Rational assembly of benzenoid rings in benzo[ghi]perylene yields a diversity of edge features with site-selective reactivity

Abstract

Judicious arrangement of the rings that comprise a polycyclic aromatic hydrocarbon seeks to maximize the diversity of edge features and reactivity while minimizing molecular size and complexity. However, that balance is not often possessed by mid-sized polycyclics. Through a combination of experimental and theoretical methods, we have determined that the historically overlooked hydrocarbon benzo[ghi]perylene boasts peripheral sites and edge features which are differentiable by venerable and routine chemical approaches such as electrophilic aromatic substitutions, metal-catalysed C–H activation, and oxidations. Such superior selectivity reinforces the simple predictive power of Clar's rule of π-electron sextets. The structural similarity of benzo[ghi]perylene to perylene and coronene implies that it might eventually supplant these two hydrocarbons for construction of advanced organic materials, once some identified challenges have been overcome.