Calcium complexing behaviour of lactate in neutral to highly alkaline medium

Dudás, Csilla; Kutus, Bence; Böszörményi, Éva; Peintler, Gábor; Attia, Amr A. A.; Lupan, Alexandru; Kele, Zoltán; Sipos, Pál; Pálinkó, István

doi:10.1016/j.molstruc.2018.12.020

Cited by 5 publications

(9 citation statements)

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“…Several experimental studies have confirmed that the carboxylate group (COO -) is capable of coordinating to alkali (Li + , Na + , K + )/alkaline earth metal ions (Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ ). [26][27][28][29][30][31][32][33] Moreover, 13 C NMR experiments, 27,28,30 1 H- 43 Ca NMR experiments 32,33 as well DFT and Hartree-Fock ab initio calculations 31 32,33 showed that in addition to the carboxylate group, a hydroxyl group can be involved in such coordination in the presence of a negatively charged group nearby (e.g. COO -).…”

Section: Resultsmentioning

confidence: 99%

“…Several experimental studies have confirmed that the carboxylate group (COO À ) is capable of coordinating to alkali (Li + , Na + , and K + )/alkaline earth metal ions (Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ). [26][27][28][29][30][31][32][33] Moreover, 13 C NMR experiments, 27,28,30 1 H- 43 Ca NMR experiments, 32,33 and DFT and Hartree-Fock ab initio calculations 3132,33 showed that in addition to the carboxylate group, a hydroxyl group can be involved in such coordination in the presence of a negatively charged group nearby (e.g., COO À ). Pallagi et al 32 reported that gluconate-another aliphatic polyhydroxy carboxylic acid-acts as a multidentate ligand in aqueous solution with Ca 2+ , with the binding sites being the oxygen of the carboxylate and hydroxyl groups on the C α , C β , and C ε .…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, Vavrusova et al 31 reported a coexistence of two conformers in a solution of calcium gluconate: (1) the conformation with Ca 2+ bound to two carboxylate oxygen and the oxygen of the hydroxyl group on the C β and (2) the conformation where Ca 2+ binds to only one oxygen of the carboxylate group and to the oxygen of the hydroxyl groups on the C α and C β . Based on the strong precedent in the literature for the interaction of Ca 2+ with the carboxylate [26][27][28][29][30][31][32][33] and hydroxyl 27,28,[30][31][32][33] groups of hydroxycarboxylates, we therefore attribute part of the spectral changes in our ECD data to such ionselective pairing. The precise conformations have yet to be determined with the help of theoretical calculations and/or 1 H- 43 Ca NMR spectroscopy experiments.…”

Section: Resultsmentioning

confidence: 99%

“…[18][19][20][21][22] This phenomenon has been recently exploited in a novel chiroptical ee sensing technique which is based on the detection of induced visible ECD bands by complexation of transition metal ions with chiral organic analytes. 24,25 In addition to transition metal ions, it has also been shown that alkali (Li + , Na + , K + ) and alkaline earth metal ions (Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ ) [26][27][28][29][30][31][32][33] have a tendency to form complexes with hydroxycarboxylates. Their presence in solutions of HCAs was shown to induce changes in the intensity and Abstract: Electronic circular dichroism (ECD) and anisotropy spectra carry information on differential absorption of leftand right-circularly polarised light (LCPL and RCPL) by optically active compounds.…”

Section: Introductionmentioning

confidence: 99%

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Concentration and pH effect on the electronic circular dichroism and anisotropy spectra of aqueous solutions of glyceric acid calcium salt

et al. 2021

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Electronic circular dichroism (ECD) and anisotropy spectra carry information on differential absorption of left-and right-circularly polarized light (LCPL and RCPL) by optically active compounds. This makes them powerful tools for the rapid determination of enantiomeric excesses (ee) in asymmetric synthetic and pharmaceutical chemistry, as well as for predicting the ee inducible by ultraviolet (UV) CPL. The ECD response of a chiral molecule is, however, critically dependent on the properties of the surrounding medium. Here, we report on the first ECD/anisotropy spectra of aqueous solutions of the calcium salt dihydrate of glyceric acid. A systematic study of the effect of the salt concentration and pH on the chiroptical response revealed significant changes and the appearance of a new ECD band of opposite sign. Based on the literature, this can be rationalized by the increase in the relative proportion of free glyceric acid/glycerate to Ca 2+ complexes with glycerate with decreasing salt concentration or pH. Glyceric acid can be readily produced under astrophysical conditions. The anisotropy spectra of the solution containing prevalently the free form of this dihydroxy carboxylic acid resemble the ones of previously investigated aliphatic chain hydroxycarboxylic acids and proteinogenic amino acids. This indicates possible common handedness of stellar CPL-induced asymmetry in the potential comonomers of primitive proto-peptides.alkaline earth metal, chiral hydroxycarboxylic acid, circularly polarized light, complexation, CPL scenario, enantiomeric excess, homochirality | INTRODUCTIONDifferentiation between enantiomers of a chiral species requires a chiral force. Circularly polarized light (CPL) represents a true chiral entity, 1 and the origin of biological homochirality-uniformity of handedness of amino [This article is part of the Special Issue: Chirality in France. See the first articles for this special issue previously published in Volumes 33:9, 33:10, 33:11, 33:12, and 34:1. More special articles will be found in this issue as well as in those to come.]

