- Oxidations of secondary alcohols to ketones using easily recyclable bis(trifluoroacetate) adducts of fluorous alkyl iodides, CF3(CF 2)n-1I(OCOCF3)2
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Reactions of commercial fluorous alkyl iodides RfnI (1-R fn; Rfn = CF3(CF2)n-1; n = 7, 8, 10, 12) with 80% H2O2 and trifluoroacetic anhydride give RfnI(OCOC
- Tesevic, Verona,Gladysz
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- Manganese Porphyrins Supported on Montmorillonite as Hydrocarbon Mono-oxygenation Catalysts: Particular Efficacy for Linear Alkane Hydroxylation
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A supported Mn-porphyrin catalyst has been prepared by immobilisation of the tetracationic Mn Cl4+ on montmorillonite, and is found to be efficient for alkene epoxidation and alkane hydroxylation by PhIO, with a higher ability to oxidize alkanes, and in particular short linear alkanes, than corresponding homogeneous or silica-supported Mn-porphyrin catalysts.
- Barloy, Laurent,Battioni, Pierrette,Mansuy, Daniel
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- Metal complexes of a tetraazacyclotetradecane bearing highly fluorinated tails: New catalysts for the oxidation of hydrocarbons under fluorous biphasic conditions
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The commercially available macrocycle tetraazacyclotetradecane (cyclam) has been converted into the fluorocarbon soluble ligand 1 by N-functionalization with R(F)CH2OCH2CH2OTs 3, wherein R(F) is a (per)fluorooxyalkylenic c
- Pozzi, Gianluca,Cavazzini, Marco,Quici, Silvio,Fontana, Simonetta
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- Nonheme iron mediated oxidation of light alkanes with oxone: Characterization of reactive oxoiron(IV) ligand cation radical intermediates by spectroscopic studies and DFT calculations
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The oxidation of light alkanes that is catalyzed by heme and nonheme iron enzymes is widely proposed to involve highly reactive {FeViO} species or {FeIViO} ligand cation radicals. The identification of these high-valent iron species and the development of an iron-catalyzed oxidation of light alkanes under mild conditions are of vital importance. Herein, a combination of tridentate and bidentate ligands was used for the generation of highly reactive nonheme {FeiO} species. A method that employs [Fe III(Me3tacn)(Cl-acac)Cl]+ as a catalyst in the presence of oxone was developed for the oxidation of hydrocarbons, including cyclohexane, propane, and ethane (Me3tacn=1,4,7-trimethyl-1,4,7- triazacyclononane; Cl-acac=3-chloro-acetylacetonate). The complex [Fe III(Tp)2]+ and oxone enabled stoichiometric oxidation of propane and ethane. ESI-MS, EPR and UV/Vis spectroscopy, 18O labeling experiments, and DFT studies point to [Fe IV(Me3tacn)({Cl-acac}.+)(O)]2+ as the catalytically active species. Highly reactive {FeiO} intermediates, such as [Fe(Tp)2(O)]+ or complex I (see Scheme), are likely to be involved in the oxidation of propane and ethane with oxone that is either mediated by [FeIII(Tp)2]+ (1) or catalyzed by iron complex 2. The cationic intermediate I features an {FeiO} moiety and is stabilized by a combination of tridentate and bidentate ligands. Copyright
- Tse, Chun-Wai,Chow, Toby Wai-Shan,Guo, Zhen,Lee, Hung Kay,Huang, Jie-Sheng,Che, Chi-Ming
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- Transition metal-substituted polyoxometalates supported on MCM-41 as catalysts in the oxidation of cyclohexane and cyclooctane with H2O2
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The Keggin type polyoxometalates (Bu4N)4HPW11CoO39, (Bu4N)4PW11FeO39, (Bu4N)4HPW11CuO39 and (Bu4N)4PW11VO40 have been synthesized and supported on MCM-41 to be used as catalysts for the solvent-free oxidation of cyclohexane and cyclooctane with H2O2.
- Jatupisarnpong, Jirarot,Trakarnpruk, Wimonrat
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- Alkane hydroxylation by a nonheme iron catalyst that challenges the heme paradigm for oxygenase action
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A nonheme iron catalyst catalyzed stereoselective oxidation of alkanes with H2O2 with remarkable efficiency and exhibiting an unprecedented high incorporation of water into the oxidized products. The present results challenge the canonical description of oxygenases, the standard oxo-hydroxo tautomerism that applies to heme systems and serves as a precedent for alternative pathways for the oxidation of hydrocarbons at nonheme iron oxygenases. Copyright
- Company, Anna,Gomez, Laura,Gueell, Mireia,Ribas, Xavi,Luis, Josep M.,Que Jr., Lawrence,Costas, Miquel
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- Iron catalysis for in situ regeneration of oxidized cofactors by activation and reduction of molecular oxygen: A synthetic metalloporphyrin as a biomimetic NAD(P)H oxidase
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(Figure Presented) An enzyme substitute: A synthetic FeIII porphyrin was used as a catalyst for the activation and reduction of O 2 into H2O with the cofactor NAD(P)H in aqueous solution. The catalyst is compatible with different preparative enzymatic oxidation reactions. Thus, a new method is provided for the in situ regeneration of the oxidized cofactor NAD(P)+ with help from a nonenzymatic, synthetic catalyst (see scheme).
- Maid, Harald,Boehm, Philipp,Huber, Stefan M.,Bauer, Walter,Hummel, Werner,Jux, Norbert,Groeger, Harald
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- Reaction of aldehydes with the H5PV2Mo10O40 polyoxometalate and cooxidation of alkanes with molecular oxygen
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The oxidation of alkalies with molecular oxygen using aldehydes as reducing agents (aldehydes are cooxidized) was studied using the α-H5PV2Mo10O40 polyoxometalate as catalyst. Emphasis was placed on the initiation of the radical chain reaction by investigation of the aldehyde-polyoxometalate interaction. Using 31P NMR and ESR spectroscopy one could differentiate between the reactivity of the five inseparable isomers of α-H5PV2Mo10O40. Contrary to previous belief, the 1,11 isomer with vanadium in distal positions is the most abundant. The 31P NMR and ESR spectra supported by UV-vis absorption-time profiles of the reduction of α-H5PV2Mo10O40 indicated that isomers with vanadium in vicinal positions were most kinetically viable in the alkane oxidation. Addition of isobutyraldehyde to α-H5PV2Mo10O40 gave in the 51V NMR spectrum a new downfield peak attributed to the formation of an aldehyde-polyoxometalate intermediate. The alkane/aldehyde/O2 oxidizing system was found to be quite effective and selective for ketone formation. Reaction probes indicated that acyl peroxo radicals were the active oxidizing intermediates. Five pathways for its reaction were identified: chain propagation, alkane oxidation, decomposition to form oxygen, decomposition to acyl oxo radicals leading to CO2 and ketone, and capture and inhibition by the polyoxometalate.
- Khenkin, Alexander M.,Rosenberger, Avi,Neumann, Ronny
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- Selective Homogeneous Catalytic Oxidation of Olefins using Oxygen/Hydrogen Mixtures: Oxygen Atom Transfer from an Iridium Hydroperoxide
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An iridium(III) hydride complex in solution catalyses the O2-co-oxidation of cyclo-octene and H2 to cyclo-octanone and water, respectively, via a hydroperoxide intermediate.
- Atlay, Mark T.,Preece, Michael,Strukul, Giorgio,James, Brian R.
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- Templating an N-heterocyclic carbene (NHC)-cyclometalated Cp?IrIII-based oxidation precatalyst on a pendant coordination platform: Assessment of the oxidative behavior via electrochemical, spectroscopic and catalytic probes
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The coordination of metalloligands to derive modified properties of the metal functionality is one of the interesting strategies practiced in materials chemistry and catalysis. In this work, a pendant terpyridine ligand has been utilized for templating a Cp?IrIII(NHC)-based (NHC = N-heterocyclic carbene) oxidation precatalyst to assess its modified oxidative behavior via electrochemical, UV-vis spectroscopic, and catalytic probes. These studies suggested that the coordination-template enhances the electron-deficiency at the IrIII redox center and affects the nature of the oxidized high-valent Ir-oxo species during chemical oxidation. Moreover, both the premodified and postmodified Cp?IrIII(NHC)-based complexes were found to be equally efficient in catalytic sp3 C-H oxidation reactions with NaIO4 as a mild sacrificial oxidant.
- Gupta, Suraj K.,Choudhury, Joyanta
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- Oxidation of Alkanes by Dioxygen Catalysed By Photoactivated Iron Porphyrins
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Cycloalkanes were oxidized by O2 itself under mild conditions (22 deg C; 200 Torr of O2) in the presence of catalytic amounts of a polyhalogenated porphyrin-iron(III)-hydroxo complex irradiated with light of wavelength between 350 and 450 nm; these oxidations occurred without consumption of a reducing agent, selectively transformed cyclohexane into cyclohexanone under appropriate conditions (about 0.2 turnover per min), and did not involve FeV=O active species but, more probably, iron-alkylperoxo intermediates.
- Maldotti, A.,Bartocci, C.,Amadelli, R.,Polo, E.,Battioni, P.,Mansuy, D.
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- Simple soluble Bi(iii) salts as efficient catalysts for the oxidation of alkanes with H2O2
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A simple catalytic system based on a soluble bismuth(iii) salt, Bi(NO3)3/H2O2/HNO3/CH3CN + H2O, exhibits pronounced activity towards the homogeneous oxidation of inert alkanes with the yield of oxygenate products up to 32% and TON up to 112. The experimental selectivity parameters and kinetic data together with theoretical DFT calculations indicate that the reaction occurs via a free radical mechanism involving the formation of the HO radicals which directly react with alkane molecules. The mechanism of the HO generation (which is the rate limiting step of the whole process) includes the substitution of a water ligand for H2O2 in the initial aqua complex [Bi(H2O)8]3+, hydrolysis of the coordinated H2O2, second H2O-for-H2O2 substitution and the homolytic HO-OH bond cleavage in complex [Bi(H2O)4(H2O2)(OOH)]2+ (6). The relatively low overall activation energy for this process (ca. 20 kcal mol-1) is accounted for by the high lability and acidity of the Bi aqua complexes and tremendous activation of coordinated H2O2 in 6 towards homolysis. This journal is
- Rocha, Bruno G. M.,Kuznetsov, Maxim L.,Kozlov, Yuriy N.,Pombeiro, Armando J. L.,Shul'Pin, Georgiy B.
