Synthesis of 17O-Labeled Cs2WO4 and Its Ambient- and Low-Temperature Solid-State 17O MAS NMR Spectra
| Autor: | Hans J. Jakobsen, Jørgen Skibsted, Ivan Hung, Zhehong Gan, Michael Brorson, Henrik Bildsøe |
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| Rok vydání: | 2011 |
| Předmět: |
Magnetic Resonance Spectroscopy
Chemistry Cesium Nuclear magnetic resonance spectroscopy Crystal structure Oxygen Isotopes Tungsten Compounds Alkali metal Spectral line Cold Temperature Oxygen Inorganic Chemistry Crystallography chemistry.chemical_compound Tungstate Quadrupole Orthorhombic crystal system Singlet state Physical and Theoretical Chemistry |
| Zdroj: | Jakobsen, H J, Bildsøe, H K, Skibsted, J, Brorson, M, Hung, I & Gan, Z 2011, ' Synthesis of 17 O-Labeled Cs 2 WO 4 and Its Ambient-and Low-Temperature Solid-State 17 O MAS NMR Spectra ', Inorganic Chemistry, vol. 50, pp. 7676-7684 . https://doi.org/10.1021/ic200722a |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic200722a |
| Popis: | Following several seemingly straightforward but unsuccessful attempts to prepare a sample of (17)O-enriched Cs(2)WO(4), we here report a simple, aqueous procedure for synthesis of pure Cs(2)WO(4), if so desired, enriched in (17)O. The purpose for the preparation of (17)O-enriched Cs(2)WO(4) is to record its solid-state (17)O MAS NMR spectrum, which would allow for a determination of its quadrupole coupling and chemical shift anisotropy (CSA) parameters and thereby for a comparison with the corresponding (33)S and (77)Se parameters in the related compounds M(2)WS(4) and M(2)WSe(4). These compounds are isomorphous and crystallize in the orthorhombic space group Pnma, and Cs(2)WO(4) turns out to be the only alkali metal tungstate with the Pnma crystal structure. Therefore, it has been mandatory to use Cs(2)WO(4) and not K(2)WO(4) (space group C2/m) for which CSA data have previously been published, to achieve a reliable comparison with the (33)S and (77)Se data and thus allow assignment of the three different sets of (17)O NMR parameters to the three distinct oxygen sites (O(1,1), O(2), and O(3)) in the Pnma crystal structure of Cs(2)WO(4). Because the ambient temperature (17)O MAS NMR spectrum of Cs(2)WO(4) exhibits a dynamically broadened singlet, resorting to low-temperature (-83 °C) conditions at 21.15 T was necessary and resulted in a high-resolution (17)O MAS spectrum that allowed both (17)O quadrupole coupling and CSA parameters to be determined. As no quadrupole coupling data were obtained from the earlier investigation on K(2)WO(4), the present results for Cs(2)WO(4) prompted a reinvestigation of the (17)O MAS spectrum for K(2)WO(4), which actually also shows the presence of (17)O quadrupole couplings for all three oxygen sites. These data for Cs(2)WO(4) and K(2)WO(4) are consistent and result in unambiguous assignments of the parameters to the three distinct oxygen sites in their crystal structures. |
| Databáze: | OpenAIRE |
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