1629-60-3Relevant articles and documents
New perspectives on polyoxometalate catalysts: Alcohol oxidation with Zn/Sb-polyoxotungstates
Ni, Lubin,Patzke, Greta R.,Patscheider, Joerg,Baldridge, Kim K.
, p. 13293 - 13298,6 (2012)
Catalytic belts are the crucial feature of Zn/Sb-polyoxometalates as efficient and selective catalysts for alcohol oxidation. Comprehensive theoretical, analytical, and catalytic studies identify the active role of the Sb atom in the polyoxometalate metal belt. This sheds new light on low-cost catalyst tuning strategies for crucial oxidative transformations.
Sandwich-type zinc-containing polyoxometalates with a hexaprismane core [{Zn2W(O)O3}2]4+ synthesized by thermally induced isomerization of a metastable polyoxometalate
Kikukawa, Yuji,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 8194 - 8196 (2010)
Two novel sandwich-type silicotungstates, TBA8[{Zn 2W(O)O3}2H4{α-SiW 9O33}2]·5H2O (α-Zn4; TBA = tetra-n-butylammonium) and TBA8[{Zn2W(O)O 3}2H4{β-SiW9O 33}2]·7H2O (β-Zn4), were synthesized by the solid-state thermally induced isomerization of metastable TBA8[{Zn(OH2)(μ3-OH)}2{Zn(OH 2)2}2{γ-HSiW10O 36}2]·9H2O (γ-Zn4). Compounds α-Zn4 and β-Zn4 consisted of two [SiW9O33] 8- subunits sandwiching the unprecedented distorted hexaprismane core [{Zn2W(O)O3}2]4+.
Chromium-Catalyzed Production of Diols From Olefins
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Paragraph 0111, (2021/03/19)
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
Enantioselective addition of selenosulfonates to α,β-unsaturated ketones
Luo, Shilong,Zhang, Nan,Wang, Zhen,Yan, Hailong
supporting information, p. 2893 - 2901 (2018/05/03)
An organo-catalyzed enantioselective addition of selenosulfonates to α,β-unsaturated ketones was developed for the first time. With a chiral squaramide as an efficient catalyst, the desired α-selenylated ketones were obtained in a good yields with high enantioselectivity up to 89% ee, and good results could be obtained on a gram scale. The products could also be efficiently transformed into useful building blocks with a propenylic stereocenter; the strategy presented in this study may find further applications in organic synthesis.
Selective catalytic oxidation of alkenes employing homobinuclear manganese(II) catalysts with TBHP
K?l??, Yal??n,Kani, ?brahim
, p. 352 - 359 (2018/01/10)
The two novel homobinuclear compounds [Mn2(II,II) (μ1,1-4-CH3-C6H4COO)2(phen)4](ClO4)2 (1) and [Mn2(II,II) (μ1,3-4-CH3-C6H4COO)2(bipy)4](ClO4)2 (2), where bipy = 2,2-bipyridine and phen = 1,10-phenanthroline, have been synthesized and characterized by elemental analyses and spectral methods (UV–Vis, FTIR, and X-ray). A single-crystal X-ray diffraction structure analysis of the compounds revealed that the manganese atom is octahedrally coordinated. In compound 1, the binuclear(II) structure is monodentate, bridged with one oxygen atom of carboxylate ligand in μ1,1 mode, and each Mn(II) center is coordinated with two phen ligands. In compound 2, the binuclear(II) structure is syn–anti bidentate, bridged with two oxygen atoms of carboxylate ligand in μ1,3 mode, and each Mn(II) center is coordinated with two bipy ligands. The Mn–Mn separation is 3.441 (1) ? and 4.450 (1) ? for 1 and 2, respectively. The catalytic potentials of these compounds have been tested for the oxidation reaction of various olefins (i.e., styrene, cyclohexene, ethyl benzene, 1-hexene, 1-octene). The oxidation reactions were carried out in the presence of catalytic amounts of 1 and 2 with a peroxide oxygen donor (TBHP = tert-Butyl hydroperoxide) in acetonitrile at 70 °C. On comparing the catalytic activities of 1 and 2, both catalysts showed good activity (～100% conv. in 24 h) in the oxidation of studied alkenes, and excellent conversion was obtained for cyclohexene (～100% conv. in 3 h; TON = 265 and TON = 257, respectively, for 1 and 2).
A carboxylate-bridged Mn(II) compound with 6-methylanthranilate/bipy: oxidation of alcohols/alkenes and catalase-like activity
Kilic, Yalcin,Bolat, Serkan,Kani, Ibrahim
, p. 2293 - 2303 (2018/05/14)
A novel manganese compound, [Mn2(μ1,3-6-CH3-2-NH2C6H4COO)2(bipy)4](ClO4)2 (bipy?=?2,2′-bipyridine), was synthesized and used as a catalyst precursor in the oxidation of alkenes and primary alcohols to corresponding aldehydes, ketones, and acids. The six-coordinate compound has a binuclear structure in which two Mn(II) ions adopt a syn-anti μ1,3-bridging mode with two carboxylate groups and two chelated bipy ligands. The compound exhibits good activity in the oxidation of cyclohexene to 2-cyclohexene-1-one as the major product (93% conv. in 3?h, 79.3% selectivity) and of cinnamyl alcohol to cinnamaldehyde as the major product with 46% selectivity (100% conv. in 1.5?h) with tert-butyl hydroperoxide (TBHP) in acetonitrile at 70?°C. Furthermore, the catalase-like activity of the compound was studied in different solvents (acetonitrile, methanol, Tris-HCl buffer; TOF?=?29,910?h?1 in Tris-HCl buffer).
