pH dependence of phosphorus-31 chemical shifts and coupling constants of some oxyacids of phosphorus

Moedritzer, Kurt

doi:10.1021/ic50051a017

Cited by 48 publications

(26 citation statements)

References 2 publications

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“…Approximate quantum chemical calculations [32, 33] have shown that the change in the chemical shift, Δ δ , for the anions may be treated by the relationship [34–36]:where Δ χ 0 is the change in the effective electronegativity of the phosphorus atom, Δ n π is the concomitant change in the phosphorus d π -orbital occupation due to variation in the π character of the P–X bonds thus induced, Δ θ is the change in the bond angle, and A is an arbitrary parameter to accommodate variations between oxoacids. Thus the change in electronegativity, Δ χ 0 , which originates from the decrease in negative charge with protonation, certainly predominates for the upfield shifts observed for the phosphorus nuclei in H m P 3 O (10− n )(NH) n ( 5− m )− ( m = 0–3, n = 0, 2) anions.…”

Section: Resultsmentioning

confidence: 99%

Intrinsic 31P NMR Chemical Shifts and the Basicities of Phosphate Groups in a Short-Chain Imino Polyphosphate

2013

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The stepwise protonation constants of two linear triphosphate ligand anions, triphosphate, and di-imidotriphosphate, , were investigated by potentiometric titration, and the intrinsic chemical shifts of the stepwise protonated species of these anions were determined from the pH-dependence of the 31P NMR chemical shifts. All stepwise protonation constants of were found to be larger than those of , and the 31P NMR signals due to P3O8(NH)2 always appeared at a lower magnetic field compared to the signals due to P3O10. These results indicate higher basicity of the P3O8(NH)2 ligand, because it contains two imino groups in the ligand molecule. The 31P NMR signals for the end phosphate groups appear at a lower magnetic field than those for the middle phosphate groups, indicating that the basicity of the end phosphate group is higher than that of the middle phosphate group. It can be expected that the high basicity of the P3O8(NH)2 ligand brings about the formation of high stability complexes with various metal ions. Furthermore, the only 31P NMR signal due to the middle phosphate group of P3O8(NH)2 ligand molecule clearly showed a low-field shift in the range of pH < 2.5. The reason for this peculiar low-field shift should be the change of the localization of imino protons around the nitrogen atom in P3O8(NH)2.Graphical Abstract

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Section: Resultsmentioning

confidence: 99%

Intrinsic 31P NMR Chemical Shifts and the Basicities of Phosphate Groups in a Short-Chain Imino Polyphosphate

2013

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“…However, the theoretical understanding of 31 P chemical shifts of P(V) oxyacids is incomplete. Several possible electronic effects, potentially of opposite signs, hydrogen bonds, O-P-O bond angles can affect δ P in a complex way [85,86,87]. For instance, the protonation of phosphates leads to an upfield shift of the 31 P resonance signal, whereas downfield shifts of thiophosphates were observed [88].…”

Section: P Nmr Titrationsmentioning

confidence: 99%

Determination of microscopic acid?base parameters from NMR?pH titrations

Szakács

Kraszni

Noszál

2004

Analytical and Bioanalytical Chemistry

108

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The theory and practice of proton microspeciation based on NMR-pH titrations are surveyed. Principles of bi-, tri-, tetra-, and n-protic microequilibrium systems are discussed. Evaluation methods are exemplified by case studies on bi- and tetraprotic biomolecules. Selection criteria and properties of 'reporter' NMR nuclei are described. Literature data on complete microspeciations of small ligands and site-specific basicity characterizations of peptides and proteins are critically reviewed.

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“…29 At pH 10, phosphate exists in the solution as HPO 4 2predominantly. There is no agreement in the literature regarding chemical shifts of different protonated species of phosphate, and the following data are reported for phosphate at pH 10 or HPO 4 2-: ~2 ppm, 37 ~-6 ppm, 38 ~6 ppm, 39 ~3 ppm. 40 The closeness of product signals obtained in our experiment to each other (3.03-3.07 ppm; Figure S4 in the Supporting Information) confirms that all the hydrazones produce the same soluble product, the phosphate ion.…”

Section: Resultsmentioning

confidence: 81%

Dephosphorylation of pyridoxal 5′‐phosphate‐derived Schiff bases in the presence of bovine alkaline phosphatase

Гамов

Murekhina

Aleksandriiskii

2021

Int J of Chemical Kinetics

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The present paper reports on the study of the dephosphorylation of pyridoxal 5′phosphate and four derived hydrazones (containing the residues of pyrazine, 2furan, 2-thiophene, 3-pyridine carboxylic acids) induced by bovine alkaline phosphatase from intestinal mucosa at 298.2 K and pH 10 (0.05 m Tris-HCl buffer).We observed and discussed characteristic changes in the UV-vis and fluorescent spectra of substrates. Michaelis-Menten parameters of the enzymatic dephosphorylation are calculated. The stability of alkaline phosphatase in the presence of hydrazones is confirmed. The dephosphorylation of the Zn(II) complex with pyridoxal 5′-phosphate-derived hydrazone is analyzed.

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pH dependence of phosphorus-31 chemical shifts and coupling constants of some oxyacids of phosphorus

Cited by 48 publications

References 2 publications

Intrinsic 31P NMR Chemical Shifts and the Basicities of Phosphate Groups in a Short-Chain Imino Polyphosphate

Intrinsic 31P NMR Chemical Shifts and the Basicities of Phosphate Groups in a Short-Chain Imino Polyphosphate

Determination of microscopic acid?base parameters from NMR?pH titrations

Dephosphorylation of pyridoxal 5′‐phosphate‐derived Schiff bases in the presence of bovine alkaline phosphatase

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