NMR quantification of H-bond donating ability for bioactive functional groups and isosteres

Phosphine oxides as NMR and IR spectroscopic probes for the estimation of the geometry and energy of PO⋯H–A hydrogen bonds

“…As mentioned in the Introduction section, recently several attempts to employ dP for the hydrogen bond characterization have been published. 52,69,[73][74][75] Practically in every case the authors saw significant potential in dP, but in order to estimate the robustness of this parameter and establish the limits of its applicability further studies seem to be necessary. In the case of complexes studied here, as can be seen in Fig.…”

“…15 shows the correlations between DdP and the pK a values of phenols, alcohols, carboxylic acids and benzoic acids considered in this work (filled symbols) and collected from ref. [73][74][75] for OH acids with one OH group (open symbols). Though there is significant scattering of data points, a linear correlation is held for each class of proton donors.…”

“…71,72 However, over the last few years several experimental papers have been devoted to Brønsted acidity exclusively. [73][74][75][76] These papers share the same essential approach; the proton-donating abilities of Brønsted acids, measured as the corresponding pK a values (in water), were correlated with the change of dP of a trialkylphosphine oxide upon complexation. In all cases, despite the significant scattering of data points that occurs sometimes, linear correlations were observed (see, for example, Fig.…”

Molecular Interactions Between Egg White Peptides and Giant Unilamellar Vesicle Membranes: Effect of Peptide Localization on Membrane Fluidity

“…The number of hydrogen bonds formed at the N-terminal amino terminus of LVEEY and ESIINF accounted for 43.175 and 44.775% of the total number of hydrogen bonds, respectively (Table ). Additionally, amino acids E (33.362%) and Y (19.317%) in LVEEY and amino acids S (14.195%) and N (18.816%) in ESIINF form more hydrogen bonds, which is related to the fact that the side chains of E, Y, S, and N contain amino, carboxyl, or hydroxyl groups, as well as the hydrophilicity of these four species. , However, the number of hydrogen bonds produced by ADWAK’s N-terminal amino acids accounted for 91.143% of the total hydrogen bonds. The number of hydrogen bonds created by D (aspartic acid, D/Asp), W (tryptophan, W/Trp), A (alanine, A/Ala), and K (lysine, K/Lys) accounted for less than 10% of the total, which could be why ADWAK was more loosely connected to the lipid membrane.…”

NMR Quantification of Hydrogen-Bond-Accepting Ability for Organic Molecules

“…This study demonstrated that 19 F NMR shifts (Δδ) correlate with logarithms of the formation constants ( K f ) of the LB + 4-FP complexes and that potential energy change in the formation of these complexes is proportional to their standard free energy change. Limbach and co-workers utilized radiolabeled pyridines and imidazoles with 15 N NMR spectroscopy to characterize H-bond strength, geometry, and structure. , First reported by Gutmann in 1975 (and then others) to quantify Lewis acidity, − we have also used 31 P NMR spectroscopy to quantify H-bond-donating ability (Figure B) − and halogen-bond-donating ability …”