- Au-Carbon Electronic Interaction Mediated Selective Oxidation of Styrene
-
The rational design of the Au-support electronic interaction is crucial for Au nanocatalysis. We herein report our observation of electronic perturbation at the Au-carbon interface and its application in controlling the reaction selectivity in styrene oxidation. Ultrasmall Au nanocatalysts were grown in situ on a nitrided carbon support where the nitrogen-doped carbon supports enriched the surface charge density and generated electron-rich Au surface sites. The Au-carbon interaction altered the binding behavior of C=C bonds to catalytic centers, leading to a solvent-polarity-dependent selectivity in C=C oxidation reactions. A high selectivity of 90% to benzaldehyde was achieved in an apolar solvent, and a selectivity of 95% to styrene epoxide was attained in a polar solvent. The Au-carbon electronic perturbation, originating from surface functional groups on the carbon support, may provide an alternative avenue to tune the selectivity and activity of more complex reactions in heterogeneous catalysis.
- Liu, Ben,Wang, Pu,Lopes, Aaron,Jin, Lei,Zhong, Wei,Pei, Yong,Suib, Steven L.,He, Jie
-
-
Read Online
- Orthoamides, LXIII [1]. Tris(dichloromethyl)amine, a new formylating reagent for aromatic compounds of wide scope
-
The reagent system formed from tris(dichloromethyl)amine (5) and aluminium chloride allows the formylation of aromatic compounds. The scope of the method is comparable with that of the Olah formylation and the Gro?-Rieche procedure, since benzene and even chlorobenzene can be formylated. One formyl group is transferred from 5 to the aromatic nucleus. In order to find optimal reaction conditions, the molar amounts of aromatic compounds, 5 and aluminum chloride were varied as well as reaction temperatures and solvents. The activation of 5 with other Lewis acids is also described.
- Kantlehner, Willi,Wezstein, Markus,Kre?, Ralf,Zschach, Franziska,Vetter, Jens,Ziegler, Georg,Mezger, Jochen,Stoyanov, Edmont V.,Goeppert, Alain,Sommer, Jean
-
-
Read Online
- Clay-anchored non-heme iron-salen complex catalyzed cleavage of C{double bond, long}C bond in aqueous medium
-
Clay-anchored iron[N,N′-ethylenebis(salicylideneaminato)] complex, synthesized by direct exchange, oxidizes various olefins and chalcones in aqueous acetonitrile using hydrogen peroxide as terminal oxidant. Aldehyde and its derivatives are obtained as oxidation products by the cleavage of C{double bond, long}C double bond. In comparison with the catalysis by iron-salen complex in solution, the clay catalyzed pathway not only increases the rate of reaction significantly, but also provides selective oxidation toward the aldehyde. Some chalcones also give very good yield in water, compared to the solution and clay catalyzed pathways.
- Dhakshinamoorthy, Amarajothi,Pitchumani, Kasi
-
-
Read Online
- Solvent-free and selective oxidation of hydroxy groups to their corresponding carbonyl functions with ferric nitrate activated by heteropoly acids
-
Keggin-type heteropoly acids revealed high catalytic activity for swift and selective oxidation of various hydroxy functionalities to the corresponding carbonyl groups using ferric nitrate as an oxidant under mild and solvent-free conditions. We have found that the catalytic activities of the heteropoly acids were much higher than mineral or solid acids such as sulfuric acid, p-toluenesulfonic acid, triflic acid, acidic Amberlyst-15, Montmorillonite-K10 clay, and HY-zeolite.
- Firouzabadi, Habib,Iranpoor, Nasser,Amani, Kamal
-
-
Read Online
- Convenient one-pot synthesis of aldehydes from carboxylic acid chlorides with sodium diethyldihydroaluminate
-
Carboxylic acid chlorides and acids were converted into the corresponding aldehydes conveniently in one-pot process with sodium diethyldihydroaluminate (SDDA) in moderate to good yields.
- Yoon,Choi,Gyoung,Jun
-
-
Read Online
- Functional hexanuclear Y(III) cluster-based MOFs supported Pd(II) single site catalysts for aerobic selective oxidation of styrene
-
Oxidation of styrene is one of the significant reactions in organic synthesis. In this work, a serious of PdCl2 moiety-decorated Y6-MOFs adopting post-synthetic strategy were fabricated as applicable single-site catalysts for oxidation of styrene. Specifically, the functional organic linker, H2bpydc (2,2′-bipyridine-5,5′-dicarboxylic acid), was first incorporated quantitatively into Y6 clusters-based MOF, [(CH3)2NH2]2[Y6(μ3-OH)8(bpdc)6] (bpdc = 4,4′-biphenyl dicarboxylic acid) via post-synthetic ligand exchange. Then post-synthetic Pd(II) metalation was performed to enhance the density of isolated single sites. The obtained Pd(II)-Y-bpydcx/bpdc1-x can be used as highly efficient heterogeneous single-site catalysts to promote selective oxidative cleavage of styrene to benzaldehyde using O2 as a oxidant under solvent-free and mild reaction conditions (1 atm and 80 °C). Importantly, when using Pd(II)-Y-bpydc0.8/bpdc0.2 (0.024 mmol Pd) as catalyst, the high conversion of styrene and the selectivity for benzaldehyde can reach 88.7 % and 82.2 %, respectively.
- Han, Zheng-Bo,Wei, Na,Xing, Zhiqiang,Zhang, Yue
-
-
Read Online
- Hexadecylphosphate-functionalized iron oxide nanoparticles: Mild oxidation of benzyl C-H bonds exclusive to carbonyls by molecular oxygen
-
We report here a specially designed catalytic system consisting of hexadecylphosphate-functionalized iron oxide nanoparticles in oil/water biphasic emulsion. The iron oxide nanoparticles act as catalytic centers and the surface-bonded hexadecylphosphates as peripheral units which tune the activity of iron oxide and the access of reactants to the catalytic centers. The catalytic system is highly effective to oxidize the benzyl C-H bonds in a series of compounds to carbonyls exclusively by molecular oxygen under mild conditions. The catalytic process, green and low cost, offers a novel concept to design highly effective catalysts with nanoparticles as active centers and surface-bonded organic phosphates as accelerants for oxidation reactions.
- Li, Lei,Lv, Jiangang,Shen, Yi,Guo, Xuefeng,Peng, Luming,Xie, Zaiku,Ding, Weiping
-
-
Read Online
- Cross-coupling of p-xylene to 2,2′,5,5′-tetramethyl 1,1′-biphenyl on supported vanadia catalysts
-
Aluminas with different textural characteristics were synthesized by carbonate, citrate and urea sol-gel methods. All supports were impregnated with an aqueous solution of ammonium metavanadate in order to obtain the same loading of vanadia (7% wt V2O5), and then characterized by XRD, N2 physisorption, Raman spectroscopy and NH3-TPD. In this way it was possible to tune the characteristics of the supported vanadia as it has also been demonstrated from the catalytic behavior of these materials in the cross-coupling of p-xylene to 2,2′,5,5′-tetramethyl 1,1′ biphenyl (biaryl) in the presence of O2. Alumina prepared via the carbonate method and calcined at 500°C proved to be the most suitable support affording, for a level of conversion of 8%, selectivities to biaryl of 96%. It corresponded to an enough high dispersion of vanadium to allow the cleavage of the C-H bonds. Recycling experiments confirmed the stability of these catalysts.
- Mitran, Gheorghi?a,Pavel, Octavian Dumitru,Florea, Mihaela,Parvulescu, Vasile I.
-
-
Read Online
- FeCl3-catalyzed oxidative decarboxylation of aryl/heteroaryl acetic acids: Preparation of selected API impurities
-
There is an ever-increasing demand for impurity compounds for use in impurity profiling as regulatory agencies seek information during registration. Herein, we report the FeCl3-catalyzed oxidative decarboxylation of aryl- and heteroaryl acetic acids to the corresponding carbonyl compounds. A variety of useful aldehydes and ketones were prepared in a simple one-pot transformation by employing an environmentally benign, low-cost, and readily available iron salt. The utility of this method has been demonstrated by preparing five valuable API impurities including a multi-gram-scale synthesis of ketorolac impurity B for the first time. This journal is
- Gangadurai, Chinnakuzhanthai,Illa, Giri Teja,Reddy, D. Srinivasa
-
-
Read Online
- Deprotection of 1,3-Dithianes by 2,2-Dichlloro-5,6-dicyano-p-benzoquinone (DDQ)
-
A variety of 1,3-dithianes were converted to the corresponding carbonyl compounds in good yields by treatment with 1.5 equiv. of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in MeCN-H2O (9:1).
- Tanemura, Kiyoshi,Dohya, Hiroshi,Imamura, Masanori,Suzuki, Tsuneo,Horaguchi, Takaaki
-
-
Read Online
- Ruthenium(ii)-supported phosphovanadomolybdates [Ru(dmso)3PMo6V3O32]6-and [Ru(PMo6V3O32)2]14-, and their use as heterogeneous catalysts for oxidation of alcohols
-
Self-assembly of cis-[RuCl2(dmso)4], NaVO3, Na2MoO4 and NaH2PO4 in a molar ratio of 1?:?3?:?6?:?1 in HOAc-NaOAc buffer (pH = 4-5) in the presence of CsCl gave a ruthenium(ii)-supported phosphovanadomolybdate [RuII(dmso)3PMoVI6VV3O32]6- (1). While a similar reaction with the reactants in a molar ratio of 1?:?6?:?12?:?2 afforded a ruthenium substituted "sandwich"type polyoxometalate [RuII(PMoVI6VV3O32)2]14- (2). Clusters 1 and 2 were well characterized by single-crystal X-ray diffraction. Their use as heterogeneous catalysts for oxidation of alcohols in the presence of molecular oxygen was also investigated.
- Shi, Hao-Yu,Zhou, Wen-Yan,Song, Xiao-Ming,Jia, Ai-Quan,Shi, Hua-Tian,Zhang, Qian-Feng
-
-
Read Online
- Heterogenization of a molybdenum Schiff base complex as a magnetic nanocatalyst: An eco-friendly, efficient, selective and recyclable nanocatalyst for the oxidation of alkenes
-
A Schiff base ligand derived from 5-bromo-2-hydroxybenzaldehyde and 2,2′-dimethylpropylenediamine (H2L) and its corresponding dioxomolybdenum(VI) complex (Mo(O)2L) has been synthesized and characterized by spectroscopic methods. The adsorption of Mo(O)2L on the surface of silica-coated magnetite nanoparticles via hydrogen bonding led to the formation of (α-Fe2O3)-MCM-41-Mo(O) 2L as a heterogeneous catalyst. FT-IR and atomic absorption spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize and investigate the new nanocatalyst. A practical catalytic method for the efficient and highly selective oxidation of a wide range of olefins with hydrogen peroxide and tert-butyl hydroperoxide in ethanol over the prepared molybdenum nanocatalyst was investigated. Under reflux conditions, the oxidation of cyclooctene with tert-butyl hydroperoxide or hydrogen peroxide led to the formation of epoxide as the sole product. The catalyst was reused at least six times without a significant decrease in catalytic activity or selectivity, and without detectable leaching of the catalyst.