Direct Synthesis of γ-Keto Sulfones from Allylic Alcohols: One-Pot Palladium(II)-Catalyzed Generation of Enones Followed by Water-Mediated 1,4-Addition of Organosulfinates
Vellakkaran, Mari,Andappan, Murugaiah M. S.,Nagaiah, Kommu,Nanubolu, Jagadeesh Babu
supporting information, p. 3575 - 3583 (2016/07/28)
Allylic alcohols were exploited as synthetic precursors of γ-keto sulfones. The reaction involved the one-pot generation of α,β-enones in situ from the allylic alcohols by using a PdII–dioxygen catalytic system and subsequent sulfa-Michael addition in the presence of water. Importantly, water was identified as a sustainable substitute for a toxic copper salt to promote organosulfonyl addition. Diverse examples of aromatic and aliphatic γ-keto sulfones were prepared. Specially, Ar–X (X = Br, Cl) bonds were tolerated, which indicated a chemoselective catalytic system for the preparation of halogen-bearing γ-keto sulfones. This one-pot method does not require an acid, a base, or isolation of any intermediate. Control experiments indicated that the active catalyst of the first step also promoted the subsequent C–S bond-formation reaction. Water was found to accelerate the reaction rate and to be involved in the protonolysis of the σ-alkylpalladium complex, as corroborated by deuterium incorporation.
Fe3O4 magnetic nanoparticles (MNPs) as an efficient catalyst for selective oxidation of benzylic and allylic C-H bonds to carbonyl compounds with tert-butyl hydroperoxide
Zarghani, Monireh,Akhlaghinia, Batool
, p. 38592 - 38601 (2016/05/24)
Fe3O4 magnetic nanoparticles (MNPs) were prepared by a co-precipitation method with oleic acid as a surfactant and characterized by FT-IR, TEM, DLS, XRD, VSM techniques. XRD, DLS and TEM analysis of this catalyst clearly showed the formation of cubic structure Fe3O4 MNPs, with a mean size of 16 nm. Moreover, a magnetization measurement revealed that the Fe3O4 MNPs had superparamagnetic behaviour and the saturation magnetization of the catalyst was 54.6 emu g-1. The Fe3O4 MNPs in combination with tert-butyl hydroperoxide catalyzed the oxidation of various benzylic and allylic C-H bonds to the corresponding carbonyl compounds in excellent yields. These oxidation reactions were effectively and economically performed under mild conditions, and therefore the dual challenge of cost effectiveness and benign nature of the processes was met.
Design and synthesis of nanoporous perylene bis-imide linked metalloporphyrin frameworks and their catalytic activity
Singh, Manoj Kumar,Bandyopadhyay, Debkumar
, p. 1 - 8 (2016/02/09)
Two nanoporous perylene bis-imide linked metalloporphyrin framework catalysts have been synthesized via condensation of 5,10,15,20-tetrakis-(4 ′ -aminophenyl) iron(III) porphyrin chloride or 5,10, 15,20-tetrakis-(4 ′ -aminophenyl) manganese(III) porphyrin chloride with perylene-3,4,9,10-tetracarboxylic dianhydride. Both the materials were crystalline in nature and were characterized by electron microscopy techniques, solid-state 1H- 13C CP/MS NMR, powder X-ray diffraction (PXRD), and magnetic susceptibility measurements. The nitrogen gas physisorption study has indicated that both materials are porous in nature and have BET surface area with 653 m2/g and 974 m2/g with uniform pore size of 2.8 nm. These materials were found to act as very good heterogeneous catalysts for selective oxidation of alkanes and alkenes with tert-butyl hydroperoxide and were not degraded even after multiple uses up to 10 cycles.
1,4-Diazabicyclo[2.2.2]octane-Promoted Aminotrifluoromethylthiolation of α,β-Unsaturated Carbonyl Compounds: N-Trifluoromethylthio-4-nitrophthalimide Acts as Both the Nitrogen and SCF3 Sources
Xiao, Qing,He, Qijie,Li, Juncheng,Wang, Jun
supporting information, p. 6090 - 6093 (2016/01/09)
A novel difunctionalization reaction is described. It uses N-trifluoromethylthio-4-nitrophthalimide as the reagent, which serves as both the nitrogen and SCF3 sources. In the presence of DABCO (1,4-diazabicyclo[2.2.2]octane), the nitrogen and SCF3 groups can be incorporated into α,β-unsaturated carbonyl compounds easily and give versatile β-amino ketones and esters in good yields. This difunctionalization reaction features mild reaction conditions, high atom-economy, and efficient access to α-SCF3 amino acids.
