solvothermal conditions. Structural analysis shows that the framework of compound 1 is built up with binary structural units composed of a classical [Cu2(CO2)4] paddle-wheel and a 3-linked expanded tetracarboxylates ligand. The entire three-dimensional framework possesses a (3,4,4)-connected fof topology. On the basis of the functional anthracene groups and the large pore volume, compound 1 can effectively adsorb cationic dyes such as methylene blue (MLB), methyl violet(MV), rhodamine 6G (Rh6G), and the neutral dye neutral red (NR), but exclude anionic dyes such as methyl orange (MO) and orange II. With the functional anthracene groups and the large pore volume, compound 1 can effectively adsorb cationic dyes, such as MLB, MV, Rh6G, and the neutral dye NR, but exclude anionic dyes such as MO and orange II. Furthermore, compound 1 has size rejection capabilities for various dye molecules, and the amount of adsorption declines with the increasing dye size. Compound 1 is capable of efficiently and selectively adsorbing the cationic dye MLB for mixed MO and MLB and orange II and MLB. Given above, compound 1 should be a promising MOF material for the adsorption and separation of organic dyes.