Carboxylate‐Functionalized Zeolitic Imidazolate Framework Enables Catalytic N‐Formylation Using Ambient CO2

摘要

Abstract Catalytic upgrading of CO2 into value‐added chemicals to build the excess carbon cycle is of great significance. In this work, carboxylate‐functionalized zeolitic imidazolate framework (F‐ZIF‐90) with good crystallinity and porosity is constructed from ZIF‐90 and employed as a robust heterogeneous catalyst to boost the reductive N‐functionalization of various amines with CO2 to furnish N‐formyl compounds (up to 99% yield) in the presence of PhSiH3 under an ambient environment. The imidazole carboxylate species (COO‐) can not only activate hydrosilane and CO2 to form the key intermediate formoxysliane but also activate amines to participate in the N‐formylation reaction to obtain the target product. Moreover, it can enhance the catalyst capture and exchange ability toward ambient CO2. The powerful adsorption capacity of the F‐ZIF‐90 catalyst toward CO2 is conducive to elevating CO2 concentration around the active species. Theoretical calculations show that the carboxylate‐mediated conversion path undergoes the transition state of hydrosilane activation with a relatively lower energy barrier (ΔG = 26.9 kcal mol–1). F‐ZIF‐90 exhibits good thermochemical stability with no obvious activity attenuation after repeated use 5 times. This strategy opens a new avenue based on ZIFs to develop heterogeneous catalysts for reductive upgrading of CO2.