20653-90-1Relevant articles and documents
Synthesis, characterization and catalytic epoxidation properties of a new tellurotungstate(iv)-supported rhenium carbonyl derivative
Lu, Jingkun,Ma, Xinyi,Wang, Ping,Feng, Junwei,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
, p. 628 - 634 (2019/01/08)
A monomeric tellurotungstate(iv)-supported rhenium carbonyl derivative: Na2H2[(CH3)4N]6[Te2W20O70{Re(CO)3}2]·20H2O (1) has been successfully isolated and structurally characterized by single crystal X-ray diffraction crystallography, IR and UV-Vis spectroscopy, thermogravimetric analysis, etc. In particular, complex 1 could act as a efficient and reusable heterogeneous catalyst for selective epoxidation of various alkenes including different cycloalkenes, styrene derivatives, internal and long-chain alkenes. For example, cis-cyclooctene undergoes up to 98.2% conversion and >99% selectivity at 75 °C in acetonitrile with 30% H2O2 as an oxidant. Additionally, the electrocatalytic property of 1 for NO2? reduction was also investigated.
Metal oxide-triazole hybrids as heterogeneous or reaction-induced self-separating catalysts
Amarante, Tatiana R.,Neves, Patrícia,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
, p. 354 - 367 (2016/07/06)
The hybrid metal oxide-triazole materials [MoO3(trz)0.5] (1) and [W2O6(trz)] (2) (trz?=?1,2,4-triazole) have been hydrothermally synthesized and characterized by different techniques (TGA, SEM, 1H and 13C MAS NMR, FT-IR spectroscopy, and structure determination by Rietveld analysis of high resolution synchrotron powder XRD data). Materials 1 and 2 display distinct behaviors when applied as catalysts for oxidation reactions with alcohol, aldehyde, olefin and sulfide substrates, and are more effective with hydrogen peroxide as the oxidant than with tert-butylhydroperoxide. The MoVI hybrid 1 transforms into soluble active species during cis-cyclooctene epoxidation with H2O2. When consumption of H2O2 reaches completion, spontaneous reassembly of the 2-dimensional molybdenum oxide network of 1 takes place and the hybrid precipitates as a microcrystalline solid that can be easily separated and recycled. Reaction-induced self-separation behavior occurs with 1, H2O2 and other substrates such as methyl oleate and methylphenylsulfide. The WVI hybrid 2 behaves differently, preserving its structural features throughout the heterogeneous catalytic process.
Fe(PyTACN)-catalyzed cis-dihydroxylation of olefins with hydrogen peroxide
Prat, Irene,Font, David,Company, Anna,Junge, Kathrin,Ribas, Xavi,Beller, Matthias,Costas, Miquel
supporting information, p. 947 - 956 (2013/05/08)
A family of iron complexes with general formula [Fe(II)( R,Y,XPyTACN)(CF3SO3)2], where R,Y,XPyTACN=1-[2′-(4-Y-6-X-pyridyl)methyl]-4,7-dialkyl-1,4, 7-triazacyclononane, X and Y refer to the groups at positions 4 and 6 of the pyridine, respectively, and R refers to the alkyl substitution at N-4 and N-7 of the triazacyclononane ring, are shown to be catalysts for efficient and selective alkene oxidation (epoxidation and cis-dihydroxylation) employing hydrogen peroxide as oxidant. Complex [Fe(II)(Me,Me,HPyTACN)(CF 3SO3)2] (7), was identified as the most efficient and selective cis-dihydroxylation catalyst among the family. The high activity of 7 allows the oxidation of alkenes to proceed rapidly (30 min) at room temperature and under conditions where the olefin is not used in large amounts but instead is the limiting reagent. In the presence of 3 mol% of 7, 2 equiv. of H2O2 as oxidant and 15 equiv. of water, in acetonitrile solution, alkenes are cis-dihydroxylated reaching yields that might be interesting for synthetic purposes. Competition experiments show that 7 exhibits preferential selectivity towards the oxidation of cis olefins over the trans analogues, and also affords better yields and high [syn-diol]/[epoxide] ratios when cis olefins are oxidized. For aliphatic substrates, reaction yields attained with the present system compare favourably with state of the art Fe-catalyzed cis-dihydroxylation systems, and it can be regarded as an attractive complement to the iron and manganese systems described recently and which show optimum activity against electron-deficient and aromatic olefins. Copyright
