Solid-support photoacids

Merocyanine photoacids are versatile molecules that allow the control of different processes with visible light, including CO 2 capture, driving molecular machines, and catalyzing reactions. However, high concentrations of the photoacid are needed for large pH changes, which makes observing other changes spectroscopically challenging, as well as requiring the laborious separation of the photoacid afterwards. Herein, we report a solidphase merocyanine-based photoacid that can generate a reversible pH change in bulk solution. The heterogeneous nature of these materials renders them “invisible” in common solution-phase spectroscopic techniques (e.g. UV-vis and NMR spectroscopy), allowing easy monitoring of pH-dependent changes of other components in the system. We demonstrated that these materials are robust through multiple switching cycles and can be used to modulate chemical and enzymatic reactions, showcasing their broad potential for different applications.