100-52-7

Synthesis of zeolite@metal-organic framework core-shell particles as bifunctional catalysts

Zhu, Guanghui,Graver, Richard,Emdadi, Laleh,Liu, Baoyu,Choi, Kyu Yong,Liu, Dongxia

, p. 30673 - 30676 (2014)

A zeolite@metal-organic framework (ZSM-5@UiO-66) core-shell composite has been synthesized for the first time by solvothermal growth of UiO-66 on the surface of ZSM-5 particles. The acidity from ZSM-5 and the basicity from the amine groups in UiO-66 obtai

Aerobic oxidation of benzyl alcohol in methanol solutions over Au nanoparticles: Mg(OH)2 vs MgO as the support

Estrada, Miguel,Costa, Vinícius V.,Beloshapkin, Sergey,Fuentes, Sergio,Stoyanov, Evgenii,Gusevskaya, Elena V.,Simakov, Andrey

, p. 96 - 103 (2014)

Magnesium oxide and magnesium hydroxide materials containing supported gold nanoparticles (NPs), Au/Mg(OH)2 and Au/MgO, were prepared from the commercial MgO through the deposition-precipitation (DP) method and characterized by XRD, XPS, HRTEM, FTIR spectroscopy and N2 adsorption techniques. It was found that the starting MgO support was fully transformed into the Mg(OH)2 phase during the DP procedure. A nearly complete dehydration of the magnesium hydroxide and formation of Au/MgO was achieved through the reductive treatment at 500 C, whereas the treatment at 350 C still resulted in the Au/Mg(OH)2 material. The FTIR analysis showed a much higher ability of the Au/MgO surface to adsorb both benzyl alcohol and benzaldehyde (ca. 10 and 3 times, respectively), as compared to Au/Mg(OH) 2. Probably for this reason, the Au/MgO catalyst exhibited ca. 50% higher catalytic activity in the aerobic oxidation/oxidative methoxylation of benzyl alcohol in the methanol solutions with respect to the amount of surface gold atoms as compared to the Au/Mg(OH)2 catalyst, in spite of a larger size of the Au NPs. In addition, the thermal treatment of the catalyst at 500 C to dehydrate the support allowed to suppress the undesired side reaction between benzyl alcohol and primarily formed benzaldehyde to give benzyl benzoate.

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Olah,Ho

, p. 610 (1976)

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A versatile metal-organic framework for carbon dioxide capture and cooperative catalysis

Park, Jinhee,Li, Jian-Rong,Chen, Ying-Pin,Yu, Jiamei,Yakovenko, Andrey A.,Wang, Zhiyong U.,Sun, Lin-Bing,Balbuena, Perla B.,Zhou, Hong-Cai

, p. 9995 - 9997 (2012)

A multi-functional MOF PCN-124 was constructed from Cu paddlewheel motifs and a judiciously designed novel ligand bearing carboxylate, pyridine, and amide groups. PCN-124 exhibits selective adsorption of CO2 over CH 4 and excellent catalytic activity in a tandem one-pot deacetalization-Knoevenagel condensation reaction as a cooperative catalyst. The Royal Society of Chemistry 2012.

Linear free-energy relationships in chromium(VI) oxidation of substituted benzylamines in nonaqueous media

Thirumoorthi,Bhuvaneshwari,Elango

, p. 362 - 369 (2007)

The kinetics of oxidation of 11 para- and meta-substituted benzylamines by imidazolium fluorochromate (IFC) in different organic solvent media has been investigated in the presence of p-toluenesulfonic acid (TsOH). The reaction was run under pseudo-first-

Immobilized V-MIL-101 on modified Fe3O4 nanoparticles as heterogeneous catalyst for epoxidation of allyl alcohols and alkenes

Farzaneh, Faezeh,Sadeghi, Yasaman

, p. 275 - 281 (2015)

As a new heterogeneous catalyst, Fe3O4 nanoparticles were prepared and modified with sodium silicate and (3-aminopropyl) trimethoxysilane (APTMS) followed by complexation with V-MIL-101 and designated as Fe3O4@SiO2@APTMS@VMIL-101. It was characterized using FTIR, TEM, and VSM techniques. The Fe3O4@SiO2@APTMS@VMIL-101 was found to successfully catalyze the epoxidation of allyl alcohols and alkenes with tert-butylhydroperoxide (TBHP) in moderate to high yields. The epoxidation of trans-stilbene, norbornen, cyclooctene, geraniol, trans-2-hexene-1ol and 1-octene-3-ol with 100% selectivity is promising. Investigation of the stability and reusability of Fe3O4@SiO2@APTMS@V-MIL-101 revealed the heterogeneity character of the catalyst with no desorption during the course of epoxidation reactions. High yields, clean reactions, ease of catalyst separation and recyclability of the solid catalyst are some advantages of this method.

Heterogeneous Permanganate Oxidations. 5. The Preparation of Aldehydes by Oxidative Cleavage of Carbon-Carbon Double Bonds

Lee, Donald G.,Chen, Tao,Wang, Zhao

, p. 2918 - 2919 (1993)

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Can Contemporary Density Functional Theory Predict Energy Spans in Molecular Catalysis Accurately Enough to Be Applicable for in Silico Catalyst Design? A Computational/Experimental Case Study for the Ruthenium-Catalyzed Hydrogenation of Olefins

Rohmann, Kai,H?lscher, Markus,Leitner, Walter

, p. 433 - 443 (2016)

