Bromine-Functionalized Lanthanide MOF with Acid-Base Dual Active Sites: Catalysis for CO₂ Cycloaddition and...

Metal-organic frameworks (MOFs) represent a prominent research direction for the heterogeneous catalytic conversion of carbon dioxide (CO₂), with substantial implications for resource utilization and sustainable development. Herein, a bromine-functionalized lanthanide MOF (Eu-DBT) was synthesized via solvothermal reaction of Eu³⁺ ions with 2,5-dibromoterephthalic acid (H₂DBT), constructing a bifunctional acid-base catalytic system. Eu-DBT exhibits excellent catalytic performance in two key CO₂ fixation reactions. It achieves a 98.4% yield and 99.5% selectivity for the cycloaddition of CO₂ with propylene oxide, and 99.8% conversion with a 99.4% target yield for N-methylaniline CO₂ mediated N-formylation under optimized conditions. Additionally, Eu-DBT demonstrates broad substrate generality and robust recyclability, retaining high activity over five consecutive reaction cycles. Mechanistic investigations reveal that its superior performance originates from the synergistic effect of Eu³⁺ and -Br acid-base dual active sites, which effectively reduce reaction energy barriers. This work provides a ligand halogenation strategy for rational designing multifunctional Ln-MOFs, highlighting bromine-functionalized Ln-MOFs as efficient heterogeneous catalysts for sustainable CO₂ resource utilization.