Multi-Stimuli Responsive Cyanostilbene Assemblies in Aqueous Media: Temporal Luminescence Modulation Through...

Cationic cyanostilbene (CS) derivatives with N-alkyl pyridinium and pyridine moieties at the periphery show self-assembly in water depending on the attached alkyl segment. The free pyridine moiety allows the modulation of the luminescence of these self-assembled aggregates in the presence of metal salts or through pH changes. The metal ion effect is especially prominent for coordinating Ag(I) ions and led to noticeable red-shifts in the emission spectra along with significant enhancements in the quantum efficiency and lifetimes. The inherent photoreactivity of the central double bond in these CS derivatives provide a convenient way to modulate their luminescence through controlled photoreaction and multiple emission colors including while light are obtained. The pH-responsive features of these assemblies are further exploited to generate transitory luminescence signals by employing a pH-feedback system and it is further utilized in time-encoded information encryption processes.