- Rayati, Saeed,Abdolalian, Payam
-
-
Read Online
- Selective Visible Light Aerobic Photocatalytic Oxygenation of Alkanes to the Corresponding Carbonyl Compounds
-
The aerobic, selective oxygenation of alkanes via C-H bond activation is an important research challenge. Photocatalysis offers the potential for the introduction of additional concepts for such reactions. Visible light photoactive semiconductors such as bismuth oxyhalides (BiOX, X = Cl and Br) used in this research typically oxidize organic compounds through photocatalyzed formation of strongly oxidizing holes. The reactive oxygen species formed react with organic compounds in one-electron processes, leading to radical intermediates and nonselective oxidation. Such oxidation reactions generally lead to total oxidation. Here, impregnation of BiOX with a polyoxometalate, H5PV2Mo10O40, as a strong electron acceptor changed the reactivity of BiOX, leading to Mars-van Krevelen-type reactivity, that is, photoactivated oxygen donation from BiOX to the organic substrate followed by reoxidation by O2 and catalysis. This conclusion was supported by mechanistic studies involving isotope labeling studies. In this way, ethane was selectively oxidized to acetaldehyde in a flow reactor with a turnover number (24 h) of 415.
- Somekh, Miriam,Khenkin, Alexander M.,Herman, Adi,Neumann, Ronny
-
-
Read Online
- Photolysis of NSAIDs. Part 3: Structural elucidation of photoproducts of tolmetin in methanol
-
Photolysis of tolmetin in methanol produces eight photoproducts via a novel α-cleavage of a ketone, decarboxylation, and oxidation. A sample of 10 mM tolmetin in methanol was photo-irradiated with a Hanovia 200 W high-pressure quartz Hg lamp for four days. In total, eight photoproducts were observed from the HPLC chromatogram. Three major photoproducts were separated, and their structures were elucidated by spectroscopic methods. The structures of all photoproducts were further determined by LC-ESI-MS. A reaction scheme of tolmetin was proposed.
- Sheu, Ming-Thau,Wu, Jender,Chen, Chih-Jui,Chao, Su-Hui,Wu, An-Bang
-
-
Read Online
- Palladium-catalyzed reductive carbonylation of aryl triflates with synthesis gas
-
A general palladium-catalyzed reductive carbonylation of aryl triflates in the presence of synthesis gas (CO/H2) has been developed. The reaction with this most simple and environmentally benign formylation source proceeds under mild conditions and various aromatic aldehydes have been prepared in good to high yield. Georg Thieme Verlag Stuttgart.
- Brennfuhrer, Anne,Neumann, Helfried,Beller, Matthias
-
-
Read Online
- Liquid-phase oxidation of some aromatic aldehydes, hydrocarbons, and alcohols by cerium(IV) catalyzed by Iridium(III) in acidic medium
-
Addition of traces of iridium(III) chloride with cerium(IV) sulfate (catalyst-substrate ratio (1:2994 to 1:10,000) in traditional water-bath heating resulted in the oxidation of p-chlorobenzaldehyde, p-nitrobenzaldehyde, benzyl alcohol, p-methoxy benzyl alcohol, p-xylene, and p-nitrotoluene dissolved in acetic acid to give 77%, 90%, 21.7%, 88.6%, 86.2%, and 18% yields of the products, respectively, while catechol and resorcinol polymerized. Oxidation of aldehydes and alcohols resulted as usual in the corresponding acids and aldehydes, respectively, while p-xylene and p-nitrotoluene gave p-tolualdehyde and p-nitrobenzoic acid. Conditions were obtained for getting the highest yields under the experimental conditions.
- Tandon, Praveen K.,Dwivedi, Priy B.,Singh, Satpal
-
-
Read Online
- Cu(II) complexes of N-rich aroylhydrazone: Magnetism and catalytic activity towards microwave-assisted oxidation of xylenes
-
The new aroylhydrazone N-(di(pyridin-2-yl)methylene)pyrazine-2-carbohydrazide (HL) species, rich in N-donor sites, has been used to synthesize Cu(ii) compounds with different nuclearities, viz. the binuclear [Cu2(μ-1κN3,2κN2O-L)(Cl)3(MeOH)] (1), the octanuclear [Cu4(μ-1κN3,2κN2O-L)2(μ-Cl)3(Cl)3]2 (2) and the 1D coordination polymer [Cu3(μ3-1κN3,2κN2O,3κN-L)(μ-NO3)(NO3)3(H2O)3]n·nNO3 (3). They have been characterized by elemental analysis, FT-IR and single crystal X-ray diffraction. The magnetic properties of 2 and 3 have been explored using variable temperature magnetic measurements. The catalytic performances of the compounds were evaluated towards the peroxidative oxidation of o-, p- A nd m-xylenes under microwave irradiation, leading to the formation of the corresponding methyl benzyl alcohol, tolualdehyde and toluic acid as the major products. Complex 3 exhibits the best catalytic activity towards the oxidation of p-xylene with a total yield of 37% (4-methylbenzyl alcohol + p-tolualdehyde + p-toluic acid).
- Sutradhar, Manas,Roy Barman, Tannistha,Alegria, Elisabete C. B. A.,Guedes Da Silva, M. Fátima C.,Liu, Cai-Ming,Kou, Hui-Zhong,Pombeiro, Armando J. L.
-
-
Read Online
- A NOVEL N-DEALKYLATION REACTION OF N,N-DIALKYLARYLCARBOXAMIDES PROMOTED BY ELECTRON TRANSFER FROM ALKALIMETALS
-
Reactions of some N,N-dialkylarylcarboxamides with either lithium or sodium metals in dry tetrahydrofuran (THF) promoted by ultrasound waves afforded the corresponding N-monoalkylarylcarboxamides in good yields.In the cases of N,N-diethylarylcarboxamides the products obtained were derived from coupling reactions rather than from N-dealkylation reactions.
- Karaman, Rafik,Fry, James L.
-
-
Read Online
- Dodecatungstophosphoric acid (H3PW12O40): A novel and efficient recyclable catalyst for synthesis of 1,1-diacetates from aromatic aldehydes in solvent-free system and their deprotection
-
A facile and efficient method for the formation of 1,1-diacetates from a variety of aldehydes in the presence of a catalytic amount of H 3PW12O40 and acetic anhydride was achieved in good yields at room temperature. The deprotection of the resulting acylals is achieved using the same catalyst in acetone. Copyright Taylor & Francis Group, LLC.
- Heravi, Majid M.,Derikvand, Fatemeh,Bamoharram, Fatemeh F.
-
-
Read Online
- Synthesis, characterization and structure of a tetrameric DABCO-bromine complex: A novel oxidizing agent for oxidation of alcohols to carbonyl compounds
-
A tetrameric DABCO-bromine complex was synthesized, characterized and utilized as a novel active bromine complex for the oxidation of alcohols to carbonyl compounds.
- Heravi, Majid M.,Derikvand, Fatemeh,Ghassemzadeh, Mitra,Neumüller, Bernhard
-
-
Read Online
- TEMPO-based ionic liquid with temperature-dependent property and application for aerobic oxidation of alcohols
-
A novel temperature-dependent ionic liquid based on 2,2,6,6- tetramethylpiperidine-1-oxyl and polyethylene glycol 600 was developed and used in oxidation of alcohols. Various alcohols were oxidized into their corresponding aldehydes or ketones with good yield and selectivity. Owing to the temperature-dependent property of the catalyst, easy recovery was achieved by simple decantation. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file.
- Zhu, Jie,Wang, Peng-Cheng,Ming, Lu
-
-
Read Online
- Synthesis, structure characterization and study of a new molybdenum Schiff base complex as an epoxidation catalyst with very high turnover numbers
-
The reaction between [MoO2(acac)2] and an ONO type Schiff-base ligand (L?=?4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol) resulted a new oligomer molybdenum complex ([MoO2(L)]n). The oligomer complex was characterized by elemental analysis, FT-IR, 1H and 13C NMR spectroscopies. A suitable single crystal of the complex was grown in DMSO and characterized by X-ray single crystal diffraction as monomer stabilized by one DMSO molecule, [MoO2L(DMSO)]. The [MoO2(L)]n complex was used as a catalyst in epoxidation of olefins. Besides the high activity and selectivity, very high turnover numbers were a remarkable advantage of the catalytic system.
- Bagherzadeh, Mojtaba,Ataie, Saeed,Mahmoudi, Hamed,Janczak, Jan
-
-
Read Online
- Environmentally Benign Oxidations of Alkenes and Alcohols to Corresponding Aldehydes over Anchored Phosphotungstates: Effect of Supports as Well as Oxidants
-
Series of catalysts comprising of parent phosphotungstate (PW12) and mono lacunary phosphotungstate (PW11) anchored to different mesoporous materials (MCM-41 and MCM-48) were prepared. Environmentally benign oxidation of alkenes and alcohols were carried out with H2O2 and molecular oxygen as oxidants. The influence of different parameters on the conversion as well as the selectivity was investigated. Comparative study was ascertained over anchored parent, lacunary phosphotungstates as active species and the supports. The kinetic and thermodynamic studies were correlated with the effect of support as well as active species. Moreover, the catalysts could be recovered and reused four times without significant loss in their activity and selectivity. Graphical Abstract: [Figure not available: see fulltext.]
- Singh, Sukriti,Patel, Anjali
-
-
Read Online
- 2,6-Dicarboxypyridinium fluorochromate: A mild and efficient reagent for oxidative deprotection of oximes, phenylhydrazones, and semicarbazones to their corresponding carbonyl compounds under solvent-free conditions
-
2,6-Dicarboxypyridinium fluorochromate as a new, rapid, and efficient reagent was prepared and used for the oxidative deprotection of oximes, phenylhydrazones, and semicarbazones to their carbonyl analogues under solvent-free conditions at room temperature.
- Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Ramzanian-Lahmali, Farhad,Sadatshahabi, Marzieh
-
-
Read Online
- Synthesis of C4 and C8 Chemicals from Ethanol on MgO-Incorporated Faujasite Catalysts with Balanced Confinement Effects and Basicity
-
A new type of catalyst has been designed to adjust the basicity and level of molecular confinement of KNaX faujasites by controlled incorporation of Mg through ion exchange and precipitation of extraframework MgO clusters at varying loadings. The catalytic performance of these catalysts was compared in the conversion of C2 and C4 aldehydes to value-added products. The product distribution depends on both the level of acetaldehyde conversion and the fraction of magnesium as extraframework species. These species form rather uniform and highly dispersed nanostructures that resemble nanopetals. Specifically, the sample containing Mg only in the form of exchangeable Mg2+ ions has much lower activity than those in which a significant fraction of Mg exists as extraframework MgO. Both the (C6+C8)/C4 and C8/C6 ratios increase with additional extraframework Mg at high acetaldehyde conversion levels. These differences in product distribution can be attributed to 1) higher basicity density on the samples with extraframework species, and 2) enhanced confinement inside the zeolite cages in the presence of these species. Additionally, the formation of linear or aromatic C8 aldehyde compounds depends on the position on the crotonaldehyde molecule from which abstraction of a proton occurs. In addition, catalysts with different confinement effects result in different C8 products.
