Coupling a dendrimer and a fullerene chromophore: a study of excited state properties of C61(poly(aryl)acetylene)2

A new methanofullerene, C61(poly(aryl)acetylene)2, where the mono-adduct contains dendrimer units, has been studied with respect to its photophysical properties. The visible absorption and the emission spectra, the triplet molar extinction coefficient as well as the near unity value of the quantum yield of singlet oxygen production upon photoexcitation reveal characteristics in keeping with other methanofullerenes previously studied, where the addend species is not an electron donating group. The results indicate that, even when the methanofullerene is photoexcited, this large addend does not electronically communicate through the methano bridge neither through space. Photophysical properties of methanofullerenes can thus be preserved when they are functionalised with such addends.