Effect of Copper Doping on Electronic Structure, Geometric Structure, and Stability of Thiolate-Protected Au₂₅ Nanoclusters

Several recent studies have attempted to impart [Au₂₅(SR)₁₈]⁻ with new properties by doping with foreign atoms. In this study, we studied the effect of copper doping on the electronic structure, geometric structure, and stability of [Au₂₅(SR)₁₈]⁻ with the aim of investigating the effect of foreign atom doping of [Au₂₅(SR)₁₈]⁻. Cu_<i>n</i>Au_{25–<i>n</i>}(SC₂H₄Ph)₁₈ was synthesized by reducing complexes formed by the reaction between metal salts (copper and gold salts) and PhC₂H₄SH with NaBH₄. Mass analysis revealed that the products contained Cu_<i>n</i>Au_{25–<i>n</i>}(SC₂H₄Ph)₁₈ (<i>n</i> = 1–5) in high purity. Experimental and theoretical analysis of the synthesized clusters revealed that copper doping alters the optical properties and redox potentials of the cluster, greatly distorts its geometric structure, and reduces the cluster stability in solution. These findings are expected to be useful for developing design guidelines for functionalizing [Au₂₅(SR)₁₈]⁻ through doping with foreign atoms