Dynamic PEGylated phenothiazine imines; synthesis, photophysical behavior and reversible luminescence switching in response to external stimuli.

[Display omitted] • PEGylated phenothiazine imines were synthetized via microwave assisted synthesis. • The novel imines proved high quantum efficiency in solution and solid state. • They showed reversible switch of their fluorescence under external stimuli. • PEG was beneficial for improving the solubility and quantum efficiency. Herein we report the synthesis, characterization, photophysical behavior and dynamic character of new PEGylated imine derivatives. Two PEGylated phenothiazine aldehydes were synthetised and reacted with two amines bearing sulfonamide moiety via microwave assisted synthesis to yield four imine derivatives. The imines and the aldehydes precursors were structurally characterized by NMR and FTIR spectroscopy and their self-assembly behaviour was investigated by polarized light microscopy (POM) and dynamic light scattering (DLS). Photophysical properties were investigated by UV–vis and photoluminescence spectroscopy and the quantum efficiency was determined using an integrating sphere. Dynamic character of the imine derivatives was explored by NMR and UV–vis spectroscopy in correlation with visual assessment of luminescence change. The new synthetized PEGylated imines showed solubility and stability in common organic solvents, high quantum efficiency in solution and solid state, self-assembling behaviour in ethanol, and dynamic character giving access to the reversible switch of their emission colour from green to yellow through shifting the imination equilibrium under the influence of external stimuli. [ABSTRACT FROM AUTHOR]