Oligo(phenothiazine)s: Twisted intramolecular charge transfer and aggregation-induced emission

Two 9,10-divinylanthracene oligomers containing phenothiazines (AnPHZ2 and AnPHZ4) are synthesized, and their intramolecular charge transfer as well as aggregation-induced emission (AIE) properties are investigated. Both oligomers show typical AIE properties as well as solvent polarity dependent emission. Time-resolved fluorescence spectra revealed that the twisted intramolecular charge transfer state formed in polar solvents accounts for the weak emission with large Stokes shifts, and the interactions between solvent and solutes facilitate the nonradiative decay. The restriction of intramolecular torsion induced by supramolecular interactions in aggregates eliminates the charge transfer state, thus resulting in efficient AIE.