Maksimovskaya R I, Maksimov G M
Boreskov Institute of Catalysis, Lavrentiev pr. 5, Novosibirsk 630090, Russia.
Inorg Chem. 2001 Mar 12;40(6):1284-90. doi: 10.1021/ic000324o.
We have used multinuclear NMR and IR spectroscopy to study the interaction of a number of metal cations with monovacant heteropolyanion P(2)W(20)O(7)(0)(H(2)O)(2)(-) (P(2)W(20)) in aqueous solutions starting from its K salt. We have also prepared and studied P(2)W(20) in an Na-only medium. The observed differences in the NMR spectra of NaP(2)W(20)and KP(2)W(20)solutions and the importance of K(+) and Na(+) for the formation of P(2)W(20) suggest that this polyanion exists only as a complex with the alkaline cations. When both cations were simultaneously present in solution, we observed the broadening of the NMR signals of P(2)W(20)due to the Na-K exchange. Li(+) does not replace K(+) or Na(+) in such complexes, and in an Li-only medium P(2)W(20) does not form. Of all the M(n)(+) cations studied (Pd(2+), Bi(3+), Sn(4+), Zr(4+), Ce(4+), Ti(4+), V(5+), and Mo(6+)) only Bi(3+), Sn(4+), and Ce(4+) form complexes with P(2)W(20) in strongly acidic solutions. The (183)W and (119)Sn NMR data suggest that Sn(4+) forms in solution two mutually interconvertable P(2)W(20)Sn complexes of the composition P(2)W(20)O(70)(H(2)O)(3)SnOH(7)(-) and (P(2)W(20)O(70)(H(2)O)(3)Sn)(2)O(14)(-) while Bi(3+) forms one complex of the proposed composition P(2)W(20)O(70)(H(2)O)(2)Bi.(7)(-) We obtained complexes with Bi and Sn as free heteropoly acids and studied their thermostability in the solid state.
我们使用多核核磁共振（NMR）和红外光谱法，从其钾盐出发，研究了多种金属阳离子与水溶液中单核缺位杂多阴离子[P₂W₂₀O₇₀(H₂O)₂]¹⁰⁻（P₂W₂₀）的相互作用。我们还制备并研究了仅含钠介质中的P₂W₂₀。在NaP₂W₂₀和KP₂W₂₀溶液的核磁共振谱中观察到的差异以及K⁺和Na⁺对P₂W₂₀形成的重要性表明，这种多阴离子仅作为与碱金属阳离子的络合物存在。当两种阳离子同时存在于溶液中时，由于Na-K交换，我们观察到P₂W₂₀的核磁共振信号变宽。Li⁺不会在这类络合物中取代K⁺或Na⁺，并且在仅含锂的介质中不会形成P₂W₂₀。在所有研究的Mⁿ⁺阳离子（Pd²⁺、Bi³⁺、Sn⁴⁺、Zr⁴⁺、Ce⁴⁺、Ti⁴⁺、V⁵⁺和Mo⁶⁺）中，只有Bi³⁺、Sn⁴⁺和Ce⁴⁺在强酸性溶液中与P₂W₂₀形成络合物。¹⁸³W和¹¹⁹Sn核磁共振数据表明，Sn⁴⁺在溶液中形成两种相互转化的P₂W₂₀Sn络合物，其组成为P₂W₂₀O₇₀(H₂O)₃SnOH⁷⁻和(P₂W₂₀O₇₀(H₂O)₃Sn)₂O₁₄⁻，而Bi³⁺形成一种推测组成为P₂W₂₀O₇₀(H₂O)₂Bi₇⁻的络合物。我们获得了含Bi和Sn的络合物作为游离杂多酸，并研究了它们在固态下的热稳定性。
