183W INADEQUATE 2D NMR Spectroscopy of Hetero Arsenato–Phosphato–Tungstate PV/AsV Substitution in Dawson-Type α-[AsxP2–xW18O62]6– (x = 0–2) and α-[H4AsyP1–yW18O62]7– (y = 0, 1) - Archive ouverte HAL Access content directly
Journal Articles Inorganic Chemistry Year : 2014

183W INADEQUATE 2D NMR Spectroscopy of Hetero Arsenato–Phosphato–Tungstate PV/AsV Substitution in Dawson-Type α-[AsxP2–xW18O62]6– (x = 0–2) and α-[H4AsyP1–yW18O62]7– (y = 0, 1)

Abstract

The Dawson-type arsenato-phosphato-tungstate alpha-[AsPW18O62](6-) has been prepared and unambiguously identified for the first time. A comparative study. including the four other already known compounds, the symmetric alpha-[X2W18O62](6-) and unsymmetric alpha-[H4XW18O62](7-) for X = P-V, As-V, has been performed by spectroscopic W-183 and P-31 NMR. 2-D W-183 INADEQUATE experiments were systematically employed to unequivocally verify structures, assign all resonances, and determine precisely (2)J(W-O-W) scalar couplings. The effects of P/As substitutions, generating unsymmetric structures, on the NMR observables delta(W-183), delta(P-31), (2)J(W-O-W), and (2)J(W-O-P) 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., beta-[X2W18O62](6-) and [As2W18O62](6-), 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.
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hal-01496385 , version 1 (27-03-2017)

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Mohamed Haouas, Israel Martyr Mbomekalle, Neus Vila, Pedro de Oliveira, Francis Taulelle. 183W INADEQUATE 2D NMR Spectroscopy of Hetero Arsenato–Phosphato–Tungstate PV/AsV Substitution in Dawson-Type α-[AsxP2–xW18O62]6– (x = 0–2) and α-[H4AsyP1–yW18O62]7– (y = 0, 1). Inorganic Chemistry, 2014, 53 (11), pp.5568-5574. ⟨10.1021/ic500286v⟩. ⟨hal-01496385⟩
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