Photophysical properties of various regioisomers of [60]fullerene-o-quinodimethane bisadducts

The absorption, fluorescence, and transient absorption spectra of three regioisomers of [60]fullerene bisadducts were remarkably different from one another and also different from those of typical monoadducts. These results indicate that the electronic structures of these bisadducts in both ground and excited states are significantly dependent on the addition pattern. The quantum yields of singlet oxygen production (ΦΔ) for these bisadducts were also dependent on the addition pattern and less affected by the solvents or substituents, whereas the quantum yields of intersystem crossing (Φisc) were almost independent of the addition pattern.