Interfullerene Electronic Interactions and Excited-State Dynamics in Fullerene Dumbbell Conjugates

Chai, Y., Liu, L., Xu, Y., Liu, X., Wang, C., Bo, Y., Zhang, Y., Wang, Z., Weng, Y., Guldi, D. M., Wu, B., Wang, C., Journal of the American Chemical Society 2023, 145, 14190-14195. 10.1021/jacs.3c03486

Several dumbbell conjugates featuring M₃N@I_h-C₈₀ (M = Sc, Y) and C₆₀ were prepared to systematically investigate interfullerene electronic interactions and excited state dynamics. From electrochemical investigations, we concluded that the redox potentials of our M₃N@I_h-C₈₀ (M = Sc, Y) dumbbells depend largely on the interfullerene electronic interactions. Assisted by DFT calculation, the unique role of metal atoms was highlighted. Most importantly, ultrafast spectroscopy experiments revealed symmetry-breaking charge separation in Sc₃N@C₈₀-dumbbell to yield an unprecedented (Sc₃N@C₈₀)^•+-(Sc₃N@C₈₀)^•– charge separated state. This is, to the best of our knowledge, the first time that symmetry-breaking charge separation following photoexcitation is corroborated in a fullerene system. As such, our work shed light on the significance of interfullerene electronic interactions and their uniqueness for modulating excited state properties.