Extra Silver Atom Triggers Room‐Temperature Photoluminescence in Atomically Precise Radarlike Silver Clusters

Luminescent metal clusters show promise for applications in imaging and sensing. However, promoting emission from metal clusters at room temperature is a challenging task owing to the lack of an efficient approach to suppress the nonradiative decay process in metal cores. We report herein that the addition of a silver atom into a metal interstice of the radarlike thiolated silver cluster [Ag₂₇ (S^t Bu)₁₄ (S)₂ (CF₃ COO)₉ (DMAc)₄ ]⋅DMAc (NC1, DMAc=dimethylacetamide), which is non-emissive under ambient conditions, produced another silver cluster [Ag₂₈ (AdmS)₁₄ (S)₂ (CF₃ COO)₁₀ (H₂ O)₄ ] (NC2) that displayed bright green room-temperature photoluminescence aided by the new ligand 1-adamantanethiol (AdmSH). The 28th Ag atom, which hardly affects the geometrical and electronic structures of the Ag-S skeleton, triggered the emission of green light as a result of the rigidity of the cluster structure.