- Zhang, Lu,Pham, Tu N.,Faria, Jimmy,Santhanaraj, Daniel,Sooknoi, Tawan,Tan, Qiaohua,Zhao, Zheng,Resasco, Daniel E.
-
-
Read Online
- Bi(NO3)3·5H2O-TBAF as an efficient reagent for in situ oxidation: Dihydropyrimidinone formation from benzyl halides
-
The oxidation of benzyl halides to aldehydes with bismuth nitrate pentahydrate in an ionic liquid was studied. Also, an efficient one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones from benzyl halides using bismuth nitrate pentahydrate in tetrabutylammonium fluoride (TBAF) as an in situ oxidant and catalyst is described. Georg Thieme Verlag Stuttgart.
- Khodaei, Mohammad Mehdi,Khosropour, Ahmad Reza,Jowkar, Mahbubeh
-
-
Read Online
- Mild and efficient deprotection of 1,3-dithianes with N,N′-diiodo-N, N′-1,2-ethanediyl-bis(p-toluenesulphonamide)
-
Aliphatic and aromatic 1,3-dithiane are oxidized to the corresponding carbonyl compounds in good yields under mild conditions by N,N′-diiodo-N, N′-1,2-ethanediyl-bis(p-toluenesulphonamide) [NIBTSl and silver nitrate.
- Ghorbani-Vaghei, Ramin,Zolfigol, Mohammad Ali
-
-
Read Online
- Generation and reactivity of simple chloro(aryl)carbenes within the cavities of nonacidic zeolites
-
A number of para-substituted chloro(aryl)carbenes are generated within the cavities of a series of dry alkali metal cation-exchanged zeolites (LiY, NaY, KY, RbY, and CsY) upon laser flash photolysis of the corresponding diazirine precursor. The absolute reactivity of the chloro(aryl)carbene is found to be strongly dependent on both the nature of the electron-donating and -withdrawing properties of the aryl substituent and the nature of the zeolite charge-balancing cations. The results strongly suggest that two opposing mechanisms for capture of the carbene can occur depending on whether the zeolite framework behaves as a nucleophilic reagent or an electrophilic reagent in its reaction with the carbene center. Hammett relationships for the decay of the carbene as a function of aryl substituent and zeolite counterion versus the σ+ substituent parameter support a change in mechanism as the carbene center toggles between being electron poor and electron rich. For the electron-poor chloro(4-nitrophenyl)carbene, a framework adduct is proposed upon reaction of the nucleophilic [Si-O-Al]- bridge with the carbene center, and for the electron-rich chloro(4-methoxyphenyl)carbene, an adduct with the tight Li+ cation is proposed.
- Moya-Barrios, Reinaldo,Cozens, Frances L.
-
-
Read Online
- Confined Pyrolysis within Metal-Organic Frameworks to Form Uniform Ru3 Clusters for Efficient Oxidation of Alcohols
-
Here we report a novel approach to synthesize atomically dispersed uniform clusters via a cage-separated precursor preselection and pyrolysis strategy. To illustrate this strategy, well-defined Ru3(CO)12 was separated as a precursor by suitable molecular-scale cages of zeolitic imidazolate frameworks (ZIFs). After thermal treatment under confinement in the cages, uniform Ru3 clusters stabilized by nitrogen species (Ru3/CN) were obtained. Importantly, we found that Ru3/CN exhibits excellent catalytic activity (100% conversion), high chemoselectivity (100% for 2-aminobenzaldehyde), and significantly high turnover frequency (TOF) for oxidation of 2-aminobenzyl alcohol. The TOF of Ru3/CN (4320 h-1) is about 23 times higher than that of small-sized (ca. 2.5 nm) Ru particles (TOF = 184 h-1). This striking difference is attributed to a disparity in the interaction between Ru species and adsorbed reactants.
- Ji, Shufang,Chen, Yuanjun,Fu, Qiang,Chen, Yifeng,Dong, Juncai,Chen, Wenxing,Li, Zhi,Wang, Yu,Gu, Lin,He, Wei,Chen, Chen,Peng, Qing,Huang, Yu,Duan, Xiangfeng,Wang, Dingsheng,Draxl, Claudia,Li, Yadong
-
-
Read Online
- Metal-free activation of dioxygen by graphene/g-C3N4 nanocomposites: Functional dyads for selective oxidation of saturated hydrocarbons
-
Graphene sheet/polymeric carbon nitride nanocomposite (GSCN) functions as a metal-free catalyst to activate O2 for the selective oxidation of secondary C-H bonds of cyclohexane. By fine-tuning the weight ratio of graphene and carbon nitride components, GSCN offers good conversion and high selectivity to corresponding ketones. Besides its high stability, this catalyst also exhibits high chemoselectivity for secondary C-H bonds of various saturated alkanes and, therefore, should be useful in overcoming challenges confronted by metal-mediated catalysis.
- Li, Xin-Hao,Chen, Jie-Sheng,Wang, Xinchen,Sun, Jianhua,Antonietti, Markus
-
-
Read Online
- Hydrothermal synthesis of dimeric lanthanide compounds: X-ray structure, magnetic study and heterogeneous catalytic epoxidation of olefins
-
A series of dimeric lanthanide carboxylato complexes [La(5-Br-NIC) 3(H2O)2]2·H2O (1); [Gd(5-Br-NIC)3(H2O)2]2 (2), [5-Br-NIC = 5-bromonicotinate] and [Sm(NIC)3(H2O) 2]2 (3) [NIC = nicotinate], have been hydrothermally synthesized and structurally characterized by single crystal X-ray analysis. Complexes 1, 2 and 3 are of similar structure and consist of a basic unit [La(carboxylato)3(H2O)2]2. In compound 1 lanthanide cation is surrounded by one chelating 5-bromo-nicotinato ligand, two bridging oxygen atoms from 5-bromo-nicotinato and two water molecules, in which each La(III) ion is nine coordinated in a tricapped prismatic geometry. However, in compounds 2 and 3 four carboxylate groups link a pair of lanthanide atoms in the O,O′-bridging mode to generate a paddle-wheel-like centrosymmetric dimer. All the compounds exhibit excellent catalytic performance in olefin epoxidation reaction. The variable temperature magnetic susceptibility measurements showed that the magnetic interaction in [Gd(5-Br-NIC)3(H2O)2]2 (2), is antiferromagnetic (J = -0.048 cm-1), while compound [Sm(NIC) 3(H2O)2]2 (3), showed a complicated low-temperature magnetic property.
- Sen, Rupam,Hazra, Dipak K.,Koner, Subratanath,Helliwell, Madeleine,Mukherjee, Monika,Bhattacharjee, Ashis
-
-
Read Online
- New formylating agents - Preparative procedures and mechanistic investigations
-
The reactivity of new formylating agents related to formamide has been investigated both experimentally and theoretically. The reaction in 1,2-dichloroethane between tris(diformylamino)methane (2) and several arenes, catalyzed by AlCl3 or BCl3, was shown to proceed in good yields to afford the corresponding para-substituted aldehydes. The nature of the active electrophilic species was also investigated theoretically. Thus, the relative stability of the O- and N-protonated forms, as well as those of AlCl3 adducts, of several formylating agents - diformamide, triformamide, N,N,N′,N′-tetraformylhydrazine, and tris(diformylamino)methane - were determined in the gas phase and in water or DCE by means of DFT calculations at the B3LYP/6-311++G(d,p) level, the solvents being modeled with the IPCM method. The amide oxygen atom in all cases appeared to be the most basic site, both in the Bronsted and Lewis sense, constituting a first step towards the understanding of the mechanism of this reaction.
- Bagno, Alessandro,Kantlehner, Willi,Scherr, Oliver,Vetter, Jens,Ziegler, Georg
-
-
Read Online
- SbCl5 Complexes of Pyridine N-Oxide and Trimethylamine Oxide as the Oxidizing Agent
-
A 1:1 complex of pyridine N-oxide or trimethylamine oxide with SbCl5 acted as an oxidizing agent to benzyl alcohol, benzoin, furoin, and thiophenols more easily than via the oxides to give benzaldehyde, benzil, furil, and the corresponding disulfides respectively.The trimethylamine oxide-SbCl5 also oxidized p-xylene to p-tolualdehyde under nitrogen and to p-toluic acid under air.
- Yamamoto, Jiro,Murakami, Mitushige,Kameoka, Noriaki,Otani, Norio,Umezu, Masahiro,Matsuura, Teruo
-
-
Read Online
- Benzylic oxidation and photooxidation by air in the presence of graphite and cyclohexene
-
Graphite is introduced as a convenient catalyst for cyclohexene-promoted photooxidation of p-xylene, ethylbenzene, and cumene by air. Availability of the reagent (air), lack of chemical waste, low toxicity, and reusability of the catalyst make the process a good green alternative of oxidation of these industrially important hydrocarbons.
- Sereda, Grigoriy,Rajpara, Vikul
-
-
Read Online
- Selective aerobic oxidation of styrene to benzaldehyde catalyzed by water-soluble palladium(II) complex in water
-
Selective oxidation of styrene to benzaldehyde has been carried out for the first time in aqueous phase by using a green and water-soluble palladium(II) complex as a catalyst under neutral, chloride and base-free conditions. The influences of reaction temperature, reaction time, palladium concentration and O2 pressure on the conversion of styrene and the selectivity to benzaldehyde have been discussed. The reaction products, benzaldehyde, benzoic acid, acetophenone are readily isolated by ether extraction at room temperature. The water-soluble catalyst immobilized in aqueous phase can be reused for eight catalytic runs with an almost constant catalytic activity for the styrene oxidation. The influence of substituting groups in the aromatic ring of styrene on the reactivity was also discussed. Spectroscopic studies revealed that the hydrophilic dipyridyl-based ligand (L) with Pd(OAc)2 formed a water-soluble Pd(II) complex. The UV/Vis spectra analysis further showed that the Pd(II)-L complex could serve as the catalytically active species in the present catalytic system. The Royal Society of Chemistry 2009.
- Feng, Bo,Hou, Zhenshan,Wang, Xiangrui,Hu, Yu,Li, Huan,Qiao, Yunxiang
-
-
Read Online
- Quinolinium fluorochromate: An efficient and convenient reagent for oxidative cleavage of thioacetals to their parent carbonyl compounds
-
Deprotection of thioacetals to their parent carbonyl compounds in high yields has been carried out using quinolinium fluorochromate under mild conditions. Copyright Taylor & Francis Inc.