The catalytic hydrogenation of cyclohexene and 1-methylcyclohexene is investigated experimentally and by means of density functional theory (DFT) computations using novel ruthenium XantphosPh (4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) and XantphosCy (4,5-bis(dicyclohexylphosphino)-9,9-dimethylxanthene) precatalysts [Ru(XantphosPh)(PhCO2)(Cl)] (1) and [Ru(XantphosCy)(PhCO2)(Cl)] (2), the synthesis, characterization, and crystal structures of which are reported. The intention of this work is to (i) understand the reaction mechanisms on the microscopic level and (ii) compare experimentally observed activation barriers with computed barriers. The Gibbs free activation energy ΔG? was obtained experimentally with precatalyst 1 from Eyring plots for the hydrogenation of cyclohexene (ΔG? = 17.2 ± 1.0 kcal/mol) and 1-methylcyclohexene (ΔG? = 18.8 ± 2.4 kcal/mol), while the Gibbs free activation energy ΔG? for the hydrogenation of cyclohexene with precatalyst 2 was determined to be 21.1 ± 2.3 kcal/mol. Plausible activation pathways and catalytic cycles were computed in the gas phase (M06-L/def2-SVP). A variety of popular density functionals (ωB97X-D, LC-ωPBE, CAM-B3LYP, B3LYP, B97-D3BJ, B3LYP-D3, BP86-D3, PBE0-D3, M06-L, MN12-L) were used to reoptimize the turnover determining states in the solvent phase (DF/def2-TZVP; IEF-PCM and/or SMD) to investigate how well the experimentally obtained activation barriers can be reproduced by the calculations. The density functionals B97-D3BJ, MN12-L, M06-L, B3LYP-D3, and CAM-B3LYP reproduce the experimentally observed activation barriers for both olefins very well with very small (0.1 kcal/mol) to moderate (3.0 kcal/mol) mean deviations from the experimental values indicating for the field of hydrogenation catalysis most of these functionals to be useful for in silico catalyst design prior to experimental work.

Conversion of acid chlorides to aldehydes by oxidation of alkoxyaluminum intermediates with pyridinium chlorochromate or pyridinium dichromate

Cha, Jin Soon,Kim, Jong Mi,Chun, Joong Hyun,Kwon, Oh Oun,Kwon, Sang Yong,Han, Sung Wook

, p. 204 - 207 (1999)

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Selective benzylic oxidation of alkylaromatics over Cu/SBA-15 catalysts under solvent-free conditions

Neeli, Chinna Krishna Prasad,Narani, Anand,Marella, Ravi Kumar,Rama Rao, Kamaraju Seetha,Burri, David Raju

, p. 5 - 9 (2013)

With the purpose of benzylic oxidation of alkylaromatics into corresponding ketones selectively under solvent-free conditions, cheap, simple and versatile Cu/SBA-15 catalyst system with the Cu loading of 5, 10, 15 and 20% has been prepared by impregnating SBA-15 support. Among Cu/SBA-15 catalysts, 10%Cu/SBA-15 exhibited superior activity and selectivity.

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Leffingwell,Bluhm

, p. 1151 (1969)

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Synthesis, structural characterization and application of a 2D coordination polymer of Mn-terephthalate as a heterogeneous catalyst for olefin oxidation

Bagherzadeh, Mojtaba,Ashouri, Fatemeh,Crossed D Signakovi?, Marijana

, p. 167 - 173 (2014)

A metal-organic coordination polymer of [Mn3(1,4- benzenedicarboxylate)3(DMF)4] ([Mn3(BDC) 3(DMF)4]n) was synthesized and characterized by IR spectra, elemental analysis (CHN), thermal gravimetric analysis (TGA) and single crystal X-ray diffraction analysis. The structure of [Mn 3(BDC)3(DMF)4]n is a 2D-periodic framework based on Mn(II)-terephthalate secondary building units (SBUs). The catalytic oxidation of various olefins was effectively carried out with [Mn 3(BDC)3(DMF)4]n. Moreover, the influence of key reaction parameters, including the solvents, reaction temperatures and nature of oxidant were studied. The optimized conditions were achieved by TBHP as the efficient oxidant in 1,2-dichloroethane solvent at 75 C. Finally, this catalyst was used for four cycles efficiently without a significant loss of yield.

A bifunctional approach towards the mild oxidation of organic halides: 2-dimethylamino-N,N-dimethylaniline N-oxide

Chandrasekhar, Sosale,Sridhar, Malayalam

, p. 5423 - 5425 (2000)

The titled reagent incorporates an oxygen-centred nucleophile and a basic moiety - in a suitably mutual orientation - in the same molecule. It oxidises various primary benzylic bromides to the corresponding aromatic aldehydes under relatively mild conditions (MeCN/rt-50°C/6-24 h) in high yields (83-97%), and is thus a useful alternative to the Kornblum procedure. (C) 2000 Elsevier Science Ltd.

Weakly distorted 8-quinolinolato iron(III) complexes as effective catalysts for oxygenation of organic compounds by hydrogen peroxide

Wang, Yongjun,Wen, Xu,Rong, Chunying,Tang, Senpei,Wu, Wenfeng,Zhang, Chao,Liu, Yachun,Fu, Zaihui

, p. 103 - 109 (2016)

This paper first discloses that two heteroleptic 8-quinolinolato iron(III) complexes (Qa1Qb2FeIII, Qa2Qb1FeIII) could be synthesized conveniently via the coordination of FeCl2·6H2O with 2 equivalents of 5,7-dichloro-8-hydroxyquinoline (Qb) or 5-chloro-8-hydroxyquinoline (Qa) under N2 and then 1 equivalent of Qa or Qb under air. In comparison with the two homoleptic counterparts (Qa3FeIII and Qb3FeIII), the proposed heteroleptic Q3FeIII complexes possessed similar coordination features to the Qb3FeIII one but showed similar catalysis performances to the Qa3FeIII one in the oxygenation of cyclohexane to cyclohexanol and cyclohexanone by hydrogen peroxide (H2O2) in acetonitrile. More importantly, both heteroleptic Q3FeIII complexes showed a better accelerating effect on this reaction and provided a slightly higher conversion than the Qa3FeIII and especially Qb3FeIII ones. Furthermore, this predominance in catalytic activity was more strikingly apparent upon both-catalyzed oxygenations of benzene, toluene, ethylbenzene or thioanisole by H2O2. This should be due to a structurally distorted effect of the heteroleptic Q3FeIII complexes that is induced by the different in ligand environment, as supported by DFT B3LYP/6-311G (d) calculation. Based the present reaction and UV-vis spectral characterization results, a free radical mechanism for the present catalysis system was proposed.

