The structures of four Ca-phosphonate phases are reported here: Ca(C6H5-PO3H)(2) (1), Ca(C6H5-PO3)center dot 2H(2)O (2), Ca(C4H9-PO3H)(2) (3) and Ca(C4H9-PO3)center dot H2O (4). Structural models were obtained ab initio by using a combined synchrotron powder diffraction, solid-state nuclear magnetic resonance, and gauge including projector augmented wave (GIPAW) calculation approach. The H-1, C-13, P-31 and Ca-43 NMR parameters calculated from these structural models were found to be in good agreement with the experimental values, thereby indicating the high accuracy of the DFT-optimized structures. Correlations between the NMR parameters and structural features around the phosphonate were then analyzed, showing in particular the high sensitivity of the P-31 asymmetry parameter.CS and the Ca-43 isotropic chemical shift to changes in local structure around the phosphonate groups and the Ca2+, respectively. Finally, the NMR data of a new mixed Na-Ca phosphonate phase, Ca1.5Na(C4H9-PO3)(2), are reported.
Structural study of calcium phosphonates: a combined synchrotron powder diffraction, solid-state NMR and first-principle calculations approach / Sene, Saad; Bouchevreau, Boris; Martineau, Charlotte; Gervais, Christel; Bonhomme, Christian; Gaveau, Philippe; Mauri, Francesco; Begu, Sylvie; Mutin, P. Hubert; Smith, Mark E.; Laurencin, Danielle. - In: CRYSTENGCOMM. - ISSN 1466-8033. - 15:43(2013), pp. 8763-8775. [10.1039/c3ce40981c]
Structural study of calcium phosphonates: a combined synchrotron powder diffraction, solid-state NMR and first-principle calculations approach
MAURI, FRANCESCO;
2013
Abstract
The structures of four Ca-phosphonate phases are reported here: Ca(C6H5-PO3H)(2) (1), Ca(C6H5-PO3)center dot 2H(2)O (2), Ca(C4H9-PO3H)(2) (3) and Ca(C4H9-PO3)center dot H2O (4). Structural models were obtained ab initio by using a combined synchrotron powder diffraction, solid-state nuclear magnetic resonance, and gauge including projector augmented wave (GIPAW) calculation approach. The H-1, C-13, P-31 and Ca-43 NMR parameters calculated from these structural models were found to be in good agreement with the experimental values, thereby indicating the high accuracy of the DFT-optimized structures. Correlations between the NMR parameters and structural features around the phosphonate were then analyzed, showing in particular the high sensitivity of the P-31 asymmetry parameter.CS and the Ca-43 isotropic chemical shift to changes in local structure around the phosphonate groups and the Ca2+, respectively. Finally, the NMR data of a new mixed Na-Ca phosphonate phase, Ca1.5Na(C4H9-PO3)(2), are reported.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
