Fluorinated Boronic Acid-Appended Pyridinium Salts and ¹⁹F NMR Spectroscopy : a valuable and highly discriminative Sensing Tool for Diols, Inorganic Anions and Hydrogen Peroxide under physiological Conditions

A pool of novel fluorinated boronic acid-appended (bi)pyridinium receptors have been synthesized and characterized. In combination with 19F NMR spectroscopy the receptors exhibit strong ability for diol sensing tasks under physiological conditions. The attached boronic acid function(s) of the one-component sensing concept provide a suitable binding site for the screening of mainly diols, inorganic anions and hydrogen peroxide whereas the attached fluorine atom(s) assisted by 19F NMR are highly sensitive probes. Connected in one molecule, the boronic acid function and fluorine offer complementary and additional advantages such highly sensitive 19F NMR fingerprints, pH robust signal response and direct signaling of the boronic acid-diol binding event with overall no disturbing fluorine background signal. The sensing mechanism relies on boron rehybridization and the specific character of the binding analyte assisted by non-invasive 19F NMR spectroscopy. Structural modifications of the receptor compounds, such as varying the amount and position of the attached fluorine probes were used for the elucidation of crucial sensing features of the receptors via 19F NMR spectroscopy. An array of receptors was used for the generation of QR-like barcodes which enable enhanced discrimination power without the need of multivariate analysis. Other highlights are the identification of fructose/glucose in mixtures, the quantification of glucose in urine as a potential diabetes pretest and the determination of the reactive oxygen species H2O2 via a chemodosimetric approach. The simple concept can be arbitrary widened with a high potential for screening diol derivatives in complex matrices such as highly demanded in medicinal diagnosis.