[4];Radialene Dication is an Unusual Hydrocarbon Monocycle: PM3 Evidence for a 4N+2 Antiaromatic Structure

Abstract

A PM3 computational study (RHF method) of radialene dications has uncovered the first non-trivial example of an antiaromatic hydrocarbon monocycle bearing 4N+2 p-electrons. This system has disjoint frontier molecular orbitals and constitutes the first example of a structure with degenerate lowest-lying singlet and triplet states, even though it is not a HÜckel triplet.