Influence of fluorine substituents on the NMR properties of phenylboronic acids

Abstract

The paper presents results of a systematic NMR studies on fluorinated phenylboronic acids. All possible derivatives were studied. The experimental (1)H, (13)C, (19)F, (11)B, and (17)O spectral data were compared with the results of theoretical calculations. The relation between the calculated natural bond orbital parameters and spectral data (chemical shifts and coupling constants) is discussed. The first examples of (10)B/(11)B isotopic effect on the (19)F spectra and (4)JFO scalar coupling in organic compounds are reported.

Fluorinated Boronic Acids: Acidity and Hydrolytic Stability of Fluorinated Phenylboronic Acids

“…Generally, introduction of fluorine atoms increases the acidic character of the boronic center. The results of systematic NMR studies of fluorinated phenylboronic acids have revealed a close correlation between their structure and spectroscopic properties . The influence of the fluorine substituent on the Lewis acidity of the boronic esters was also investigated .…”

“…The results of systematic NMR studies of fluorinated phenylboronic acids have revealed a close correlation between their structure and spectroscopic properties. [9] The influence of the fluorine substituent on the Lewis acidity of the boronic esters was also investigated. [10] Recently, the influence of the position of the fluorine atom on the structures, spectral characteristics, and biological activity has been investi-bility studies have been carried out by spectrophotometry.…”

Merging Electron Deficient Boronic Centers with Electron-Withdrawing Fluorine Substituents Results in Unique Properties of Fluorinated Phenylboronic Compounds

“…The crystal structure of 7-fluorobenzoxaborole has not been studied so far. However, based on the analysis of 19 F NMR data showing similar chemical shifts in pairs of analogs [ 38 , 40 ], it can be concluded that an intramolecular hydrogen bond is formed in this compound; the chemical shift values are similar to the analogs of boronic acids ( Scheme 1 ).…”

“…In 2014, a paper covering the full NMR spectroscopic characterization ( 1 H, 19 F, 13 C, 11 B and 17 O) of all the fluoro-substituted phenylboronic acids was published [ 40 ]. The work includes chemical shifts, as well as coupling constants, and the experimental data are compared with the results of the calculations.…”

17o NMR

“…The Gaussian, 66 NWChem, 68 Dalton, 73 CFOUR, 74 ADF 75 and CASTEP 78 codes allow the calculation of these indirect spin-spin couplings, with different degrees of approximation. 137 One theoretical paper specifically devoted to such calculations is due to Bryce, 138 who computed the J-coupling between 31 P, 27 Al and 17 O in small molecules and cluster. These were constructed as models of aluminophosphate and grossite minerals, and included also triphenylphosphine oxide.…”