Visible-light mediated C-C bond cleavage of 1,2-diols to carbonyls by cerium-photocatalysis

Schwarz, Johanna,K?nig, Burkhard

, p. 486 - 488 (2019)

We describe a photocatalytic method for the cleavage of vicinal diols to aldehydes and ketones. The reaction is catalyzed by blue light and a cerium-catalyst and the scope includes aryl as well as alkyl substituted diols. The simple protocol which works under air and at room temperature enables the valorization of abundant diols.

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Corey,Fleet

, p. 4499,4500 (1973)

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Synthesis, characterisation and catalytic activities of manganese(III) complexes of pyridoxal-based ONNO donor tetradenatate ligands

Maurya, Mannar R.,Saini, Priyanka,Haldar, Chanchal,Avecilla, Fernando

, p. 710 - 720 (2012)

Reaction of MnII(CH3COO)2 with dibasic tetradentate ligands, N,N′-ethylenebis(pyridoxylideneiminato) (H 2pydx-en, I), N,N′-propylenebis(pyridoxylideneiminato) (H 2pydx-1,3-pn, II) and 1-methyl-N,N′- ethylenebis(pyridoxylideneiminato) (H2pydx-1,2-pn, III) followed by aerial oxidation in the presence of LiCl gives complexes [MnIII(pydx- en)Cl(H2O)] (1) [MnIII(pydx-1,3-pn)Cl(CH3OH)] (2) and [MnIII(pydx-1,2-pn)Cl(H2O)] (3), respectively. Crystal and molecular structures of [Mn(pydx-en)Cl(H2O)] (1) and [Mn(pydx-1,3-pn)Cl(CH3OH)] (2) confirm their octahedral geometry and the coordination of ligands through ONNO(2-) form. Reaction of manganese(II)-exchanged zeolite-Y with these ligands in refluxing methanol followed by aerial oxidation in the presence of NaCl leads to the formation of the corresponding zeolite-Y encapsulated complexes, abbreviated herein as [MnIII(pydx-en)]-Y (4), [MnIII(pydx-1,3-pn)]-Y (5) and [MnIII(pydx-1,2-pn)]-Y (6). These encapsulated complexes are used as catalysts for the oxidation, by H2O2, of methyl phenyl sulfide, styrene and benzoin efficiently. Oxidation of methyl phenyl sulfide under the optimized reaction conditions gave ca. 86% conversion with two major products methyl phenyl sulfoxide and methyl phenyl sulfone in the ca. 70% and 30% selectivity, respectively. Oxidation of styrene catalyzed by these complexes gave at least five products namely styrene oxide, benzaldehyde, benzoic acid, 1-phenylethane-1,2-diol and phenylacetaldehyde with a maximum of 76.9% conversion of styrene by 4, 76.3% by 5 and 76.0% by 6 under optimized conditions. The selectivity of the obtained products followed the order: benzaldehyde > benzoic acid > styrene oxide > phenylacetaldehyde > 1-phenylethane-1,2-diol. Similarly, ca. 93% conversion of benzoin was obtained by these catalysts, where the selectivity of the products followed the order benzil > benzoic acid > benzaldehyde-dimethylacetal. Tests for the recyclability and heterogeneity of the reactions have also been carried. Neat complexes are equally active. However, the recycle ability of encapsulated complexes makes them better over neat ones.

Silica chromate as an oxidising agent for the chemoselective oxidation of alcohols and the oxidative deprotection of trimethylsilyl ethers

Zolfigol, Mohammad A.,Shirini, Farhad,Mohammadpoor-Baltork, Iraj,Choghamarani, Arash Gh.,Hajjami, Maryam,Sedaghat, Abdol M.

, p. 113 - 116 (2005)

Silica chromate easily converts primary and secondary alcohols to corresponding carbonyl compounds in the presence of wet SiO2 both in dichloromethane and under solvent-free conditions at room temperature with good to excellent yields. Primary and secondary trimethylsilyl ethers were converted into the corresponding carbonyl compounds or alcohols by using silica chromate and wet SiO2 in dichloromethane at room temperature with good to excellent yields.

Utilizing Benign Oxidants for Selective Aerobic Oxidations Using Heterogenized Platinum Nanoparticle Catalysts

Hinde, Christopher S.,Gill, Arran M.,Wells, Peter P.,Hor, T. S. Andy,Raja, Robert

, p. 1226 - 1230 (2015)

By using platinum nanoparticle catalysts that are generated in situ by extrusion from a porous copper chlorophosphate framework, the role of oxidants in the selective oxidation of benzyl alcohol to benzaldehyde was evaluated, with a view to establishing s

HETEROGENEOUS PHOTOCATALYTIC OXIDATION OF AROMATIC COMPOUNDS ON SEMICONDUCTOR MATERIALS: THE PHOTO-FENTON REACTION

Fujihira, Masamichi,Satoh, Yoshiharu,Osa, Tetsuo

, p. 1053 - 1056 (1981)

Heterogeneous photocatalytic oxidation of aromatic compounds by H2O2 formed from dissolved O2 in the presence of illuminated TiO2 powders was investigated with reference to the Fenton reaction.All the products expected from the Fenton reaction were obtained.The effect of other semiconductor materials and Fe(2+) on the reaction was also investigated.

