Photophysics of Open C60 Derivatives

In this report we examine the photophysical properties of two novel C 60 derivatives. These compounds consist of a ring-opened C 60 derivative ( 2 ) and its dihydro precursor ( 1 ), both of which include an orifice. The ground-state absorption spectra and the triplet−triplet absorption spectra were recorded for both derivatives. Extinction coefficients for the ground-state absorption (ε) and the triplet excited state (Δε T - T ) were calculated. The derivatives have triplet energies ( E T ) lower than that of C 60, and the triplet quantum yields (φ T ) are somewhat lower than that of C 60 . These compounds remain good photosensitizers for the formation of singlet oxygen, with high quantum yields (φ Δ ). Thus, in many respects the photophysics of these buckyballs with an orifice still resemble pristine fullerenes.