Multi‐Stimuli Responsive Cyanostilbene Assemblies in Aqueous Media: Temporal Luminescence Modulation Through pH‐Feedback Network

Abstract 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.