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- Efficient catalytic cycloalkane oxidation employing a "helmet" phthalocyaninato iron(III) complex
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We have examined the catalytic activity of an iron(III) complex bearing the 14,28-[1,3-diiminoisoindolinato]phthalocyaninato (diiPc) ligand in oxidation reactions with three substrates (cyclohexane, cyclooctane, and indan). This modified metallophthalocyaninato complex serves as an efficient and selective catalyst for the oxidation of cyclohexane and cyclooctane, and to a far lesser extent indan. In the oxidations of cyclohexane and cyclooctane, in which hydrogen peroxide is employed as the oxidant under inert atmosphere, we have observed turnover numbers of 100.9 and 122.2 for cyclohexanol and cyclooctanol, respectively. The catalyst shows strong selectivity for alcohol (vs. ketone) formation, with alcohol to ketone (A/K) ratios of 6.7 and 21.0 for the cyclohexane and cyclooctane oxidations, respectively. Overall yields (alcohol + ketone) were 73% for cyclohexane and 92% for cyclooctane, based upon the total hydrogen peroxide added. In the catalytic oxidation of indan under similar conditions, the TON for 1-indanol was 10.1, with a yield of 12% based upon hydrogen peroxide. No 1-indanone was observed in the product mixture.
- Brown, Elizabeth S.,Robinson, Jerome R.,McCoy, Aaron M.,McGaff, Robert W.
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- Structural studies and physico-chemical properties of new oxodiperoxomolybdenum complexes with nicotinic acid
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Three new oxodiperoxomolybdenum complexes with nicotinic acid have been synthesized and characterized with the use of single-crystal analysis, XRPD versus temperature, TG/DSC, SEM and IR spectroscopy. The investigated compounds are: 1 - (NH4)2·[MoO(O2) 2.N-nicO]2, 2 - (nicH)2·[MoO(O 2)2.NnicO]2·2(H2O), 3 - MoO(O2)2(H2O)nicH; (N-nicO, nicH - denote nicotinic acid N-oxide and protonated nicotinic acid, respectively). Compounds 1, 2 are salts of the same acid with cyclic dinuclear anions, whereas compound 3 can be regarded as an inner salt. Compounds 1-3 are stable in ambient conditions, the respective percentages of oxygen in peroxo groups are 19.21%, 14.06% and 20.19%, respectively. Above 125 °C peroxo compounds 1-3 decompose, forming nanometric MoO2 and MoO3. TG/DSC curves reveal clear effects connected with the release of oxygen and strong exothermic effects connected with final loss of organic components. All the investigated complexes were found to be active in the oxidation of cyclooctane to cyclooctanone and cyclooctanol with molecular oxygen.
- Szymańska, Anna,Nitek, Wojciech,Mucha, Dariusz,Karcz, Robert,Pamin, Katarzyna,Po?towicz, Jan,?asocha, Wies?aw
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- V(iv), Fe(ii), Ni(ii) and Cu(ii) complexes bearing 2,2,2-tris(pyrazol-1-yl)ethyl methanesulfonate: Application as catalysts for the cyclooctane oxidation
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Water-soluble compounds [VOCl2{CH3SO2OCH2C(pz)3}] (pz = pyrazol-1-yl) 1, [FeCl2{CH3SO2OCH2C(pz)3}] 2, [NiCl2{CH3SO2OCH2C(pz)3}] 3 and [Cu{CH3SO2OCH2C(pz)3}2](OTf)24 were obtained by reactions between the corresponding metal salts and 2,2,2-tris(pyrazol-1-yl)ethyl methanesulfonate, CH3SO2OCH2C(pz)3. They were isolated as air-stable solids and fully characterized by IR, FTIR, NMR (for 2), EPR (for 1), ESI-MS(+/-), elemental analysis and (for 4) single-crystal X-ray diffraction. In all, half- (1-3) or full-sandwich (4), compounds the C-scorpionate ligand shows the N,N,N-coordination mode. 3 and 4 appear to provide the first examples of a Ni(ii) and a full-sandwich Cu(ii) compound respectively, bearing that scorpionate ligand. Compound 3 is the first Ni(ii) tris(pyrazol-1-yl)methane type complex to be applied as catalyst for the oxidation of alkanes. Compounds 1-4 exhibit catalytic activity for the peroxidative (with aq. H2O2) oxidation, in water/acetonitrile medium and under mild homogeneous conditions, of cyclooctane to the corresponding alcohol and ketone (yields up to ca. 27%). The effect of the presence of additives, such as nitric acid or pyridine, was studied.
- Silva, Telma F. S.,Rocha, Bruno G. M.,Guedes Da Silva, M. Fátima C.,Martins, Luísa M. D. R. S.,Pombeiro, Armando J. L.
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- Cobalt(II) Catalyzed Biomimetic Oxidation of Hydrocarbons in the Presence of Dioxygen and 2-Methylpropanal
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Cobalt(II) Schiff base complex 1 catalyses the oxidation of aliphatic and aromatic hydrocarbons in the presence of 2-methylpropanal under 1 atmosphere of dioxygen to give corresponding ketones and alcohols.
- Punniyamurthy, T.,Kalra, Swinder Jeet Singh,Iqbal, Javed
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- Oxidation of cycloalkanes with molecular oxygen in the presence of salen metallocomplexes in thermomorphic conditions
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The oxidation of cycloalkanes with molecular oxygen, catalyzed by two groups of metallosalen complexes, was studied. The first group consisted of salen complexes with different metals such as Mn, Fe, Co, Ni, Cu, Zn, while the second group was composed of manganese salen complexes with different substituents (t-butyl electron-donating substituents and/or electron-withdrawing perfluoroalkyl substituents). Mn, Fe and Co salen complexes are the most active catalysts, while Ni, Cu and Zn salen complexes are far less efficient. The introduction of t-butyl electron-donating substituents into Mnsalen complex increases the catalytic activity and catalysts solubility in the reaction mixture. The introduction of perfluoroalkyl electron-withdrawing substituents enhances the catalytic activity and renders the solubility of the catalyst temperature dependent (thermomorphic behaviour), thus allowing one to recover them easily after the reaction by simply cooling the system to room temperature. The synthesis of two new manganese salen complexes with perfluoroalkyl substituents was elaborated.
- Pamin, Katarzyna,Pozzi, Gianluca,Tabor, Edyta,Bukowski, Wiktor,Po?towicz, Jan
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- Hydrogen Peroxide Oxygenation of Alkanes catalysed by Manganese(III)-tetraarylporphyrins: the Remarkable Co-catalytic Effect of Lipophilic Carboxylic Acids and Heterocyclic Bases
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Oxygenation of alkanes promoted by 30percent H2O2 and catalysed by chemically robust manganese(III)-tetraaryl porphyrins 2-4 is strongly accelerated by addition of small amounts of lipophilic carboxylic acids and lipophilic heterocyclic bases; cycloalkanes are converted into mixtures of alcohols and ketones at a rate of up to 125 turnovers min-1 in CH2Cl2-H2O solution at 0 deg C.
- Banfi, Stefano,Maiocchi, Alessandro,Moggi, Alberto,Montanari, Fernando,Quici, Silvio
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- Rhodium mediated C-H Bond functionalisation leading to carboxylate: Derivatives
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Selective functionalisation of 15-cyclooctadiene either to a carboxylic acid or to a γ-lactone is achieved by a novel sequence of reactions involving quantitative oxygenation with oxygen and C-C coupling with carbon monoxide (see graphic). The rhodium hydroxy-alkyl-allyl complex shown is the active intermediate that promotes the elimination of the organic compounds.
- Tejel, Cristina,Del Rio, M. Pilar,Lopez, Jose A.,Ciriano, Miguel A.
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- Oxidation of alkanes catalyzed by manganese(III) porphyrin in anionic liquid at room temprature
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Efficient oxidation of alkanes is achieved by using an electron-deficient manganese(III) porphyrin catalyst in combination with iodobenzene diacetate in an ionic liquid at room temperature; a high-valent manganese-oxo porphyrin complex (MnV=O) was considered as the reactive oxidation intermediate.
- Li, Zhen,Xia, Chun-Gu,Xu, Chuan-Zhi
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- Polymer- And silica-supported iron BPMEN-inspired catalysts for C-H bond functionalization reactions
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Direct catalytic C-H bond functionalization is a key challenge in synthetic chemistry, with many popular C-H activation methodologies involving precious-metal catalysts. In recent years, iron catalysts have emerged as a possible alternative to the more common precious-metal catalysts, owing to its high abundance, low cost, and low toxicity. However, iron catalysts are plagued by two key factors: the ligand cost and the low turnover numbers (TONs) typically achieved. In this work, two approaches are presented to functionalize the popular N1,N2-dimethyl-N1,N2-bis(pyridin-2-ylmethyl)-ethane-1,2-diamine (BPMEN) ligand, so that it can be supported on porous silica or polymer resin supports. Four new catalysts are prepared and evaluated in an array of catalytic C-H functionalization reactions by using cyclohexane, cyclohexene, cyclooctane, adamantane, benzyl alcohol, and cumene with aqueous hydrogen peroxide. Catalyst recovery and recycling is demonstrated by using supported catalysts, which allows for a modest increase in the TON achieved with these catalysts.
- Feng, Yan,Moschetta, Eric G.,Jones, Christopher W.
