Reaction-based sensing of fluoride ions using built-in triggers for intramolecular charge transfer and photoinduced electron transfer

Two Bodipy derivatives with silyl-protected phenolic functionalities signal fluoride concentrations both In solution and in a poly(methyl methacrylate) matrix. The exact location of the "nascent" phenolate group is Important. If it Is at the meso position, photoinduced electron transfer is triggered; however, if It is In full conjugation via a styryl moiety to the Bodipy core, strong intramolecular charge transfer Is triggered, resulting In a large red shift in the absorbance peak. In either case, a selective methodology for fluoride sensing is the Invariable result.