Synergistic Regulation of Excited-State Electrons Enables Sunlight-Driven C─Br Bond Activation Through In Situ...

While gold nanoclusters (AuNCs) offer unique molecule-like properties and discrete energy levels, their potential in photocatalysis remains largely untapped due to inherent stability and recombination issues. Herein, we report a ternary gold superclusters (AuSCs) architecture, AuSCs@SiW₉@PDA, that overcomes these limitations through cooperative regulation of excited-state electron dynamics. The composite is constructed via depletion-driven assembly of glutathione-protected AuNCs with a Keggin-type polyoxometalate, (Na₁₀SiW₉O₃₄ or SiW₉), followed by encapsulation within a polydopamine (PDA) network. In this system, SiW₉ serves as an efficient electron sink, while PDA enhances solar light absorption, promotes interfacial charge transport, and suppresses recombination, collectively increasing the density of photogenerated electrons. As a result, AuSCs@SiW₉@PDA enables efficient sunlight-driven activation of the thermodynamically robust C─Br bond in CBr₄, affording (1,3,3,3-tetrabromopropyl)benzene from terminal aryl alkenes in yields up to 90%. The activity markedly exceeds that of the corresponding binary analogues (AuSCs@SiW₉ and AuSCs@PDA) and their physical mixtures, highlighting the critical role of synergistic excited-state electron-transfer. Mechanistic investigations reveal accelerated electron transfer to CBr₄ and suppressed charge recombination as key factors governing C─Br bond cleavage. Overall, this work establishes AuSCs as robust, sunlight-driven photocatalysts and demonstrates excited-state electron management as a strategy for sunlight-driven bond activation.