Functional helquats: helical cationic dyes with marked, switchable chiroptical properties in the visible region

Chem Commun (Camb). 2015 Jan 31;51(9):1583-6. doi: 10.1039/c4cc08967g.

Abstract

Helquat dyes are the first helicene-like cationic styryl dyes obtained as separate enantiomers. Their remarkable chiroptical properties are due to the unique combination of a cationic hemicyanine chromophore and a helicene-like motif. The magnitude of the ECD response and the pH switching along with their positioning in the visible region are unprecedented among helicenoids.