Carbon Dioxide Capture by a Metal–Organic Framework with Nitrogen-Rich Channels Based on Rationally Designed Triazole-Functionalized Tetraacid Organic Linker

A semirigid tetraacid linker H4L functionalized with
1,2,3-triazole was rationally designed and synthesized to access nitrogen-rich
MOFs for selective adsorption of CO2. The cadmium MOF,
that is, Cd-L, obtained by the reaction of H4L with Cd­(NO3)2, is found to be a 3D porous framework structure that is robust
to desolvation. Crystal structure analysis reveals channels that are
decorated by the triazole moieties of L. Gas adsorption
studies show that Cd-L MOF permits remarkable CO2 uptake to the extent of 99 and 1000 cc/g at 1 and 30 bar,
respectively, at 0 °C. While literature survey reveals that MIL-112, constructed from a 1,2,3-triazole functionalized
linker, exhibits no porosity to gas adsorption due to structural flexibility,
the results with Cd-L MOF described herein emphasize how rigidification of the organic linker
improves gas uptake properties of the resultant MOF.