Preparation, Structural Determination, and Characterization of Electronic Properties of Bis-silylated and Bis-germylated Lu3N@Ih-C80

Bis‐silylated and bis‐germylated derivatives of Lu3N@Ih‐C80 (3, 4, 5) were successfully synthesized by the photochemical addition of disiliranes 1 a, 1 b or digermirane 2, and fully characterized by spectroscopic, electrochemical, and theoretical studies. Interestingly, digermirane 2 reacts more efficiently than disiliranes 1 a and 1 b because of its good electron‐donor properties and lower steric hindrance around the GeGe bond. The 1,4‐adduct structures of 3, 4, 5 were unequivocally established by single‐crystal X‐ray crystallographic analyses. The electrochemical and theoretical studies reveal that the energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the 1,4‐adducts are remarkably smaller than those of Lu3N@Ih‐C80, because the electron‐donating groups effectively raise the HOMO levels. It is also observed that germyl groups are slightly more electron‐donating than the silyl groups on the basis of the redox properties and the HOMO–LUMO energies of 4 and 5. Bis‐silylation and bis‐germylation are effective and versatile methods for tuning the electronic characteristics of endohedral metallofullerenes. Electronic tuning of fullerenes: Bis‐silylated and bis‐germylated Lu3N@Ih‐C80 derivatives have been synthesized using photochemical additions of disilirane and digermirane. The electrochemical and theoretical studies of these adducts demonstrate that bis‐silylation and bis‐germylation are effective methods for tuning the electronic characteristics of Lu3N@Ih‐C80.