Ultrafast Conversion of CO₂ into Quinazoline-2,4(1H,3H)-diones Catalyzed by a [Co₃] Cluster-Based Metal-Organic...

The conversion of CO₂ into quinazoline-2,4(1H,3H)-diones is a vital process in the pharmaceutical industry; however, developing efficient catalysts to realize ultrafast reaction rates remains challenging due to the complex reaction steps. Herein, the novel metal-organic framework {[(CH₃)₂NH₂][Co₃(μ₃-OH)(BTB)₂(BPT)]·4DMF·2H₂O}_n (Z-1) was synthesized, exhibiting high solvent and thermal stability, and featuring asymmetric [Co₃]-clusters, abundant open metal sites, and nanocages. Remarkably, Z-1 catalyzed the reaction between CO₂ and 2-amino-N-methylbenzamide at an ultrafast rate, achieving a 92% yield of 3-methylquinazoline-2,4(1H,3H)-diones within 2 min at room temperature. Its turnover frequency (613 h^-1) is the highest value recorded in all catalytic systems for synthesizing quinazoline-2,4(1H,3H)-diones. Additionally, Z-1 accommodated 16 diverse substrates and maintained a high yield over ten catalytic cycles. Mechanistic studies revealed that the [Co₃]-clusters effectively activated the amino group of substrates (the rate-determining step), while the thiadiazole moieties created alkaline microenvironments that enriched and activated CO₂. Density functional theory calculations further confirmed that Z-1 effectively reduced the activation energy barrier of the rate-determining step, thereby accelerating the generation of the carbamate intermediate from CO₂ and 2-aminobenzamide. This work presents the first heterogeneous catalyst capable of efficiently catalyzing the reaction between 2-aminobenzamide and CO₂, providing new insights into the design of catalysts for the chemical fixation of CO₂.