Layered Double Hydroxide-Stabilized AgI Photocatalyst for Efficient Arene Arylation and Alkylation

Developing clean and efficient methods for carbon–carbon bond formation remains a central challenge in sustainable chemistry. Here, we report a unified photocatalytic strategy for direct arene arylation and alkylation under visible light. By integrating silver iodide (AgI) nanoparticles with magnesium–aluminum-layered double hydroxide (Mg2Al1-LDH), we achieve efficient cross-coupling of arenes with both aryl and unactivated alkyl iodides under mild conditions and natural sunlight. This system operates without external bases or photoredox cocatalysts and tolerates base-sensitive functional groups, producing only water and iodine as byproducts. Mechanistic studies reveal a synergistic process in which photogenerated electrons reduce halides via an inner-sphere transfer mechanism, while photogenerated holes oxidize surface hydroxyl groups to generate ·OH radicals. These radicals enable hydrogen abstraction and C–H bond activation, completing the coupling process. The availability of surface hydroxyls and oxygen vacancies, along with favorable band alignment between AgI and Mg2Al1-LDH, is critical to catalyst performance. This work demonstrates the first example of a single catalyst system enabling both arylation and alkylation through a unified radical mechanism, offering a sustainable platform for light-driven C–H functionalization and expanding the frontiers of green synthetic chemistry.