Building N-Heterocyclic Carbene into Triazine-Linked Polymer for Multiple CO₂ Utilization

The development of new CO₂ detection technologies and CO₂ "capture-conversion" materials is of great significance due to the growing environmental crisis. Here, multifunctional triazine-linked polymers with built-in N-heterocyclic carbene (NHC) sites (designated as NHC-triazine@polymer) are presented for simultaneous CO₂ detection, capture, activation, and catalytic conversion. NHC-triazine@polymer were readily obtained through polymerization of cyanophenyl-substituted NHC. The obtained film-like polymers exhibited interesting CO₂ -triggered fluorescence "turn-on" response and CO₂ -sensitive reversible color change. Both NHC and triazine sites could act as efficient binding sites for CO₂ , and the CO₂ uptake of NHC and triazine reached 1.52 and 1.36 mmol g^-1 , respectively. Notably, after being captured by NHC, CO₂ was activated into a zwitterionic adduct NHC-CO₂ that could be easily transformed into cyclic carbonate in the presence of epoxides. Moreover, NHC-triazine@polymer were stable and active catalysts for the conversion of low-concentration CO₂ in a gas mixture (7 vol %) into cyclic carbonates as well as for hydrosilylation of CO₂ to formamides.