Fluoride-ion-mediated 1H/2D exchange in anion receptors: A 19 F NMR probe

This review work highlights the exchange process between two isotopes of hydrogen i.e., proton and deuterium within the molecule of anion receptors. Emphasis is mainly given to the proton to deuterium (1H -> 2D) exchange process which is facilitated by fluoride ion. In order to monitor the exchange studies, both 1 H NMR and 19 F NMR spectroscopy can be useful. However, 19 F NMR spectroscopy furnishes more detailed information as compared to 1 H NMR spectroscopy. Thus, the 19 F NMR spectroscopic method is important in order to investigate the solution state structural behavior of fluoride ion complexes. The work includes the exchange studies of exchangeable protons in the binding sites of various amide-, thioamide-, and pyrrole-based monocyclic, bicyclic, and polycyclic anion receptors. The study not only fo-cuses on the fluoride ion binding with the synthetic receptors in solution, but also gives direct evidence about the random but sequential substitution of protons with deuterium atoms present in the solvent molecules.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

This study focuses on the exchange process between proton and deuterium isotopes within the molecule of anion receptors, with particular emphasis on the proton to deuterium (1H -> 2D) exchange facilitated by fluoride ion. Both 1H NMR and 19F NMR spectroscopy are useful for monitoring the exchange studies, but 19F NMR spectroscopy provides more detailed information than 1H NMR spectroscopy. Therefore, the 19F NMR spectroscopic method is important for investigating the solution state structural behavior of fluoride ion complexes. This study also investigates the exchangeable protons in various types of anion receptors, providing direct evidence of sequential substitution of protons with deuterium atoms in solvent molecules. (c) 2023 Elsevier B.V. All rights reserved.