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- 作者：Keigo Kamata ; Shinjiro Kuzuya ; Kazuhiro Uehara ; Syuhei Yamaguch ; Noritaka Mizuno
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：April 30, 2007
- 年：2007
- 卷：46
- 期：9
- 页码：3768 - 3774
- 全文大小：188K
- 年卷期：v.46,no.9(April 30, 2007)
- ISSN：1520-510X
文摘
The reaction of the dinuclear peroxotungstate, [(n-C4H9)4N]2[{WO(O2)2}2(
-O)] (II), with H2O2 gives the novel -
1:1-peroxo-bridging dinuclear tungsten species, [(n-C4H9)4N]2[{WO(O2)2}2(-O2)] (I), which has been characterizedby X-ray crystallography, elemental analysis, IR, Raman, UV-vis, and 183W NMR. Only I is active for the epoxidationof cyclic, internal, and terminal olefins, whereas II is inactive for each. The low XSO (XSO = (nucleophilic oxidation)/(total oxidation)) value of I (0.18 ± 0.02) in comparison with that of II (0.39 ± 0.01) for the stoichiometric oxidationof thianthrene 5-oxide, which is a mechanistic probe for determining the electronic character of an oxidant, revealsthat I is more electrophilic than II. On the basis of the kinetic and spectroscopic results, the catalytic epoxidationproceeds by the reaction of I with an olefin to form II and the corresponding epoxide followed by the regenerationof I by the reaction of II with H2O2.
-O)] (II), with H2O2 gives the novel -1:1-peroxo-bridging dinuclear tungsten species, [(n-C4H9)4N]2[{WO(O2)2}2(-O2)] (I), which has been characterizedby X-ray crystallography, elemental analysis, IR, Raman, UV-vis, and 183W NMR. Only I is active for the epoxidationof cyclic, internal, and terminal olefins, whereas II is inactive for each. The low XSO (XSO = (nucleophilic oxidation)/(total oxidation)) value of I (0.18 ± 0.02) in comparison with that of II (0.39 ± 0.01) for the stoichiometric oxidationof thianthrene 5-oxide, which is a mechanistic probe for determining the electronic character of an oxidant, revealsthat I is more electrophilic than II. On the basis of the kinetic and spectroscopic results, the catalytic epoxidationproceeds by the reaction of I with an olefin to form II and the corresponding epoxide followed by the regenerationof I by the reaction of II with H2O2.