Ultrafast Size Expansion and Turn-On Luminescence of Atomically Precise Silver Clusters by Hydrogen Sulfide

The formation of high-nuclearity silver(I) clusters remains elusive and their potential applications are still underdeveloped. Herein, we firstly prepared a chain-like thiolated Ag^I complex {[Ag₁₈ (S^t Bu)₁₀ (NO₃ )₈ (CH₃ CN)₂ (H₂ O)₂ ] ⋅ [Ag₁₈ (S^t Bu)₁₀ (NO₃ )₈ (CH₃ CN)₆ ]}_n (abbreviated as Ag₁₈ ) in which two similar Ag₁₈ clusters are assembled by NO₃ ^- anions. The solution containing Ag₁₈ reacted with hydrogen sulfide with controlled concentration, promptly producing another identifiable and bright red-emitting high-nuclearity silver(I) cluster, Ag₆₂ (S)₁₃ (S^t Bu)₃₂ (NO₃ )₄ (abbreviated as Ag₆₂ ). We tracked the transformation using time-dependent electrospray ionization mass spectrometry (ESI-MS), UV/Vis absorption and photoluminescence spectra. Based on this cluster transformation, we further developed an ultra-sensitive turn-on sensor detecting H₂ S gas with an ultrafast response time (30 s) at a low detection limit (0.13 ppm). This work opens a new way of understanding the growth of metal clusters and developing their luminescent sensing applications.