4,7,11,14,18,21-Hexa-t-butyltribenzodecacyclenyl radical: A six-stage amphoteric redox system

Abstract

A six-stage amphoteric redox hydrocarbon radical 3. containing three phenalenyl units was prepared. Cyclic voltammogram of 3. exhibits six reversible redox waves with a small numerical sum (Esum1) of first oxidation (Eox1) and reduction (Ered1) potentials. Some redox states of 3. were successfully generated from the neutral 3. and characterized by NMR, ESR, UV-vis-NIR spectroscopies, and theoretical calculations. The spin and the charges are delocalized over the entire C3 molecule of 33+, 3.2+, 3., and 33-. On the other hand, 3.2- shows the localization of the spin on one phenalenyl unit; these results are consistent with the distorted C2 structure caused by the Jahn-Teller effect.