Photophysical properties of a 1,2,3,4,5,6-hexasubstituted fullerene derivative

The photophysical properties of a novel 1,2,3,4,5,6-hexasubstituted fullerene derivative (1) are examined in this study. In addition to the ground state absorption spectrum of 1, we report its triplet-triplet absorption spectrum and molar extinction coefficient (Aε_T-T), as well as the triplet quantum yield (φ_T), lifetime (τ_T), and energy (E_T)- The saturation of a single six-member ring on the fullerene cage results in significant changes in the triplet state properties as compared to that of pristine C₆₆. The triplet-triplet absorption spectrum shows a hypsochromic shift in long wavelength absorption, and both the triplet state lifetime and the triplet quantum yield are decreased. The triplet energy was found to be similar to that of C₆₀. In addition, the quantum yield (ΦΔ) of singlet oxygen generated by 1 was calculated and is found to be significantly less than in the case of C_60..