CO2-Involved and Isocyanide-based Three-component Polymerization toward Functional Heterocyclic Polymers with Self-assembly and Sensing Properties

CO₂ utilization has been a hot research topic in academic and industrial respects. Besides converting CO₂ into chemicals and fuels, incorporating it into the polymers to construct functional materials is another promising strategy. However, the CO₂-involved polymerization techniques should be further developed. In this work, a facile and efficient CO₂-involved multicomponent polymerization is successfully developed. The reaction of monomers of CO₂, isocyanides and 2-iodoanilines readily produces soluble and thermally stable poly(benzoyleneurea)s with well-defined structures under mild conditions. Thanks to the formed amide groups in the heterocyclic units in the main-chains, the resultant polymers could self-assemble into spheres with sizes between 200 and 1000 nm. The polymers containing tetraphenylethylene (TPE) unit show the unique aggregation-enhanced emission (AEE) features, which could be used to visualize the self-assembly process and morphologies under UV irradiation, and serve as fluorescence probe to selectively and sensitively detect Au³⁺ ions. Notably, the polymers containing cis- and trans-TPE units exhibit different behaviors in self-assembly and limit of detection for Au³⁺ ions due to the different intermolecular interactions. Thus, this work not only provides a new strategy for CO₂ utilization but also furnishes a series of functional heterocyclic polymers for diverse applications.