One‐Step Synthesis of a [20]Silafullerane with an Endohedral Chloride Ion

Silicon analogues of the most prominent carbon nanostructures, namely, hollow spheroidals such as C₆₀ and the fullerene family, have been unknown to date. Herein we show that discrete Si₂₀ dodecahedra, stabilized by an endohedral guest and valence saturation, are accessible in preparative yields through a chloride‐induced disproportionation reaction of hexachlorodisilane in the presence of tri(n‐butyl)amine. X‐ray crystallography revealed that each silicon dodecahedron contains an endohedral chloride ion that imparts a net negative charge. Eight chloro substituents and twelve trichlorosilyl groups are attached to the surface of each cluster in a strictly regioregular arrangement, a thermodynamically preferred substitution pattern according to quantum‐chemical assessment. Our results demonstrate that the wet‐chemical self‐assembly of a complex, monodisperse Si nanostructure is possible under mild conditions starting from simple Si₂ building blocks.