90482-62-5Relevant academic research and scientific papers
Catalytic oxygen atom transfer promoted by tethered Mo(VI) dioxido complexes onto silica-coated magnetic nanoparticles
Colaiezzi, Roberta,Crucianelli, Marcello,Di Giuseppe, Andrea,Ferella, Francesco,Lazzarini, Andrea,Paolucci, Valentina
, (2021/11/30)
The preparation of three novel active and stable magnetic nanocatalysts for the selective liquid-phase oxidation of several olefins, has been reported. The heterogeneous systems are based on the coordination of cis-MoO2 moiety onto three different SCMNP@Si-(L1-L3) magnetically active supports, functionalized with silylated acylpyrazolonate ligands L1, L2 and L3. Nanocatalysts thoroughly characterized by ATR-IR spectroscopy, TGA and ICP-MS analyses, showed excellent catalytic performances in the oxidation of conjugated or unconjugated olefins either in organic or in aqueous solvents. The good magnetic properties of these catalytic systems allow their easy recyclability, from the reaction mixture, and reuse over five runs without significant decrease in the activity, either in organic or water solvent, demonstrating their versatility and robustness.
Rational Construction of an Artificial Binuclear Copper Monooxygenase in a Metal-Organic Framework
Feng, Xuanyu,Song, Yang,Chen, Justin S.,Xu, Ziwan,Dunn, Soren J.,Lin, Wenbin
supporting information, p. 1107 - 1118 (2021/01/25)
Artificial enzymatic systems are extensively studied to mimic the structures and functions of their natural counterparts. However, there remains a significant gap between structural modeling and catalytic activity in these artificial systems. Herein we report a novel strategy for the construction of an artificial binuclear copper monooxygenase starting from a Ti metal-organic framework (MOF). The deprotonation of the hydroxide groups on the secondary building units (SBUs) of MIL-125(Ti) (MIL = Matériaux de l'Institut Lavoisier) allows for the metalation of the SBUs with closely spaced CuI pairs, which are oxidized by molecular O2 to afford the CuII2(μ2-OH)2 cofactor in the MOF-based artificial binuclear monooxygenase Ti8-Cu2. An artificial mononuclear Cu monooxygenase Ti8-Cu1 was also prepared for comparison. The MOF-based monooxygenases were characterized by a combination of thermogravimetric analysis, inductively coupled plasma-mass spectrometry, X-ray absorption spectroscopy, Fourier-transform infrared spectroscopy, and UV-vis spectroscopy. In the presence of coreductants, Ti8-Cu2 exhibited outstanding catalytic activity toward a wide range of monooxygenation processes, including epoxidation, hydroxylation, Baeyer-Villiger oxidation, and sulfoxidation, with turnover numbers of up to 3450. Ti8-Cu2 showed a turnover frequency at least 17 times higher than that of Ti8-Cu1. Density functional theory calculations revealed O2 activation as the rate-limiting step in the monooxygenation processes. Computational studies further showed that the Cu2 sites in Ti8-Cu2 cooperatively stabilized the Cu-O2 adduct for O-O bond cleavage with 6.6 kcal/mol smaller free energy increase than that of the mononuclear Cu sites in Ti8-Cu1, accounting for the significantly higher catalytic activity of Ti8-Cu2 over Ti8-Cu1.
Dendrimer crown-ether tethered multi-wall carbon nanotubes support methyltrioxorhenium in the selective oxidation of olefins to epoxides
Bizzarri, Bruno Mattia,Botta, Lorenzo,Crucianelli, Marcello,Fanelli, Angelica,Ferella, Francesco,Gontrani, Lorenzo,Sadun, Claudia,Saladino, Raffaele
, p. 17185 - 17194 (2020/05/18)
Benzo-15-crown-5 ether supported on multi-wall carbon nanotubes (MWCNTs) by tethered poly(amidoamine) (PAMAM) dendrimers efficiently coordinated methyltrioxorhenium in the selective oxidation of olefins to epoxides. Environmentally friendly hydrogen peroxide was used as a primary oxidant. Up to first and second generation dendrimer aggregates were prepared by applying a divergent PAMAM methodology. FT-IR, XRD and ICP-MS analyses confirmed the effective coordination of methyltrioxorhenium by the benzo-15-crown-5 ether moiety after immobilization on MWCNTs. The novel catalysts converted olefins to the corresponding epoxides in high yield without the use of Lewis base additives, or anhydrous hydrogen peroxide, the catalyst being stable for more than six oxidative runs. In the absence of the PAMAM structure, the synthesis of diols largely prevailed.
