Direct evidence of complete charge separation in the excited triplet state of 1,2-(N-arylaziridino)-[60] fullerenes by means of time-resolved electron paramagnetic resonance

Some of 1,6-(N-substituted) aza-[60] fulleroids (1) and their corresponding photochemical reaction products, 1,2-(N-substituted) aziridino-[60] fullerenes (2) showed peculiar transient absorption peaks depending on the N-substituents. Although these bands are considered to concern with very slow photochemical rearrangements 1 → 2 in the excited triplet state, no definitive evidence has been obtained yet. We report on the character of the excited triplet states in these compounds by means of a time-resolved electron paramagnetic resonance technique. Definitive evidence on the involvement of intra-molecular charge transfer states is shown in this Letter.