Reduction of 1, 3, 5, 7, 9-penta-t-butyl-corannulene: Isomeric sandwiches with multiple lithium cations inside and out

Four reduction stages were observed for 1, 3, 5, 7, 9-penta-t-Bu-corannulene(2), two of which exhibited diamagnetic character: a paratropic dianion 22− and a diatropic tetraanion 24−. In the last stage of reduction three distinct tetraionic species are detected. Two of them are sandwhich-type compounds with eight Li cations each and a tetraionic monomer.