Mn(III) complexes with tridentate N,N,O-ligands as catalysts for the epoxidation of alkenes

Aghmiz,Mostfa,Iksi,Rivas,Gonzalez,Diaz,El Guemmout,El Laghdach,Echarri,Masdeu-Bulto

, p. 2567 - 2577 (2013)

Mn(III) complexes with tridentate Schiff bases have been prepared and applied as catalyst precursors in epoxidation of alkenes using iodosobenzene as an oxidant providing high conversions and high selectivities when cyclohexene derivatives were studied.

Highly ordered mesoporous zirconia-polyoxometalate nanocomposite materials for catalytic oxidation of alkenes

Armatas, Gerasimos S.,Bilis, Georgios,Louloudi, Maria

, p. 2997 - 3005 (2011)

A series of well-ordered mesoporous ZrO2-based heteropoly acid nanocomposite frameworks has been prepared through a surfactant-assisted sol-gel copolymerization route. The pore walls of these materials consist of nanocrystalline tetragonal ZrO2 and Keggin-type 12-phosphomolybdic acid (PMA) components with different PMA loadings, i.e. 12, 22 and 37 wt%. Small angle X-ray scattering, high-resolution TEM and N2 physisorption measurements indicated mesoporous property in hexagonal p6mm symmetry with large internal BET surface areas and narrow-sized pores. The incorporated PMA clusters preserve intact their Keggin structure into the mesoporous frameworks according to EDX, FT-IR and diffuse-reflectance UV/vis/NIR spectroscopy. The obtained ZrO2-PMA nanocomposites demonstrated great application potential in oxidative catalysis, exhibiting exceptional stability and catalytic activity in oxidation of alkenes using hydrogen peroxide as oxidant. The Royal Society of Chemistry 2011.

Oxidation of styrene oxide via chemical and photochemical methods using TiO2-CeO2-V2O5 catalysts

Castro, Laura V.,Manríquez, Ma. Elena,Ortiz-Islas, Emma,Pliego, Andrea Sánchez,Valdez, Martín Trejo

, (2020)

This work reports the preparation of the TiO2-CeO2 (TiCe) catalytic support of V2O5 catalysts, which was tested in the oxidation process of styrene oxide via chemical and photochemical methods. The TiCe-V2O5 catalytic support was prepared by the co-precipitated method from the individual metal oxides, varying the amount of vanadium oxide by 3, 6, and 10 % mol with respect to the support. The obtained catalysts were characterized by different spectroscopies, as well as by the N2 adsorption-desorption technique. The catalytic reaction test was carried out in the liquid phase during 120 min with/without ultraviolet light irradiation at 50 °C. There was no V2O5 effect on the surface area, pore volume, and pore diameter since all catalysts had similar textural values. In all samples the structures identified by X-ray diffraction were the Anatase phase and CeO2 in the cubic phase. XPS results revealed the formation of surface carbonate species, which were also identified by infrared spectroscopy. The conversion rate was better when employing ultraviolet light, and the rate increased as the V2O5 amount rose. The main reaction products were 2-phenylethanol and 1-phenylethanol. However, a low amount of benzaldehyde was detected. The selectivity to the desirable product (2-phenylethanol) increased when the reaction was irradiated with UV light and the catalyst contained a higher amount of vanadium. It was observed that the effect of UV radiation on the electric mobility produces an acceleration of the reaction to 2-phenylethanol, avoiding the 1-phenylethanol formation. The bandgap value decreased as the vanadium oxide amount increased, boosting the electric mobility.

Cobalt(III)-Catalyzed Functionalization of Unstrained Carbon-Carbon Bonds through β-Carbon Cleavage of Alcohols

Ozkal, Erhan,Cacherat, Bastien,Morandi, Bill

, p. 6458 - 6462 (2015)

We demonstrate that a simple Co(III)-complex can efficiently catalyze the cleavage of unstrained C-C bonds via the β-carbon elimination of secondary and tertiary alcohols bearing a directing group. The cobalt-aryl intermediate generated under the reaction conditions can be trapped by different electrophiles to generate a new carbon-carbon bond. Some essential features of this new Co-based mechanistic manifold were revealed by preliminary mechanistic studies.

Direct synthesis of carbonyl compounds from THP ethers with IBX in the presence of β-cyclodextrin in water

Narender,Reddy, M. Somi,Kumar, V. Pavan,Nageswar,Rao, K. Rama

, p. 1971 - 1973 (2005)

Water, an environmentally friendly reaction medium, has been utilized for the oxidative deprotection of tetrahydropyranyl ethers 1 with IBX at room temperature in the presence of β-cyclodextrin to give the corresponding carbonyl compounds 2.

An investigation of two copper(ii) complexes with a triazole derivative as a ligand: magnetic and catalytic properties

Doroshchuk, Roman O.,Gumienna-Kontecka, Elzbieta,Khomenko, Dmytro M.,Lampeka, Rostyslav D.,Martins, Luísa M. D. R. S.,Novitchi, Ghénadie,Petrenko, Yuliia P.,Piasta, Karolina,Shova, Sergiu,Toporivska, Yuliya

, p. 23442 - 23449 (2021)

Two new copper(ii) complexes [Cu2(L)2(OAc)2(H2O)2] (1) (L = 3-methyl-5-pyridin-2-yl-1,2,4-triazole) and [CuL2] (2) were prerared and thoroughly studied. The complexes are able to selectivel

RHODIUM(II) ACETATE: AN EFFECTIVE HOMOGENEOUS CATALYST FOR SELECTIVE ALLYLIC OXIDATION AND CARBON-CARBON BOND FISSION OF OLEFINS

Uemura, Sakae,Patil, Suresh R.

