Highly solvatochromic fluorescence of anthraquinone dyes based on triphenylamines

• Anthraquinone dyes based on phenylamine/triphenylamines was synthesized.
• The prepared dyes exhibited remarkable solvatochromic fluorescence.
• The dyes showed large Stokes shifts (210–306 nm) in different organic solvents.
• The nanometer cavity structure of prepared dye 3 was observed.

Five donor-acceptor anthraquinone dyes based on phenylamine/triphenylamines with different substituted groups were synthesized by Suzuki reaction in good yields, and the photophysical properties were studied in organic solvents with different polarity. The title dyes exhibited remarkable solvatochromic fluorescence (>190 nm emission shift in polar media), which was derived from intramolecular charge transfer (ICT) character that revealed by DFT/TD-DFT calculation. And large Stokes shifts (210–306 nm) were observed in different organic solvents, along with rich color changes from blue to green, yellow, orange and even purple-red. The Stokes shifts were linearly dependent on the solvent polarity function ET(30). Interestingly, it was found from the single-crystal X-ray diffraction analysis that dye 3 displayed two different interleaved channel structures, which was seldom seen in organic compounds and could be used as host for complexation potentially. Electrochemical characterization suggested that the different substituted phenylamine groups attached to anthraquinone unit could lead to tunable potentials and energy levels.