Synthesis, the electronic properties and efficient photoinduced electron transfer of new pyrrolidinefullerene- and isoxazolinefullerene-BODIPY dyads: nitrile oxide cycloaddition under mild conditions using PIFA†
Two new BODIPY-C60 dyads, with a pyrrolidine linker (BDP-Pyr) and an isoxazoline linker (BDP-Is) between the two electroactive units, have been synthesized and characterized. Their photophysical and electrochemical properties have been studied in solution by comparing with the reference compounds BDP and fullerene. Both BODIPY-C60 derivatives strongly absorb visible light and by photoexcitation at the BDP unit, these dyads undergo photoinduced electron transfer affording the corresponding charge-separated species. Based on their redox potentials, also the direction of the charge transfer is revealed and a comparison between the dyads with respect to C60 suggested that the new BDP-Is derivative showed a better electron affinity than BDP-Pyr and C60. In addition, the experimental studies were complemented by a theoretical analysis based on semiempirical computations which allowed confirming of the charge transfer mechanism from the BDP core to the C60 cages.