Reversible CO 2 Capture by Conjugated Ionic Liquids through Dynamic Covalent Carbon–Oxygen Bonds

The strong chemisorption of CO 2 is always accompanied by a high absorption enthalpy, and traditional methods to reduce the absorption enthalpy lead to decreased CO 2 capacities. Through the introduction of a large π‐conjugated structure into the anion, a dual‐tuning approach for the improvement of CO 2 capture by anion‐functionalized ionic liquids (ILs) resulted in a high capacity of up to 0.96 molCO2  mol - 1ILand excellent reversibility. The increased capacity and improved desorption were supported by quantum chemical calculations, spectroscopic investigations, and thermogravimetric analysis. The increased capacity may be a result of the strengthened dynamic covalent bonds in these π‐electron‐conjugated structures through anion aggregation upon the uptake of CO 2 , and the improved desorption originates from the charge dispersion of interaction sites through the large π‐electron delocalization. These results provide important insights into effective strategies for CO 2 capture.