The anti-aromatic dianion and aromatic tetraanion of [18]annulene - Nature Chemistry

A previous investigation of the anti-aromatic dianion of [18]annulene concluded that it consists of a mixture of two isomers. Now it has been shown that this dianion exists as a single isomer, with a different geometry from neutral [18]annulene, and that it can be reduced further to an aromatic tetr...