Ring-current aromaticity in triplet states of 4n π electron monocycles

The ipsocentric approach to orbital contributions to current density predicts that a triplet state of a 4n π-electron Hückel monocycle should be aromatic, in the sense of supporting a diatropic ring current, and that this current should be carried by just four of the π electrons (three for n=1). The magnetic criterion of aromaticity is thus in agreement with Baird’s classic energy-based prediction of aromatic stabilisation for these species.