Resonance energy transfer in new fullerene-coumarin diads

The fluorescence properties of new [60] and [70] fullerene-coumarin diads are studied. These diads were synthesized by covalently linking a coumarin dye to a fullerene (C-60 or C-70) by a cyclopropanation reaction. The absorption and fluorescence spectra, quantum yields and lifetimes of the diads are reported. The fluorescence quenching of the coumarin moiety by the fullerene was observed in all diads, indicating the occurrence of resonance energy transfer between the coumarin and fullerene moieties.