Development of Catalytic Reaction Fiekl From Nano-to Subnano-Scale by Utilizing Properties of Large Oxide Cluster

Dinuclear peroxotungstate，K2 [{W（= O）（O_2）_2（H_2 O）}_2（μ-O）]·2 H_2 O（W2），可以act as an effective epoxidation catalyst using H_2 O_2 in water under mild reaction conditions。进一步，我们通过共同锚定的二氢咪唑基离子液体片段，将SiO_2转化为可恢复和可循环的环氧化催化剂的可再生和可循环的环氧化催化剂的合成有机-无机混合支持材料，用H_2O_2催化的环氧化（[γ-SiW_O_（H_2O）_2]^&lt;4-&gt;）用[大于或等于] 99%的环氧化物选择性，<10>[大于或等于] H_2O_2的有效性，高立体声，一种新颖的S形分散性同位素，[（γ-SiW_O_（H_2O）_2（μ-O）_2]^&lt;4-&gt;，发现了一种部分受保护的分离乳酸型聚氧酸盐的脱氢性条件，[γ-SiW_O ^（H_2O）_2]^&lt;4-&gt;，在CF_3SO_3H的一种有机溶液中发现。<34><10><32><10><34>在对比之下，（[γ-SiW_O_（H_2O）_2]^&lt;4-&gt;没有CF_3SO_3H结果的形成，（[γ-SiW_O_2（μ-O）_4]^&lt;8-&gt;）。<10><34><10><32>While（While）（[γ-SiW_O_（H_2O）_2]^&lt;4-&gt; and（[γ-SiW_O_2（μ-O）_4]^&lt;8-&gt;常见的[SiW_O ^]片段几乎不活跃，S形的集群。（[γ-SiW_O_（H_2O）_2]^&lt;4-&gt;有效地推广基于H_2O_2的Baeyer-Villiger环氧化物在另一只手里，一种新的钛-替代硅酸盐状态簇（[γ-SiTi_2W_O_（OH）_2}_]^&lt;8-&gt;通过钛（IV）的介绍合成为一个分离的乳酸γ-Keggin-type silicotungstate of（[--SiW_O_]^&lt;8-&gt;.<10><34><10><32><10><32><10><34><10><36><10><36>这种钛基物质的聚氧化物被展示为一种半氧化物结构，其外氧化物与（[γ-SiTi_2W_O_（OH）_2]^&lt;8-&gt;是立体空间。<10><36>

The dinuclear peroxotungstate, K2[{W(=O)(O_2)_2(H_2O)}_2(μ-O)]・2H_2O (W2), could act as an effective epoxidation catalyst using H_2O_2 in water under mild reaction conditions. Further, we synthesized organic-inorganic hybrid support materials by covalently anchoring dihydroimidazorium based ionic liquid fragments onto the SiO_2 to heterogenize W2 for the development of recoverable and recyclable epoxidation catalysts.The epoxidation with H_2O_2 catalyzed by lacunary silicodecatungstate ([γ-SiW_<10>O_<34>(H_2O)_2]^<4->) proceeded with 【greater than or equal】99% selectivity to epoxide, 【greater than or equal】99% efficiency of H_2O_2 utilization, high stereospecificity.A novel S-shaped disilicoeicosatungustate, [(γ-SiW_<10>O_<32>(H_2O)_2)_2(μ-O)_2]^<4->, is obtained by dehydrative condensation of a partially protonated divacant lacunary Keggin-type polyoxometalate, [γ-SiW_<10>O^<34>(H_2O)_2]^<4->, in an anhydrous organic solvent with CF_3SO_3H. In contrast, the dimerization of ([γ-SiW_<10>O_<34>(H_2O)_2]^<4-> without CF_3SO_3H results in the formation of a closed-shape cluster, ([γ-SiW_<10>O_<32>_2(μ-O)_4]^<8->. While ([γ-SiW_<10>O_<34>(H_2O)_2]^<4-> and ([γ-SiW_<10>O_<32>_2(μ-O)_4]^<8-> with the common [SiW_<10>O^<32>] fragment are almost inactive, the S-shaped cluster ([γ-SiW_<10>O_<34>(H_2O)_2]^<4-> efficiently promotes the H_2O_2-based Baeyer-Villiger oxidations of cycloalkanones.On the other hand, a novel titanium-substituted silicotungstate cluster of ([γ-SiTi_2W_<10>O_<36>(OH)_2}_]^<8-> is synthesized by the introduction of titanium(IV) ions into a divacant lacunary γ-Keggin-type silicotungstate of ([γ-SiW_<10>O_<36>]^<8->. This titanium-substituted polyoxometalate exhibits a dimeric structure The epoxidation with ([γ-SiTi_2W_<10>O_<36>(OH)_2]^<8-> is stereospecific.