Single-Site Palladium “Microreactor” for Carbon Dioxide Coupling/Cyclization Reactions

The strategic conversion of carbon dioxide into valuable substances is fundamental to realizing the goal of carbon neutrality. However, the high thermodynamic stability and kinetic inertness of carbon dioxide pose considerable challenges to the fields of catalytic activation and chemical conversion. This study designed and prepared a recyclable single-site palladium metal–organic ligand porous polymer catalyst with a “microreactor” catalytic environment. In this single-site palladium “microreactor”, the coupling/cyclization reaction of carbon dioxide with 2-bromoaniline and isonitrile was precisely achieved at atmospheric pressure, allowing for the efficient synthesis of N3-substituted quinazoline-2,4(1H,3H)-diones. Notably, the single-site palladium “microreactor” demonstrated exceptional catalytic efficiency, achieving a turnover number (TON) of up to 4750, which is 150 times higher than the previous record. Its outstanding thermal stability and carbon dioxide adsorption capacity facilitated the conversion of carbon dioxide into valuable products. This groundbreaking development in catalysis is set to profoundly influence the industry, presenting a sustainable strategy to repurpose a major greenhouse gas into materials of substantial economic value, thereby bolstering environmental sustainability.