CHAPTER 2: ¹¹B NMR and Its Uses in Structural Characterization of Boronic Acids and Boronate Esters

¹¹B NMR spectroscopy is frequently used to characterize boron-containing compounds, including boronic acids and boronate esters. A wealth of chemical shift data has been amassed, and selected examples are tabulated here. This chemical shift data can be generalized from representative compounds to other similar structures. ¹¹B NMR data is largely qualitative, but can occasionally be used quantitatively as well. It is often used in conjunction with other techniques such as X-ray crystallography, pH titrations, other spectroscopic methods, and modeling. ¹¹B NMR has been used to identify a change in the hybridization and/or protonation state of boron during a reaction, determine the mode of binding including stoichiometry, and calculate binding affinities. This chapter details examples of this characterization work.