One-pot construction of nitrogen-rich polymeric ionic porous networks for effective CO2 capture and fixation

Abstract

Facile preparation of ionic porous networks (IPNs) with large and permanent porosity is highly desirable for CO₂ capture and transformation but remains a challenge. Here we report a one-pot base-mediated construction of nitrogen-rich IPNs through a combination of nucleophilic substitution and quaternisation chemistry from H-imidazole. This strategy, as proven by the model reactions of 1H-imidazole or 1-methyl-1H-imidazole with cyanuric chloride, allows for fine regulation of porosity and physicochemical properties, leading to nitrogen-rich IPNs featuring abundant ionic units and radicals. The as-prepared networks, termed IPN-CSUs, efficiently capture CO₂ (80.1 cc g⁻¹ at 273 K/1 bar) with an ideal CO₂/N₂ selectivity of 139.7. They can also effectively catalyse the cycloaddition reaction between CO₂ and epoxides with high yields of up to 99% under mild conditions (0.1 MPa, 298 K), suggesting their possible applications in the fields of both selective molecular separation and conversion. Unlike the previously known strategies generally involving single coupling chemistry, our strategy combining two coupling routes in one pot appears to be unique and potentially applicable to other building blocks.