A Golden Fullerene Encapsulating Schmid Gold

Since its first synthesis in 1981, determining the structure of the "Schmid gold"─initially determined as a Au₅₅(PPh₃)₁₂Cl₆ cluster─has remained a big challenge. In this study, fluorine chemistry is exploited to stabilize the largest structurally resolved gold nanocluster stabilized by phosphine ligands, Au₇₅(P(C₆H₄-4-CF₃)₃)₂₀Cl₁₂, with which the atomically precise structure of the Schmid gold was optimized. The Au₇₅ nanocluster displays a Russian doll-like shell-by-shell configuration of Au₁₃@Au₄₂@Au₂₀@Cl₁₂@(PR)₂₀. The first two shells resemble the metallic core of the Schmid gold, which is encapsulated by an Au₂₀ shell showcasing a fullerene-like topology. Consequently, the structure of the Au₇₅ nanocluster is referred to as the "golden fullerene encapsulating Schmid gold". The geometric constraints of Au₂₀@Au₅₅ dominate over size effects in dictating photodynamics in the Au₇₅ nanocluster. Density functional theory analysis revealed the superatomic character of the fluorinated Au₇₅ nanocluster and molecular dynamics simulations up to three microsecond time scale confirmed the role of fluorine chemistry in stabilizing its structure. This study demonstrates the potential to stabilize large phosphine-protected gold nanoclusters by fluorine chemistry opening doors to understanding their functionality in catalysis and biological applications.