More insight in the structure of silicophosphate gels by 31P–29Si CP MAS multidimensional experiments and 1H–31P–29Si triple resonance experiments
| Autor: | Cristina Coelho, Jocelyne Maquet, Christian Bonhomme, Thierry Azaïs, Laure Bonhomme-Coury |
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| Rok vydání: | 2006 |
| Předmět: |
General Chemical Engineering
Analytical chemistry General Chemistry chemistry.chemical_compound chemistry Solid-state nuclear magnetic resonance Heteronuclear molecule X-ray crystallography Triple-resonance nuclear magnetic resonance spectroscopy Physical chemistry Molecule Phosphorous acid Phosphoric acid Powder diffraction |
| Zdroj: | Comptes Rendus Chimie. 9:472-477 |
| ISSN: | 1631-0748 |
| DOI: | 10.1016/j.crci.2005.06.025 |
| Popis: | Solid-state 29 Si, 31 P MAS and CP MAS NMR and X-ray powder diffraction have been used to study phosphosilicate gels of molar composition (TEOS/H 3 PO 4 = 1) treated under various temperature conditions. It was found that the gel treated at 100 °C for 30 h had a structure consisting of a silica matrix including isolated molecules of phosphorous acid. In contrast, cross condensation (leading to the formation of Si–O–P bonds) was observed when the gel was treated at 136 °C for 6 days. Evidence for the formation of Si–O–P bonds was provided first by XRD, which showed the formation of the crystalline phosphosilicate phases Si 5 O(PO 4 ) 6 and Si(HPO 4 ) 2 ·H 2 O, and then by the use of two-dimensional (2D) NMR techniques: 31 P– 29 Si heteronuclear correlation (HETCOR) experiments, based on cross polarization transfer. Very few data concerning this type of experiments are available in the literature: therefore, CP dynamics was carefully studied under MAS. To cite this article: C. Coelho et al., C. R. Chimie 9 (2006) . |
| Databáze: | OpenAIRE |
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