Polar Pore Surface Guided Selective CO₂ Adsorption in a Prefunctionalized Metal–Organic Framework

Abstract

Selective\nCO₂ adsorption over other small gases has\nbeen realized in an ultra-microporous metal–organic framework\n(MOF). In the quest of manifesting such selective carbon capture performance,\nthe prefunctionalized linker strategy has been espoused. A new Zn­(II)-based\nthree-dimensional, 3-fold interpenetrated metal–organic framework\nmaterial [Zn­(PBDA)­(DPNI)]_<i>n</i>·<i>x</i>G (PBDA: 4,4′-((2-(<i>tert</i>-butyl)-1,4-phenylene)­bis­(oxy))­dibenzoic\nacid; DPNI: <i>N</i>,<i>N</i>′-di­(4-pyridyl)-1,4,5,8-naphthalenetetracarboxydiimide; <i>x</i>G: <i>x</i> number of guest species) with unusual\nrob topology is synthesized following a typical solvothermal synthesis\nprotocol, which gleans a modest CO₂-selective adsorption\ntrend over its congener gases (saturation CO₂ uptake capacity:\n2.39 and 3.44 mmol g^–1, at 298 and 273 K; volumetric\nsingle component isotherm based separation ratios at 0.2 bar: 189.4\n(CO₂/N₂, 256.5 (CO₂/H₂), 12.3 (CO₂/CH₄); at 1 bar: 6.8 (CO₂/N₂, 17.1 (CO₂/H₂), 7.1 (CO₂/CH₄)). The compound also exhibits selective benzene\nsorption over its aliphatic C₆-analogue cyclohexane. The\nstructure–property correlation guided results supported by\ntheoretical introspection further emphasize the omnipresent role of\ncrystal engineering principles behind culmination of such targeted\nproperties in the nanoporous MOF domain, to realize selective sorption\nfacets.