Reactivity of Bis(μ-hydroxo) Divanadium Site in γ-H2SiV2W10O404- with Hydroxo Compounds
Reactivity of Bis(μ-hydroxo) Divanadium Site in γ-H2SiV2W10O404- with Hydroxo Compounds
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DOI：
10.1021/ic051163x
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发表时间：
2005-10
影响因子：
4.6
通讯作者：
Y. Nakagawa;Kazuhiro Uehara;N. Mizuno
中科院分区：
文献类型：
--
作者：
Y. Nakagawa;Kazuhiro Uehara;N. Mizuno
报道了钒取代钨酸硅γ-H2SiV2W10O404- (I)与醇、羧酸和水的羟基化合物的反应性。I中的双（μ-羟基）钒位点与伯醇和甲酸的反应顺利进行，分别生成相应的单酯和单甲酸酯，并测定了I的单甲酯、单乙酯和单甲酸酯的晶体结构。羟基和水之间的氧交换很容易进行。另一方面，体积较大的2-丙醇、叔丁醇和乙酸由于甲基和多金属氧酸框架之间的空间拥挤而难以与双（μ-羟基）钒位点（平衡常数< 0.01）反应。
The reactivity of divanadium-substituted silicotungstate, γ-H2SiV2W10O404- (I), with hydroxo compounds of alcohols, carboxylic acids, and water is reported. The reaction of the bis(μ-hydroxo) divanadium site in I with primary alcohols and formic acid smoothly proceeds to form corresponding monoesters and monoformate, respectively, and the crystal structures of the monomethyl and monoethyl esters and the monoformate of I are determined. The oxygen exchange between the hydroxo group and water proceeds easily. On the other hand, bulky compounds of 2-propanol, tert-butyl alcohol, and acetic acid hardly react with the bis(μ-hydroxo) divanadium site (equilibrium constant < 0.01) because of the steric crowding between the methyl groups and the polyoxometalate framework.