183W INADEQUATE 2D NMR Spectroscopy of Hetero Arsenato鈥揚hosphato鈥揟ungstate PV/AsV Substitution in Dawson-Type 伪-[AsxP2鈥?i>xW18
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- 作者：Mohamed Haouas ; Isra毛l-Martyr Mbomekall茅 ; Neus Vila ; Pedro de Oliveira ; Francis Taulelle
- 刊名：Inorganic Chemistry
- 出版年：2014
- 出版时间：June 2, 2014
- 年：2014
- 卷：53
- 期：11
- 页码：5568-5574
- 全文大小：358K
- 年卷期：v.53,no.11(June 2, 2014)
- ISSN：1520-510X
文摘
The Dawson-type arsenato鈥損hosphato鈥搕ungstate 伪-[AsPW18O62]6鈥?/sup> has been prepared and unambiguously identified for the first time. A comparative study including the four other already known compounds, the symmetric 伪-[X2W18O62]6鈥?/sup> and unsymmetric 伪-[H4XW18O62]7鈥?/sup> for X = PV, AsV, has been performed by spectroscopic 183W and 31P NMR. 2-D 183W INADEQUATE experiments were systematically employed to unequivocally verify structures, assign all resonances, and determine precisely 2JW鈥揙鈥揥 scalar couplings. The effects of P/As substitutions, generating unsymmetric structures, on the NMR observables 未W-183, 未P-31, 2JW鈥揙鈥揥, and 2JW鈥揙鈥揚 are discussed in relation to their bond length and bond angle alteration. General trends with respect to NMR parameter variations have been found when filling central cavities with P or As atoms, with less pronounced effects for As than for P. In addition, NMR characterization of three other isomers, i.e., 尾-[X2W18O62]6鈥?/sup> and 纬-[As2W18O62]6鈥?/sup>, were also provided for comparison. The present NMR results could serve as representative reference data for understanding the relationship between structure and NMR observables in polyoxotungstates.