Fullerene pyrazine dyads: Intramolecular energy transfer route to the fullerene moiety

A synthetic route to 1,4-diazine-fused [60]fullerenes has been developed based on the Diels-Alder reaction of 2,3-bis(trimethylsiloxy)butadiene and [60]fullerene followed by oxidation to the corresponding 1,2-diketone and condensation with 1,2-diamines. These bichromophoric compounds promote the UV/Vis absorption and act as light-harvesting systems involving energy transfer from the pyrazine chromophor to the fullerene unit. A detailed investigation of the photophysical steps will be presented which finally lead to fullerene triplet states.