- Tajbakhsh, Mahmood,Alimohammadi, Kamal,Ramzanian-Lehmali, Farhad,Barghamadi, Mohamad,Shakeri, Alireza
-
-
Read Online
- Europium-Catalyzed Aerobic Oxidation of Alcohols to Aldehydes/Ketones and Photoluminescence Tracking
-
Europium is a lanthanide rare-earth metal and is known as a key element in luminophore development. Since europium has two relatively stable oxidation states, Eu2+ and Eu3+, which is exceptional among the various lanthanide elements, we have developed a europium-catalyzed aerobic oxidation with external oxidants utilizing the redox cycle of Eu2+/Eu3+. The reaction was performed under mild conditions with a wide substrate scope. The photoluminescence spectra clearly demonstrate the oxidation state changes that occur during the presented europium-catalyzed aerobic oxidation. (Figure presented.).
- Kim, Seongwoo,Kim, Youngik,Jin, Hyomin,Park, Myung Hwan,Kim, Youngjo,Lee, Kang Mun,Kim, Min
-
-
Read Online
- Morphology dependant oxidation of aromatic alcohols by new symmetrical copper(II) metallatriangles formed by self-assembly of a shared bis-benzimidazolyl diamide ligand
-
A new bis-benzimidazole-based diamide ligand N2,N 2′-bis((1H-benzo[d]imidazol-2-yl)methyl)-[1,1′-biphenyl] -2,2′-dicarboxamide, L and its three Cu(II) metallatriangles of general formula [Cu3(L)3X3]·3X·nH 2O (where X = Cl, Br, NO3) have been synthesized and one of them is structurally characterized. X-ray diffraction work reveals that the metallatriangle [Cu3(L)3Cl3] ·3Cl·15H2O crystallizes in trigonal R3? space group with two independent molecules in the asymmetric unit. The asymmetric unit contains only one-third of the molecules and the rest are generated by the crystallographic 3? axis. Each copper(II) ion adopts a highly distorted square pyramidal geometry. The copper(II) metallatriangles are used as catalyst to carry out the oxidation of substituted benzyl alcohols heterogeneously, in the presence of tert-butyl hydroperoxide. Interestingly, the ratio of product profile and the percentage conversion of the products changes with the surface morphology of the metallatriangle employed as a catalyst. A kite type morphology is found to be highly selective to the formation of acid product over the aldehyde, while a hexagonal type morphology results in a mixed acid + aldehyde product. The initial rate of formation of the aldehyde is found to be almost independent of the amount of catalyst employed.
- Mahiya, Kuldeep,Mathur, Pavan
-
-
Read Online
- Formation Pathways toward 2- and 4-Methylbenzaldehyde via Sequential Reactions from Acetaldehyde over Hydroxyapatite Catalyst
-
Condensation reactions of biomass derived C2 and C4 aldehydes form both ortho- and para-tolualdehydes (2-MB and 4-MB, respectively). The complete reaction network and the detailed mechanisms, however, have not been fully described. H
- Moteki, Takahiko,Rowley, Andrew T.,Bregante, Daniel T.,Flaherty, David W.
-
-
Read Online
- Selective reduction of hydroxy carbonyl to carbonyl compounds with trialkylborane/trifluoromethanesulfonic acid
-
Triethyl- or triisopropylborane/trifluoromethanesulfonic (triflic) acid is a convenient reagent for the selective reduction of hydroxy substituted carboxylic acids, ketones and aldehydes to yield the corresponding carbonyl compounds. The scope of the reaction, experimental conditions and suggested mechanism are discussed.
- Olah,Wu
-
-
Read Online
- Synthesis and characterization of molybdenum (VI) complex immobilized on polymeric Schiff base-coated magnetic nanoparticles as an efficient and retrievable nanocatalyst in olefin epoxidation reactions
-
In this study, a new polymeric functionalized magnetic nanocatalyst containing a molybdenum Schiff base complex was prepared using a few consecutive steps. Poly (methylacrylate)-coated magnetic nanoparticles were synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups with hydrazine. Polymeric functionalization efficiently provides the advantage that more catalytic units can be grafted on the surface of magnetic nanoparticles. The functionalization process was continued with salicylaldehyde which introduced Schiff base groups on to the surface of the polymeric support. In the final step, the desired catalytic system was prepared via complexation of the Schiff base groups with MoO2(acac)2. The resulting nanoparticles were characterized by infrared spectroscopy, powder X-ray diffraction, scanning and transmission electron microscopy, elemental analysis, inductively coupled plasma optical emission spectrometry, vibrating sample magnetometry and thermogravimetric analysis. This heterogenized catalytic system was also found to be highly active, sustainable and recyclable nanocatalyst in alkene epoxidation. Eventually, the attractive features of the synthesized catalyst such as simple work-up, good stability, magnetic separation, high TOF and high surface area; make it appropriate for oxidation reactions.
- Mortazavi-Manesh, Anahita,Bagherzadeh, Mojtaba
-
-
Read Online
- Allyltriphenylphosphonium Peroxodisulfate (CH2=CHCH 2PPh3)2S2O8: An Efficient and Convenient Reagent for the Oxidation of Alcohols and Silyl and THP-Ethers under Nonaqueous Conditions
-
The preparation of allyltriphenylphosphonium peroxodisulfate (ATPPD) as a new and efficient reagent for the oxidation of primary and secondary alcohols, trimethylsilyl and tetrahydropyranyl (THP) ethers to their corresponding carbonyl compounds in refluxing acetonitrile with 1.1:1 molar equivalents of the oxidant is described.
- Tajbakhsh,Lakouraj,Fadavi
-
-
Read Online
- Au-Pd alloy nanoparticle catalyzed selective oxidation of benzyl alcohol and tandem synthesis of imines at ambient conditions
-
Alloy nanoparticles (NPs) of gold and palladium on ZrO2 support (Au-Pd@ZrO2) were found to be highly active in oxidation of benzyl alcohols and can be used for the tandem synthesis of imines from benzyl alcohols and amines via a one-
- Cui, Wenjing,Xiao, Qi,Sarina, Sarina,Ao, Wulan,Xie, Mengxia,Zhu, Huaiyong,Bao, Zhaorigetu
-
-
Read Online
- Selective Oxygenation of Ring-Substituted Toluenes with Electron-Donating and -Withdrawing Substituents by Molecular Oxygen via Photoinduced Electron Transfer
-
A ring-substituted toluene with an electron-withdrawing substituent, p-tolunitrile, is oxygenated by molecular oxygen to yield the corresponding aldehyde with tetrafluoro-p-dicyanobenzene as a photocatalyst under photoirradiation with an Hg lamp (λ > 300 nm). The oxygenation of a ring-substituted toluene with an electron-donating substituent, p-xylene, by molecular oxygen is also achieved with 10-methyl-9-phenylacridinium ion as a photocatalyst under visible light irradiation, yielding p-tolualdehyde exclusively as the final oxygenated product. Both the oxygenation reactions are initiated by photoinduced electron transfer from the ring-substituted toluene to the singlet excited state of the photocatalyst. The reason for the high selectivity in the photocatalytic oxygenation of various toluene derivatives by molecular oxygen is discussed on the basis of the photoinduced electron transfer mechanism that does not involve the autoxidation process (radical chain reactions). The reactive intermediates in the photocatalytic cycle are successfully detected as the transient absorption spectra and the electron spin resonance spectra.
- Ohkubo, Kei,Suga, Kyou,Morikawa, Kohei,Fukuzumi, Shunichi
-
-
Read Online
- Iron oxide functionalised MIL-101 materials in aqueous phase selective oxidations
-
A highly active Fe containing MIL-101 material has been prepared by using a simple microwave-assisted deposition methodology. The material, characterized by several techniques including N2 physisorption, XPS and TEM, was found to have a significantly enhanced acidity due to the incorporation of ca. 2 wt.% Fe in the form of hematite Fe2O3 phase. Fe/MIL-101 exhibited excelling activities in aqueous phase oxidations of alcohols and alkenes using hydrogen peroxide as green oxidant.
- Balu, Alina Mariana,Lin, Carol Sze Ki,Liu, Hongli,Li, Yingwei,Vargas, Carolina,Luque, Rafael
-
-
Read Online
- Palladium-Catalyzed Synthesis ofΔ2-Isoxazoline from Toluene Derivatives Enabled by the Triple Role of Silver Nitrate
-
A palladium-catalyzed direct synthesis ofΔ2-isoxazoline from toluene derivatives has been established. The present reaction proceeds through nondirected Csp3-H activation, benzylic nitration, dehydration, and cycloaddition. This protocol also features the unusual triple role of silver nitrate in a one-pot reaction.
- Li, Chengliang,Deng, Hongmei,Li, Chunju,Jia, Xueshun,Li, Jian
-
-
Read Online
- New, highly acidic ionic liquid systems and their application in the carbonylation of toluene
-
Based on the surprisingly high solubility of AlCl3 in ionic liquids of type [cation][(CF3SO2)2N], a new class of highly acidic, ionic systems has been developed. First tests in toluene carbonylation revealed high potential of these new acidic ionic liquids as catalyst for arene functionaliziation reactions.
- Brausch, Nicole,Metlen, Andreas,Wasserscheid, Peter
-
-
Read Online
- Manganese porphines-NH2@SBA-15 as heterogeneous catalytic systems with homogeneous behavior: Effect of length of linker in immobilized manganese porphine catalysts in oxidation of olefins
-
Two types of SBA-15 mesoporous silica were functionalized with different nitrogen-carbon chain lengths (long and short-chain) and then used as solid supports for immobilization of manganese(III) complex of meso-tetrakis(4-carboxyphenyl)porphine, [SBA-15-short-chain-NH2@Mn(TCPP)OAc] and [SBA-15-long-chain-NH2@Mn(TCPP)OAc]. The prepared catalysts were characterized by powder X-ray diffraction (XRD), FT-IR and UV–vis spectroscopy. The loading of catalyst onto porous materials was determined by atomic absorption spectroscopy. Thermal analysis also demonstrated that the immobilized catalysts are thermally stable up to almost 400?°C. A comparative study based on the difference in chain length of the functional groups of SBA-15 in the oxidation of olefins was carried out in the presence of urea hydrogen peroxide (UHP) as oxidant and acetic anhydride as an activator. The novel long-chain catalyst was designed to improve performance of the catalytic activity.
