Molecular-orbital treatment of a new type of heteroaromatic compound

Abstract

The π-electron systems in four electron-rich heterocyclic nitrogen compounds of a new type were studied by the simple molecular-orbital method. Resonance energies, π-electron densities and energies of excited states were studied as a function of the nitrogen electronegativity parameter. Although only one of the compounds has yet been synthesized, the present results suggest that all would be stable once formed. Definite predictions of the positions of highest chemical reactivity towards electrophils can be made in the case of the two tricyclic compounds (I) and (II).