Significant Improvements in CO 2 Capture by Pyridine‐Containing Anion‐Functionalized Ionic Liquids through Multiple‐Site Cooperative Interactions

A strategy for improving CO 2 capture by new anion‐functionalized ionic liquids (ILs) making use of multiple site cooperative interactions is reported. An extremely high capacity of up to 1.60 mol CO 2 per mol IL and excellent reversibility were achieved by introducing a nitrogen‐based interacting site on the phenolate and imidazolate anion. Quantum‐chemical calculations, spectroscopic investigations, and calorimetric data demonstrated that multiple‐site cooperative interactions between two kinds of interacting sites in the anion and CO 2 resulted in superior CO 2 capacities, which originated from the π‐electron delocalization in the pyridine ring.