- Rayati, Saeed,Sheybanifard, Zahra,Amini, Mostafa M.,Aliakbari, Azam
-
-
Read Online
- One-step solvent-free aerobic oxidation of aliphatic alcohols to esters using a tandem Sc-Ru?MOF catalyst
-
Esters are an important class of chemicals in industry. Traditionally, ester production is a multi-step process involving the use of corrosive acids or acid derivatives (e.g. acid chloride, anhydride, etc.). Therefore, the development of a green synthetic protocol is highly desirable. This work reports the development of a metal-organic framework (MOF) supported tandem catalyst that can achieve direct alcohol to ester conversion (DAEC) using oxygen as the sole oxidizing agent under strictly solvent-free conditions. By incorporating Ru nanoparticles (NPs) along with a homogeneous Lewis acid catalyst, scandium triflate, into the nanocavities of a Zr MOF, MOF-808, the compound catalyst, Sc-Ru?MOF-808, can achieve aliphatic alcohol conversion up to 92% with ester selectivity up to 91%. A mechanistic study reveals a unique “via acetal” pathway in which the alcohol is first oxidized on Ru NPs and rapidly converted to an acetal on Sc(iii) sites. Then, the acetal slowly decomposes to release an aldehyde in a controlled manner for subsequent oxidation and esterification to the ester product. To the best of our knowledge, this is the first example of DAEC of aliphatic alcohols under solvent-free conditions with high conversion and ester selectivity.
- Feng, Tingkai,Li, Conger,Li, Tao,Zhang, Songwei
-
supporting information
p. 1474 - 1480
(2022/03/08)
-
- Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources
-
Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.
- Doyle, Abigail G.,Gandhi, Shivaani S.,Jiang, Shutian,Kariofillis, Stavros K.,Martinez Alvarado, Jesus I.,?urański, Andrzej M.
-
supporting information
p. 1045 - 1055
(2022/01/19)
-
- Highly atom efficient synthesis of 2,2,4,5-tetrasubstituted 3(2H)-furanones having both hydroxyl and amino substituents
-
We have developed a highly atom efficient synthesis of tetrasubstituted 3(2H)-furanones from easily accessible starting materials such as C,N-diarylaldonitrones and dibenzoylacetylene. Control experiments revealed that reaction of aldonitrones having electron-withdrawing groups on the C-aryl substituent in polar aprotic solvents exhibited high product selectivity while reaction temperature has only a negligible effect on product yield and selectivity.
- Antony, Jesna,Mathai, Sindhu,Natarajan, Rakesh,P. Musthafa, Sumi,Rappai, John P.,S. Devaky, Karakkattu
-
supporting information
(2022/02/25)
-
- Controlled reduction of activated primary and secondary amides into aldehydes with diisobutylaluminum hydride
-
A practical method is disclosed for the reduction of activated primary and secondary amides into aldehydes using diisobutylaluminum hydride (DIBAL-H) in toluene. A wide range of aryl and alkyl N-Boc, N,N-diBoc and N-tosyl amides were converted into the corresponding aldehydes in good to excellent yields. Reduction susceptible functional groups such as nitro, cyano, alkene and alkyne groups were found to be stable. Broad substrate scope, functional group compatibility and quick conversions are the salient features of this methodology.
- Azeez, Sadaf,Kandasamy, Jeyakumar,Sabiah, Shahulhameed,Sureshbabu, Popuri
-
supporting information
p. 2048 - 2053
(2022/03/31)
-
- A novel selective oxidative cleavage of C–C bond mediated by black nickel oxide in the presence of molecular oxygen
-
A selective aerobic oxidative cleavage of C–C bond is developed with black nickel oxide (NiOx) as the catalyst. For the oxidation of 1-phenyl-1, 2-ethanediol, a 97.5% conversion in 96.7% selectivity of benzaldehyde is obtained under 0.3 MPa of O2 at 140 °C for 3 h. The relationship between the catalytic performance of NiOx and structure is discussed. It is concluded that the existence of Ni3+ should be crucial to the activity of catalyst. Moreover, the recycling experiments showed that the catalyst can retain a high activity even after being reused for five times.
- Meng, Lingwu,Li, Wei,Guo, Pengfei,Wang, Shun,Tong, Xinli
-
-
- Synergistic Catalytic?Effect?of N-Hydroxyphthalimide/Cobalt Tetraamide Phthalocyanine and Its Application for Aerobic Oxidation of Hydrocarbons and Alcohols
-
Abstract: The activation of oxygen?for?selective?oxidation?of?organic molecules, such as hydrocarbons and alcohols, remains a major catalytic?challenge. We have developed a catalytic system combining N-hydroxyphthalimide (NHPI) with cobalt tetraamide phthalocyanine [CoPc(CONH2)4] for the oxidation of hydrocarbons and alcohols at 75?°C under an oxygen atmosphere. CoPc(CONH2)4 was synthesized by trimellitic anhydride-urea method, and its structure was confirmed by FT-IR, UV–Vis and XRD. This catalyst, in synergy with NHPI/O2 system, exhibited excellent catalytic ability and high selectivity in the oxidation of hydrocarbons and alcohols. Based on the experimental results, a reasonable reaction mechanism was proposed for the oxidation of alkanes and alcohols, respectively. Graphic Abstract: Cobalt tetraamide phthalocyanine (CoPc(CONH2)4) was synthesized by a simple solid-thermal method, and the synergistic catalysis oxidation of NHPI and CoPc(CONH2)4 was studied. A synergistic catalysis system for the aerobic oxidation of hydrocarbons and alcohols by N-hydroxyphthalimide combined with cobalt tetraamide phthalocyanine has been developed.[Figure not available: see fulltext.]
- Li, Fei,Tang, Shuo,Tang, Zhilin,Ye, Lingjun,Li, Hehua,Niu, Fanfan,Sun, Xiaoling
-
-
- Merging N-Hydroxyphthalimide into Metal-Organic Frameworks for Highly Efficient and Environmentally Benign Aerobic Oxidation
-
Two highly efficient metal-organic framework catalysts TJU-68-NHPI and TJU-68-NDHPI have been successfully synthesized through solvothermal reactions of which the frameworks are merged with N-hydroxyphthalimide (NHPI) units, resulting in the decoration of pore surfaces with highly active nitroxyl catalytic sites. When t-butyl nitrite (TBN) is used as co-catalyst, the as-synthesized MOFs are demonstrated to be highly efficient and recyclable catalysts for a novel three-phase heterogeneous oxidation of activated C?H bond of primary and secondary alcohols, and benzyl compounds under mild conditions. Based on the high efficiency and selectivity, an environmentally benign system with good sustainability, mild conditions, simple work-up procedure has been established for practical oxidation of a wide range of substrates.
- Wang, Man,Liang, Gan,Wang, Yunhao,Fan, Tao,Yuan, Baoling,Liu, Mingxian,Yin, Ying,Li, Liangchun
-
supporting information
p. 9674 - 9685
(2021/06/09)
-
- Tunable Artificial Enzyme-Cofactor Complex for Selective Hydrolysis of Acetals
-
Enzymes frequently use unimpressive functional groups such as weak carboxylic acids for efficient, highly selective catalysis including hydrolysis of acetals and even amides. Much stronger acids generally have to be used for such purposes in synthetic systems. We report here a method to position an acidic group near the acetal oxygen of 2-(4-nitrophenyl)-1,3-dioxolane bound by an artificial enzyme. The hydrolytic activity of the resulting artificial enzyme-cofactor complex was tuned by the number and depth of the active site as well as the hydrophobicity and acidity of the cofactor. The selectivity of the complex was controlled by the size and shape of the active site and enabled less reactive acetals to be hydrolyzed over more reactive ones.
- Bose, Ishani,Fa, Shixin,Zhao, Yan
-
p. 1701 - 1711
(2021/02/05)
-
- Nickel catalyzed hydrosilane reduction of (het)arenecarboxylic acids into aldehydes
-
Nickel-catalyzed reduction of (het)arenecarboxylic acids with hydrosilanes in the presence of dimethyl dicarbonate as the activator affords the corresponding aldehydes. The role of the activator is the conversion of the acids into their anhydrides undergoing C–O cleavage. The good yields were achieved in case of substrates bearing electron-donating and electron-neutral groups.
- Wang, Liang,Wang, Yaoyao,Tao, Yu,Zhang, Nana,Li, Shubai
-
p. 271 - 273
(2021/05/04)
-
- Nitrosoarene-Catalyzed HFIP-Assisted Transformation of Arylmethyl Halides to Aromatic Carbonyls under Aerobic Conditions
-
A rare metal-free nucleophilic nitrosoarene catalysis accompanied by highly hydrogen-bond-donor (HBD) solvent, 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), organocatalytically converts arylmethyl halides to aromatic carbonyls. This protocol offers an effective means to access a diverse array of aromatic carbonyls with good chemoselectivity under mild reaction conditions. The activation of arylmethyl halides by HFIP to generate stable carbocation and autoxidation of in situ generated hydroxylamine to nitrosoarene in the presence of atmospheric O2 are the keys to success.
- Pradhan, Suman,Sharma, Vishali,Chatterjee, Indranil
-
supporting information
p. 6148 - 6152
(2021/08/03)
-
- Zirconium-based metal-organic framework as an efficiently heterogeneous photocatalyst for oxidation of benzyl halides to aldehydes
-
The development of efficient heterogeneous catalysts for fine chemical synthesis is critical for practical applications. Herein, for the first time, the zirconium-based metal-organic framework (UiO-66-NH2) is applied as an efficiently heterogeneous photocatalyst for conversion of benzyl halides to corresponding aldehydes with high selectivity (about 80 %) and conversion (up to 99 %) in the presence of oxygen and DMF as solvent. Through a series of experiments and analysis, the reaction mechanism is proposed to involve nucleophilic attack of the N-oxide. This study provides a general, environmental and high selective method to prepare benzaldehydes and broadens the application fields of UiO-66-NH2.
- Xue, Ping,Huang, Jiming,Lin, Liguang,Li, Rong,Tang, Mi,Wang, Zhengbang
-
-
- Ferric ion concentration-controlled aerobic photo-oxidation of benzylic C–H bond with high selectivity and conversion
-
A Fe(III)-promoted highly selective photo-oxidation of benzylic C–H bond delivering relative carbonyl products is reported. By altering the concentration of ferric salt, methylarenes can be selectively oxidized under UV irradiation to furnish aromatic aldehydes or acids, respectively. By this protocol, the oxidation of ethylarenes provides the corresponding acetophenones. The reaction is inferred to involve divergent pathways in different concentrations of catalyst for the alternative selectivity between aldehydes and aicds. The reusable catalyst, high conversion and selectivity make this oxidation a green and economic protocol for the synthesis of aromatic carbonyl compounds.
- Bu, Hongzhong,Gu, Jiefan,Li, Yufeng,Ma, Hongfei,Wan, Yuting,Wu, Zheng-Guang,Zhang, Weijian,Zhou, Ying'ao,Zhu, Hongjun
-
-
- Selective Electrochemical Oxygenation of Alkylarenes to Carbonyls
-
An efficient electrochemical method for benzylic C(sp3)-H bond oxidation has been developed. A variety of methylarenes, methylheteroarenes, and benzylic (hetero)methylenes could be converted into the desired aryl aldehydes and aryl ketones in moderate to excellent yields in an undivided cell, using O2 as the oxygen source and lutidinium perchlorate as an electrolyte. On the basis of cyclic voltammetry studies, 18O labeling experiments, and radical trapping experiments, a possible single-electron transfer mechanism has been proposed for the electrooxidation reaction.
