1H and 19F NMR chemical shifts for hydrogen bond strength determination: Correlations between experimental and computed values

Abstract

1H and 19F NMR methods based on chemical shift measurements of different hydrogen bond donors used for quantifying hydrogen bond strength were analyzed and compared. The extracted values from these different methods are shown to be highly correlated with each other and with several experimental and ab initio computed quantities characterizing hydrogen bond formation. The titration method based on 19F NMR spectroscopy was performed for detecting and quantifying the formation of very weak hydrogen bond complexes such as those involving fluorine atoms as hydrogen bond acceptors. This approach represents a powerful and reliable method for studying and characterizing these complexes that, although weak, are very relevant.

Keywords

• 19F NMR spectroscopy
• 1H NMR water chemical shift
• Hydrogen bond strength
• Solvents