An Imide-Decorated Indium-Organic Framework for Efficient and Selective Capture of Carcinogenic Dyes with Diverse Adsorption Interactions

A functional indium-organic framework with an anionic skeleton, [(CH3)(2)NH2 ][In(BDCPPI)]center dot 0.5DMF-H2O (compound 1, H4BDCPPI = N,N'-bis(3,5-dicarboxyphenyl)pyromellitic diimide, DMF = N,N-dimethylformamide), has been solvothermally synthesized. Compound 1 with a (4, 4)-connected pts network is constructed by negative [In(OOC)(4)](-) secondary building units (SBUs) and expanded tetracarboxylate ligands with functional imide groups. Meanwhile, the overall framework possesses large open channels of 17.3 x 5.5 angstrom with a high solvent-accessible volume that occupied about 69.2% of the total cell volume. Due to its anionic skeleton and imide-functional channels, compound 1 can efficiently adsorb large-sized carcinogenic Basic Red 9 (BR9) and Basic Violet 14 (BV14) under the synergetic promotion of Coulombic interaction, hydrogen bonding, and ion exchange and can display a repelling effect to anionic dyes. In addition, the maximum adsorption capacities for BR9 and BV14 are as high as 245 and 227 mg g(-1), respectively. With regard to series of mixtures with oppositely charged dyes, compound 1 can selectively trap carcinogenic dyes. Therefore, compound 1 should be a promising metal-organic framework (MOF)-based material for the efficient and selective adsorption of carcinogenic dyes.