- Li, Xue,Bai, Fang,Liu, Chaogan,Ma, Xiaowei,Gu, Chengzhi,Dai, Bin
-
supporting information
p. 7445 - 7449
(2021/10/02)
-
- SBA-15 Supported Silver Catalyst for the Efficient Aerobic Oxidation of Toluene Under Solvent-Free Conditions
-
The efficient SBA-15 supported silver catalysts(Ag/SBA-15) were prepared and characterized by ICP-OES, XRD, TEM, SEM, XPS and N2 adsorption–desorption techniques. The catalysts exhibited an excellent catalytic activity for the aerobic oxidation of toluene to benzaldehyde under solvent-free conditions. Conversion of toluene and selectivity of benzaldehyde were 50% and 89% respectively over catalyst with 9.1 wt% Ag loading (10Ag/SBA-15). A wide range of substrates were tolerated under the selected reaction conditions. The kinetic study shows that the oxidation of toluene over 10Ag/SBA-15 is pseudo-first-order reaction and the activation energy Ea is 45.1?kJ/mol. A plausible mechanism involving oxygen free radicals was proposed for the aerobic oxidation reaction. Compared with the traditional method, the newly designed heterogeneous catalytic system shows better economic applicability, environmental friendliness and broader application prospects. Graphical abstract: [Figure not available: see fulltext.]
- Chen, Lei,Chen, Yanjiao,Dai, Xuan,Guo, Jiaming,Peng, Xinhua
-
-
- Core-shell Co-MOF-74@Mn-MOF-74 catalysts with Controllable shell thickness and their enhanced catalytic activity for toluene oxidation
-
A series of core-shell Co-MOF-74@Mn-MOF-74 samples with different shell thicknesses were prepared by the seed growth method, which were characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), inductively coupled plasma mass spectrometry (ICP-MS), X-ray photoelectron spectroscopy, nitrogen adsorption-desorption and scanning electron microscopy (SEM). The shell thickness of these MOF samples were successfully controlled by adjusting the mass ratio between MnCl2·4H2O and Co-MOF-74. On this basis, these MOFs were applied to the catalytic oxidation of toluene. The results showed that with the growth of Mn-MOF-74 in the outer layer of Co-MOF-74, the oxidative selectivity of the substrate to benzaldehyde was greatly improved for the synergy between the core layer and shell layer. The conversion of toluene was 22.4%, and the selectivity of benzaldehyde was 98.1%. In addition, the catalyst can transform various substituted toluene into the corresponding aldehydes in highly selectivity and still keep good stability after four catalytic cycles. The selectivity of the corresponding aldehyde is generally above 80%.
- Gu, Xiangyu,Huang, Cheng,Xu, Zengchuang,Wu, Hao,Dong, Ruilan,Liu, Rui,Chen, Jing,Zhu, Hongjun
-
-
- Oxidation/ MCR domino protocol for direct transformation of methyl benzene, alcohol, and nitro compounds to the corresponding tetrazole using a three-functional redox catalytic system bearing TEMPO/Co(III)-porphyrin/ Ni(II) complex
-
A redox catalytic system for oxidation-reduction reactions and the domino preparation of tetrazole compounds from nitro and alcohol precursors was designed, prepared and characterized by UV–vis, GPC, TGA, XRD, EDX, XPS, VSM, FE-SEM, TEM, DLS, BET, NMR, and ICP analyses. The catalyst was prepared via several successive steps by demetalation of chlorophyll b, copolymerization with acrylated TEMPO monomers, complexation with Ni and Co metals (In two different steps), then immobilized on magnetic nanoparticles. The presence of three functional groups including TEMPO, coordinated cobalt, and coordinated nickel in the catalyst, allowed the oxidation of various types of alcohols, alkyl benzenes as well as the reduction of nitro compounds by a single catalyst. All reactions yielded up to 97 % selectivity for oxidation and reduction reactions. Next, the ability of the catalyst to successfully convert alcohol, methyl benzenes and nitro to their corresponding tetrazoles was studied.
- Mahmoudi, Boshra,Rostami, Amin,Kazemnejadi, Milad,Hamah-Ameen, Baram Ahmed
-
-
- Metal- And additive-free C-H oxygenation of alkylarenes by visible-light photoredox catalysis
-
A metal- and additive-free methodology for the highly selective, photocatalyzed C-H oxygenation of alkylarenes under air to the corresponding carbonyls is presented. The process is catalyzed by an imide-acridinium that forms an extremely strong photooxidant upon visible light irradiation, which is able to activate inert alkylarenes such as toluene. Hence, this is an easy to perform, sustainable and environmentally friendly oxidation that provides valuable carbonyls from abundant, readily available compounds.
- García Manche?o, Olga,Kuhlmann, Jan H.,Pérez-Aguilar, María Carmen,Piekarski, Dariusz G.,Uygur, Mustafa
-
supporting information
p. 3392 - 3399
(2021/05/21)
-
- Integration of Earth-Abundant Photosensitizers and Catalysts in Metal-Organic Frameworks Enhances Photocatalytic Aerobic Oxidation
-
We report here the construction of two metal-organic frameworks (MOFs), Zr6-Cu/Fe-1 and Zr6-Cu/Fe-2, by integrating earth-abundant cuprous photosensitizers (Cu-PSs) and Fe catalysts for photocatalytic aerobic oxidation. Site isolation and pore confinement stabilize both Cu-PSs and Fe catalysts, while the proximity between active centers facilitates electron and mass transfer. Upon visible light irradiation and using O2 as the only oxidant, Zr6-Cu/Fe-1 and Zr6-Cu/Fe-2 efficiently oxidize alcohols and benzylic compounds to afford corresponding carbonyl products with broad substrate scopes, high turnover numbers of up to 500 with a 9.4-fold enhancement over homogeneous analogues, and excellent recyclability in four consecutive runs. Control experiments, spectroscopic evidence, and computational studies revealed the photo-oxidation mechanism: Oxidative quenching of [Cu-PS]? by O2 affords [CuII-PS], which efficiently oxidizes FeIII-OH to generate a hydroxyl radical for substrate oxidation. This work highlights the potential of MOFs in promoting earth-abundant metal-based photocatalysis.
- Feng, Xuanyu,Pi, Yunhong,Song, Yang,Xu, Ziwan,Li, Zhong,Lin, Wenbin
-
p. 1024 - 1032
(2021/01/26)
-
- Homogeneous CuCl2/TMEDA/TEMPO-Catalyzed chemoselective base- and halogen- free aerobic oxidation of primary alcohols in mild conditions
-
This article describes the developing of a base- and halogen- free homogeneous system aiming to chemoselectively oxidize allyl, furyl, aryl and heteroaryl primary alcohols. The current easy-to-handle aerobic system uses few amounts of CuCl2/TMEDA/TEMPO system under mild reaction conditions to produce aldehydes in high yields. Moreover, the CuCl2/TMEDA cyclic voltammetry was measured for the first time, disclosing that TMEDA as ligand substantially affects the redox potential (E1/2) of the couple E1/2Cu2+/Cu+ to E1/2Cu2+/Cu+-TMEDA by 454 mV in the redox system.
- Alves, Otávio A. L.,Chagas, Rafael C. R.,Princival, Jefferson L.,Ribeiro, RogérioT.,Silva, Emmanuel D.,Villar, José A. F. P.
-
-
- C70Fullerene Catalyzed Photoinduced Aerobic Oxidation of Benzylamines to Imines and Aldehydes
-
C70 fullerene catalyzed photoinduced oxidation of benzylic amines at ambient conditions has been explored here. The developed strategy's main feature includes the additive/oxidant-free conversion of benzylic amine to corresponding imine and aldehydes. The reaction manifests broad substrate scope with excellent function group leniency and is applicable up to the gram scale. Further, symmetrical secondary amines can also be synthesized from benzylic amine in a one-pot two-step process. Various experiments and density functional theory studies revealed that the current reaction involves the generation of reactive oxygen species, single electron transfer reaction, and benzyl radical formation as key steps under photocatalytic conditions.
- Kumar, Inder,Kumar, Rakesh,Gupta, Shiv Shankar,Sharma, Upendra
-
supporting information
p. 6449 - 6457
(2021/05/29)
-
- One-Pot Direct Oxidation of Primary Amines to Carboxylic Acids through Tandem ortho-Naphthoquinone-Catalyzed and TBHP-Promoted Oxidation Sequence
-
Biomimetic oxidation of primary amines to carboxylic acids has been developed where the copper-containing amine oxidase (CuAO)-like o-NQ-catalyzed aerobic oxidation was combined with the aldehyde dehydrogenase (ALDH)-like TBHP-mediated imine oxidation protocol. Notably, the current tandem oxidation strategy provides a new mechanistic insight into the imine intermediate and the seemingly simple TBHP-mediated oxidation pathways of imines. The developed metal-free amine oxidation protocol allows the use of molecular oxygen and TBHP, safe forms of oxidant that may appeal to the industrial application.
- Kim, Hun Young,Oh, Kyungsoo,Si, Tengda
-
supporting information
p. 18150 - 18155
(2021/12/09)
-
- Scalable Negishi Coupling between Organozinc Compounds and (Hetero)Aryl Bromides under Aerobic Conditions when using Bulk Water or Deep Eutectic Solvents with no Additional Ligands
-
Pd-catalyzed Negishi cross-coupling reactions between organozinc compounds and (hetero)aryl bromides have been reported when using bulk water as the reaction medium in the presence of NaCl or the biodegradable choline chloride/urea eutectic mixture. Both C(sp3)-C(sp2) and C(sp2)-C(sp2) couplings have been found to proceed smoothly, with high chemoselectivity, under mild conditions (room temperature or 60 °C) in air, and in competition with protonolysis. Additional benefits include very short reaction times (20 s), good to excellent yields (up to 98 %), wide substrate scope, and the tolerance of a variety of functional groups. The proposed novel protocol is scalable, and the practicability of the method is further highlighted by an easy recycling of both the catalyst and the eutectic mixture or water.