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Concentration and pH effect on the electronic circular dichroism and anisotropy spectra of aqueous solutions of glyceric acid calcium salt

et al. 2021

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“…Towards more alkaline pH values, this effect seems to decrease, together with reduced proton concentration, leading to an increase in T 2 . At even stronger basic pH regimes, the formation of lactate–metal complexes with added Na + -ions and deprotonation of the hydroxy group (p K a = 15.8) start to decrease T 2 [ 52 , 53 ].…”

Section: Discussionmentioning

confidence: 99%

pH Dependence of T2 for Hyperpolarizable 13C-Labelled Small Molecules Enables Spatially Resolved pH Measurement by Magnetic Resonance Imaging

et al. 2021

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Hyperpolarized 13C magnetic resonance imaging often uses spin-echo-based pulse sequences that are sensitive to the transverse relaxation time T2. In this context, local T2-changes might introduce a quantification bias to imaging biomarkers. Here, we investigated the pH dependence of the apparent transverse relaxation time constant (denoted here as T2) of six 13C-labelled molecules. We obtained minimum and maximum T2 values within pH 1–13 at 14.1 T: [1‑13C]acetate (T2,min = 2.1 s; T2,max = 27.7 s), [1-13C]alanine (T2,min = 0.6 s; T2,max = 10.6 s), [1,4‑13C2]fumarate (T2,min = 3.0 s; T2,max = 18.9 s), [1-13C]lactate (T2,min = 0.7 s; T2,max = 12.6 s), [1‑13C]pyruvate (T2,min = 0.1 s; T2,max = 18.7 s) and 13C-urea (T2,min = 0.1 s; T2,max = 0.1 s). At 7 T, T2‑variation in the physiological pH range (pH 6.8–7.8) was highest for [1‑13C]pyruvate (ΔT2 = 0.95 s/0.1pH) and [1‑13C]acetate (ΔT2 = 0.44 s/0.1pH). Concentration, salt concentration, and temperature alterations caused T2 variations of up to 45.4% for [1-13C]acetate and 23.6% for [1-13C]pyruvate. For [1-13C]acetate, spatially resolved pH measurements using T2-mapping were demonstrated with 1.6 pH units accuracy in vitro. A strong proton exchange-based pH dependence of T2 suggests that pH alterations potentially influence signal strength for hyperpolarized 13C-acquisitions.

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Complex Formation in Hyperalkaline Solutions

Kutus,

Sipos

2023

Metal Ions and Complexes in Solution

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Strongly alkaline conditions in aqueous systems may give rise to the formation of novel, so far undiscovered metal complexes, and crystallization from these systems often yields solid materials with peculiar local structures. This is of particular importance from a practical point of view, since the knowledge of the structure and dynamics of these solution species could be the key to understand and to manipulate a large variety of processes, both industrial and geochemical. The current contribution is focused on solution species with ligands as hydroxides, organic molecules with O-donor atoms, or both, which do not form or are undetectable at moderate pH. The possible formation of polynuclear complexes as well as various dehydration products is also discussed. A further important aspect is the characterization of the solids obtained from these systems in terms of both the local symmetry of the complexing ion, i.e. interrelations between solution and the solid structure or the lack of them, and their morphology and/or composition. The general theme of this chapter is that hyperalkalinity, an extreme condition, and unusual chemical events are expected to occur under such conditions.

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Calcium complexing behaviour of lactate in neutral to highly alkaline medium

Cited by 5 publications

References 57 publications

Concentration and pH effect on the electronic circular dichroism and anisotropy spectra of aqueous solutions of glyceric acid calcium salt

Concentration and pH effect on the electronic circular dichroism and anisotropy spectra of aqueous solutions of glyceric acid calcium salt

pH Dependence of T2 for Hyperpolarizable 13C-Labelled Small Molecules Enables Spatially Resolved pH Measurement by Magnetic Resonance Imaging

Complex Formation in Hyperalkaline Solutions

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