, p. 1743 - 1746 (1982)

Treatment of some cyclic olefins and allylbenzene with Rh2(OAc)4 in acetic acid in the presence of t-BuOOH gave the corresponding enones and allylic acetates, the former being predominant, Application to several styrene derivatives resulted in a selective C=C bond fission to give benzaldehyde or acetophenone.It is suggested that the reaction proceeds catalytically with Rh(II) acetate via an ionic pathway.

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Omura,K.,Swern,D.

, p. 1651 - 1660 (1978)

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Disulfide-Catalyzed Visible-Light-Mediated Oxidative Cleavage of C=C Bonds and Evidence of an Olefin–Disulfide Charge-Transfer Complex

Deng, Yuchao,Wei, Xiao-Jing,Wang, Hui,Sun, Yuhan,No?l, Timothy,Wang, Xiao

, p. 832 - 836 (2017)

A photocatalytic method for the aerobic oxidative cleavage of C=C bonds has been developed. Electron-rich aromatic disulfides were employed as photocatalyst. Upon visible-light irradiation, typical mono- and multi-substituted aromatic olefins could be converted into ketones and aldehydes at ambient temperature. Experimental and computational studies suggest that a disulfide–olefin charge-transfer complex is possibly responsible for the unconventional dissociation of S?S bond under visible light.

Oxidative deprotection of cyclic acetals and trimethylsilyl ethers by γ-picolinium chlorochromate under nonaqueous conditions

Salehi,Khodaei,Goodarzi

, p. 1671 - 1673 (2002)

Deprotection of cyclic acetals and oxidative desilylation of trimethylsilyl ethers into the corresponding carbonyl compounds with γ-picolinium chlorochromate (γ-PCC) under nonaqueous conditions at room temperature is described. Oxidation of aldehydes to carboxylic acids was not observed in any case.

Nitrogen kinetic isotope effects for the monoamine oxidase B-catalyzed oxidation of benzylamine and (1,1-2H2)benzylamine: Nitrogen rehybridization and CH bond cleavage are not concerted

MacMillar, Susanna,Edmondson, Dale E.,Matsson, Olle

, p. 12319 - 12321 (2011)

Nitrogen kinetic isotope effects for the oxidation of benzylamine and (1,1-2H2)benzylamine by recombinant human monoamine oxidase B show that cleavage of the CH bond is not concerted with rehybridization of the nitrogen atom.

A Ruthenium Heteropolyanion as Catalyst for Alkane and Alkene Oxidation

Neumann, Ronny,Abu-Gnim, Chalil

, p. 1324 - 1325 (1989)

A ruthenium heteropolyanion, SiRu(H2O)W11O395-, has been synthesized which catalyses the liquid phase oxidation of alkanes and alkenes with various primary oxidants including potassium persulphate, sodium periodate, t-butyl hydroperoxide, and iodosylbenzene; the activity and selectivity with the oxidant used.

Copper-Functionalized Metal–Organic Framework as Catalyst for Oxidant-Controlled Partial Oxidation of Cyclohexene

Chotmongkolsap, Pannapat,Bunchuay, Thanthapatra,Klysubun, Wantana,Tantirungrotechai, Jonggol

, p. 703 - 712 (2018)

Microwave irradiation is exploited for the facile, one-step functionalization of Cu(acac)2 to –NH2 pendant groups of MIL-53(Al)-NH2, a metal–organic framework material, under mild reaction conditions and a short reaction time. PXRD, XPS, XAS, and EPR spectroscopy are used to investigate the structure and chemical nature of the copper species on the framework. The copper center exists in the +2 oxidation state with a square-planar geometry and NO3 coordination environment. The copper complex is anchored to the framework by imine bond formation. This copper-functionalized MIL-53(Al)-NH2 or MIL-53[Cu] is employed in the catalytic oxidation of olefins using molecular oxygen (O2) or tert-butyl hydroperoxide (TBHP) as the oxidant. The chemoselectivities of the oxidation products depend on the type of oxidant and substrate. When O2 is used as the oxidant and isobutyraldehyde as the co-oxidant in the oxidation of cyclohexene with MIL-53[Cu], cyclohexene oxide is the major product. However, when TBHP is employed as the oxidant, 2-cyclohexen-1-one is the major product. Furthermore, the catalyst can be reused at least three times without a significant loss in activity.

Potassium iodide-catalyzed three-component synthesis of 2-arylquinazolines via amination of benzylic C-H bonds of methylarenes

Zhao, Dan,Shen, Qi,Li, Jian-Xin

, p. 339 - 344 (2015)

A novel potassium iodide-catalyzed three-component synthesis of quinazolines via benzylic C-H bonds amination was developed. Commonly used ammonia salt and the sp3 carbon in commercially available methylarenes were used as nitrogen and C1 sources, respectively. Mechanistic studies indicated that an aryl aldehyde is involved as a key intermediate in the reaction.

Photochemical Electron-Transfer Reactions between Sulfides and Tetranitromethane. Oxidation vs Fragmentation of the Sulfide Radical-Cation Intermediate

Adam, Waldemar,Argueello, Juan E.,Penenory, Alicia B.

