Functionally enhanced polyether-bridged amidopyridinium dicationic ionic liquids for highly efficient and sustainable fixation of CO2 to cyclic carbonates.

Functionally enhanced polyether-bridged amidopyridinium dicationic ionic liquids for highly efficient and sustainable fixation of CO 2 to cyclic carbonates. [Display omitted] • Polyether-bridged amidopyridinium dicationic ionic liquids were synthesized. • An enhanced activity was observed in the cycloaddition reaction. • At a very low loading of 0.01 mol%, the TON value is as high as 7700. • The synergistic activation of epoxides by two amidopyridinium cations. Task-specific ionic liquids integrated with multi-active sites display promising potential for use in the cycloaddition reaction of CO 2 and epoxides. Utilizing the functional enhancement strategy, we successfully synthesized a novel range of polyether-bridged amidopyridinium dicationic ionic liquids (PE-PyDILs) via efficient bisamidation and biquaternization reactions. Under relatively mild reaction conditions, PE-PyDILs can catalyze the coupling of CO 2 with various epoxides to produce cyclic carbonates in quantitative yields, demonstrating an enhanced effectiveness and a longer service life compared to previous DILs. At a very low loading of 0.01 mol%, the TON value is as high as 7700. The excellent catalytic performance can be attributed to the intramolecular cooperative activation of epoxides with two amidopyridinium cations bridged by polyether, as supported by the spectroscopic analysis and kinetic studies. This mechanism led to a reduction in activation energy and improved the efficiency of the cycloaddition reaction. [ABSTRACT FROM AUTHOR]