Cationic [6]Helicenes: Tuning (Chir)Optical Properties up to the Near Infra-Red

The intramolecular condensation of ortho substituents triaryl carbenium ions can lead to the formation cationic helicenes. These chiral and configurationally stable molecules exhibit extended optical properties reminiscent their parent methylium ions. Among them, [6]helicenes are particularly interesting as orthogonal late-stage functionalization strategies allow introduction a variety auxochromes with different regiochemistry. Intense chiroptical thus be tailored in far red up near infra-red (NIR) spectral windows. A wealth applications foreseen, particular material sciences.