Photophysical and photochemical properties of bis-silylated C-60 derivatives

Photophysical and photochemical properties of bis-silylated C-60 derivative s have been examined using steady-state and time-resolved spectroscopies. A bsorption band edges of 1,2- and 1,4-bis-silylated C-60 derivatives ranged to about 800 nm. Fluorescence quantum yields of 1,2- and 1,16-adducts were slightly larger than that of C-60, while 1,4-adducts did not show fluoresce nce. By laser irradiation to the bis-silylated C-60 derivatives, transient absorption bands due to their triplet excited states were confirmed in the visible and near-IR regions. Photoinduced electron transfer from electron d onor to excited triplet states of bis-silylated C-60 derivatives was also c onfirmed in transient absorption spectra. The acceptor-abilities of the exc ited triplet states changed with the position of the C-60-silicon bonds, wh ich can be explained mainly on the basis of reduction potentials and triple t energies of the bis-silylated C-60 derivatives.