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- Efficient and selective oxidation of hydrocarbons with tert-butyl hydroperoxide catalyzed by oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles
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The catalytic activity of an oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles, γ-Fe2O3@[VO(salenac-OH)] in which salenac-OH = [9-(2′,4′-dihydroxyphenyl)-5,8-diaza-4
- Samani, Mahnaz,Ardakani, Mehdi Hatefi,Sabet, Mohammad
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p. 1481 - 1494
(2022/01/22)
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- Synthesis of Visible-Light–Activated Hypervalent Iodine and Photo-oxidation under Visible Light Irradiation via a Direct S0→Tn Transition
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Heavy atom-containing molecules cause a photoreaction by a direct S0→Tn transition. Therefore, even in a hypervalent iodine compound with a benzene ring as the main skeleton, the photoreaction proceeds under 365–400nm wavelength light, where UV-visible spectra are not observed by usual measurement method. Some studies, however, report hypervalent iodine compounds that strongly absorb visible light. Herein, we report the synthesis of two visible light-absorbing hypervalent iodines and their photooxidation properties under visible light irradiation. We also demonstrated that the S0→Tn transition causes the photoreaction to proceed under wavelengths in the blue and green light region.
- Matsuda, Yu,Matsumoto, Koki,Nagasawa, Sho,Nakajima, Masaya,Nemoto, Tetsuhiro
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p. 235 - 239
(2022/03/16)
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- Efficient oxidation of cycloalkanes with simultaneously increased conversion and selectivity using O2 catalyzed by metalloporphyrins and boosted by Zn(AcO)2: A practical strategy to inhibit the formation of aliphatic diacids
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The direct sources of aliphatic acids in cycloalkanes oxidation were investigated, and a strategy to suppress the formation of aliphatic acids was adopted through enhancing the catalytic transformation of oxidation intermediates cycloalkyl hydroperoxides to cycloalkanols by Zn(II) and delaying the emergence of cycloalkanones. Benefitted from the delayed formation of cycloalkanones and suppressed non-selective thermal decomposition of cycloalkyl hydroperoxides, the conversion of cycloalkanes and selectivity towards cycloalkanols and cycloalkanones were increased simultaneously with satisfying tolerance to both of metalloporphyrins and substrates. For cyclohexane, the selectivity towards KA-oil was increased from 80.1% to 96.9% meanwhile the conversion was increased from 3.83 % to 6.53 %, a very competitive conversion level with higher selectivity compared with current industrial process. This protocol is not only a valuable strategy to overcome the problems of low conversion and low selectivity lying in front of current cyclohexane oxidation in industry, but also an important reference to other alkanes oxidation.
- Shen, Hai-Min,Wang, Xiong,Ning, Lei,Guo, A-Bing,Deng, Jin-Hui,She, Yuan-Bin
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- Three metal centers (Co _AOMARKENCODEAMPX0AOA) Cu _AOMARKENCODEAMPX0AOA Method using Zn) 2D MOFs/ultraviolet light to catalyze oxidation of cycloalkane
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The invention relates to a three-metal center (Co _AOMARKENCODEAMPX0AOA). Cu _AOMARKENCODEAMPX0AOA The method comprises Zn) 2D MOFs/ultraviolet light catalytic oxidation of cycloalkane to synthesize cycloalkyl alcohol and cycloalkanone, and belongs to the field of industrial catalysis and fine organic synthesis. To the application method, metalloporphyrin three-metal center (Co _AOMARKENCODEAMPX0AOA) is used. Cu _AOMARKENCODEAMPX0AOA Zn) 2D MOFs dispersed in cycloalkane, wherein metalloporphyrin three-metal center (Co _AOMARKENCODEAMPX0AOA) Cu _AOMARKENCODEAMPX0AOA Zn) 2D MOFs mass is 0.01% - 20%, g / mol of the substance of the cycloalkane, and the reaction system is sealed. An oxidant is introduced, the ultraviolet lamp is a light source, and the reaction liquid of the stirring reaction 2.0-24 . 0h. is subjected to post-treatment to obtain the product cycloalkyl alcohol and cycloalkyl ketone. The method provided by the invention has the advantages of low reaction temperature, mild reaction conditions, high reaction efficiency, high selectivity of cycloalkyl alcohol and cycloalkyl ketone, less byproducts and small environmental impact. The invention provides a high efficiency. Available, safe cycloalkanes selectively catalyze the oxidative synthesis of cycloalkyl alcohols and cycloalkyl ketones.
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Paragraph 0028; 0079-0080
(2021/11/06)
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- Cu6- And Cu8-Cage Sil- And Germsesquioxanes: Synthetic and Structural Features, Oxidative Rearrangements, and Catalytic Activity
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This study reports intriguing features in the self-assembly of cage copper(II) silsesquioxanes in the presence of air. Despite the wide variation of solvates used, a series of prismatic hexanuclear Cu6 cages (1-5) were assembled under mild conditions. In turn, syntheses at higher temperatures are accompanied by side reactions, leading to the oxidation of solvates (methanol, 1-butanol, and tetrahydrofuran). The oxidized solvent derivatives then specifically participate in the formation of copper silsesquioxane cages, allowing the isolation of several unusual Cu8-based (6 and 7) and Cu6-based (8) complexes. When 1,4-dioxane was applied as a reaction medium, deep rearrangements occurred (with a total elimination of silsesquioxane ligands), causing the formation of mononuclear copper(II) compounds bearing oxidized dioxane fragments (9 and 11) or a formate-driven 1D coordination polymer (10). Finally, a "directed"self-assembly of sil- and germsesquioxanes from copper acetate (or formate) resulted in the corresponding acetate (or formate) containing Cu6 cages (12 and 13) that were isolated in high yields. The structures of all of the products 1-13 were established by single-crystal X-ray diffraction, mainly based on the use of synchrotron radiation. Moreover, the catalytic activity of compounds 12 and 13 was evaluated toward the mild homogeneous oxidation of C5-C8 cycloalkanes with hydrogen peroxide to form a mixture of the corresponding cyclic alcohols and ketones.
- Astakhov, Grigorii S.,Levitsky, Mikhail M.,Zubavichus, Yan V.,Khrustalev, Victor N.,Titov, Aleksei A.,Dorovatovskii, Pavel V.,Smol'Yakov, Alexander F.,Shubina, Elena S.,Kirillova, Marina V.,Kirillov, Alexander M.,Bilyachenko, Alexey N.
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p. 8062 - 8074
(2021/05/26)
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- Gold-Catalyzed Direct C(sp3)?H Acetoxylation of Saturated Hydrocarbons
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In this communication we report our studies towards the development of a gold-catalyzed direct acetoxylation of C(sp3)?H bonds. We achieve this through the use of the hypervalent iodine reagent PhI(OAc)2 in combination with a simple gold salt (HAuBr4) as the catalyst. Through a comparison of the reactivities of cyclooctane and adamantane we judge the reaction to proceed via hydride transfer. This is further substantiated through computational studies of the relative energies for the anions, radicals and cations derived from C?H bond cleavage of cyclooctane and adamantane relevant to the C?H cleaving step.
- Jo, Tae Geun,Klein, Johannes E. M. N.
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p. 4087 - 4091
(2021/08/25)
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- Nonheme Diiron Oxygenase Mimic That Generates a Diferric-Peroxo Intermediate Capable of Catalytic Olefin Epoxidation and Alkane Hydroxylation including Cyclohexane
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Herein are described substrate oxidations with H2O2 catalyzed by [FeII(IndH)(CH3CN)3](ClO4)2 [IndH = 1,3-bis(2′-pyridylimino)isoindoline], involving a spectroscopically characterized (μ-oxo)(μ-1,2-peroxo)diiron(III) intermediate (2) that is capable of olefin epoxidation and alkane hydroxylation including cyclohexane. Species 2 also converts ketones to lactones with a decay rate dependent on [ketone], suggesting direct nucleophilic attack of the substrate carbonyl group by the peroxo species. In contrast, peroxo decay is unaffected by the addition of olefins or alkanes, but the label from H218O is incorporated into the the epoxide and alcohol products, implicating a high-valent iron-oxo oxidant that derives from O-O bond cleavage of the peroxo intermediate. These results demonstrate an ambiphilic diferric-peroxo intermediate that mimics the range of oxidative reactivities associated with O2-activating nonheme diiron enzymes.
- Kaizer, József,Oloo, Williamson N.,Que, Lawrence,Szávuly, Miklós
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- Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge
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Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV–Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols.
- Kakavand, Meysam,Mastrorilli, Piero,Mesto, Ernesto,Neshat, Abdollah,Osanlou, Farzane,Schingaro, Emanuela,Todisco, Stefano
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- Time-Dependent Self-Assembly of Copper(II) Coordination Polymers and Tetranuclear Rings: Catalysts for Oxidative Functionalization of Saturated Hydrocarbons
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This study describes a time-dependent self-assembly generation of new copper(II) coordination compounds from an aqueous-medium reaction mixture composed of copper(II) nitrate, H3bes biobuffer (N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid), ammonium hydroxide, and benzenecarboxylic acid, namely, 4-methoxybenzoic (Hfmba) or 4-chlorobenzoic (Hfcba) acid. Two products were isolated from each reaction, namely, 1D coordination polymers [Cu3(μ3-OH)2(μ-fmba)2(fmba)2(H2O)2]n (1) or [Cu2(μ-OH)2(μ-fcba)2]n (2) and discrete tetracopper(II) rings [Cu4(μ-Hbes)3(μ-H2bes)(μ-fmba)]·2H2O (3) or [Cu4(μ-Hbes)3(μ-H2bes)(μ-fcba)]·4H2O (4), respectively. These four compounds were obtained as microcrystalline air-stable solids and characterized by standard methods, including the single-crystal X-ray diffraction. The structures of 1 and 2 feature distinct types of metal-organic chains driven by the μ3- or μ-OH- ligands along with the μ-benzenecarboxylate linkers. The structures of 3 and 4 disclose the chairlike Cu4 rings assembled from four μ-bridging and chelating aminoalcoholate ligands along with μ-benzenecarboxylate moieties playing a core-stabilizing role. Catalytic activity of 1-4 was investigated in two model reactions, namely, (a) the mild oxidation of saturated hydrocarbons with hydrogen peroxide to form alcohols and ketones and (b) the mild carboxylation of alkanes with carbon monoxide, water, and peroxodisulfate to generate carboxylic acids. Cyclohexane and propane were used as model cyclic and gaseous alkanes, while the substrate scope also included cyclopentane, cycloheptane, and cyclooctane. Different reaction parameters were investigated, including an effect of the acid cocatalyst and various selectivity parameters. The obtained total product yields (up to 34% based on C3H8 or up to 47% based on C6H12) in the carboxylation of propane and cyclohexane are remarkable taking into account an inertness of these saturated hydrocarbons and low reaction temperatures (50-60 °C). Apart from notable catalytic activity, this study showcases a novel time-dependent synthetic strategy for the self-assembly of two different Cu(II) compounds from the same reaction mixture.
