Single-Atom Synergy of Luminescence and Catalytic Stability in Silver-Encapsulated Gold Nanoclusters

The classic "silver effect" in gold(I) catalysis has long been confined to its role as a halide abstractor or transient stabilizer of catalytic intermediates. Here, we fundamentally redefine this concept by demonstrating that trace residual Ag(I) ions from halide abstraction of Ph₃PAuCl act as a dynamic template to drive the hierarchical assembly of organogold(I) precursors into a high-nuclearity bimetallic nanocluster [Au₁₁Ag₁]. Alternatively, an independently synthesized hollow [Au₁₁] nanocage can selectively and strongly encapsulate a single silver(I) ion (K_a ∼ 10⁵ M^-1) to reproduce [Au₁₁Ag₁], showcasing a rare example of heterometal recognition driven solely by metallophilic interactions. This single-atom encapsulation dramatically enhances the phosphorescence quantum yield of [Au₁₁Ag₁] over 13-fold (up to 40.8%) of [Au₁₁] by participating in the triplet excited state. In addition, such single-atom synergy further provides critical structural reinforcement via 9-fold Au(I)-Ag(I) interactions to prevent the structural collapse of [Au₁₁Ag₁] under catalytic conditions, in sharp contrast to the instable hollow [Au₁₁] analogue. Consequently, the silver(I)-incorporated cluster enables efficient photocatalytic aerobic oxidation of sulfides.