Templated Atom‐Precise Galvanic Synthesis and Structure Elucidation of a [Ag₂₄Au(SR)₁₈]⁻ Nanocluster

Synthesis of atom‐precise alloy nanoclusters with uniform composition is challenging when the alloying atoms are similar in size (for example, Ag and Au). A galvanic exchange strategy has been devised to produce a compositionally uniform [Ag 24 Au(SR) 18 ] − cluster (SR: thiolate) using a pure [Ag 25 (SR) 18 ] − cluster as a template. Conversely, the direct synthesis of Ag 24 Au cluster leads to a mixture of [Ag 25− x Au x (SR) 18 ] − , x =1–8. Mass spectrometry and crystallography of [Ag 24 Au(SR) 18 ] − reveal the presence of the Au heteroatom at the Ag 25 center, forming Ag 24 Au. The successful exchange of the central Ag of Ag 25 with Au causes perturbations in the Ag 25 crystal structure, which are reflected in the absorption, luminescence, and ambient stability of the particle. These properties are compared with those of Ag 25 and Ag 24 Pd clusters with same ligand and structural framework, providing new insights into the modulation of cluster properties with dopants at the single‐atom level.