- Costa, Ines F. M.,Kirillova, Marina V.,André, Vania,Fernandes, Tiago A.,Kirillov, Alexander M.
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supporting information
p. 14491 - 14503
(2021/07/19)
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- Mild oxidative functionalization of cycloalkanes catalyzed by novel dicopper(II) cores
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The search for new transition metal based catalytic systems that are active in the oxidative functionalization of such inert substrates as saturated hydrocarbons continues to be an important research direction in molecular catalysis. In the present study, two new copper(II) coordination compounds, namely a discrete dimer [Cu2(μ-H2tea)2(nfa)2]·2H2O (1) and a 1D coordination polymer [Cu2(μ-H2tea)2(μ-Htma)]n·4nH2O (2) were synthesized and applied as homogeneous catalysts for the mild oxidative functionalization of cycloalkanes (cyclopentane, cyclohexane, cycloheptane, and cyclooctane). Both products 1 and 2 were self-assembled in aqueous medium from copper(II) nitrate, triethanolamine (H3tea), sodium hydroxide, and 2-naphthoic (Hnfa) or trimesic (H3tma) acids, isolated as stable crystalline solids, and fully characterized by standard methods including single-crystal X-ray diffraction. Their structures feature a similar type of dicopper(II) triethanolaminate cores that are decorated by terminal or bridging aromatic carboxylate ligands. Two model catalytic reactions were investigated, namely the oxidation of cycloalkanes by H2O2 to produce cycloalkyl hydroperoxides as intermediate products and then a mixture of cyclic alcohols and ketones as final products, and the carboxylation of cycloalkanes with CO/S2O82?/H2O to form cycloalkanecarboxylic acids as main products. These model reactions undergo under very mild conditions (50?60 °C) and show good efficiency. Substrate scope, selectivity features, and the effects of reaction parameters were investigated and discussed in detail. This study widens the family of multicopper(II) cores capable of catalyzing the oxidative functionalization of saturated hydrocarbons under mild conditions.
- Trusau, Kiryl I.,Kirillova, Marina V.,André, Vania,Usevich, Andrew I.,Kirillov, Alexander M.
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- Mangana(iii/iv)electro-catalyzed C(sp3)-H azidation
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Manganaelectro-catalyzed azidation of otherwise inert C(sp3)-H bonds was accomplished using most user-friendly sodium azide as the nitrogen-source. The operationally simple, resource-economic C-H azidation strategy was characterized by mild reaction conditions, no directing group, traceless electrons as the sole redox-reagent, Earth-abundant manganese as the catalyst, high functional-group compatibility and high chemoselectivity, setting the stage for late-stage azidation of bioactive compounds. Detailed mechanistic studies by experiment, spectrophotometry and cyclic voltammetry provided strong support for metal-catalyzed aliphatic radical formation, along with subsequent azidyl radical transfer within a manganese(iii/iv) manifold.
- Meyer, Tjark H.,Samanta, Ramesh C.,Del Vecchio, Antonio,Ackermann, Lutz
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p. 2890 - 2897
(2021/03/14)
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- Ionic liquids vs conventional solvents: A comparative study in the selective catalytic oxidations promoted by oxovanadium(IV) complexes
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Two oxovanadium(IV) complexes containing 4-acyl-5-pyrazolonate-κ2-O,O' bidentate ligands with different chain lengths in the acyl moiety, namely HQC6 (complex I) and HQC17 (complex II), have been synthetized and full characterized, to study their catalytic activity toward the mild and selective oxidation of olefins or model organosulphur substrates, promoted by H2O2 or tert-butyl hydroperoxide (TBHP). The influence due to the type of solvent, likewise ionic liquids (ILs) or conventional medium, was analysed. H2O2 has proven less efficient, in comparison to TBHP. Quantum-chemical calculations have shown that, the key catalytic species involved and, consequently, the actual mechanism might be slightly different according to the oxidant used, i.e. the peroxo VO(QMe)(O2) adduct in the case of H2O2 and the tert-butylperoxo VO(QMe)2(OOt-Bu) adduct in the case of TBHP. Preliminary calculations suggested that, in ionic liquids, the VO(QMe)2 complex might reveal relatively unstable, hence qualitatively explaining the moderate efficiency observed in these media.
- Aschi, Massimiliano,Campitelli, Patrizio,Crucianelli, Marcello,Di Nicola, Corrado,Marchetti, Fabio,Pettinari, Riccardo
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- Homogeneous catalytic oxidation of alkenes employing mononuclear vanadium complex with hydrogen peroxide
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Abstract: Homogeneous liquid-phase oxidation of alkenes (allylbenzene, cis-cyclooctene, 4-chlorostyrene, styrene, 2-norbornene, 1-methyl cyclohexene, indene, lemonine, and 1-hexene) were catalyzed by using vanadium complex [VO(hyap)(acac)2] in existence of H2O2. The complex [VO(hyap)(acac)2] was formed as a crystal by the reaction of [VO(acac)2] and 2-hydroxyacetophenone (hyap) in the presence of methanol by refluxing the reaction mixture. Various analytical and spectroscopic techniques, namely FTIR, ESI–MS, UV–Vis, single-crystal XRD, and EPR, were used to analyze and optimize the structure of the complexes. Graphic abstract: [Figure not available: see fulltext.].
- Maurya, Abhishek
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p. 3261 - 3269
(2020/07/14)
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- Method for catalytic oxidation of cycloalkane by confinement porphyrin Co (II)
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The invention relates to a method for catalytic oxidation of cycloalkane by confinement porphyrin Co (II). The method comprises the following steps: dispersing confinement cobalt porphyrin (II) in cycloalkane, sealing the reaction system, heating to 100-130 DEG C while stirring, introducing oxygen to 0.2-3.0 MPa, keeping the set temperature and oxygen pressure, stirring to react for 3.0-24.0 h, and carrying out post-treatment on a reaction solution to obtain products naphthenic alcohol and naphthenic ketone. The method achieves high selectivity of naphthenic alcohol and naphthenic ketone, andeffectively inhibits the generation of aliphatic diacid. The aliphatic diacid is low in selectivity, so that the continuity of the cycloalkane oxidation process and the separation of the products arefacilitated; the method has the potential of solving the problem that naphthenic alcohol and naphthenic ketone are easily and deeply oxidized to generate aliphatic diacid in the industrial cycloalkanecatalytic oxidation process; and the method is a novel efficient and feasible method for selective catalytic oxidation of cycloalkane.
- -
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Paragraph 0071; 0072
(2020/05/01)
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- Confinement porphyrin Co (II), and preparation method and application thereof
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Confinement porphyrin Co (II). A preparation method includes: under acidic condition, performing condensation on aromatic aldehyde and pyrrole in equal molar ratio to obtain a phenylporphyrin compound, and carrying out metallization in a chloroform-methanol solution to obtain porphyrin Cu (II), performing bromination and demetalization by perchloric acid to obtain confinement porphyrin, performingstirring reflux on the confinement porphyrin in a methanol solution for 12.0-24.0 h to obtain confinement porphyrin Co (II). An application includes: dissolving the confinement porphyrin Co (II) in naphthenic hydrocarbon and sealing the reaction system, stirring and heating the reaction system to 100-130 DEG C and feeding oxygen to 0.2-3.0 MPa; maintaining the set temperature and oxygen pressureand performing a stirring reaction for 3.0-24.0 h; performing after treatment on the reaction liquid to prepare the product. In the invention, generation of fatty diacid is effectively inhibited, andcontinuity of a naphthenic hydrocarbon oxidization process and product separation is facilitated. The invention has the potential of solving the problem that naphthene alcohols and naphthene ketones are liable to undergo deep oxidization and form the fatty diacid in an industrial naphthenic hydrocarbon catalytic oxidation process.
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Paragraph 0103-0104
(2020/04/17)
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- Method for synergistically catalyzing and oxidizing cycloparaffin through confined metalloporphyrin cobalt (II)/Cu (II) salt
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The invention discloses a method for synergistically catalyzing and oxidizing cycloparaffin through confined metalloporphyrin cobalt (II)/Cu (II) salt. The preparation method comprises the following steps: dispersing confined metalloporphyrin cobalt (II) (0.001%-5%, g/mol) and Cu (II) salt (0.01%-10%, mol/mol) into cycloparaffin; and sealing the reaction system, heating the temperature to 90-150 DEG C while stirring, introducing an oxidant, keeping the set temperature and pressure, carrying out stirring and reacting for 2.0-24.0 hours, and carrying out after-treatment on the reaction solutionto obtain the products cycloalkyl alcohol and cycloalkyl ketone. The method disclosed by the invention has the advantages of high cycloalkyl alcohol and cycloalkyl ketone selectivity, low reaction temperature, few byproducts, small environmental influence and the like. In addition, the content of cycloalkyl hydroperoxide is low, and the safety coefficient is high. The invention provides an efficient, feasible and safe method for synthesizing cycloalkyl alcohol and cycloalkyl ketone through selective catalytic oxidation of cycloparaffin.
