Polyoxometalate@copper catalyst for electrocatalytic coupling of halo-(hetero)aromatic hydrocarbons and carbon dioxide for synthesis of (hetero)aromatic acid

Carbon dioxide (CO2) is an abundant, non-toxic C1 feedstock, while (hetero)aromatic carboxylic acids are crucial structural frameworks and synthetic precursors in organic, materials, and medicinal chemistry. Herein, we report a Polyoxometalate@Copper (SiW12@Cu NPs) catalyst deposited on copper foam (CF) via simple electrodeposition (potential range: 0.6 V to -0.8 V, scan rate: 50 mV·s⁻¹) for the electrocatalytic carboxylation of halo-(hetero)aromatic hydrocarbons with CO2. The composite electrode leverages the synergistic effects of SiW12 (redox stability, Lewis acidity) and Cu NPs (multivalent states, high conductivity), enhancing electron transfer and CO2 activation. Under mild reaction conditions (room temperature, 1 atm CO2, and no noble metals added), this system enables not only arenes but also electron-deficient (hetero)arenes such as halopyridines to undergo direct carboxylation with carbon dioxide, achieving a target product yield of over 65% in merely 40 minutes at a current density of 20 mA. Mechanistic studies confirm substrate electroreduction initiates the reaction, followed by CO2 fixation. This strategy simplifies drug intermediate modification, avoids structural damage to sensitive molecules, and optimizes drug properties via post-carboxylation, offering sustainable technical support for medicinal chemistry innovation.