Here, we present the first example of reductive silylation for oxygen defect formation at the surface of a polyoxometalate. Upon addition of 1,4-bis(trimethylsilyl)dihydropyrazine (Pyz(SiMe₃)₂) to [V₆O₇(OMe)₁₂]¹⁻, quantitative formation of the oxygen-deficient vanadium oxide assembly, [V₆O₆(OMe)₁₂]¹⁻ was observed. Substoichiometric reactions of Pyz(SiMe₃)₂ with the parent cluster revealed the mechanism of defect formation; addition of 0.5 equiv. of Pyz(SiMe₃)₂ to [V₆O₇(OMe)₁₂]¹⁻ results in isolation of [V₆O₆(OSiMe₃)(OMe)₁₂]¹⁻. This reactivity was extended to reduced and oxidized forms of the cluster, [V₆O₇(OMe)₁₂]ⁿ (n = 2-, 0), revealing the consequences of modifying the oxidation states of remote transition metal ions on the stability of the siloxide functional group, and thus the extent of reactivity of the cluster surface with Pyz(SiMe₃)₂. The work offers a new understanding of the mechanisms of surface activation of reducible metal oxides via reductive silylation, and reveals new chemical routes for the formation of oxygen atom vacancies in polyoxometalate ions.

中文翻译：

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使用 Mashima 试剂还原硅烷化聚氧钒酸盐表面

在这里，我们展示了在多金属氧酸盐表面形成氧缺陷的还原硅烷化的第一个例子。在将 1,4-双(三甲基甲硅烷基)二氢吡嗪 (Pyz(SiMe ₃ ) ₂ ) 添加到 [V ₆ O ₇ (OMe) ₁₂ ] ^{1- 后}，定量形成缺氧钒氧化物组装体，[V ₆ O ₆观察到(OMe) ₁₂ ] ^1-。Pyz(SiMe ₃ ) ₂与母团的亚化学计量反应揭示了缺陷形成的机制；添加 0.5 当量 Pyz(SiMe ₃ ) ₂至[V₆ O ₇ (OMe) ₁₂ ] ^1-导致[V ₆ O ₆ (OSiMe ₃ )(OMe) ₁₂ ] ^{1- 的分离}。这种反应性扩展到簇的还原和氧化形式，[V ₆ O ₇ (OMe) ₁₂ ] ⁿ ( n = 2-, 0)，揭示了改变远程过渡金属离子的氧化态对稳定性的影响硅氧化物官能团，因此簇表面与 Pyz(SiMe ₃ ) ₂的反应程度. 该工作为通过还原性硅烷化作用对可还原金属氧化物的表面活化机制提供了新的理解，并揭示了在多金属氧酸盐离子中形成氧原子空位的新化学途径。