- Dilauro, Giuseppe,Azzollini, Claudia S.,Vitale, Paola,Salomone, Antonio,Perna, Filippo M.,Capriati, Vito
-
supporting information
p. 10632 - 10636
(2021/04/09)
-
- DIBALH: From known fundamental to an unusual reaction; Chemoselective partial reduction of tertiary amides in the presence of esters
-
This study presents a quick and reliable approach to the chemoselective partial reduction of tertiary amides to aldehydes in the presence of readily reducible ester groups using commercial DIBALH reagent. Moreover, the developed method was also extended to multi-functional molecules bearing ester moieties, which were successfully chemoselectively reduced to the corresponding aldehydes. This journal is
- An, Duk Keun,Heo, Yu Jin,Jaladi, Ashok Kumar,Kim, Hyun Tae
-
p. 33809 - 33813
(2021/12/09)
-
- The: In situ fabrication of ZIF-67 on titania-coated magnetic nanoparticles: A new platform for the immobilization of Pd(ii) with enhanced catalytic activity for organic transformations
-
Considering the outstanding characteristics of metal organic frameworks (MOFs) and magnetic nanoparticles, herein we report a facile approach for the synthesis of a magnetic zeolitic-imidazolate-framework-supported palladium(ii) catalyst. In brief, zeolitic imidazolate framework-67 (ZIF-67) was successfully incorporated onto the surface of titania-coated magnetic nanoparticles using ethane-1,2-diamine as a linker, and then Pd(ii) was immobilized onto this. The resulting Pd@ZIF-67-Fe3O4-TiO2 catalyst possesses a high surface area (205 m2 g-1), a large pore volume (0.10 cm3 g-1), good magnetic responsivity (10.71 emu g-1), and high stability. A comparative analysis of Pd@ZIF-67-Fe3O4-TiO2 and Pd@Fe3O4-TiO2 catalysts for the oxidation, reduction, and oxidative deprotection of oximes was done to investigate the effects of ZIF-67 on the catalytic performance of Pd species. Substantial differences in activity and stability were observed in the presence of ZIF-67, suggesting that ZIF-67 plays an important role in enhancing the activity of Pd(ii). This superior catalytic activity and stability arises due to a synergistic effect between well-dispersed palladium species and highly porous ZIF-67, which was confirmed via XPS analysis. Moreover, the catalyst retains its structure, chemical environment, and good magnetic response even after five catalytic runs, as confirmed via FTIR, XRD, XPS, and VSM studies of reused catalyst samples.
- Kaur, Manpreet,Paul, Satya,Sharma, Chandan,Sharma, Sukanya
-
p. 20309 - 20322
(2021/11/22)
-
- The Highly Effective Cobalt Based Metal–Organic Frameworks Catalyst for One Pot Oxidative Esterification Under Mild Conditions
-
The cobalt-based metal organic frameworks (Co-MOFs) catalyst has been prepared with using terephthalic acid and 4,4′-bipyridine as organic linkers by facile solvothermal method for one pot oxidative esterification. The prepared catalyst was pyrolysed at different temperature and then applied for oxidation of aldehyde using molecular oxygen as benign oxidant under mild conditions. The Co-MOFs pyrolysed at 800?°C (denoted as Co-MOFs-800) catalyst exhibited excellent catalytic activity, selectivity and recyclability toward the oxidative esterification of benzaldehydes. Furthermore, it can be reused up to 5 runs without significant loss of activity. Graphic Abstract: [Figure not available: see fulltext.]
- Chindawong, Chakkresit,Mekrattanachai, Pagasukon,Setthaya, Naruemon,Song, Wei Guo,Zhu, Lei
-
-
- Method for generating benzaldehyde by catalyzing alpha-monosubstituted styrene to be oxidized by N-hydroxyphthalimide
-
The invention discloses a method for generating benzaldehyde by catalyzing alpha-mono-substituted styrene to be oxidized through N-hydroxyphthalimide. According to the method, N-hydroxyphthalimide isused as a catalyst, oxygen is used as an oxidizing agent, and an alpha mono-substituted styrene compound is oxidized in an organic solvent to obtain the benzaldehyde derivative. The method has the advantages of simple reaction operation, low cost, mild conditions, high yield, no heavy metal pollution and the like.
- -
-
Paragraph 0036-0038
(2021/01/24)
-
- Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
-
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
- Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
-
p. 6591 - 6597
(2021/09/10)
-
- Photo-induced oxidative cleavage of C-C double bonds for the synthesis of biaryl methanoneviaCeCl3catalysis
-
A Ce-catalyzed strategy is developed to produce biaryl methanonesviaphotooxidative cleavage of C-C double bonds at room temperature. This reaction is performed under air and demonstrates high activity as well as functional group tolerance. A synergistic Ce/ROH catalytic mechanism is also proposed based on the experimental observations. This protocol should be the first successful Ce-catalyzed photooxidation reaction of olefins with air as the oxidant, which would provide inspiration for the development of novel Ce-catalyzed photochemical synthesis processes.
- Xie, Pan,Xue, Cheng,Du, Dongdong,Shi, SanShan
-
supporting information
p. 6781 - 6785
(2021/08/20)
-
- Decatungstate-mediated solar photooxidative cleavage of CC bonds using air as an oxidant in water
-
With the increasing attention for green chemistry and sustainable development, there has been much interest in searching for greener methods and sources in organic synthesis. However, toxic additives or solvents are inevitably involved in most organic transformations. Herein, we first report the combination of direct utilization of solar energy, air as the oxidant and water as the solvent for the selective cleavage of CC double bonds in aryl olefins. Various α-methyl styrenes, diaryl alkenes as well as terminal styrenes are well tolerated in this green and sustainable strategy and furnished the desired carbonyl products in satisfactory yields. Like heterogeneous catalysis, this homogeneous catalytic system could also be reused and it retains good activity even after repeating three times. Mechanism investigations indicated that both O2- and 1O2 were involved in the reaction. Based on these results, two possible mechanisms, including the electron transfer pathway and the energy transfer pathway, were proposed.
- Du, Dongdong,Luo, Junfei,Shi, Sanshan,Xie, Pan,Xue, Cheng
-
p. 5936 - 5943
(2021/08/23)
-
- Thiol-initiated photocatalytic oxidative cleavage of the C=C bond in olefins and its extension to direct production of acetals from olefins
-
The oxidative cleavage of olefins to produce aldehydes/ketones is an important reaction in organic syntheses. In this manuscript, a mild and operationally simple protocol for the aerobic oxidation of olefins to produce carbonyl compounds was realized over ZnIn2S4under visible light, using air as the oxidant and a thiol as the initiator. It was proposed that the photogenerated holes over ZnIn2S4attack the thiol to produce thiyl radicals, which initiate the oxidative cleavage of the C=C bond in olefins to produce aldehydes/ketones. By further coupling with the condensation between the as-obtained aldehydes/ketones and alcohols, this strategy can also be applied to the production of different acetals directly from the olefins. This study demonstrates a new pathway to realize the oxidative cleavage of olefins to produce aldehydes/ketones, and also provides a new protocol for the production of acetals directly from the olefins.
- Wang, Xinglin,Li, Yuanyuan,Li, Zhaohui
-
p. 1000 - 1006
(2021/02/26)
-
- g-C3N4@Ce-MOF Z-scheme heterojunction photocatalyzed cascade aerobic oxidative functionalization of styrene
-
A special composite of the cerium-based metal-organic framework (Ce-UiO-66) modified with graphitic carbon nitride nanosheets (g-C3N4) has been synthesized. In order to make a comparison, a series of composites comprising g-C3N4and Ce-MOF were synthesized as well. Their structural features were investigated using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), sorption of nitrogen (BET and BJH), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), X-ray fluorescence spectroscopy (XRF) and diffuse reflectance UV-Vis spectroscopy (UV-Vis DRS) and electron spin resonance (ESR) techniques. According to the obtained results, it was found that nanosheets of mesoporous g-C3N4act as linkers between the cerium sites, playing a critical role in the formation of composites. In fact, the embedded g-C3N4nanoparticles in the Ce-MOF cause a new kind of meso-porosity. Moreover, the coordination of nitrogen atoms in the graphitic carbon nitride structure to cerium atoms of the crystal brings about substantial changes in the optical properties, increasing the photoreactivity. On the other hand, since there is a physical contact between Ce-UiO-66 and g-C3N4in the composite, the unaltered pore volume and optical properties lead to the formation of a physical mixture rather than a composite. The g-C3N4@Ce-MOF as a photocatalyst was employed in photocatalytic aerobic oxidative Hantzsch pyridine synthesis of styrene and indicated high performance under visible light. The stability and reusability of g-C3N4@Ce-MOF were also examined and showed high efficiency up to the 5th run. Besides, the PXRD and FT-IR analyses taken from the retrieved g-C3N4@Ce-MOF nanocomposite confirmed the catalyst stability after the completion of the cascade aerobic oxidative reaction. Despite the photocatalytic performance, the synergistic effect of open metal sites in the MOF as Lewis acid and nitrogen in g-C3N4have greatly improved the efficiency of the catalyst. Moreover, the study of the reaction mechanism using ESR indicates the positive effect of composite formation on the performance of the photocatalytic aerobic oxidation reaction by the superoxide radical (O2˙—), as a selective oxidant species.
- Karimia, Meghdad,Sadeghia, Samira,Gavinehroudi, Reza Ghahremani,Mohebali, Haleh,Mahjoub, Alireza,Heydari, Akbar
-
p. 6671 - 6681
(2021/04/22)
-
- A highly stable metal-organic framework with cubane-like clusters for the selective oxidation of aryl alkenes to aldehydes or ketones
-
Triazine derivatives, a class of electron-deficient π-conjugated molecules with high photochemical activity and excellent luminescent characteristics, have been utilized as a kind of electron-acceptor for the construction of molecular cages, luminescent and photochromic materials. In this paper, a novel and highly stable MOF with cubane-like clusters, [Co4(SO4)3(F)3(tpt)2(tatb)] (1) (tpt = 2,4,6-tris-(4-pyridyl)-1,3,5-triazine, H3tatb = 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl)tribenzoic acid), has been successfully synthesized based on a triazine derivative, and possesses unprecedented sulfate- and fluoride-bridged cubane-type tetranuclear cobalt clusters and a 3D + 3D → 3D open framework. Compound1shows a rather high BET surface area and exhibits excellent thermal stability and high chemical stability in common solvents and even in acidic or basic solutions (in a pH range from 4 to 12). Moreover, catalytic measurements show that compound1is an excellent heterogeneous catalyst for the selective oxidation of aryl alkenes to aldehydes or ketones with conversions of 97%.
- He, Chixian,Liu, Jiaming,Liu, Jian-Jun,Liu, Teng,Shen, Xianfu,Shen, Xiang
-
p. 4667 - 4673
(2021/07/11)
-
- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
-
The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
- -
-
Paragraph 0041-0042; 0089-0090
(2021/06/06)
-
- Fe-S Catalyst Generated in Situ from Fe(III)- And S3?--Promoted Aerobic Oxidation of Terminal Alkenes
-
An iron-sulfur complex formed by the simple mixture of FeCl3 with S3?- generated in situ from K2S is developed and applied to selective aerobic oxidation of terminal alkenes. The reaction was carried out under an atmosphere of O2 (balloon) and could proceed on a gram scale, expanding the application of S3?- in organic synthesis. This study also encourages us to explore the application of an Fe-S catalyst in organic reactions.
