Optimizing the performance of porous pyridinium frameworks for carbon dioxide transformation

Multifunctional catalysts derived from the integration of discrete catalytic partners in a confined space represent an important approach to emulate some of the design philosophies of enzymes. In an effort to design concepts for highly active catalysts for CO₂ transformations, we synthesize and contrast the performance of two porous pyridinium frameworks. The activity is found to be significantly amplified by the introduction of the amine group on the ortho position of the pyridinium moieties. The resulting catalyst is capable of highly active and selective cycloaddition of aziridines with CO₂ to 5-substituted-2-oxazolidinone, even under ambient conditions (1 bar, 22 °C). Its high activity originates from CO₂ activation by the pendant amine group in the vicinity of the active species, which facilitates the subsequent catalytic steps.