Folding of fluorinated oligoarylenes into non-alternant PAHs with various topological shapes

Abstract

An unprecedented [6]helicene's cavity closure indicating the possibility of introducing seven-membered rings via alumina-mediated C–F activation is shown. This finding, in combination with a directed quadruple annulation of fluorinated oligoarylenes, opens a short pathway to elusive non-alternant PAHs. Starting with one fluorinated block, we have synthesized through a two-step procedure three new representatives with helical-, bowl- and saddle-shapes. Additionally, the structure–property relationship in these new PAHs is explored via theoretical, optical, and X-ray crystallographic studies.