Co(II) porphyrin-integrated Zr-MOF containing imidazolium-based ionic liquid for boosting cocatalyst-free CO2 cycloaddition

The efficient transformation of CO 2 into high-value chemicals remains a significant challenge, particularly in the design of heterocatalysts capable of simultaneous multi-site activation towards the substrate. In this work, we develop the novel Zr-MOF catalysts incorporating both cobalt(II) meso-tetra(4-carboxyphenyl)porphine (CoTCPP) complex and the imidazolium bromide-based ionic liquid (IL) containing different alkyl chain (RImBr), where R = Et, Pr, Bu, and Pe), denoted as CoTCPP-UiO-66-IL(RImBr). The catalysts were synthesized through a solvothermal method followed by a post-synthetic modification. Among the prepared catalysts, CoTCPP-UiO-66-IL(BuImBr) demonstrated exceptional performance on the solventless and cocatalyst-free conversion of epichlorohydrin into chloropropene carbonate, achieving a remarkable 99% yield under mild conditions (90 °C and 1.0   bar CO 2 ). This outstanding catalytic efficiency was attributed to the synergistic effects of the dual Lewis-acid active sites offered by Zr-MOF node and the integrated CoTCPP complex, the strong nucleophilicity resulting from the incorporated imidazolium bromide-type IL, and the improved CO 2 adsorption capacity. Additionally, the CoTCPP-UiO-66-IL(BuImBr) catalyst exhibited excellent recyclability and broad substrate versatility in epoxide cycloaddition. These findings provide valuable insights into the development of multifunctional MOF-based heterogeneous catalysts with high activity and sustainability for CO 2 conversion applications.