Fullerene C₆₀ bound to insoluble hydrophilic polymer: Synthesis, photophysical behavior, and generation of singlet oxygen in water suspensions

Fullerene C60 has been covalently bound to an insoluble hydrophilic polymeric matrix: Sephadex® G-200, The new polymeric equivalent of C60 swells in H2O to form gel-like suspensions. The transient photochemical behavior of this polymeric fullerene has been studied in dry and H2O-suspended samples. Both samples show a transient absorption similar to the absorption of the parent C60 solution. There is a lack of triplet-triplet annihilation and of a O2-quenching process in the dry sample. On the contrary, the O2-quenching process is very efficient in the H2O-suspended samples (kq(O2) = (1.9 ± 0.5) × 108 dm3 mol-1 s-1) and results in the formation of singlet oxygen, which is detected by its emission at 1270 nm. These results point to this hydrophilic polymeric equivalent of C60 as a good candidate for use as a singlet-oxygen solid sensitizer in H2O suspensions.