Benz‐Bisimidazole‐Bridged Perylenes – Linearly Expanded Chromophores

The synthesis and characterization of a new type of very large perylene‐based molecules 9 are reported. The extension of the conjugated π system was accomplished by the facile condensation of two bay‐functionalized perylene moieties with 1,2,4,5‐tetraaminobenzene. The resulting chromophore in 9 consists of 35 conjugated π‐electron pairs and, therefore, is comparable to pentarylenes and hexarylenes containing 31 and 36 conjugated π‐electron pairs, respectively. The unsubstituted imine N atoms of the benz‐bisimidazole bridges in 9 can be readily and reversibly protonated to give the dications 9a H 2 2+ . The twofold protonation of 9 is accompanied by a bathochromic shift of the main absorption band and pronounced fluorescence quenching. The experimental results were corroborated by quantum mechanical calculations.