Anticipating π-Bond Dispositions in Cyclic, Even, Classical Hydrocarbons

Abstract

A new technique, which employs π-bond placement coefficients, is presented. That technique, in conjunction with a few parameters that are readily available from traditional Hückel theory, permits one to systematically anticipate π-bond placements for optimized lowest-lying singlet states. One may then foresee the relative magnitudes of calculated ΔHf values for selected sets of structural isomers. Structural predictions are compared with parameterization method 3 (PM3) calculations, density functional theory calculations and experimental results. Reasonable expectations for the most stable structure narrow the choice of molecules that may then be scrutinized by more exact computations or by experiment.