- Organoruthenium-supported polyoxotungstate - Synthesis, structure and oxidation of n-hexadecane with air
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A ruthenium complex, KNa[Ru2(C6H6) 2(CH3COO)6] (Ru-KNa), and its polyoxotungstate derivative, Na6[{Ru(C6H6)}2W 8O28(OH)2]·16H2O (Ru-Na), have been successfully isolated from routine synthetic reactions and characterized by X-ray single-crystal structure analysis, IR spectroscopy and elemental analysis. A remarkable aspect of Ru-KNa is that it has two ligand types, benzene and acetate, and the acetate ligands are connected exclusively by a central Na cation to form a dimeric sandwich-type structure, which is further connected by K cations to construct the 3D structures. Based on complex Ru-KNa, the compound Ru-Na was synthesized, and it consists of two {Ru(C 6H6)} units linked to a [W8O 28(OH)2]10- fragment by three Ru-O(W) bonds to result in an assembly with idealized C2 symmetry in which the polyanions form 3D structures by the connection of Na chains. Subsequently, the compound Ru-Na was anchored on (3-aminopropyl)triethoxysilane (apts) modified SBA-15 to prepare the solid catalysts, which were characterized by powder XRD, N2 adsorption measurements and FTIR spectroscopy. Finally, the catalytic efficiency of Ru-Na was assessed in the oxidation of n-hexadecane with air without any additives and solvents. The results indicated that Ru-Na is a heterogeneous catalyst and exhibits higher catalytic activity than previously reported Ru-containing polyoxotungstates. Copyright
- Meng, Rui-Qi,Wang, Bin,Sui, Hui-Min,Li, Bao,Song, Wei,Wu, Li-Xin,Zhao, Bing,Bi, Li-Hua
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p. 1935 - 1942
(2013/05/23)
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- The reactivity of epoxides with lithium 2,2,6,6-tetramethylpiperidide in combination with organolithiums or grignard reagents
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(Chemical Equation Presented) The scope and limitations of lithium 2,2,6,6-tetramethylpiperidide (LTMP)-modified reductive alkylation of epoxides is detailed. A variety of organolithiums are added to terminal and 2,2-disubstituted epoxides in the presence of LTMP to generate alkenes in a completely regio- and highly stereoselective manner. Arylated alkenes, dienes, allylsilanes, and enynes are accessed using this procedure. The methodology is applied in the synthesis of the roller leaf moth pheromone, (3E,5Z)-dodecadienyl acetate. The corresponding reaction without LTMP has also been examined, and a study using deuterated epoxides provides insight into the mechanism. In the presence of LTMP, Grignard reagents are also shown to produce E-alkenes directly from epoxides.
- Hodgson, David M.,Fleming, Matthew J.,Stanway, Steven J.
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p. 4763 - 4773
(2008/02/04)
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