Photocatalytic Asymmetric Epoxidation of Terminal Olefins Using Water as an Oxygen Source in the Presence of a Mononuclear Non-Heme Chiral Manganese Complex
Shen, Duyi,Saracini, Claudio,Lee, Yong-Min,Sun, Wei,Fukuzumi, Shunichi,Nam, Wonwoo
supporting information, p. 15857 - 15860 (2016/12/23)
Photocatalytic enantioselective epoxidation of terminal olefins using a mononuclear non-heme chiral manganese catalyst, [(R,R-BQCN)MnII]2+, and water as an oxygen source yields epoxides with relatively high enantioselectivities (e.g., up to 60% enantiomeric excess). A synthetic mononuclear non-heme chiral Mn(IV)-oxo complex, [(R,R-BQCN)MnIV(O)]2+, affords similar enantioselectivities in the epoxidation of terminal olefins under stoichiometric reaction conditions. Mechanistic details of each individual step of the photoinduced catalysis, including formation of the Mn(IV)-oxo intermediate, are discussed on the basis of combined results of laser flash photolysis and other spectroscopic methods.
Synthesis and oxidation catalysis of a Ti-substituted phosphotungstate, and identification of the active oxygen species
Takahashi, Eri,Kamata, Keigo,Kikukawa, Yuji,Sato, Sota,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 4778 - 4789 (2015/10/05)
In this paper, we report the synthesis of a Ti-substituted phosphotungstate, TBA6[(γ-PW10O36)2Ti4(μ-O)2(μ-OH)4] (I, TBA = tetra-n-butylammonium), and its application to H2O2-based oxidation. Firstly, an organic solvent-soluble dilacunary phosphotungstate precursor, TBA3[γ-PW10O34(H2O)2] (PW10), has been synthesized. By the reaction of PW10 and TiO(acac)2 (acac = acetylacetonate) in an organic medium (acetonitrile), I can be obtained. Compound I possesses a tetranuclear Ti core which can effectively activate H2O2 and shows high catalytic performance for several oxidation reactions, such as epoxidation of alkenes, oxygenation of sulfides, oxidative bromination of unsaturated compounds, and hydroxylation of anisole, giving the corresponding oxidation products with high efficiencies and selectivities. The catalytic performance of I is much superior to those of previously reported Ti-substituted polyoxometalates. In addition, I is highly durable during catalysis and can be reused several times while keeping its high catalytic performance. Furthermore, we have successfully isolated the truly catalytically active species for the present I-catalyzed oxidation, TBA6[(γ-PW10O36)2Ti4(μ-η2:η2-O2)4] (II), and its anion structure has been determined by X-ray crystallographic analysis. All of the four Ti2-μ-η2:η2-peroxo species in II are active for stoichiometric oxidation (without H2O2), and II is included in the catalytic cycle for I-catalyzed oxidation.
