1H/31P NMR pH indicator series to eliminate the glass electrode in NMR spectroscopic pKa determinations

Szakács, Zoltán; Hägele, Gerhard; Tyka, R.

doi:10.1016/j.aca.2004.07.005

Cited by 75 publications

(92 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chemical shifts are referenced to TMS ( 0.00) for 1 H spectra and 1,4 dioxane ( 66.5) for 13 C spectra.…”

Section: Multicomponent Nmr Titrationmentioning

confidence: 99%

“…As another example, the pH dependences of 13 were measured by low temperature NMR ( 28 ). The A value of an imidazolyl group was thereby found to be 2.2 ± 0.1 kcal/mol.…”

Section: Electrodeless Ph Titrationsmentioning

confidence: 99%

“…Isotope effects were determined by 13 C NMR titration for a wide variety of carboxylic acids, including the 18 O effect on formic acid, acetic acid, and glycine acidities, the 15 N isotope effect on glycine acidity, and the 13 C isotope effect on acetic acid and glycine acidities ( 61 ).…”

Section: Heavy Atom Isotope Effects On Aciditymentioning

confidence: 99%

“…The ( The method was also applied to secondary deuterium isotope effects on the acidities of a wide variety of carboxylic acids, including formic, acetic, propionic, butyric, caproic, and also glycine and alanine ( 73 ). The pK a ratios could be evaluated from the variation with the degree of protonation of the measured 13 …”

Section: Secondary Deuterium Isotope Effects On Aciditymentioning

confidence: 99%

“…Trifluoroethanol d 2 is less acidic than trifluoroethanol, according to 13 C NMR pH titration, with a pK a of 0.056 ( 74 ).…”

Section: Secondary Deuterium Isotope Effects On Aciditymentioning

confidence: 99%

See 4 more Smart Citations

pH-Free Measurement of Relative Acidities, Including Isotope Effects

Perrin

2017

Measurement and Analysis of Kinetic Isotope Effects

View full text Add to dashboard Cite

A powerful pH free multicomponent NMR titration method can measure relative acidities, even of closely related compounds, with excellent accuracy. The history of the method is presented, along with details of its implementation and a comparison with earlier NMR titrations using a pH electrode. Many of its areas of applicability are described, especially equilibrium isotope effects. The advantages of the method, some practical considerations, and possible pitfalls are considered.

show abstract

“…Chemical shifts are referenced to TMS ( 0.00) for 1 H spectra and 1,4 dioxane ( 66.5) for 13 C spectra.…”

Section: Multicomponent Nmr Titrationmentioning

confidence: 99%

“…As another example, the pH dependences of 13 were measured by low temperature NMR ( 28 ). The A value of an imidazolyl group was thereby found to be 2.2 ± 0.1 kcal/mol.…”

Section: Electrodeless Ph Titrationsmentioning

confidence: 99%

Section: Heavy Atom Isotope Effects On Aciditymentioning

confidence: 99%

Section: Secondary Deuterium Isotope Effects On Aciditymentioning

confidence: 99%

“…Trifluoroethanol d 2 is less acidic than trifluoroethanol, according to 13 C NMR pH titration, with a pK a of 0.056 ( 74 ).…”

Section: Secondary Deuterium Isotope Effects On Aciditymentioning

confidence: 99%

See 3 more Smart Citations

pH-Free Measurement of Relative Acidities, Including Isotope Effects

Perrin

2017

Measurement and Analysis of Kinetic Isotope Effects

View full text Add to dashboard Cite

show abstract

Physicochemical Profiling of α‐Lipoic Acid and Related Compounds

Mirzahosseini

Szilvay

Noszál

2016

Chemistry & Biodiversity

View full text Add to dashboard Cite

Lipoic acid, the biomolecule of vital importance following glycolysis, shows diversity in its thiol/disulfide equilibria and also in its eight different protonation forms of the reduced molecule. In this paper, lipoic acid, lipoamide, and their dihydro derivatives were studied to quantify their solubility, acid-base, and lipophilicity properties at a submolecular level. The acid-base properties are characterized in terms of six macroscopic, 12 microscopic protonation constants, and three interactivity parameters. The species-specific basicities, the pH-dependent distribution of the microspecies, and lipophilicity parameters are interpreted by various intramolecular effects, and contribute to understanding the antioxidant, chelate-forming, and enzyme cofactor behavior of the molecules observed.

show abstract

Characterization of the Site‐Specific Acid‐Base Equilibria of 3‐Nitrotyrosine

Pálla

Fogarasi

Noszál

et al. 2019

Chemistry & Biodiversity

View full text Add to dashboard Cite

The complete macro‐ and microequilibrium analyses of 3‐nitrotyrosine, a biomarker of oxidative stress damage, are presented for the first time. The protonation macroconstants were determined by 1H‐NMR‐pH titration, while microconstants were elucidated by a combination of deductive and NMR methods, in which properties of the methyl ester derivative as an auxiliary compound were also studied. Combination of the NMR‐pH characterization of the title and auxiliary compounds and the pair‐interactivity parameters of 3‐iodotyrosine provided the sufficient system to evaluate all the microconstants. NMR‐pH profiles, macroscopic and microscopic protonation schemes, and species‐specific distribution diagrams are included. The phenolate basicity of 3‐nitrotyrosine is 500 times below that of tyrosine, and it is even lower than that of 3‐iodotyrosine. This phenomenon can be explained by the stronger electron withdrawing and the negative mesomeric effect of the nitro group. Based on our results, 89 % of the phenolic OH groups are deprotonated in 3‐NT molecules at the pH of the blood plasma.

show abstract

1H/31P NMR pH indicator series to eliminate the glass electrode in NMR spectroscopic pKa determinations

Cited by 75 publications

References 51 publications

pH-Free Measurement of Relative Acidities, Including Isotope Effects

pH-Free Measurement of Relative Acidities, Including Isotope Effects

Physicochemical Profiling of α‐Lipoic Acid and Related Compounds

Characterization of the Site‐Specific Acid‐Base Equilibria of 3‐Nitrotyrosine

Contact Info

Product

Resources

About