Abstract
Since its first synthesis in 1981, determining the structure of the "Schmid gold"─initially determined as a Au(55)(PPh(3))(12)Cl(6) 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, Au(75)(P(C(6)H(4)-4-CF(3))(3))(20)Cl(12), with which the atomically precise structure of the Schmid gold was optimized. The Au(75) nanocluster displays a Russian doll-like shell-by-shell configuration of Au(13)@Au(42)@Au(20)@Cl(12)@(PR)(20). The first two shells resemble the metallic core of the Schmid gold, which is encapsulated by an Au(20) shell showcasing a fullerene-like topology. Consequently, the structure of the Au(75) nanocluster is referred to as the "golden fullerene encapsulating Schmid gold". The geometric constraints of Au(20)@Au(55) dominate over size effects in dictating photodynamics in the Au(75) nanocluster. Density functional theory analysis revealed the superatomic character of the fluorinated Au(75) 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.