Cobalt-Cluster-Based Metal–Organic-Framework-Catalyzed Carboxylative Cyclization of Propargylic Amines with CO 2 from Flue Gas

The fixation of carbon dioxide (CO 2 ) directly from flue gas into valuable chemicals like 2-oxazolidinones is of great significance for economic and environmental benefits, which is typically catalyzed by noble-metal catalysts and under harsh conditions. Herein, a novel 2-fold interpenetrated framework {[Co 3 (μ 2 -O)(TCA) 2 (HDPTA) 2 ]·2H 2 O·2DMF} n [Co(II)-based metal–organic framework ( Co-MOF )] containing [Co 3 ] clusters and highly dense amino groups (−NH 2 ) dispersed in the channel was prepared, exhibiting high solvent/pH stability and CO 2 adsorption capacity (24.9 cm 3 ·g –1 ). Catalytic experiments demonstrated that Co-MOF could catalyze the carboxylative cyclization of propargylic amines to generate 2-oxazolidinones with yields of up to 98% under mild conditions with CO 2 directly from flue gas. In addition, Co-MOF retained its structure and catalytic activity after five-cycle catalytic experiments, showing the promising practical application. Density functional theory (DFT) calculation suggested that the [Co 3 ] centers in the MOF activated the C≡C of propargylic amines with much more binding energy than Co(NO 3 ) 2, partly accounting for the high catalytic activity of Co-MOF . This work demonstrates the first Co-based MOF material that is highly efficient for carboxylative cyclization of propargylic amines with flue gas as the CO 2 source, inspiring further rational design of porous catalysts for efficient CO 2 utilization.