Cationic Porous Organic Polymer Gels from Tandem Condensation Reactions of Amino Acid Amides

Abstract

Ionic porous organic polymers (iPOPs) have been extensively studied in various research areas, including molecular adsorption, separation, and mass transport. Nevertheless, most of the reported iPOPs are crystalline or amorphous powders with poor processability and it is challenging to manipulate the structures and functionalities, restricting their practical applications. In this study, we developed a reaction between amino acid amides and aldehydes to fabricate positively charged imidazolidinone-based skeletons under mild conditions, leveraging a tandem condensation–cyclization–condensation mechanism. This synthetic approach was applied to integrate various amino acids into POPs, yielding iminium-tagged imidazolidinone skeletons and enabling the in situ formation of iPOP gels during polymerization. Owing to the positively charged backbones, intrinsic porosity and excellent structural versatility, iPOP MeG1-Tpy was tested for hydroxide ion transport and demonstrated high ion conductivity. This work provides a robust method to design processable iPOPs with tunable structures and properties, paving the way for their potential applications in energy-related devices.