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Paragraph 0045-0046
(2020/12/10)
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- Catalytic Oxidative Deamination by Water with H2Liberation
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Selective oxidative deamination has long been considered to be an important but challenging transformation, although it is a common critical process in the metabolism of bioactive amino compounds. Most of the synthetic methods developed so far rely on the use of stoichiometric amounts of strong and toxic oxidants. Here we present a green and efficient method for oxidative deamination, using water as the oxidant, catalyzed by a ruthenium pincer complex. This unprecedented reaction protocol liberates hydrogen gas and avoids the use of sacrificial oxidants. A wide variety of primary amines are selectively transformed to carboxylates or ketones in good to high yields. It is noteworthy that mechanistic experiments and DFT calculations indicate that in addition to serving as the oxidant, water also plays an important role in assisting the hydrogen liberation steps involved in amine dehydrogenation.
- Tang, Shan,Rauch, Michael,Montag, Michael,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 20875 - 20882
(2020/12/23)
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- Electronic Asymmetry of an Annelated Pyridyl-Mesoionic Carbene Scaffold: Application in Pd(II)-Catalyzed Wacker-Type Oxidation of Olefins
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The two donor modules of an annelated pyridyl-mesoionic carbene ligand (aPmic) have different σ- and π-bonding characteristics leading to its electronic asymmetry. A Pd(II) complex 1 featuring aPmic catalyzes the oxidation of a wide range of terminal olefins to the corresponding methyl ketones in good to excellent yields in acetonitrile. The catalytic reaction is proposed to proceed via syn-peroxypalladation and a subsequent rate-limiting 1,2-hydride shift, which is supported by kinetic studies. The electronic asymmetry of aPmic renders a well-defined coordination sphere at Pd. The favored arrangement of reactants on the metal center features an olefin trans to the pyridyl module and a tbutylperoxide trans to the carbene. This arrangement gains added stability by the π-delocalization paved by the compatible orbitals on Pd, the pyridyl module, and the olefin that is perpendicular to the Pd(aPmic) plane. The π-interactions are absent in an alternate arrangement wherein the olefin is trans to the carbene. Density functional theory studies reveal the matching orbital overlaps responsible for the preferred arrangement over the other. This work provides an orbital description for the electronic asymmetry of aPmic.
- Bera, Jitendra K.,Dutta, Indranil,Kunnikuruvan, Sooraj,Reshi, Noor U Din,Saha, Sayantani,Yadav, Suman
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p. 11385 - 11393
(2020/11/23)
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- Catalytic Acceptorless Dehydrogenation of Aliphatic Alcohols
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We developed the first acceptorless dehydrogenation of aliphatic secondary alcohols to ketones under visible light irradiation at room temperature by devising a ternary hybrid catalyst system comprising a photoredox catalyst, a thiophosphate organocatalyst, and a nickel catalyst. The reaction proceeded through three main steps: hydrogen atom transfer from the α-C-H bond of an alcohol substrate to the thiyl radical of the photo-oxidized organocatalyst, interception of the generated carbon-centered radical with a nickel catalyst, and β-hydride elimination. The reaction proceeded in high yield under mild conditions without producing side products (except H2 gas) from various alcohols, including sterically hindered alcohols, a steroid, and a pharmaceutical derivative. This catalyst system also promoted acceptorless cross-dehydrogenative esterification from aldehydes and alcohols through hemiacetal intermediates.
- Fuse, Hiromu,Mitsunuma, Harunobu,Kanai, Motomu
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supporting information
p. 4493 - 4499
(2020/03/05)
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- Palladium supported on a novel ordered mesoporous polypyrrole/carbon nanocomposite as a powerful heterogeneous catalyst for the aerobic oxidation of alcohols to carboxylic acids and ketones on water
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Preparation of an ordered mesoporous polypyrrole/carbon (PPy/OMC) composite has been described through a two-step nanocasting process using KIT-6 as a template. Characterization of the PPy/OMC nanocomposite by various analysis methods such as TEM, XRD, TGA, SEM and N2 sorption confirmed the preparation of a material with ordered mesoporous structure, uniform pore size distribution, high surface area and high stability. This nanocomposite was then used for the immobilization of palladium nanoparticles. The nanoparticles were almost uniformly distributed on the support with a narrow particle size of 20-25 nm, confirmed by various analysis methods. Performance of the Pd?PPy/OMC catalyst was evaluated in the aerobic oxidation of various primary and secondary alcohols on water as a green solvent, giving the corresponding carboxylic acids and ketones in high yields and excellent selectivity. The catalyst could also be reused for at least 10 reaction runs without losing its catalytic activity and selectivity. High catalytic efficiency of the catalyst can be attributed to a strong synergism between the PPy/OMC and that of supported Pd nanoparticles.
- Ganji, Nasim,Karimi, Babak,Najafvand-Derikvandi, Sepideh,Vali, Hojatollah
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p. 13616 - 13631
(2020/04/24)
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- Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation
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An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstratedviathe facile oxidation of structurally complicated natural products.
- Ye, Danfeng,Liu, Zhiyuan,Sessler, Jonathan L.,Lei, Chuanhu
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supporting information
p. 11811 - 11814
(2020/10/13)
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- Alcohol Oxidations by Schiff Base Manganese(III) Complexes
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Asymmetric Schiff base manganese(III) complexes involving salen ligands, N,N'-bis(salicylidene)2,3-diaminopyridine, N,N'-bis(3-methoxysalicylidene)2,3-diaminopyridine, N,N'-bis(3,5-di-tert-butylsalicylidene)2,3-diaminopyridine and N,N'-bis(3,5-di-chloro-salicylidene)2,3-diaminopyridine were prepared and their catalytic activity was investigated in the oxidation of some primary and secondary alcohols. During optimization of oxidation reactions, Mn-4, bearing electron withdrawing N,N'-Bis(3,5-di-chloro-salicylidene)2,3-diaminopyridine ligand, showed higher activity than other catalysts tested. The catalytic reactions were carried out in the presence of various oxidants such as oxygen, hydrogen peroxide or tert-butyl hydroperoxide (TBHP) and additives such as acetic acid and imidazole. The oxidant/additive combination of TBHP and imidazole was shown to be effective for the oxidation process and the degree of their impact on oxidation reaction was found highly dependent on a balanced ratio between them. Mn-4 was selected as the most effective catalyst under optimized reaction conditions and revealed efficient for the oxidation of secondary alcohols.
- Neshat, Abdollah,Kakavand, Meysam,Osanlou, Farzane,Mastrorilli, Piero,Schingaro, Emanuela,Mesto, Ernesto,Todisco, Stefano
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p. 480 - 490
(2020/02/05)
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- Rare earth Ce- and Nd-doped spinel nickel ferrites as effective heterogeneous catalysts in the (ep)oxidation of alkenes
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Cerium (Ce)- and neodymium (Nd)-doped spinel nickel ferrites catalysts system were synthesized using a cost-effective sol–gel route. The as-prepared nickel ferrites and its doped Ce and Nd nanomaterials were characterized in terms of Fourier transform infrared spectrophotometry, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, selected area diffraction pattern, zeta potential and magnetism techniques. Their catalytic potential was examined in the (ep)oxidation of 1,2-cyclooctene by using hydrogen peroxide (H2O2) or tert-butylhydroperoxide (t-BuOOH). Optimization of various parameters, including solvent, oxidant and catalyst type revealed that chloroform (CHCl3) or 1,2-dichloroethane as a solvent and t-BuOOH as an oxidant were found to be the best choice for this catalytic system. The catalytic efficiency was found as Nd–NiFe2O4 > Ce–NiFe2O4 > NiFe2O4. Further, the applied nanocatalysts could be easily renovated and exhibited high catalytic reactivity for 5 times of recycling experiments with long-time durability. A reasonable discussion of the mechanism reaction reinforced the action of these spinel catalysts.
- Adam, Mohamed Shaker S.,Hafez, Aly M.,Khalaf, Mai M.
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p. 3237 - 3250
(2020/07/09)
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- Catalytic oxidation of cycloalkanes by porphyrin cobalt(II) through efficient utilization of oxidation intermediates
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The catalytic oxidation of cycloalkanes using molecular oxygen employing porphyrin cobalt(II) as catalyst was enhanced through use of cycloalkyl hydroperoxides, which are the primary intermediates in oxidation of cycloalkanes, as additional oxidants to further oxidize cycloalkanes in the presence of porphyrin copper(II), especially for cyclohexane, for which the selectivity was enhanced from 88.6 to 97.2% to the KA oil; at the same time, the conversion of cyclohexane was enhanced from 3.88 to 4.41%. The enhanced efficiency and selectivity were mainly attributed to the avoided autoxidation of cycloalkanes and efficient utilization of oxidation intermediate cycloalkyl hydroperoxides as additional oxidants instead of conventional thermal decomposition. In addition to cyclohexane, the protocol presented in this research is also very applicable in the oxidation of other cycloalkanes such as cyclooctane, cycloheptane and cyclopentane, and can serve as a applicable and efficient strategy to boost the conversion and selectivity simultaneously in oxidation of alkanes. This work also is a very important reference for the extensive application of metalloporphyrins in catalysis chemistry.
- Shen, Hai M.,Wang, Xiong,Guo, A. Bing,Zhang, Long,She, Yuan B.
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p. 1166 - 1173
(2020/09/17)
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- H2-free Synthesis of Aromatic, Cyclic and Linear Oxygenates from CO2
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The synthesis of oxygenate products, including cyclic ketones and phenol, from carbon dioxide and water in the absence of gas-phase hydrogen has been demonstrated. The reaction takes place in subcritical conditions at 300 °C and pressure at room temperature of 25 barg. This is the first observation of the production of cyclic ketones by this route and represents a step towards the synthesis of valuable intermediates and products, including methanol, without relying on fossil sources or hydrogen, which carries a high carbon footprint in its production by conventional methods. Inspiration for these studies was taken directly from natural processes occurring in hydrothermal environments around ocean vents. Bulk iron and iron oxides were investigated to provide a benchmark for further studies, whereas reactions over alumina and zeolite-based catalysts were employed to demonstrate, for the first time, the ability to use catalyst properties such as acidity and pore size to direct the reaction towards specific products. Bulk iron and iron oxides produced methanol as the major product in concentrations of approximately 2–3 mmol L?1. By limiting the hydrogen availability through increasing the initial CO2/H2O ratio the reaction could be directed to yield phenol. Alumina and zeolites were both observed to enhance the production of longer-chained species (up to C8), likely owing to the role of acid sites in catalysing rapid oligomerisation reactions. Notably, zeolite-based catalysts promoted the formation of cyclic ketones. These proof-of-concept studies show the potential of this process to contribute to sustainable development through either targeting methanol production as part of a “methanol economy” or longer-chained species including phenol and cyclic ketones.
