Aggregation‐Free, Perylene‐Containing π‐Extended Kekulene with Improved Photoluminescence Quantum Yield

An aggregation-free, perylene-containing π-extended kekulene derivative 1 was synthesized and characterized, retaining frontier molecular orbitals similar to those of perylene and displaying high oscillator strengths, which together yield a fluorescence quantum efficiency of up to 60% in solution.

Abstract

Kekulene and expanded kekulenes are rigid, nearly planar cycloarenes with potential optoelectronic applications. However, their highly symmetric structures and localized aromaticity typically result in low photoluminescence quantum yield (PLQY). Here, we incorporate a perylene unit into the kekulene framework and synthesize a π-extended kekulene derivative (1) via macrocy-clization using Suzuki coupling, followed by bismuth(III) triflate-catalyzed cyclization of vinyl ethers. X-ray crystallography reveals a slightly distorted extended kekulene backbone, while peripheral aryl substituents effectively suppress intermolecular π–π stacking. Notably, 1 retains the frontier molecular orbital characteristics of perylene and exhibits high oscillator strengths for frontier electronic transitions, achieving a PLQY of up to 60% in solution.

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