Singly Occupied Molecular Orbital-Highest Occupied Molecular Orbital (SOMO-HOMO) Conversion

Singly occupied molecular orbital-highest occupied molecular orbital (SOMO-HOMO) conversion (inversion), SHC, is a phenomenon in which the SOMO is lower in energy than the doubly occupied molecular orbitals (DOMO, HOMO). A non-Aufbau electronic structure leads to unique properties such as a switch in bond dissociation energy and the generation of high-spin species on one-electron oxidation. In addition, the pronounced photostability of these species has been reported recently for application in organic light-emitting devices. In this review article, we summarise the chemistry of SOMO-HOMO converted (inverted) species reported to date.