- Ai, Jing-Jing,Huang, Cheng-Mi,Li, Jian,Liu, Bei-Bei,Rao, Weidong,Wang, Fei,Wang, Shun-Yi
-
supporting information
p. 4705 - 4709
(2021/06/28)
-
- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
-
The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
-
p. 4985 - 4992
(2021/10/16)
-
- Photocatalytic one-pot multidirectional N-alkylation over Pt/D-TiO2/Ti3C2: Ti3C2-based short-range directional charge transmission
-
Visible-light-induced one-pot, multistep, and chemoselectivity adjustable reactions highlight the economical, sustainable, and green process. Herein, we report Pt nanoparticles dispersed on S and N co-doped titanium dioxide/titanium carbide (MXene) (3%Pt/
- Jiang, Heyan,Sheng, Meilin,Li, Yue,Kong, Shuzhen,Bian, Fengxia
-
-
- Preparation of a platinum nanoparticle catalyst located near photocatalyst titanium oxide and its catalytic activity to convert benzyl alcohols to the corresponding ethers
-
A novel platinum nanoparticle catalyst closely located near the surface of titanium oxide, PtNP/TiO2, has been prepared. This catalyst has both the properties of a photocatalyst and a metal nanoparticle catalyst, and acquired environmentally friendly catalytic activity, which cannot be achieved by just one of these catalysts, to afford ethers from benzyl alcohols under the wavelength of 420 nm.
- Akiyama, Toshiki,Arisawa, Mitsuiro,Harada, Kazuo,Honma, Tetsuo,Naka, Hiroshi,Saito, Susumu,Wada, Yuki
-
p. 22230 - 22237
(2021/07/02)
-
- Samarium-based Grignard-type addition of organohalides to carbonyl compounds under catalysis of CuI
-
Grignard-type additions were readily achieved under the mediation of CuI (10 mol%) and samarium (2 equiv.) by employing various organohalides,e.g.benzyl, aryl, heterocyclic and aliphatic halides (Cl, Br or I), and diverse carbonyl compounds (e.g.carbonic esters, carboxylic esters, acid anhydrides, acyl chlorides, ketones, aldehydes, propylene epoxides and formamides) to afford alcohols, ketones and aldehydes, respectively, with high efficiency and chemoselectivity, in which the organosamarium intermediate might be involved.
- Liu, Chen,Liu, Yongjun,Qi, Yan,Song, Bin,Wang, Liang,Xiao, Shuhuan
-
supporting information
p. 6169 - 6172
(2021/06/30)
-
- Aerobic epoxidation of olefins by carboxylate ligand-based cobalt (II) compound: synthesis, X-ray crystallography, and catalytic exploration
-
A new quinoline carboxylate-based cobalt (II) metal compound, [Co (HL1)2(H2O)4] (1) (H2L1 = 2-hydroxyquinoline-4-carboxylic acid) has been hydrothermally synthesized, and fully characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared (FT-IR), elemental and thermo-gravimetric analysis. Compound 1 shows high thermal stability up to ~300°C. Single-crystal X-ray diffraction study of 1 exhibited monomeric structure experiences further stabilized in solid state through different non-covalent interaction, for example, H-bonding and π···π stacking interaction and extended to 3D supramolecular H-bonded network. Compound 1 efficiently catalyzes epoxidation reactions of olefins under homogeneous conditions using molecular oxygen as an oxidizer. Another reported quinoline carboxylate-based nickel (II) monomer [Ni(L2)2(H2O)2] (2) (HL2 = thiazole-4-carboxylic acid) has been synthesized and characterized to compare it with compound 1 towards aerobic epoxidation reactions, where 1 comes as superior.
- Brandao, Paula,Debnath, Rakesh,Gayen, Saikat,Ghosh, Pameli,Koner, Subratanath,Lin, Zhi,Maity, Tanmay,Mal, Dasarath,Patra, Birendra Nath,Pratihar, Jahar Lal,Sepay, Nayim
-
-
- Iodine-catalyzed alcohol disproportionation method
-
The invention relates to the technical field of catalysis, in particular to an iodine-catalyzed alcohol disproportionation method which comprises the following steps: sequentially adding alcohol, iodine and a solvent into a high-temperature and high-pressure reaction kettle, introducing a certain amount of nitrogen, conducting reacting for a certain time, collecting an organic phase after the reaction is ended, and conducting fractionating to obtain corresponding alkane and aldehyde/ketone. Alcohol disproportionation is efficient and atom-economical conversion without any additional oxidizing agent and reducing agent, and hydrocarbon and aldehyde/ketone molecules which are easy to separate can be formed at the same time. Meanwhile, the method has wide functional group tolerance, various substrate samples including aryl alcohol derivatives, heterocyclic alcohol derivatives, allyl alcohol derivatives and dihydric alcohol are tested, and the result shows that most of the substrate samples show good or extremely good yield.
- -
-
Paragraph 0028-0029
(2021/06/13)
-
- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
-
The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
-
supporting information
p. 8108 - 8115
(2021/10/29)
-
- Aerobic oxidative C?C bond cleavage of aromatic alkenes by a high valency iron-containing perovskite catalyst
-
High valency iron-containing perovskite catalyst BaFeO3-dcould efficiently promote the additive-free oxidative C?C bond cleavage of various aromatic alkenes to the corresponding aldehydes or ketones using O2as the sole oxidant. This system was applicable to the gram-scale oxidation of 1,1-diphenylethylene, in which 2.71 g (75% yield) of the analytically pure ketone could be isolated.
- Shibata, Satomi,Kamata, Keigo,Hara, Michikazu
-
p. 2369 - 2373
(2021/04/22)
-
- Aerobic epoxidation of styrene over Zr-based metal-organic framework encapsulated transition metal substituted phosphomolybdic acid
-
Catalytic epoxidation of styrene with molecular oxygen is regarded as an eco-friendly alternative to producing industrially important chemical of styrene oxide (STO). Recent efforts have been focused on developing highly active and stable heterogeneous catalysts with high STO selectivity for the aerobic epoxidation of styrene. Herein, a series of transition metal monosubstituted heteropolyacid compounds (TM-HPAs), such as Fe, Co, Ni or Cu-monosubstituted HPA, were encapsulated in UiO-66 frameworks (denoted as TM-HPA@UiO-66) by direct solvothermal method, and their catalytic properties were investigated for the aerobic epoxidation of styrene with aldehydes as co-reductants. Among them, Co-HPA@UiO-66 showed relatively high catalytic activity, stability and epoxidation selectivity at very mild conditions (313 K, ambient pressure), that can achieve 82 % selectivity to STO under a styrene conversion of 96 % with air as oxidant and pivalaldehyde (PIA) as co-reductant. In addition, the hybrid composite catalyst can also efficiently catalyze the aerobic epoxidation of a variety of styrene derivatives. The monosubstituted Co atoms in Co-HPA@UiO-66 are the main active sites for the aerobic epoxidation of styrene with O2/PIA, which can efficiently converting styrene to the corresponding epoxide through the activation of the in-situ generated acylperoxy radical intermediate.
- Hu, Dianwen,Song, Xiaojing,Zhang, Hao,Chang, Xinyu,Zhao, Chen,Jia, Mingjun
-
-
- Gold Catalysts Can Generate Nitrone Intermediates from a Nitrosoarene/Alkene Mixture, Enabling Two Distinct Catalytic Reactions: A Nitroso-Activated Cycloheptatriene/Benzylidene Rearrangement
-
Gold-catalyzed reactions of cycloheptatrienes with nitrosoarenes yield nitrone derivatives efficiently. This reaction sequence enables us to develop gold-catalyzed aerobic oxidations of cycloheptatrienes to afford benzaldehyde derivatives using CuCl and nitrosoarenes as co-catalysts (10-30 mol %). Our density functional theory calculations support a novel nitroso-activated rearrangement, tropylium → benzylidene. With the same nitrosoarenes, we developed their gold-catalyzed [2 + 2 + 1]-annulations between nitrosobenzene and two enol ethers to yield 5-alkoxyisoxazolidines using 1,4-cyclohexadienes as hydrogen donors.
- Cheng, Mu-Jeng,Kardile, Rahul Dadabhau,Kuo, Tung-Chun,Liu, Rai-Shung,More, Sayaji Arjun
-
supporting information
p. 5506 - 5511
(2021/07/31)
-
- 1,2,3-Triazole framework: a strategic structure for C-H?X hydrogen bonding and practical design of an effective Pd-catalyst for carbonylation and carbon-carbon bond formation
-
1,2,3-Triazole is an interesting N-heterocyclic framework which can act as both a hydrogen bond donor and metal chelator. In the present study, C-H hydrogen bonding of the 1,2,3-triazole ring was surveyed theoretically and the results showed a good agreement with the experimental observations. The click-modified magnetic nanocatalyst Pd@click-Fe3O4/chitosan was successfully prepared, in which the triazole moiety plays a dual role as both a strong linker and an excellent ligand and immobilizes the palladium species in the catalyst matrix. This nanostructure was well characterized and found to be an efficient catalyst for the CO gas-free formylation of aryl halides using formic acid (HCOOH) as the most convenient, inexpensive and environmentally friendly CO source. Here, the aryl halides are selectively converted to the corresponding aromatic aldehydes under mild reaction conditions and low Pd loading. The activity of this catalyst was also excellent in the Suzuki cross-coupling reaction of various aryl halides with phenylboronic acids in EtOH/H2O (1?:?1) at room temperature. In addition, this catalyst was stable in the reaction media and could be magnetically separated and recovered several times.
- Hajipour, Abdol Reza,Hosseini, Seyed Mostafa,Jahromi, Maryam Dehdashti,Mohammadsaleh, Fatemeh,Niknam, Khodabakhsh
-
p. 20812 - 20823
(2021/07/01)
-
- A Magnetically Recyclable Palladium-Catalyzed Formylation of Aryl Iodides with Formic Acid as CO Source: A Practical Access to Aromatic Aldehydes
-
A magnetically recyclable palladium-catalyzed formylation of aryl iodides under CO gas-free conditions has been developed by using a bidentate phosphine ligand-modified magnetic nanoparticles-anchored- palladium(II) complex [2P-Fe 3O 4@SiO 2-Pd(OAc) 2] as catalyst, yielding a wide variety of aromatic aldehydes in moderate to excellent yields. Here, formic acid was employed as both the CO source and the hydrogen donor with iodine and PPh 3as the activators. This immobilized palladium catalyst can be obtained via a simple preparative procedure and can be facilely recovered simply by using an external magnetic field, and reused at least 9 times without any apparent loss of catalytic activity.
- You, Shengyong,Zhang, Rongli,Cai, Mingzhong
-
p. 1962 - 1970
(2021/01/25)
-
- Synergistic catalysis of the Br?nsted acid and highly dispersed Cu on the mesoporous Beta zeolite in the intermolecular aminoazidation of styrene
-
Acidic mesoporous Beta zeolite supported Cu (Cu/Beta-M) catalyst shows superior catalytic performance in the difunctionalization of styrenes with N-fluorobenzenesulfonimide (F-N(SO2Ph)2) and azidotrimethylsilane, compared with basic
- Fu, Wenqian,Yin, Chengyou,Feng, Yu,Zhang, Lei,Cheng, Feng,Fang, Zhongxue,Zhu, Chaojie,Tang, Tiandi
-
-