- Gomez, Laura Quintana,Shehab, Amal K.,Al-Shathr, Ali,Ingram, William,Konstantinova, Mariia,Cumming, Denis,McGregor, James
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p. 647 - 658
(2020/01/24)
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- Oxidation of Alkenes by Water with H2 Liberation
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Oxidation by water with H2 liberation is highly desirable, as it can serve as an environmentally friendly way for the oxidation of organic compounds. Herein, we report the oxidation of alkenes with water as the oxidant by using a catalyst combination of a dearomatized acridine-based PNP-Ru complex and indium(III) triflate. Compared to traditional Wacker-type oxidation, this transformation avoids the use of added chemical oxidants and liberates hydrogen gas as the only byproduct.
- Ben-David, Yehoshoa,Milstein, David,Tang, Shan
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supporting information
p. 5980 - 5984
(2020/04/27)
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- Heavy-Metal-Free Fischer-Tropsch Type Reaction: Sequential Homologation of Alkylborane Using a Combination of CO and Hydrides as Methylene Source
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Carbon homologation reactions occur within the well-known Fischer-Tropsch process, usually mediated by transition metal catalysts at high temperature. Here we report the low-temperature, heavy-metal-free homologation of a carbon chain using CO as a C1-source showing for the first time that transition-metal catalysts are not required for Fischer-Tropsch-type reactivity. Reaction of an alkylborane in the presence of either LiHBEt3 or LiAlH4 resulted in multiple CO insertion/reduction events to afford elongated chains by more than two methylene (-CH2-) units, affording aldehyde products upon oxidative aqueous workup. Theoretical and experimental mechanistic studies indicate that the boron terminus is responsible for CO incorporation as well as sequential hydride delivery leading to reduction of acylborane intermediates to alkylboranes.
- Phanopoulos, Andreas,Pal, Shrinwantu,Kawakami, Takafumi,Nozaki, Kyoko
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supporting information
p. 14064 - 14068
(2020/09/02)
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- Anodic oxidation triggered divergent 1,2- And 1,4-group transfer reactions of β-hydroxycarboxylic acids enabled by electrochemical regulation
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We report a set of electrochemically regulated protocols for the divergent synthesis of ketones and β-keto esters from the same β-hydroxycarboxylic acid starting materials. Enabled by electrochemical control, the anodic oxidation of carboxylic acids proceeded in either a one-electron or a two-electron pathway, leading to a 1,4-aryl transfer or a semipinacol-type 1,2-group transfer product with excellent chemoselectivity. The 1,4-aryl transfer represents an unprecedented example of carbon-to-oxygen group transfer proceeding via a radical mechanism. In contrast to previously reported radical group transfer reactions, this 1,4-group transfer process features the migration of electron-rich aryl substituents. Furthermore, with these chemoselective electrochemical oxidation protocols, a range of ketones and β-keto esters including those possessing a challenging-to-access medium-sized ring could be synthesized in excellent yields. This journal is
- Jiang, Yangye,Lu, Gang,Mo, Fanyang,Yang, Jianxin,Yang, Yang,Yin, Yunxing,Zeng, Chengchu,Zhang, Lei,Zhang, Xianhao,Zhang, Zhenxing
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p. 12021 - 12028
(2020/11/26)
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- One-pot biosynthesis of 1,6-hexanediol from cyclohexane by: De novo designed cascade biocatalysis
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1,6-Hexanediol (HDO) is an important precursor in the polymer industry. The current industrial route to produce HDO involves energy intensive and hazardous multistage (four-pot-four-step) chemical reactions using cyclohexane (CH) as the starting material, which leads to serious environmental problems. Here, we report the development of a biocatalytic cascade process for the biotransformation of CH to HDO under mild conditions in a one-pot-one-step manner. This cascade biocatalysis operates by using a microbial consortium composed of three E. coli cell modules, each containing the necessary enzymes. The cell modules with assigned functions were engineered in parallel, followed by combination to construct E. coli consortia for use in biotransformations. The engineered E. coli consortia, which contained the corresponding cell modules, efficiently converted not only CH or cyclohexanol to HDO, but also other cycloalkanes or cycloalkanols to related dihydric alcohols. In conclusion, the newly developed biocatalytic process provides a promising alternative to the current industrial process for manufacturing HDO and related dihydric alcohols. This journal is
- Kang, Lixin,Li, Aitao,Li, Qian,Li, Renjie,Wang, Fei,Yu, Xiaojuan,Zhang, Zhongwei,Zhao, Jing
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p. 7476 - 7483
(2020/11/23)
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- Method for preparing naphthenic alcohol and naphthenone by using molecular oxygen to selectively oxidize naphthenic hydrocarbon under synergistic catalysis of cobalt (II) salt/copper (II) salt
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The invention provides a method for preparing naphthenic alcohol and naphthenone by using molecular oxygen to selectively oxidize naphthenic hydrocarbon under synergistic catalysis of a cobalt (II) salt/copper (II) salt. The method comprises the following steps: in an agate ball-milling tank, ball-milling a main catalyst cobalt (II) salt and a cocatalyst copper (II) salt at room temperature according to a molar ratio to obtain a cobalt (II) salt/copper (II) salt composite catalyst; in a stainless steel high-pressure reaction kettle with a polytetrafluoroethylene liner, dispersing the cobalt (II) salt/copper (II) salt composite catalyst into the naphthenic hydrocarbon, sealing the reaction kettle, conducting stirring and heating, and introducing an oxidizing agent oxygen; maintaining a settemperature and oxygen pressure to perform stirring reaction; and after the reaction, adding triphenylphosphine into a reaction mixture, and conducting stirring to reduce a generated peroxide at roomtemperature, so as to obtain the naphthenic alcohol and the naphthenone. The catalyst is cheap and easily available and the synthesis cost is low; the selectivity is high and generation of aliphatic diacid is effectively inhibited; and the aliphatic diacid selectivity is low, and continuity of the naphthenic hydrocarbon oxidization process and separation of products are facilitated.
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Paragraph 0108-0109
(2020/01/03)
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- Method for synergistically catalyzing and oxidizing cycloalkane by porphyrin cobalt (II)/zinc (II) salt
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The invention discloses a method for synergistically catalyzing and oxidizing cycloalkane by porphyrin cobalt (II)/zinc (II) salt. The method comprises the following steps: dispersing porphyrin cobalt(II) and a zinc (II) salt in cycloalkane, sealing the reaction system, carrying out heating to 100-130 DEG C while stirring, introducing oxygen to 0.2-3 MPa, keeping a set temperature and oxygen pressure, carrying out stirring for reacting for 3-24 hours, and then carrying out after-treatment on the reaction solution to obtain product naphthenic alcohol and naphthenic ketone. According to the method disclosed by the invention, the naphthenic alcohol and the naphthenic ketone are high in selectivity, and generation of aliphatic diacid is effectively inhibited; a cocatalyst is cheap and is easily available, and synthesis cost of the naphthenic alcohol and naphthenic ketone is low; the aliphatic diacid is low in selectivity, so that continuity of a cycloalkane oxidation process and separation of products are facilitated; and the method has a potential of solving the problem that naphthenic alcohol and naphthenic ketone are easily and deeply oxidized to generate aliphatic diacid in industrial cycloalkane catalytic oxidation processes. The method is a novel efficient feasible method for selective catalytic oxidation of cycloalkane.
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Paragraph 0087; 0088
(2019/12/25)
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- A mild reaction conditions of the catalytic oxidation of cyclooctane new method (by machine translation)
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A cyclooctane catalytic oxidation method, said method comprising: the metal porphyrin, cyclooctane mixing, at a temperature of 80 - 120 °C, O2 The pressure 0.6 - 2 mpa reaction under the condition of 2 - 48 H-, after processing reaction liquid, separating the oxidation product [...], cyclooctanol, ring octanone; the invention relates to a new method of cyclooctane catalytic oxidation reaction temperature is low, the catalyst amount is less, but in order to O2 As the oxidizing agent, environmental protection, cyclooctane can be the highly selective oxide cyclooctanol, ring octanone and [...], the catalytic oxidation of cyclooctane new method also has the simple operation, does not use an organic solvent, ring octanone selectivity and the like. (by machine translation)
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Paragraph 0017-0018; 0021-0022; 0031-0032
(2019/03/28)
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- Method for (II) preparing/cycloalkanol and cycloalkanone by synergetic (II) catalysis of molecular oxygen-selective oxidation of cycloalkane by using cobalt salt, namely, zinc salt of zinc salt (by machine translation)
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In a stainless steel (II) high /(II) pressure reaction kettle with a polytetrafluoroethylene inner container, the cobalt salt is stirred and heated at room temperature to give an oxidant oxygen (II); a set temperature (II) and an oxygen pressure stirring reaction are kept; and the reaction (II) mixture/is (II) stirred and reduced to generate a peroxide, namely cycloalkanol and cycloalkanone (II)/(II). The catalyst has the advantages of cheap and easily available catalyst, low synthesis cost, high selectivity, effective inhibition of generation of aliphatic diacid, low selectivity of aliphatic diacid, and facilitation of serialization of the naphthenic acid process and separation of products. (by machine translation)
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Paragraph 0105-0106
(2019/12/08)
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- Synthesis, structural characterization and C–H activation property of a tetra-iron(III) cluster
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A non-heme tetra-iron cluster, [Fe4 III(μ-O)2(μ-OAc)6(2,2′-bpy)2(H2O)2](NO3 ?)(OH?) (1), [OAc = acetate; 2,2′-bpy = 2,2′-bipyridine] containing oxido- and acetato-bridges was synthesized and structurally characterized by different spectroscopic methods including single crystal X-ray diffraction studies. X-ray crystal structure analysis of 1 revealed that tetra-iron complex was crystallized in monoclinic system with C2/c space group. Each of the Fe centres in 1 was found to exist in octahedral geometry and interconnected by oxido- and acetato-bridges. Bond valence sum (BVS) calculation recommended the existence of iron centres in +3 oxidation state. Variable temperature magnetic measurement authenticated the dominating antiferromagnetic ordering among the iron centres in the solid state of 1. This tetra-iron cluster was also evaluated as an efficient catalytic system towards the oxidation of both linear & cyclic alkanes without production of primary C–H bond oxidation products. Oxidation of secondary C–H bonds attested the formation of both the corresponding alcohols & ketones in 27–900 TONs. The tetra-iron catalytic system with Alcohol/Ketone values 0.2–1.7 indicated the involvement of freely diffusing carbon-centered radicals rather than metal based oxidant.
