Synthesis of perylene-3,4-mono(dicarboximide)-fullerene C60 dyads as new light-harvesting systems

Fullerene C-60-perylene-3,4-mono(dicarboximide) (C-60-PMI) dyads 1-3 were synthesized in the search for new light-harvesting systems. The synthetic strategy to the PMI intermediate used a cross-coupling Suzuki reaction for the introduction of a formyl group in the ortho, meta, or para position. Subsequent 1,3-dipolar cycloaddition with C-60 led to the target C-60-PMI dyad. Cyclic voltammetry showed that the first one-electron reduction process unambiguously occurs onto the C-60 moiety and the following two-electron process corresponds to the concomitant second reduction Of C-60 and the first reduction of PMI. A quasi-quantitative quenching of fluorescence was shown in dyads 1-3, and an intramolecular energy transfer was suggested to occur from the PMI to the fullerene moiety. These C-60-PMI dyads constitute good candidates for future photovoltaic applications with expected well-defined roles for both partners, i.e., PMI acting as a light-harvesting antenna and C-60 playing the role of the acceptor in the photoactive layer.