Calcium binding environments probed by 43Ca NMR spectroscopy

Bryce, David L.

doi:10.1039/c0dt00416b

Cited by 56 publications

(53 citation statements)

References 52 publications

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“…Analytical line shape modeling of the static 43 Ca SSNMR spectrum allows us to report a calcium CS tensor span of 31 ± 5 ppm (Fig. 3a), which represents the fifth measurement of calcium CSA in the literature 73 and the first where oxygen atoms are not coordinated to the calcium. The calcium CS tensor span for CaCl 2 is moderate, as calcium CS tensor spans range Table 2.…”

Section: Resultsmentioning

confidence: 99%

A multinuclear solid-state magnetic resonance and GIPAW DFT study of anhydrous calcium chloride and its hydrates

Widdifield

Bryce

2011

Can. J. Chem.

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The group 2 metal halides and corresponding metal halide hydrates serve as useful model systems for understanding the relationship between the electric field gradient (EFG) and chemical shift (CS) tensors at the halogen nuclei and the local molecular and electronic structure. Here, we present a 35/37 Cl and 43 Ca solid-state nuclear magnetic resonance (SSNMR) study of CaCl2. The 35 Cl nuclear quadrupole coupling constant, 8.82(8) MHz, and the isotropic chlorine CS, 105(8) ppm (with respect to dilute NaCl(aq)), are different from the values reported previously for this compound, as well as those reported for CaCl2·2H2O. Chlorine-35 SSNMR spectra are also presented for CaCl2·6H2O, and when taken in concert, the SSNMR observations for CaCl2, CaCl2·2H2O, and CaCl2·6H2O clearly demonstrate the sensitivity of the chlorine EFG and CS tensors to the local symmetry and to changes in the hydration state. For example, the value of diso decreases with increasing hydration. Gauge-including projector-augmented wave (GIPAW) density functional theory (DFT) calculations are used to substantiate the experimental SSNMR findings, to rule out the presence of other hydrates in our samples, to refine the hydrogen positions in CaCl2·2H2O, and to explore the isostructural relationship between CaCl2 and CaBr2. Finally, the 43 Ca CS tensor span is measured to be 31 (5) ppm for anhydrous CaCl2, which represents only the fifth CS tensor span measurement for calcium. Résumé : Les halogénures des métaux du groupe 2 et les hydrates d'halogénures métalliques sont des systèmes modèles qui permettent comprendre la relation entre le gradient du champ électrique (GCE) et les tenseurs du déplacement chimique (DC) au niveau du noyau d'halogène et la structure électronique et moléculaire locale. Dans ce travail, on présente les résul-tats d'une étude de résonance magnétique nucléaire à l'état solide (RMN-ES) du 35/37 Cl et 43 Ca du CaCl 2 . Les valeurs de la constante de couplage quadripolaire nucléaire du 35 Cl, 8,82(8) MHz, et le DC isotrope du chlore, 105(8) ppm [par rapport au NaCl(aq) dilué], sont différentes de celles rapportées pour ce composé ainsi que les valeurs rapportés pour le CaCl 2 ·2H 2 O. Les spectres RMN-ES du 35 Cl sont aussi presentés pour le CaCl 2 ·6H 2 O et, lorsqu'on les compare, les observations relatives aux spectres RMN-ES du CaCl 2 , du CaCl 2 ·2H 2 O et du CaCl 2 ·6H 2 O démontrent clairement la sensibilité du GCE du chlore et des tenseurs du DC sur la symétrie locale et aux changements dans l'état d'hydratation. Par exemple, les valeurs de d iso diminuent avec une augmentation de l'hydratation. On a fait appel à des calculs selon la théorie de la fonctionnelle de la densité en utilisant une onde améliorée par un opérateur de projection comportant une jauge (« GIPAW-DFT ») pour corroborer les observations faites par RMN-ES, pour éliminer la présence d'autres hydrates dans nos échantil-lons, pour affiner les positions des atomes d'hydrogène dans le CaCl 2 ·2H 2 O et pour explorer la relation isostructurale entre le CaCl 2 et...

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Section: Resultsmentioning

confidence: 99%

A multinuclear solid-state magnetic resonance and GIPAW DFT study of anhydrous calcium chloride and its hydrates

Widdifield

Bryce

2011

Can. J. Chem.

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“…First 43 Ca NMR experiments started to appear from the late 90s, [12][13][14][15] and demonstrated the correlation between 43 Ca NMR parameters and Ca environment. However, 43 Ca solid state NMR is intrinsically difficult because 43 Ca is a quadrupolar nucleus (spin ¼7/2) with a very low natural abundance (0.135%) and a small gyromagnetic ratio (γ).…”

Section: Introductionmentioning

confidence: 97%

Calcium environment in silicate and aluminosilicate glasses probed by 43Ca MQMAS NMR experiments and MD-GIPAW calculations

Gambuzzi

Pedone

Menziani

et al. 2015

Solid State Nuclear Magnetic Resonance

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“…Furthermore, the NMR-active isotope, 43 Ca, is a spin-7/2 low-nucleus (i.e. with a small magnetic moment) of low natural abundance (< 0.14%), [38,83] which makes it particularly difficult to study by NMR. Nevertheless, we have recently shown that natural abundance 43 Ca solid state NMR is well adapted to the study of apatite phases.…”

Section: C Analysis Of the Local Environment Of The Calciummentioning

confidence: 99%

Magnesium incorporation into hydroxyapatite

Laurencin¹,

Almora‐Barrios²,

Leeuw³

et al. 2011

Biomaterials

315

190

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The incorporation of Mg in hydroxyapatite (HA) was investigated using multinuclear solid state NMR, X-ray absorption spectroscopy (XAS) and computational modeling. High magnetic field 43 Ca solid state NMR and Ca K-edge XAS of a ~10% Mg-substituted HA were performed, bringing direct evidence of the preferential substitution of Mg in the Ca(II) position. 1 H and 31 P solid state NMR show that the environment of the anions is disordered in this substituted apatite phase. Both Density Functional Theory (DFT) and interatomic potential computations of Mg-substituted HA structures are in agreement with these observations. Indeed, the incorporation of low levels of Mg in the Ca(II) site is found to be more favourable energetically, and the NMR parameters calculated from these optimized structures are consistent with the experimental data. Calculations provide direct insight in the structural modifications of the HA lattice, due to the strong contraction of the M•••O distances around Mg. Finally, extensive interatomic potential calculations also suggest that a local clustering of Mg within the HA lattice is likely to occur.

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Calcium binding environments probed by 43Ca NMR spectroscopy

Cited by 56 publications

References 52 publications

A multinuclear solid-state magnetic resonance and GIPAW DFT study of anhydrous calcium chloride and its hydrates

A multinuclear solid-state magnetic resonance and GIPAW DFT study of anhydrous calcium chloride and its hydrates

Calcium environment in silicate and aluminosilicate glasses probed by 43Ca MQMAS NMR experiments and MD-GIPAW calculations

Magnesium incorporation into hydroxyapatite

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