Dependence of spin coupling in non-kekulé molecules on the π-electron network

Abstract

Several specifically chosen non-Kekulé π-electron biradicals are studied using semiempirical AM1/CI calculations to analyze the dependence of the singlet-triplet gap on the topology and π-electron network. A simple algorithm is developed to predict the singlet-triplet gap using spin densities at atomic sites and the π-electron pathways. The significance of this model in experimental studies of the ground-state spin of non-Kekulé systems and the design of organic ferromagnets is outlined. © 1992 American Chemical Society.