Masanori YASUI (安井 正憲)

The photoreactions of C₇₀ 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.

The addition reaction of C₆₀ with silylene 1, a silicon analog of carbene, yielded the corresponding bis-adduct 3. The structure of 3 was determined by single-crystal X-ray structure analysis, representing the first example of a crystal structure of a silirane (silacyclopropane) derivative of fullerenes. Electrochemical measurements confirmed that the redox potentials of 3 are shifted cathodically compared to those of the parent mono-adduct 2. Density functional theory (DFT) calculations provided the basis for the electronic properties of compound 3.