Solid-State NMR Study of the Role of H and Na in AB-Type Carbonate Hydroxylapatite

Mason, Harris E.; Kozlowski, Andrew L.; Phillips, Brian L.

doi:10.1021/cm0716598

Cited by 55 publications

(82 citation statements)

References 33 publications

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“…A chemical shift of δ H = −0.3 ppm is close to that previously assigned to hydroxyl groups in hydroxylapatite [28,51] and its relative intensity in this spectrum, about 26%, is similar to the relative phase abundance of ApPb50B determined by Reitveld analysis. This interpretation was tested using 1 H/ 207 Pb double resonance methods.…”

Section: H Mas Nmrsupporting

confidence: 85%

Solid‐state NMR spectroscopy of Pb‐rich apatite

Mason

Hirner

et al. 2009

Magnetic Reson in Chemistry

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Pb-containing hydroxylapatite phases synthesized under aqueous conditions were investigated by X-ray diffraction and solid-state nuclear magnetic resonance (NMR) techniques to determine the Pb, Ca distribution. 31P and 1H magic-angle spinning (MAS) NMR results indicate slight shifts of the isotropic chemical shift with increased Ca content and complex lineshapes at compositions with near equal amounts of Ca and Pb. 31P{207Pb} and 1H{207Pb} rotational-echo double resonance (REDOR) results for intermediate compositions show that resolved spectral features cannot be assigned simply in terms of local Ca, Pb configurations or coexisting phases. 207Pb MAS NMR spectra are easily obtained for these materials and contain well-resolved resonances for crystallographically unique A1 and A2 Pb sites. Splitting of the A1 and A2 207Pb resonances for pure hydroxyl-pyromorphite (Pb10(PO4)6(OH)2) compared to natural pyromorphite (Pb5(PO4)3Cl) suggests symmetry reduced from hexagonal. We find that 207Pb{1H} CP/MAS NMR is impractical in Pb-rich hydroxylapatites due to fast 207Pb relaxation.

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Section: H Mas Nmrsupporting

confidence: 85%

Solid‐state NMR spectroscopy of Pb‐rich apatite

Mason

Hirner

et al. 2009

Magnetic Reson in Chemistry

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“…The presence of Na + inside the apatite phase of HB and CT is not fully surprising given that previous studies of crystalline Na-substituted calcium-phosphate phases have shown that Ca 2+ is readily replaced by Na + in phosphates, 63,98 despite the difference in charge between the two cations. Such a situation is likely to be related to the close similarity between ionic radii of Na + and Ca 2+ (1.02 Å vs. 1.00 Å ), 103 leading to similar average MÁ Á ÁO bond distances in sodium and calcium phosphates (B2.42 AE 0.70 Å for M = Na, 104 vs. B2.45 AE 0.60 Å for M = Ca).…”

Section: H{mentioning

confidence: 92%

“…51 In addition, 23 Na MRI has been used to analyse the structure of biological tissues like mummified bone and cartilage, 61,62 and it has recently been shown that the local environment of sodium in synthetic carbonated apatites can be studied by 23 Na solid state NMR. 63 In 2005, in a review on ''Solid State NMR Studies of Bone'', 24 Kolodziejski concluded that ''quadrupolar nuclei like 23 Na and…”

Section: àmentioning

confidence: 99%

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Probing the calcium and sodium local environment in bones and teeth using multinuclear solid state NMR and X-ray absorption spectroscopy

Laurencin

Wong

Chrzanowski

et al. 2010

Phys. Chem. Chem. Phys.

110

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International audienceDespite the numerous studies of bone mineral, there are still many questions regarding the exact structure and composition of the mineral phase, and how the mineral crystals become organised with respect to each other and the collagen matrix. Bone mineral is commonly formulated as hydroxyapatite, albeit with numerous substitutions, and has previously been studied by 31P and 1H NMR, which has given considerable insight into the complexity of the mineral structure. However, to date, there has been no report of an NMR investigation of the other major component of bone mineral, calcium, nor of common minority cations like sodium. Here, direct analysis of the local environment of calcium in two biological apatites, equine bone (HB) and bovine tooth (CT), was carried out using both 43Ca solid state NMR and Ca K-edge X-ray absorption spectroscopy, revealing important structural information about the calcium coordination shell. The 43Ca diso in HB and CT is found to correlate with the average Ca–O bond distance measured by Ca K-edge EXAFS, and the 43Ca NMR linewidths show that there is a greater distribution in chemical bonding around calcium in HB and CT, compared to synthetic apatites. In the case of sodium, 23Na MAS NMR, high resolution 3Q-MAS NMR, as well as 23Na{31P} REDOR and 1H{23Na} R3-HMQC correlation experiments give the first direct evidence that some sodium is located inside the apatite phase in HB and CT, but with a greater distribution of environments compared to a synthetic sodium substituted apatite (Na-HA)

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“…The structural role of carbonate in hydroxyapatite (HAP) and fluorapatite (FAP) has been investigated extensively by X-ray powder and single-crystal and neutron powder diffraction methods [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], as well as by infrared (IR, FTIR), Raman and nuclear magnetic resonance (NMR) spectroscopy [23][24][25][26][27][28][29][30][31][32]. It has been established that the carbonate ion can be accommodated either in the c-axis structural channel or as a substituent for the phosphate group: the former carbonate is known as type A and the latter as type B.…”

Section: Introductionmentioning

confidence: 99%