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

The absorption, fluorescence, and transient absorption spectra of three reg ioisomers of [60]fullerene bisadducts were remarkably different from one an other and also different from those of typical monoadducts. These results i ndicate that the electronic structures of these bisadducts in both ground a nd excited states are significantly dependent on the addition pattern. The quantum yields of singlet oxygen production (Phi(Delta)) for these bisadduc ts wear also dependent on the addition pattern and less affected by the sol vents or substituents, whereas the quantum yields of intersystem crossing ( Phi(isc)) were almost independent of the addition pattern.