Imidazolium hydrogen carbonate ionic liquids: Versatile organocatalysts for chemical conversion of CO2 into valuable chemicals

N-heterocyclic carbenes (NHCs) are found to be efficient halogen-free organocatalysts for chemical conversion of CO2, however, their inherent nature is sensitive to water and air, which leads to limitations in practical applications. In this work, we demonstrate the halogen- and metal-free methods for chemical fixation of CO2 into valuable chemicals of cyclic carbonates and methylamines using air and water-stable organocatalysts of imidazolium hydrogen carbonate ionic liquids (C(n)C(m)ImHCO(3)). Good to excellent yields of cyclic carbonates and methylamines are obtained for varied substrates under mild conditions. Mechanism insight shows that the C(n)C(m)ImHCO(3), as an organic pre-catalysts for N-heterocyclic carbene, can balance to carbene CO2 adduct (C(n)C(m)ImHCO(2)) serving as the active species for conversion of CO2. As a result, the halogen- and metal-free organocatalysts of C(n)C(m)ImHCO(3) again emphasize that are possible to replace traditional carbenes and offer an environment-friendly methodology for chemical fixation of CO2.