An Anion Metal–Organic Framework with Lewis Basic Sites-Rich toward Charge-Exclusive Cationic Dyes Separation and Size-Selective Catalytic Reaction

Organic dye pollutants become a big
headache due to their toxic
nature to the environment, and it should be one of the best solutions
if we can separate and reuse them. Here, we report the synthesis and
characterization of a microporous anion metal–organic framework
(MOF) with Lewis basic sites-rich based on TDPAT (2,4,6-tris­(3,5-dicarboxyl­phenyl­amino)-1,3,5-triazine)
ligand, FJI-C2, which shows high adsorption and separation
of cationic dye based on the charge-exclusive effect. Compared to
other MOF materials, FJI-C2 shows the largest adsorption
amount of methylene blue (1323 mg/g) at room temperature due to the
nature of the anion frameworks and high surface area/pore volume.
Furthermore, motivated by the adsorption properties of large guest
molecules, we proceeded to investigate the catalytic behaviors of FJI-C2, not only because the large pore facilitates the mass
transfer of guest molecules but also because the high density of Lewis
basic sites can act as effective catalytic sites. As expected, FJI-C2 exhibits excellent catalytic performance for size-selective
Knoevenagel condensation under mild conditions and can be reused several
times without a significant decrease of the activity.