Atomic and Isomeric Separation of Thiolate-Protected Alloy Clusters

Techniques to control the chemical compositions and geometric structures of alloy clusters are indispensable to understand the correlation between the structures and physical/chemical properties of alloy clusters. In this study, we established a method to separate thiolate-protected 25-atom gold–silver alloy clusters (Au25–x Ag x (SR)18) according to their chemical composition and structural isomer. Furthermore, using this method, we revealed that an isomeric distribution of the products exists in Au25–x Ag x (SR)18 (x ≥ 2) and that the distribution of these isomers depends on the synthesis method and standing time in solution. In this study, it was also demonstrated that the continuous discretization of the electronic structure is induced by the Ag substitution. This method can also be used to separate mixtures of [Au24M­(SR)18]0 (M = Au, Pt, or Pd) and other Au–Ag alloy clusters ([Au36–x Ag x (SR)24]0 and [Au38–x Ag x (SR)24]0). This method is expected to be used to obtain comprehensive knowledge of the structural–property correlation of alloy clusters.