- Dey, Dhananjay,Patra, Moumita,Al-Hunaiti, Afnan,Yadav, Hare Ram,Al-mherat, Afrah,Arar, Sharif,Maji, Milan,Choudhury, Angshuman Roy,Biswas, Bhaskar
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p. 220 - 226
(2019/01/05)
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- Three Generations of Cobalt Porphyrins as Catalysts in the Oxidation of Cycloalkanes
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Three generations of cobalt porphyrins were synthesized, physicochemically characterized by FTIR and UV/Vis spectroscopy as well as cyclic voltammetry and applied as catalysts in the oxidation of cycloalkanes with atmospheric molecular oxygen under mild c
- Pamin, Katarzyna,Tabor, Edyta,Górecka, Sylwia,Kubiak, W?adys?aw W.,Rutkowska-Zbik, Dorota,Po?towicz, Jan
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p. 684 - 691
(2018/12/13)
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- Iron-catalyzed oxidative functionalization of C(sp3)-H bonds under bromide-synergized mild conditions
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An efficient oxidation and functionalization of C-H bonds with an inorganic-ligand supported iron catalyst and hydrogen peroxide to prepare the corresponding ketones was achieved using the bromide ion as a promoter. Preliminary mechanistic investigations indicated that the bromide ion can bind to FeMo6 to form a supramolecular species (FeMo6·2Br), which can effectively catalyze the reaction.
- Yu, Han,Zhao, Qixin,Wei, Zheyu,Wu, Zhikang,Li, Qi,Han, Sheng,Wei, Yongge
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supporting information
p. 7840 - 7843
(2019/07/12)
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- Direct Observation of Primary C?H Bond Oxidation by an Oxido-Iron(IV) Porphyrin π-Radical Cation Complex in a Fluorinated Carbon Solvent
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Oxido-iron(IV) porphyrin π-radical cation species are involved in a variety of heme-containing enzymes and have characteristic oxidation states consisting of a high-valent iron center and a π-conjugated macrocyclic ligand. However, the short lifetime of the complex has hampered detailed reactivity studies. Reported herein is a remarkable increase in the lifetime (80 s at 10 °C) of FeIV(TMP+.)(O)(Cl) (2; TMP=5,10,15,20-tetramesitylporphyrin dianion), produced by the oxidation of FeIII(TMP)(Cl) (1) by ozone in α,α,α-trifluorotoluene (TFT). The lifetime is 720 times longer compared to that of the currently most stable species reported to date. The increase in the lifetime improves the reaction efficiency of 2 toward inert alkane substrates, and allowed observation of the reaction of 2 with a primary C?H bond (BDEC-H=ca. 100 kcal mol?1) directly. Activation parameters for cyclohexane hydroxylation were also obtained.
- Morimoto, Yuma,Shimaoka, Yuki,Ishimizu, Yuri,Fujii, Hiroshi,Itoh, Shinobu
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supporting information
p. 10863 - 10866
(2019/07/17)
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- Novel cycloalkane catalytic oxidation method promoted with copper porphyrin
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The invention discloses a cycloalkane catalytic oxidation method promoted with copper porphyrin, which comprises the following steps of mixing cycloalkane, a main catalyst and a cocatalyst, performingreaction for 2-48 h under the conditions that the temperature is 100-160 DEG C and O2 pressure is 0.8-2 MPa, and then performing aftertreatment on a reaction liquid to obtain alkyl diacid, cycloalkylalcohol and cycloalkyl ketone as oxidative products. The novel cycloalkane catalytic oxidation method involved is high in selectivity of oxidative products, low in reaction temperature and less in dosage of catalyst, is environmentally friendly by taking O2 as an oxidant, can highly selectively realize cycloalkane catalytic oxidation and also has the advantages of simpleness in operation, no useof an organic solvent and the like.
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Paragraph 0049; 0050
(2019/03/28)
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- A practical innovative method for highly selective oxidation of alkenes and alkanes using Fe (III) and Mn (III) porphyrins supported onto multi-wall carbon nanotubes as reusable heterogeneous catalysts
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Functionalized multi-walled carbon nanotubes were used for covalent immobilization of meso-tetrakis(4-carboxyphenyl) porphyrinatoiron (III) chloride [Fe (TCPP)Cl] and meso-tetrakis(4-carboxyphenyl) porphyrinatomanganese (III) acetate [Mn (TCPP)OAc]. The full characterization of the hybrid porphyrinic nanomaterials, by Fourier transform-infrared and UV–Vis spectroscopy, transmission electron microscopy, thermogravimetry and flame atomic absorption spectrometry is described. The oxidation of alkenes and alkanes with molecular oxygen as green oxidant in the presence of Mn- and Fe-catalysts has been studied in a comparative manner. The Fe-catalyst was shown to have higher catalytic activity compared with the Mn-catalyst. In addition, both separable solid catalysts can be recovered and reused at least 10 times along with good yields.
- Rayati, Saeed,Nafarieh, Parinaz
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- Sonochemical Preparation of Dipicolinamide Mn-complexes and Their Application as Catalysts Towards Sono-synthesis of Ketones
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A series of non-heme Mn-complexes has been synthesized by the sonication of manganese (II)chloride and bis-amides (condensation products of 2-picolinic acid and o-phenylenediamines). The Mn-complexes effectively promote the oxidation of unactivated aliphatic and benzylic C─H and N-bearing heterocycles substrates with low catalyst loading using eco-friendly hydrogen peroxide in the presence of acetic acid as additive under ultrasonic irradiation. Chromatographic studies revealed that the corresponding ketones are the only detectable products. Noteworthy, the presence of electron donors in the catalyst structure significantly increased the reaction yields. The substantial lowering of the oxidation reaction yields by adding ionol (2,6-di-tert-butyl-4-methylphenol) as a free radical trap suggesting a free radical reaction pathway.
- Arafa, Wael A. A.
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p. 1403 - 1412
(2019/02/25)
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- Novel method for zinc protoporphyrin promoted catalyzed oxidation of cycloalkanes
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The invention relates to a method for zinc protoporphyrin promoted catalyzed oxidation of cycloalkanes. The method comprises the following steps: mixing the cycloalkanes, a main catalyst and a cocatalyst, carrying out a reaction for 2 to 48 hours under the condition that the temperature is 100 DEG C to 160 DEG C and the O2 pressure is 0.8MPa to 2MPa, then, subjecting a reaction solution to aftertreatment, thereby obtaining oxidation products, i.e., alkyl diacid, cycloalkyl alcohol and cycloalkyl ketone. According to the novel method for catalyzed oxidation of the cycloalkanes, provided by theinvention, the selectivity of the oxidation products is high, the reaction temperature is low, and the consumption of catalysts is low; O2 serves as an oxidant, so that the method is environmentally friendly, and the catalyzed oxidation of the cycloalkanes is achieved in a high-selectivity manner; the novel method for catalyzed oxidation of the cycloalkanes further has the advantages that the operation is simple, no organic solvent is used, and the like.
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Paragraph 0049; 0050
(2019/03/28)
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- Ruthenium Trichloride Catalyst in Water: Ru Colloids versus Ru Dimer Characterization Investigations
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An easy-to-prepare ruthenium catalyst obtained from ruthenium(III) trichloride in water demonstrates efficient performances in the oxidation of several cycloalkanes with high selectivity toward the ketone. In this work, several physicochemical techniques were used to demonstrate the real nature of the ruthenium salt still unknown in water and to define the active species for this Csp3-H bond functionalization. From transmission electron microscopy analyses corroborated by SAXS analyses, spherical nanoobjects were observed with an average diameter of 1.75 nm, thus being in favor of the formation of reduced species. However, further investigations, based on X-ray scattering and absorption analyses, showed no evidence of the presence of a metallic Ru-Ru bond, proof of zerovalent nanoparticles, but the existence of Ru-O and Ru-Cl bonds, and thus the formation of a water-soluble complex. The EXAFS (extended X-ray absorption fine structure) spectra revealed the presence of an oxygen-bridged diruthenium complex [Ru(OH)xCl3-x]2(μ-O) with a high oxidation state in agreement with catalytic results. This study constitutes a significant advance to determine the true nature of the RuCl3·3H2O salt in water and proves once again the invasive nature of the electron beam in microscopy experiments, routinely used in nanochemistry.
