Photophysical properties of non-homoconjugated 1,2-dihydro, 1,2,3,4-tetrahydro and 1,2,3,4,5,6-hexahydro-C60 derivatives.

The photophysical properties of a novel series of non-homoconjugated 1,2-di-, 1,2,3,4-tetra-, and 1,2,3,4,5,6-hexasubstituted fullerenes (compounds 1, 2, and 3, respectively) have been systematically investigated. In this report, we examine the effect of substitution pattern of non-homoconjugated derivatized fullerenes on the ground state UV-Vis absorption, triplet state properties (lifetime, quantum yield, extinction coefficient), and singlet oxygen quantum yield. The non-homoconjugated fullerene derivatives 1–3 exhibit higher singlet oxygen quantum yield than analogous homoconjugated Bingel adducts with the same number of saturated CC bonds and exhibit decreasing quantum yield of singlet oxygen generation upon increasing the degree of functionalization on a single six member ring on the fullerene cage. This trend is similar for triplet quantum yield and triplet lifetime. The triplet extinction coefficient increases with functionalization. A detailed discussion comparing 1, 2, and 3 with functionalized homoconjugated systems and with other non-homoconjugated derivatives is presented.