Fullerene C60 Bound to Insoluble Hydrophilic Polymer: Synthesis, Photophysical Behavior, and Generation of Singlet Oxygen in Water Suspensions

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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.