The 8-Silyloxyquinoline Scaffold as a Versatile Platform for the Sensitive Detection of Aqueous Fluoride

Utilizing a novel 8-silyloxyquinoline scaffold, we demonstrate the ability to synthesize fluorogenic probes for the sensitive and selective detection of inorganic fluoride (NaF) in aqueous samples. Our initial probe design (2) is capable of detecting inorganic fluoride at levels as low as 3.8 μM (72 ppb) in aqueous solutions, well below PHS recommended levels for drinking water (0.7-1.2 ppm), placing this probe among the most sensitive fluoride sensors reported to date. Furthermore, our results highlight the utility of the readily modifiable 8-silyloxyquinoline scaffold for the design of tailored fluoride sensing platforms. We demonstrate the ability to rationally tune the fluorescence and physical properties of the 8-silyloxyquinoline scaffold, producing a red-shifted fluoride probe (4) capable of detecting 50 μM (0.95 ppm) NaF in aqueous samples using a straightforward test-strip-based assay format. Taken together this work provides a template for the design of fluoride sensors capable of reporting on relevant concentrations of fluoride in the laboratory and in the field.