Phenothiazine and pyridine-N-oxide-based AIE-active triazoles: synthesis, morphology and photophysical properties

Aggregation-induced emission (AIE) low molecular weight compounds based on triazoles, phenothiazine and pyridine-N-oxide units bonded by short flexible chains have been obtained by a click chemistry reaction. The photophysical properties were explored by UV-vis and photoluminescence spectroscopy in solution, water suspension, and amorphous and crystalline films. The UV-vis absorption spectra indicated a typical behavior for nanoparticle formation. An emission intensity enhancement of 233-fold higher was registered for the crystalline films compared to solutions, clearly indicating an aggregation-induced emission behavior. The morphology study, in suspension and film, monitored by dynamic light scattering, scanning electron microscopy and polarized light microscopy methods, indicated that nano- and micro-crystals of rose-like shapes and fibers were formed.