A novel redox switch for fluorescence: drastic UV–vis and fluorescence spectral changes upon electrolysis of a hexaphenylethane derivative of 10,10′-dimethylbiacridan

The newly prepared title donor 1 has a very long CC bond [1.635(2) Å], which was readily cleaved upon oxidation to give dication 22+ containing two 10-methylacridinium chromophores. Colorless donor 1 (Eox +0.18 V) is non-fluorescent whereas orange dication 22+ (Ered −0.27 V) emits strong green fluorescence, so that, this pair can be considered as a novel redox switch for fluorescence with high electrochemical bistability.