The matter of anti

An international team has brought the story of aromaticity full circle from the apocryphal tale of Kekule's dream of Ouroboros the snake. Jonathan Sessler and colleagues have stabilized an aromatic molecule in the anti-aromatic form, a rare achievement, using rational design modifications on a porphyrin compound they first synthesized in 1992. The final product is a meso-pentafluorophenyl-substituted o-phenylene-bridged annulated rosarin, with the bulky groups forcing the previously aromatic skeleton into the antiaromatic state. The team also identified, but are yet to name, an intermediate compound that lies between the aromatic and the anti-aromatic state in a kind of chemical limbo of planarity and non-planarity and electron resonances.