Corannulene reduction: spectroscopic detection of all anionic oxidation states

Nuclear magnetic resonance and electron paramagnetic resonance spectroscopies of the corannulene reduction indicate a stable diamagnetic dianion and negligible counterion effects in the mono- and dianion. The reduced form of trianion and tetraanion is obtained with lithium as the reducing metaly, but not with potassium. The anions with lithium and potassium are counterions.