- Lebedeva, Anastasia,Albuquerque, Brunno L.,Domingos, Josiel B.,Lamonier, Jean-Fran?ois,Giraudon, Jean-Marc,Lecante, Pierre,Denicourt-Nowicki, Audrey,Roucoux, Alain
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p. 4141 - 4151
(2019/03/26)
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- Mild C-H functionalization of alkanes catalyzed by bioinspired copper(ii) cores
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Three new copper(ii) coordination compounds formulated as [Cu(H1.5bdea)2](hba)·2H2O (1), [Cu2(μ-Hbdea)2(aca)2]·4H2O (2), and [Cu2(μ-Hbdea)2(μ-bdca)]n (3) were generated by aqueous medium self-assembly synthesis from Cu(NO3)2, N-butyldiethanolamine (H2bdea) as a main N,O-chelating building block and different carboxylic acids [4-hydroxybenzoic (Hhba), 9-anthracenecarboxylic (Haca), or 4,4′-biphenyldicarboxylic (H2bdca) acid] as supporting carboxylate ligands. The structures of products range from discrete mono- (1) or dicopper(ii) (2) cores to a 1D coordination polymer (3), and widen a family of copper(ii) coordination compounds derived from H2bdea. The obtained compounds were applied as bioinspired homogeneous catalysts for the mild C-H functionalization of saturated hydrocarbons (cyclic and linear C5-C8 alkanes). Two model catalytic reactions were explored, namely the oxidation of hydrocarbons with H2O2 to a mixture of alcohols and ketones, and the carboxylation of alkanes with CO/S2O82- to carboxylic acids. Both processes proceed under mild conditions with a high efficiency and the effects of different parameters (e.g., reaction time and presence of acid promoter, amount of catalyst and solvent composition, substrate scope and selectivity features) were studied and discussed in detail. In particular, an interesting promoting effect of water was unveiled in the oxidation of cyclohexane that is especially remarkable in the reaction catalyzed by 3, thus allowing a potential use of diluted, in situ generated solutions of hydrogen peroxide. Moreover, the obtained values of product yields (up to 41% based on alkane substrate) are very high when dealing with the C-H functionalization of saturated hydrocarbons and the mild conditions of these catalytic reactions (50-60 °C, H2O/CH3CN medium). This study thus contributes to an important field of alkane functionalization and provides a notable example of new Cu-based catalytic systems that can be easily generated by self-assembly from simple and low-cost chemicals.
- Kirillova, Marina V.,Fernandes, Tiago A.,André, Vania,Kirillov, Alexander M.
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supporting information
p. 7706 - 7714
(2019/08/30)
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- Oxidation of secondary alcohols using solid-supported hypervalent iodine catalysts
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It is shown how secondary alcohols are oxidized to provide the corresponding ketones by use of Oxone and solid-supported hypervalent iodine catalysts. Under experimentally simple conditions with acetonitrile at elevated temperatures, excellent conversions were achieved with low catalyst loadings (0.2-5 mol%) when employing the conjugates 5 and 6 derived from IBX and IBS. The catalysts are broadly applicable to a range of alcohol substrates. Of primary importance with respect to sustainability issues, the metal-free catalysts are easily removed from the reaction mixture through filtration, and they can be re-used in oxidation processes for multiple times, without loss of catalytic activity.
- Ballaschk, Frederic,Kirsch, Stefan F.
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supporting information
p. 5896 - 5903
(2019/11/11)
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- Synthesis, crystal structure and immobilization of a new cobalt(ii) complex with a 2,4,6-tris(2-pyridyl)-1,3,5-triazine ligand on modified magnetic nanoparticles as a catalyst for the oxidation of alkanes
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A new Co(ii) complex with formula [Co(tptz)Cl2]·2H2O (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine) has been synthesized and characterized by X-ray crystallography, elemental analyses and spectroscopic methods. It was then supported on modified Fe3O4 nanoparticles using tetraethylorthosilicate (TEOS) and (3-aminopropyl)trimethoxysilane (APTMS) and designated as a Fe3O4@SiO2@APTMS@complex nanocatalyst. The prepared nanocatalyst was characterized by means of FT-IR, Raman, XPS, EDX, XRD, VSM, SEM and TEM studies. The catalytic activity of the [Co(tptz)Cl2]·2H2O complex and Fe3O4@SiO2@APTMS@complex designated as catalysts A and B was used for oxidation of activated secondary alkanes such as fluorene, diphenyl methane, ethylbenzene, cyclooctane and adamantane. Observation of 39-99% conversions and 27-100% selectivities toward the corresponding ketones as well as the heterogeneity and reusability of the catalyst B seem promising.
- Azarkamanzad, Zahra,Farzaneh, Faezeh,Maghami, Mahboobeh,Simpson, Jim
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p. 12020 - 12031
(2019/08/07)
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- Method for preparing lactone compound by cycloalkane compound through oxidation
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The invention discloses a method for preparing a lactone compound by a cycloalkane compound through oxidation. The method comprises the following steps of using the cycloalkane compound as the raw material, and further oxidizing by a catalysis system under the oxygen-containing atmosphere, so as to obtain the lactone compound, wherein the catalysis system comprises a catalyst and an additive; thecatalyst is selected from a cyclic organic nitrogen and oxygen free radical precursor in formulas (I), (II), (III) and (IV); in the formula, R1, R2 and R3 are independently selected from hydrogen atom, alkyl, cycloalkyl, aryl, heterocycle, hydroxyl, nitryl, or halogen, or at least two of R1, R2 and R3 form loops; the additive is selected from an aldehyde compound. The preparation method has the advantages that the corresponding lactone is prepared by the cycloalkane compound through a one-step method; the conditions are mild, the safety is high, and the metal catalytic oxidization is avoided;the selectivity of the target product, namely the lactone compound, is high. The formulae are shown in the description.
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Paragraph 0064; 0065; 0116-0119
(2019/02/04)
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- A Cu-Doped ZIF-8 metal organic framework as a heterogeneous solid catalyst for aerobic oxidation of benzylic hydrocarbons
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Mixed-metal metal organic frameworks have received considerable attention in recent years and it has been shown that the activity of the parent metal organic framework (MOF) is often enhanced upon doping with external metal ions within the framework. In this context, Cu2+ ions with different loadings were incorporated within the ZIF-8 framework to obtain a series of Cu-doped ZIF-8 materials and their activity was examined in the aerobic oxidation of hydrocarbons. The as-synthesized Cu-doped solids were characterized by powder X-ray diffraction (XRD), ultraviolet diffuse reflectance spectroscopy (UV-DRS), scanning electron microscopy (SEM), Fourier Transform infrared (FT-IR), electron paramagnetic resonance (EPR) and inductively coupled plasma (ICP) analysis. The experimental results revealed that the activity of Cu-doped ZIF-8 is much higher than that of the parent ZIF-8 in all the tested substrates at 120 °C. Furthermore, the activity of the Cu-doped ZIF-8 with the highest Cu loading was eight fold higher than that of the parent ZIF-8 in the aerobic oxidation of cyclooctane (1) at 120 °C with more than 80% selectivity to the corresponding cyclooctanol/cyclooctanone (ol/one) mixture. Cu-doped ZIF-8 was reused two times with no significant drop in its activity under identical conditions. Furthermore, comparison of the two times reused solid with that of the fresh solid by powder XRD and SEM analysis revealed identical structural integrity and morphology, respectively during the oxidation reactions.
- Nagarjun, Nagarathinam,Dhakshinamoorthy, Amarajothi
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supporting information
p. 18702 - 18712
(2019/12/09)
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- Molybdenum(II) Complexes with α-Diimines: Catalytic Activity in Organic and Ionic Liquid Solvents
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The new [MoX(η3-C3H5)(CO)2(α-diimine)] complexes with: (i) X = Br or triflate and α-diimine = 1,10-phenanthroline (phen) and dipyridophenazine (dppz); and (ii) X = Br and α-diimine = phen and dppz, with several substituents, are synthesized and characterized. The structures of [MoBr(η3-C3H5)(CO)2(Cl-phen)] and [Mo(CF3SO3)(η3-C3H5)(CO)2(dppz)] are determined by using single-crystal X-ray diffraction. These and three complexes of 2,2′-bipyridyl (bpy), and its two derivatives with Me and tBu substituents, are tested in the homogeneous catalytic epoxidation of several olefins in dichloromethane, exhibiting, in general, a good selectivity towards the respective epoxide and relatively low TOFs. For the first time, the oxidation of cis-cyclooctene with some of these catalysts is also conducted in a variety of room-temperature ionic liquids (RTILs). In the presence of [MoBr(η3-C3H5)(CO)2(phen)], the conversions, in general, increase, compared with the reactions in organic solvents. Interestingly, different chemoselectivity is found when [C6mim][Ntf2] and [C2mim][FAP] are used with diol (24–26 %). On the other hand, [MoBr(η3-C3H5)(CO)2(L)] (L = Me-phen or dppz) exhibits much lower conversions in the RTILs tested than in common organic solvents.
- Saraiva, Marta S.,Nunes, Carla D.,Félix, Vítor,Ribeiro, Ana P. C.,de Castro, Carlos Nieto,Calhorda, Maria José
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supporting information
p. 3922 - 3932
(2018/09/10)
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- Liquid-phase oxidation of alkanes with molecular oxygen catalyzed by high valent iron-based perovskite
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Hexagonal BaFeO3-δ containing high valent iron species acted as an efficient heterogeneous catalyst for the aerobic oxidation of alkanes without the need for additives. The activity of BaFeO3-δ was much higher than that of typical Fe3+/Fe2+-containing iron oxide-based catalysts, and the recovered catalyst could be reused without significant loss of catalytic performance.
- Shibata, Satomi,Sugahara, Kosei,Kamata, Keigo,Hara, Michikazu
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supporting information
p. 6772 - 6775
(2018/06/26)
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- ATP3 and MTP3: Easily Prepared Stable Perruthenate Salts for Oxidation Applications in Synthesis
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The Ley–Griffith tetra-n-propylammonium perruthenate (TPAP) catalyst has been widely deployed by the synthesis community, mainly for the oxidation of alcohols to aldehydes and ketones, but also for a variety of other synthetic transformations (e.g. diol cleavage, isomerizations, imine formation and heterocyclic synthesis). Such popularity has been forged on broad reaction scope, functional group tolerance, mild conditions, and commercial catalyst supply. However, the mild instability of TPAP creates preparation, storage, and reaction reproducibility issues, due to unpreventable slow decomposition. In search of attributes conducive to catalyst longevity an extensive range of novel perruthenate salts were prepared. Subsequent evaluation unearthed a set of readily synthesized, bench stable, phosphonium perruthenates (ATP3 and MTP3) that mirror the reactivity of TPAP, but avoid storage decomposition issues.
- Moore, Peter W.,Read, Christopher D. G.,Bernhardt, Paul V.,Williams, Craig M.
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supporting information
p. 4556 - 4561
(2018/03/13)
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