Calcium phosphates (including hydroxyapatite) are inorganic components of numerous compounds such as bones and teeth. The in-depth characterization of their structures is of crucial importance for the understanding of the properties of biocompatible materials. Multinuclear solid-state NMR (including H-1, O-17 and P-31) appears as a valuable tool of investigation. In this paper, we show that full assignments of spectra were obtained through extensive use of first-principles calculations, based on the GIPAW (Gauge Included Projector Augmented Wave) approach [C.J. Pickard, F. Mauri, Phys. Rev. B 63 (2001) 245101]. H-1 and P-31 calculations (isotropic chemical shifts and CSA tensors) were validated by comparison with MAS experiments. In the case of H-1, full resolution was not obtained and subsequent assignment of resonances was obtained by taking into account the calculated isotropic chemical shifts. Interesting correlations involving delta(iso) (H-1) values and H-bond networks (characterized by intemuclear distances) were established, in good agreement with empirical data already published in the literature. H-1 CSA tensors were also analyzed. Furthermore, O-17 is a suitable spectroscopic target for the characterization of X-O-Y bonds, which may be present at bioinorganic interfaces. First-principles calculations showed that PO-, P-O-P, POH, CaO (and H2O) entities could be distinguished on the basis of O-17 chemical shifts and quadrupolar constants in MQ-MAS experiments.
Calcium phosphates: First-principles calculations vs. solid-state NMR experiments / Pourpoint, Frederique; Gervais, Christel; Bonhomme-Coury, Laure; Mauri, Francesco; Alonso, Bruno; Bonhomme, Christian. - In: COMPTES RENDUS CHIMIE. - ISSN 1631-0748. - 11:4-5(2008), pp. 398-406. [10.1016/j.crci.2007.09.011]
Calcium phosphates: First-principles calculations vs. solid-state NMR experiments
Mauri, Francesco;
2008
Abstract
Calcium phosphates (including hydroxyapatite) are inorganic components of numerous compounds such as bones and teeth. The in-depth characterization of their structures is of crucial importance for the understanding of the properties of biocompatible materials. Multinuclear solid-state NMR (including H-1, O-17 and P-31) appears as a valuable tool of investigation. In this paper, we show that full assignments of spectra were obtained through extensive use of first-principles calculations, based on the GIPAW (Gauge Included Projector Augmented Wave) approach [C.J. Pickard, F. Mauri, Phys. Rev. B 63 (2001) 245101]. H-1 and P-31 calculations (isotropic chemical shifts and CSA tensors) were validated by comparison with MAS experiments. In the case of H-1, full resolution was not obtained and subsequent assignment of resonances was obtained by taking into account the calculated isotropic chemical shifts. Interesting correlations involving delta(iso) (H-1) values and H-bond networks (characterized by intemuclear distances) were established, in good agreement with empirical data already published in the literature. H-1 CSA tensors were also analyzed. Furthermore, O-17 is a suitable spectroscopic target for the characterization of X-O-Y bonds, which may be present at bioinorganic interfaces. First-principles calculations showed that PO-, P-O-P, POH, CaO (and H2O) entities could be distinguished on the basis of O-17 chemical shifts and quadrupolar constants in MQ-MAS experiments.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.