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.