(Invited) Metallofullerenes – Enabling Long-Lived Radical Ion Pair States

Abstract

The “holy grail” of artificial photosynthesis is the realization of long lived radical ion pair states that power catalytic centers and, consequently, the production of solar fuels. Notably, magnetic field effects, especially internal magnetic field effects, are rarely employed in this context. Here, we report on severalelectron donor-acceptor conjugates, in which the presence of the Lu3N cluster in electron donating Lu3N@Ih -C80 exerts an appreciable electron nuclear hyperfine coupling on the charge transfer dynamics. As such, a fairly efficient radical ion pair intersystem crossing converts the initially formed singlet radical ion pair state, 1[(Lu3N@Ih -C80)•+-PDI•-]/ 1[(Lu3N@Ih -C80)•+-C60 •-], to the corresponding triplet radical ion pair state, 3[(Lu3N@Ih -C80)•+-PDI•-] / 3[(Lu3N@Ih -C80)•+-C60 •-]. Most notably, the radical ion pair state lifetime of the latter is up to 1000 times longer than that of the earlier.