Tailoring optical and photocatalytic properties by single-Ag-atom exchange in Au₁₃Ag₁₂(PPh₃)₁₀Cl₈ nanoclusters

Precise mono-doping of metal atom into metal particles at a specific particle position (e.g., the central site) in a highly controllable manner is still a challenge. In this work, we develop a highly controllable strategy for exchanging a single Ag atom into the central gold site of Au₁₃Ag₁₂(PPh₃)₁₀Cl₈ (Ph = phenyl) nanoclusters. Interestingly, a “pigeon-pair” cluster of {[Au₁₃Ag₁₂(PPh₃)₁₀Cl₈]·[Au₁₂Ag₁₃(PPh₃)₁₀Cl₈]}²⁺ is obtained and confirmed by electrospray ionization mass spectrometry (ESI-MS), thermogravimetric analysis (TGA) and single crystal X-ray diffraction (SCXRD) analysis. The experimental results and density functional theory (DFT) calculations suggest that the single-metal-atom exchanging from [Au₁₃Ag₁₂(PPh₃)₁₀Cl₈]⁺ to [Au₁₂Ag₁₃(PPh₃)₁₀Cl₈]⁺ occurs at the central position through the side entry of the μ₃-bridging Cl atoms. Finally, the effects on the electronic structure and properties caused by the single-atom exchange at the central site are shown by the enhancement of fluorescence and catalytic activity in the photocatalytic oxidation of ethanol.