Incorporation of Cu ²⁺ into Mn ₃ O Cluster-Based MOF for Catalytic Carboxylative Cyclization of Propargylic Amines with Flue Gas CO ₂ To Synthesize Oxazolidinones

Efficient transformation of flue gas CO 2 is of great significance, but it remains a formidable challenge. Herein, we constructed four isostructural metal–organic frameworks (MOFs) with anionic frameworks, including a homometallic Mn-MOF and three heterometallic MOFs: Mn/Co-MOF, Mn/Ce-MOF, and Mn/Eu-MOF . All of these MOFs exhibited unsatisfactory activity in the catalytic carboxylative cyclization of propargylic amines with CO 2 . To overcome this limitation, Cu 2+ was introduced into Mn-MOF via a cation exchange strategy, yielding composite Cu 2+ -Mn-MOF . Remarkably, Cu 2+ -Mn-MOF not only catalyzed the carboxylative cyclization of propargylic amines with pure CO 2 but also enabled the reaction using flue gas CO 2 to afford oxazolidinone products. The catalyst retained high activity and stability over five successive cycles. Control experiments and density functional theory (DFT) calculations revealed that Cu 2+ interacted with the uncoordinated −NH 2 groups in the channels and that the synergistic effect between Cu 2+ and the Mn-MOF strongly activated both the amino and alkynyl groups of the substrate, thereby facilitating the catalysis. This work presents the first detailed investigation of metal-node doping and Cu 2+ incorporation in Mn-based MOFs for the catalytic conversion of flue gas CO 2 .