A Small Dye Puzzle: π-Conjugation of Perylenes with External Aromatic Compounds via Imidazo-Quinoxaline Bridges

The synthesis and characterization of a library of unprecedented pi-extended perylenes is reported. For this purpose, a successful step-by-step connection of three puzzle pieces, namely a perylene, an imidazole-quinoxaline bridge and an o-quinone was developed. Our synthetic route allows for facile access to linearly pi-extended perylenes in a highly chemoselective manner. The absorption and fluorescence properties are solvent dependent and are bathochromically shifted relative to unbridged perylene references. Overall, the fluorescence quantum yields are high with values ranging from 46 % to 11 %. To complete the physico-chemical characterization, differential pulse and cyclic voltammograms were recorded showing two reductions and two oxidations for each of the linearly pi-extended perylenes.

Automated summary

A library of unprecedented pi-extended perylenes was successfully synthesized and characterized, showing high fluorescence quantum yields. The absorption and fluorescence properties are solvent dependent with a bathochromic shift relative to unbridged perylene references. Physico-chemical characterization through differential pulse and cyclic voltammetry revealed two reductions and two oxidations for each linearly pi-extended perylene.