Synthesis of novel magnetic chitosan supported protonated peroxotungstate and its catalytic performance for oxidation
Zhu, Jie,Wang, Peng Cheng,Lu, Ming
, p. 2587 - 2592 (2013/02/22)
A novel magnetically recoverable catalyst in which protonated peroxotungstate was immobilized into a network of cross-linked chitosan with a superparamagnetic Fe3O4 core (Fe3O 4-CS/HWO) was prepared, characterized and used in oxidation reactions. With H2O2 as oxidant, a wide range of substrates including olefins, sulfides, amines and allylic alcohols could be oxidized selectively, exhibiting a relatively high utilization percentage of H2O2. Due to the existence of peroxotungstate as well as the magnetic core, both improved catalytic performance and facilitated separation were achieved for the reaction process. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
Epoxidation of alkenes with hydrogen peroxide catalyzed by selenium-containing dinuclear peroxotungstate and kinetic, spectroscopic, and theoretical investigation of the mechanism
Kamata, Keigo,Lshimoto, Ryo,Hirano, Tomohisa,Kuzuya, Shinjiro,Uehara, Kazuhiro,Mizuno, Noritaka
experimental part, p. 2471 - 2478 (2010/05/15)
The dinuclear peroxotungstate with a SeO42- ligand, (TBA)2[SeO4{WO(O2)2}2] (I; TBA=[(n-C4Hg)4N]+), could act as an efficient homogeneous catalyst for the selective oxidation of various kinds of organic substances such as olefins, alcohols, and amines with H 2O2 as the sole oxidant. The turnover frequency (TOF) was as high as 210 h-1 for the epoxidation of cyclohexene catalyzed by I with H2O2. The catalyst was easily recovered and reused with maintenance of the catalytic performance. The SeO42- ligand in I played an important role in controlling the Lewis acidity of the peroxotungstates, which significantly affects their electrophilic oxygen-transfer reactivity. Several kinetic and spectroscopic results showed that the present catalytic epoxidation included the following two steps: (I) formation of the subsequent peroxo species [SeWmOn] o- (II; m=1 and 2) by the reaction of I with an olefin and (ii) regeneration of I by the reaction of Il with H2O2. Compound I was the dominant species under steady-state turnover conditions. The reaction rate for the catalytic epoxidation showed a first-order dependence on the concentrations of olefin and I and a zero-order dependence on the concentration of H2O2. The rate of the stoichiometric epoxidation with I agreed well with that of the catalytic epoxidation with H2O2 by I. All of these kinetic and spectroscopic results indicate that oxygen transfer from I to the C=C double bond is the rate-determining step. The computational studies support that the oxygen-transfer step is the rate-determining step.
Olefin-dependent discrimination between two nonheme HO-Fev=O tautomeric species in catalytic H2O2 epoxidations
Company, Anna,Feng, Yan,Gueell, Mireia,Ribas, Xavi,Luis, Josep M.,Que Jr., Lawrence,Costas, Miquel
supporting information; experimental part, p. 3359 - 3362 (2009/12/06)
A study was conducted to demonstrate olefin-dependent discrimination of two nonheme HO-Fev=O tautomeric species in catalytic H2O 2 epoxidations. Mechanistic studies were carried out under the condition of excess of olefin to minimize over-oxidation reactions and all reactions for the study were carried out under a N2 atmosphere to prevent auto-oxidation process due to presence of O2. It was observed that the diol/epoxide (D/E) ration for these reaction was dependent on the specific olefin and ranged from 3/2 (cyclooctene) to 6/1 (1-octene). The oxidation of cyclooctene using H218O2 revealed that only 28% of the oxygen atoms in the epoxide derived from H 2O2. Mechanistic results suggested that HO-Fe v=O oxidant need to be labeled before its reaction with substrates.
Steel-promoted oxidation of olefins in supercritical carbon dioxide using dioxygen in the presence of aldehydes
Loeker, Frank,Leitner, Walter
, p. 2011 - 2015 (2007/10/03)
Oxidation of olefins occurs effectively in supercritical carbon dioxide as the reaction medium with dioxygen as the primary oxidant and aldehydes as sacrificial co-oxidants. No catalyst is required, but the reaction is promoted by the stainless steel of the reactor walls. Depending on the substrate, vinylic oxidation or epoxidation can be the prevailing pathway. Epoxidation is particularly effective for substrates with internal double bonds and for long-chain terminal olefins.
