Sumanene, a bowl-shaped aromatic molecule, possesses the partial structure of C60 and shows unique structural and physical properties based on its curved pi-conjugated system. One of the characteristic features of sumanene is the presence of three benzylic carbons, which allow us to generate the corresponding cation, anion, and carbene species. Here we report the successful generateon, isolateon and redox property of sumanenyl tri-cations.

Sumanenyl tri-cations (1) were obtained in high yield by acid-triggered generateon o\from the corresponding hydroxyl-substituted sumanene derivative as a precursor. 1 reacted with the hydride donor, giving a tri-phenyl sumanene (2, 2’) and quinoidal sumanene (3’) in the presence and the absence of acid, respectively. Cyclic voltammetry revealed multi-step redox property of 1. Reductive wave at −1.28 V was observed as 2 electrons reduction without acid. In contrast, reductive wave at −1.17 V and −1.68 V were observed as 1 electron reduction with acid.