Photovermellogens: Minimalistic Pyridinium-Based Acylhydrazones with Photoswitchable Basicity for Operation in Aqueous Media

Abstract

Examples of a new class of synthetically straightforward and hydrolytically inert photoswitchable acylhydrazones, named photovermellogens, have been successfully developed and comprehensively studied using state-of-the-art spectroscopic and computational techniques. These compounds present photoswitchable basicity, with irradiation promoting E→Z photoisomerizations, which result in the generation of a less acidic species. The observed ΔpKa values > 1.5 within the biologically relevant window underscore the potential of photovermellogens as versatile platforms for light-triggered pH control.