, p. 3905 - 3910 (1998)

Oxidation and/or fragmentation products are observed in the photochemical reaction of the alkyl phenyl sulfides 1a-d with tetranitromethane (TNM). The product distribution depends markedly on the substrate structure. Thus, methyl phenyl sulfide (1a) and benzyl phenyl sulfide (1b) give only the corresponding sulfoxides (oxidation). However, when the radical cation 1b?+ is generated by chemical oxidation with triarylaminium salts (Ar3N?+) in acetonitrile, in addition to oxidation fragmentation is also observed, and with an excess of Ar3N?+ oxidation is facilitated and no fragmentation is produced. For the photoreaction of diphenylmethyl phenyl sulfide (1c) with TNM, fragmentation is the main reaction, while for triphenylmethyl phenyl sulfide (1d) only this process is observed. The ease of C-S bond scission in these sulfur-centered radical cations 1.+ follows the ease of alkyl cation formation, i.e., Ph3C > Ph2CH > PhCH2 > CH3.

Efficient selective oxidation of alcohols to carbonyl compounds catalyzed by Ru-terpyridine complexes with molecular oxygen

Han, Qi,Guo, Xiao-Xuan,Zhou, Xian-Tai,Ji, Hong-Bing

, (2020)

The oxidation of alcohols with molecular oxygen is a promising approach to produce corresponding carbonyl compounds. In this work, efficient aerobic oxidation of alcohols to carbonyl compounds catalyzed by ruthenium-terpyridine [(tpy-PhCH3)RuCl3] with isobutyraldehyde as co-substrate was developed. Various alcohols including primary and secondary alcohols are smoothly converted to corresponding carbonyl compounds in good yield. In a 100 times large-scale oxidation of benzyl alcohol, benzaldehyde was obtained with 92% isolated yield. Moreover, a plausible mechanism involving high-valence ruthenium species was proposed based on in situ UV–vis spectroscopy.

Selective activation of C-H bonds on the ring of ethylbenzene catalyzed by several diperoxovanadate complexes

Liu, Qiuyuan,Zhu, Liangfang,Li, Li,Guo, Bin,Hu, Xiaoke,Hu, Changwei

, p. 71 - 77 (2010)

The competitive oxidation of the C-H bonds on the aromatic ring and side-chain of ethylbenzene (EB) with hydrogen peroxide is investigated over four diperoxovanadate catalysts, that is, K3[VO(O2) 2(ox)] (bpV(ox)), K2

Reusable catalysts based on dendrimers trapped in poly(p-xylylene) nanotubes

Lindner, Jean-Pierre,Roben, Caren,Studer, Armido,Stasiak, Michael,Ronge, Ramona,Greiner, Andreas,Wendorff, Hans-Joachim

, p. 8874 - 8877 (2009)

Catalysts in a bottle are readily prepared by coelectrospinning of PAMAM dendrimers and polyethylene oxide) (PEO). The nanofibers thus obtained can be coated with poly(p-xylylene) by chemical vapor deposition. Removal of the core PEO fibers by extraction

Double-helical ruthenium complexes of 2,2′:6′,2″,2?:6?,2″″-quinquepyridine (qpy) for multi-electron oxidation reactions

Ho, Paul Kwok-Keung,Cheung, Kung-Kai,Che, Chi-Ming

, p. 1197 - 1198 (1996)

Double-helical ruthenium complexes of 2,′:6′,2″:6″,2?:6?,2″″- quinquepyridine (qpy) are prepared from RuCl3·xH2O and qpy and the crystal structure of [Ru2(qPy)2(C2O4)][CF 3SOsub

Cucurbituril-mediated supramolecular acid catalysis

Kloeck, Cornelius,Dsouza, Roy N.,Nau, Werner M.

, p. 2595 - 2598 (2009)

The rates of acid hydrolysis of N-benzoyl-cadaverine (1), mono-N-(tert-butoxy)carbonyl cadaverine (2), and benzaldoxime (3) with binding motifs for cucurbit[6]uril (1,2) and cucurbit[7]uril (1,3) were investigated in the absence and presence of these hosts. Significant rate enhancements (up to a factor of ca. 300 for the hydrolysis of 3) were observed. Competitive inhibition due to encapsulation of added cadaverine and the successful use of sub-stoichiometric amounts of macrocycle confirmed the function of cucurbiturils in promoting acid hydrolysis.

Synergistic catalysis within TEMPO-functionalized periodic mesoporous organosilica with bridge imidazolium groups in the aerobic oxidation of alcohols

Karimi, Babak,Vahdati, Saleh,Vali, Hojatollah

, p. 63717 - 63723 (2016)

Anchoring 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) within the nanospaces of a periodic mesoporous organosilica with bridged imidazolium groups led to an unprecedented powerful bifunctional catalyst (TEMPO@PMO-IL-Br), which showed enhanced activity in the metal-free aerobic oxidation of alcohols. The catalyst and its precursors were characterized by N2 adsorption-desorption analysis, transmission electron microscopy (TEM), small angle X-ray scattering (SAXS), thermal gravimetric analysis (TGA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), solid state electron paramagnetic resonance (EPR) spectroscopy, elemental analysis, transmission electron microscopy (TEM) and high resolution TEM. It was clearly found that the catalytic activity of SBA-15-functionalized TEMPO (TEMPO@SBA-15) not bearing IL, TEMPO@PMO-IL-Cl, PMO-IL-AMP, or individual catalytic functionalities (PMO-IL/TEMPO@SBA-15) was inferior as compared with those obtained from TEMPO@PMO-IL-Br in the metal-free aerobic oxidation of benzyl alcohol, suggesting the critical role of co-supported TEMPO and imidazolium bromide in obtaining high catalytic activity in the described catalyst system. Our observation clearly points to the fact that the combination of imidazolium bromide units in close proximity to TEMPO moieties in the nanospaces of TEMPO@PMO-IL-Br might be indeed one of the key factors explaining the enhanced catalytic activity observed for this catalyst in the oxidation of benzyl alcohol, possibly through a synergistic catalysis relay pathway. A proposed model was suggested for the observed synergistic effect.

