Structural Determination and Characterization of Electronic Properties of Photosilylated Derivatives of C₇₀

The photoreactions of C 70 and mesityl‐substituted disilirane (disilacyclopropane) 1a afforded the corresponding adducts 2a and 3a , the former of which was reported previously. The structures of 2a and 3a are unequivocally established respectively as a 1,4‐adduct at the [ d , d' ] site and as a 1,2‐adduct at the [ a , b ] bond, respectively, using single‐crystal X‐ray crystallographic analyses. The latter structure represents the first example of crystallographic study of 1,3‐disilolane (1,3‐disilacyclopentane) derivatives of fullerenes. The electronic properties of these products are characterized based on electrochemical and theoretical studies elucidating the electron‐donating effects of silyl groups.