Facilitating Electron Transfer by Resizing Cyclocarbon Acceptor from C 18 to C 16 .

Recent advances in synthetic methods, combined with tip-induced on-surface chemistry, have enabled the formation of numerous cyclocarbon molecules. Here, we investigate computationally the experimentally studied C 16 and C 18 molecules as well as their van der Waals (vdW) complexes with several typical donor and acceptor molecules. Our results demonstrate a remarkable electron-withdrawing ability of cyclocarbon molecules. The vdW complexes of C 16 and C 18 exhibit a thermodynamically favorable photoinduced electron transfer (ET) from the donor partner to the cyclocarbons that occurs on a picosecond time scale. The lower reorganization energy of C 16 compared to C 18 leads to a significant acceleration of the ET reactions.