Exceptionally Facile Reduction of Acid Chlorides to Aldehydes by Sodium Tri-tert-butoxyaluminohydride

Cha, Jin Soon,Brown, Herbert C.

, p. 4732 - 4734 (1993)

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Facile cleavage reactions of styrylic olefins using electrochemical methods

Maki, Shojiro,Niwa, Haruki,Hirano, Takashi

, p. 1385 - 1386 (1997)

Negative constant current electrolysis of styrylic olefins in an aqueous solvent resulted in the oxidative cleavage of the double bonds, giving carbonyl compounds in good yields. The double bond conjugated with more than one aromatic ring was selectively cleaved.

Amey,R.L.,Martin,J.C.

, p. 5294 - 5299 (1979)

Triplet State and Photodecarboxylation of Phenylglyoxylic Acid in the Presence of Water

Kuhn, Hans Jochen,Goerner, Helmut

, p. 6208 - 6219 (1988)

The photodecarboxylation of phenylglyoxylic acid (PA) was studied by quantum yield (Φd) and time-resolved conductivity measurements in polar solvents at room temperature. Φd is substantial (>/=0.3) in the presence of 3-30 M water in acetonitrile and at pH a = 1.1 in neat water.The triplet states of PA, of its ethyl ester, and of 4-carboxybenzaldehyde were observed by nanosecond laser flash photolysis and emission spectroscopy.The initial transient obtained from PA (e.g., in acetonitrile λmax = 322 nm; lifetime >/= 3 μs) is assigned to the n,?* triplet state, and a second transient (in 2-propanol; λmax = 313 nm; t1/2 > 100 μs) is assigned to the Ph-COH-COOH radical.Phosphorescence was observed in glassy matrices at -196 deg C and in acetonitrile, acetone, and acetic acid at 25 deg C.In the latter ("inert") solvents the phosphorescence intensity and the triplet lifetime (up to 20 μs) are reduced by addition of alcohols or water.The rate constant of H-atom abstraction by triplet PA from 2-propanol is 1.5 * 106 M-1 s-1 in acetonitrile.Addition of water to PA in the "inert" solvents results in a non-Stern-Volmer behavior for triplet quenching.Excitation of PA in neat aqueous solution yields the triplet of benzaldehyde, the excited photoproduct, as main transient whereas triplet PA could not be detected.A mechanism accounting for the dependences of Φd on the pH and on the H2O concentration in mixtures with acetonitrile is proposed.Water governs the photochemistry of PA in three respects, via the acid-base equilibrium, as triplet quencher, and by reducing the quantum yield of intersystem crossing to the anion triplet.

Encapsulation of a double-helical water-nitrate chain inside unique double helical chiral channels formed from Keggin POM and hexaquo-cobalt(II) units

Chatterjee, Rajarshi,Paul, Luna,Hazra, Dipak K.,Pal, Nabanita,Jana, Atish Dipankar,Mukherjee, Monika,Ali, Mahammad

, p. 265 - 271 (2014)

A new inorganic-organic hybrid chiral molecule [Co(H2O) 6][C5H6N]H4[CoW12O 40]NO3·3H2O has been prepared by the hydrothermal method and was characterized by elemental analysis, IR and UV spectra, TG-DTA and single crystal X-ray diffraction techniques. The asymmetric unit consists of [CoW12O40]6- and NO 3- anions, the charge of which are counterbalanced by one octahedral [Co(H2O)6]2+ cation, a pyridinium [C5H6N]+ ion and 4H+ ions. The molecular structure of the title complex reveals a 3D supramolecular framework formed through intermolecular hydrogen bonds. This constitutes the first example in which a chiral architecture has been generated from achiral building blocks, where centrosymmetrically related cobalt octahedra and polyoxoanion tetrahedra are entangled through pairs of hydrogen bonds in a double helical way with a channel that houses a 1D water-NO3- double helix. This chiral POM shows good efficiency in the oxidation of common olefins in the presence of an environmentally benign oxidant, H2O2, under mild conditions.

A green and efficient oxidation of benzylic alcohols using H2O2 catalyzed by Montmorillonite-K10 supported MnCl2

Najafi, Gholam Reza

, p. 1162 - 1164 (2010)

Primary and secondary benzylic alcohols were oxidized to the corresponding carbonyl compounds in good to high yields by environmentally friendly and green oxidant, H2O2 catalyzed by Montmorillonite-K10 supported manganese(II) chlorid

A nanoscale iron catalyst for heterogeneous direct: N - And C -alkylations of anilines and ketones using alcohols under hydrogen autotransfer conditions

Nallagangula, Madhu,Sujatha, Chandragiri,Bhat, Venugopal T.,Namitharan, Kayambu

, p. 8490 - 8493 (2019)

Here, we report a commercially available nanoscale Fe catalyst for heterogeneous direct N- and C-alkylation reactions of anilines and methyl ketones with alcohols. A hydrogen autotransfer mechanism has been found to operate in these reactions by deuterium labelling studies. In addition, dehydrogenative quinoline synthesis has been demonstrated from amino benzyl alcohols and acetophenones.

Synthesis, structural characterization, and catalytic reactivity of a new molybdenum(VI) complex containing 1,3,4-thiadiazole derivative as a tridentate NNO donor ligand

Moradi-Shoeili, Zeinab,Zare, Maryam,Bagherzadeh, Mojtaba,Kubicki, MacIej,Boghaei, Davar M.

