Highly effective selectively removal of carcinogenic dyes and iodine adsorption and release via a metal-organic framework based on multiple helical chains

A novel porous metal-organic framework Cu-BCPPy based on a desymmetrized heterofunctional ligand 3,5-di(4-carboxyphenyl)pyridine has been successfully synthesized under solvothermal conditions. The framework possesses two sizes of 2D straight channels, which are constructed by one pair and three pairs of helixes, respectively. The distortion of the ligand leads to the structure exhibiting a new type of (3,6)-connected topology. According to the structural characteristic, Cu-BCPPy can effectively adsorb large carcinogenic organic dyes sudan III (SD III) and direct black 38 (DB 38) but exclude small molecular dyes. Hence, Cu-BCPPy exhibits effective and selective adsorption performance for the carcinogenic dye DB 38 on the equal proportional mixture dyes methyl orange (MO) and DB 38, fluorescein and DB 38, and basic red 2 (BR 2) and DB 38 with different sizes. In addition, Cu-BCPPy can be also provided with the characteristic of high iodine adsorption and release, which indicates that it is a promising candidate material for selectively adsorption and separation of many substances.