Flapping Peryleneimide as a Fluorescent Viscosity Probe: Comparison with BODIPY and DCVJ Molecular Rotors

Flexible and aromatic photofunctional system (FLAP) has been recognized as an emerging class of versatile pi-conjugated molecules. Here we report a viscosity-probing function of flapping peryleneimide and compare its photophysical properties with representative molecular rotors, DCVJ and BODIPY, as well as flapping anthraceneimide. In this comparison, polarity dependence is not negligible in the fluorescence (FL) of the flapping peryleneimide, but it shows more sensitive FL response in a low viscosity range (0.3-3.1 cP), which enables discrimination of different n-alkanes by the FL lifetime measurement. Extremely high photostability of the flapping peryleneimide has also been confirmed, which is promising for the characteristic FL imaging.