, p. 548 - 559 (2015)

A new cis-dioxo molybdenum(VI) complex was obtained by reaction of 2,4-dihydroxybenzylidene(5-N,N-methylphenylamino-1,3,4-thiadiazol-2-yl)hydrazone as ligand and [MoO2(acac)2] in methanol and was characterized by elemental analyses,

A Binuclear Iron Peroxide Complex Capable of Olefin Epoxidation

Murch, Bruce P.,Bradley, Fontaine C.,Que, Lawrence

, p. 5027 - 5028 (1986)

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Functionalized-1,3,4-oxadiazole ligands for the ruthenium-catalyzed Lemieux-Johnson type oxidation of olefins and alkynes in water

Hkiri, Shaima,Touil, Soufiane,Samarat, Ali,Sémeril, David

, (2021/11/30)

Three arene-ruthenium(II) complexes bearing alkyloxy(5-phenyl-1,3,4-oxadiazol-2-ylamino)(4-trifluoromethylphenyl)methyl ligands were quantitatively obtained through the reaction of (E)-1-(4-trifluoromethylphenyl)-N-(5-phenyl-1,3,4-oxadiazol-2-yl)-methanimine with the ruthenium precursor [RuCl2(η6-p-cymene)]2 in a mixture of the corresponding alcohol and CH2Cl2 at 50 °C. The obtained complexes were fully characterized by elemental analysis, infrared, NMR and mass spectrometry. Solid-state structures confirmed the coordination of the 1,3,4-oxadiazole moiety to the ruthenium center via their electronically enriched nitrogen atom at position 3 in the aromatic ring. These complexes were evaluated as precatalysts in the Lemieux-Johnson type oxidative cleavage of olefins and alkynes in water at room temperature with NaIO4 as oxidizing agent. Good to full conversions of olefins into the corresponding aldehydes were measured, but low catalytic activity was observed in the case of alkynes. In order to get more insight into the mechanism, three analogue arene-ruthenium complexes were synthesized and tested in the oxidative cleavage of styrene. The latter tests clearly demonstrated the importance of the hemilabile alkyloxy groups, which may form more stable (N,O)-chelate intermediates and increase the efficiency of the cis-dioxo-ruthenium(VI) catalyst.

Catalyst-Controlled Selectivity in Oxidation of Olefins: Highly Facile Success to Functionalized Aldehydes and Ketones

Shen, Chao,Sun, Nabo,Wu, Huizhen,Xu, Hao,Yu, Wenbo,Zheng, Kai

, (2022/02/01)

The attractive challenge in green chemistry is exploring novel heterogeneous catalyst system for catalyst-controlled product selectivity for oxidation of olefins. Hence, we proposed efficient and green catalytic methods for the selective synthesis of alde

Efficient and selective oxidation of hydrocarbons with tert-butyl hydroperoxide catalyzed by oxidovanadium(IV) unsymmetrical Schiff base complex supported on γ-Fe2O3 magnetic nanoparticles

Ardakani, Mehdi Hatefi,Sabet, Mohammad,Samani, Mahnaz

, (2022/01/22)

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

Oxygen Atom Transfer Mechanism for Vanadium-Oxo Porphyrin Complexes Mediated Aerobic Olefin Epoxidation

Han, Qi,Huang, Jia-Ying,Ji, Hong-Bing,Liu, Xiao-Hui,Tao, Lei-Ming,Xue, Can,Yu, Hai-Yang,Zhou, Xian-Tai,Zou, Wen

supporting information, p. 115 - 122 (2021/12/04)

The development of catalytic aerobic epoxidation by numerous metal complexes in the presence of aldehyde as a sacrificial reductant (Mukaiyama epoxidation) has been reported, however, comprehensive examination of oxygen atom transfer mechanism involving free radical and highly reactive intermediates has yet to be presented. Herein, meso-tetrakis(pentafluorophenyl) porphyrinatooxidovanadium(IV) (VOTPFPP) was prepared and proved to be efficient toward aerobic olefin epoxidation in the presence of isobutyraldehyde. In situ electron paramagnetic resonance spectroscopy (in situ EPR) showed the generation, transfer pathways and ascription of free radicals in the epoxidation. According to the spectral and computational studies, the side-on vanadium-peroxo complexes are considered as the active intermediate species in the reaction process. In the cyclohexene epoxidation catalyzed by VOTPFPP, the kinetic isotope effect value of 1.0 was obtained, indicating that epoxidation occurred via oxygen atom transfer mechanism. The mechanism was further elucidated using isotopically labeled dioxygen experiments and density functional theory (DFT) calculations.

Selective catalytic synthesis of bio-based high value chemical of benzoic acid from xylan with Co2MnO4@MCM-41 catalyst

Fan, Minghui,He, Yuting,Li, Quanxin,Luo, Yuehui,Yang, Mingyu,Zhang, Yanhua,Zhu, Lijuan

, (2021/12/20)

The efficient synthesis of bio-based chemicals using renewable carbon resources is of great significance to promote sustainable chemistry and develop green economy. This work aims to demonstrate that benzoic acid, an important high added value chemical in petrochemical industry, can be selectively synthesized using xylan (a typical model compound of hemicellulose). This novel controllable transformation process was achieved by selective catalytic pyrolysis of xylan and subsequent catalytic oxidation. The highest benzoic acid selectivity of 88.3 % with 90.5 % conversion was obtained using the 10wt%Co2MnO4@MCM-41 catalyst under the optimized reaction conditions (80 °C, 4 h). Based on the study of the model compounds and catalyst's characterizations, the reaction pathways for the catalytic transformation of xylan to bio-based benzoic acid were proposed.