Chemistry Letters, Vol.49, No.5, 457-460, 2020
The Substituent Effect of Bridged Triarylamine Helicenes on Light-emitting and Charge Transfer Properties
Methoxy-(7a), bromo-(7b), CF3-(7c) and hydroxyl-(7d) substituted bridged triarylamine helicenes were synthesized under mild conditions in 65-98% yield. Their luminescence red-shifted with n-donating substituents and blue-shifted with the electron-withdrawing CF3-substituent. The absorption and emission of the hydroxyl-substituted derivative (7d) was found to be pH-dependent, particularly under alkaline conditions. Moreover, all derivatives of 7 showed additional reversible negative redox potential, and may be useful as charge transfer materials.