Open‐Cage Fullerene as a Selective Molecular Trap for LiF/[BeF]⁺

The insertion of ionic compounds into open‐cage fullerenes is a challenging task due to the electropositive nature of the cavity. The present work reports the preparation of an open‐cage C 60 derivative with a hydroxy group pointing towards the centre of the cavity, which can coordinate to a metal cation, thus acting as a bait/hook to trap the metal cation such as the lithium cation in neutral LiF and the beryllium cation in the cationic [BeF] + species. Other metal salts could not be inserted under similar conditions. The structure of MF in the cage was unambiguously determined by single‐crystal X‐ray diffraction. Owing to its tendency to undergo polycoordination, Li + monomer salts have not been isolated before, despite extensive research on Li bonds. The present results provide a unique example of a Li bond.