Catalytic Non‐Oxidative C–C Coupling of Benzene to Biphenyl Over Sub‐Nanostructured Europium Hydride

Abstract Catalytic coupling of benzene to biphenyl through direct C─H bond activation and C─C bond construction represents an ideal, atom‐economical strategy, offering a streamlined alternative to classical multi‐step functionalization approaches, and thus has been a long‐sought after goal. Herein, we report that such a pathway can be realized over a sub‐nanostructured europium hydride (Eu–H) catalyst under mild condition. The Eu–H catalyst achieved a biphenyl production of 53.7 mmol g Eu −1 with a turnover number (TON) of 16.3 over 144 h at 150 °C. Mechanistic studies suggest that hydride species (H − ) in Eu–H preferentially deprotonate benzene to form a [C 6 H 5 –Eu] intermediate, which subsequently undergoes nucleophilic attack on another benzene molecule, resulting in biphenyl formation and regeneration of the Eu–H species to complete the catalytic cycle. This work not only provides a strategy for benzene coupling to biphenyl but also demonstrates the promising role of hydrides in transforming arenes into value‐added molecules.