Ab Initio Density Functional vs Hartree Fock Predictions for the Structure of [18]-Annulene: Computational Evidence for Bond Localization and Diminished Ring Currents in Bicycloannelated [18]Annulenes.

Kim K. Baldridge and Jay S. Siegel

Although computational chemistry has become an everyday part of chemistry, there remain seemingly simple hydrocarbon structures, such as the higher annulenes, that cannot be correctly predicted without the implementation of higher order basis sets and dynamical electron correlation. This study establishes the threshold levles for the correct prediction of a delocalized [18]-annulene, a classic in aromatic chemistry. Computation of 2,8,14-trisbicyclo[2.1.1]hexeno[18]-annulene at the same level of theory predicts a clear bond localized structure and sets a new synthetic challenge for novel aromatic chemistry.

Angewandt Chemie Manuscript