- Singly Unified Driving Force Dependence of Outer-Sphere Electron-Transfer Pathways of Nonheme Manganese(IV)-Oxo Complexes in the Absence and Presence of Lewis Acids
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Epoxidation of styrene derivatives, sulfoxidation of thioanisole derivatives, and hydroxylation of toluene derivatives by a nonheme manganese(IV)-oxo complex binding triflic acid, [(N4Py)MnIV(O)]2+-(HOTf)2 [1-(H+/sup
- Sharma, Namita,Lee, Yong-Min,Li, Xiao-Xi,Nam, Wonwoo,Fukuzumi, Shunichi
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- Characterization and catalytic property of manganese(III) complexes with Schiff bases
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Two mononuclear manganese(III) complexes, [MnL1(OH2)(CH3OH)]·ClO4 (1) and [MnL2] (2), where L1 and L2 are the deprotonated forms of N,N′-bis(5-chloro-2-hydroxybenzylidene)ethane-
- Li,Zhang
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- Tris{2-[(5-fluorosalicylidene)amino]ethyl}amine and its manganese(iii) complex: Synthesis, characterization, crystal structures, and catalytic property
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A tris-Schiff base tris{2-[(5-fluorosalicylidene)amino]ethyl}amine (H3L) was prepared by the reaction of 1:3 molar ratio of tris(2-aminoethy1)amine with 5-fluorosalicylaldehyde in methanol. The Schiff base reacted with manganese perchlorate to
- Wei, Fen-Yan
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- Synthesis, structures, and catalytic property of manganese(III) complexes derived from N,N′-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine
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Two mononuclear manganese(III) complexes, [Mn(L)(NCS)] (I) and [Mn(L)(OH2)2] · Hfac · H2O (II), where L is the deprotonated form of N,N′-bis(5-fluoro-2-hydroxybenzylidene)ethane-1,2-diamine, Hfac is hexafluoroacetylacetona
- Li,Zhang
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- Synthesis, characterization, and catalytic activity of supported molybdenum Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation reaction
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A heterogeneous nanocatalyst was prepared via covalent anchoring of dioxomolybdenum(VI) Schiff base complex on core-shell structured Fe3O4@SiO2. The properties and the nature of the surface-fixed complex have been identifi
- Moradi-Shoeili, Zeinab,Zare, Maryam,Bagherzadeh, Mojtaba,Ozkar, Saim,Akbayrak, Serdar
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- Aerobic oxidation of olefins in the presence of a new amine functionalized core–shell magnetic nanocatalyst
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In this study meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese(III) acetate was immobilized onto the surface of amine functionalized Fe3O4 magnetic nanoparticles through covalent linkage. The new magnetic nanocatalyst [Fe3/s
- Rayati, Saeed,Nejabat, Fatemeh,Panjiali, Fatemeh
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- Substituent effects in dioxovanadium(V) schiff-base complexes: Tuning the outcomes of oxidation reactions
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Dioxovanadium(V) salicylaldehyde semicarbazone complexes with substituents on the ligand that span the range of electron donating (methoxy) to electron withdrawing (nitro) have been synthesized and characterized by NMR, IR, CV and EPR. The reactivity of these complexes toward the oxidation of styrene (as compared to the proteo complex and vanadyl acetylacetonate) has been studied in the presence of two different oxidants (hydrogen peroxide and tert-butyl hydrogen peroxide, TBHP). The complexes have been shown to exhibit different selectivity towards epoxidation versus oxidative cleavage based on the substitution of the ligand and the oxidant chosen. Epoxidation is favored with the methoxy substituted complex in the presence of hydrogen peroxide, while oxidative cleavage is the preferred reaction pathway for the nitro substituted complex with hydrogen peroxide. Conversions for these reaction are comparable to similar catalysts but with improved selectivity.
- McCaffrey, Vanessa P.,Conover, Olivia Q.,Bernard, Michael A.,Yarranton, Jonathan T.,Lessnau, Nicholas R.,Hempfling, Jordan P.
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- MeOTf/KI-catalyzed efficient synthesis of 2-arylnaphthalenesviacyclodimerization of styrene oxides
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The MeOTf/KI-catalyzed synthesis of 2-arylnaphthalene derivatives from aryl ethylene oxides in alcohol under ambient conditions is described. The present protocol has a higher atom efficiency and wider substrate applicability with excellent yields. The reaction proceeded using the aryl ethylene oxides to give 2-arylnaphthalenes either in homo-coupling or in cross-coupling. The reaction could also be carried out at the gram scale in minutes.
- Chen, Chao,Xi, Chanjuan,Zhang, Zeyu,Zou, Song
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supporting information
p. 8559 - 8565
(2021/10/20)
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- Aldehyde-catalyzed epoxidation of unactivated alkenes with aqueous hydrogen peroxide
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The organocatalytic epoxidation of unactivated alkenes using aqueous hydrogen peroxide provides various indispensable products and intermediates in a sustainable manner. While formyl functionalities typically undergo irreversible oxidations when activating an oxidant, an atropisomeric two-axis aldehyde capable of catalytic turnover was identified for high-yielding epoxidations of cyclic and acyclic alkenes. The relative configuration of the stereogenic axes of the catalyst and the resulting proximity of the aldehyde and backbone residues resulted in high catalytic efficiencies. Mechanistic studies support a non-radical alkene oxidation by an aldehyde-derived dioxirane intermediate generated from hydrogen peroxide through the Payne and Criegee intermediates.
- Kokotos, Christoforos G.,Kokotou, Maroula G.,Lotter, Dominik,Sparr, Christof,Triandafillidi, Ierasia
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p. 10191 - 10196
(2021/08/12)
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- Rate-Limiting Step of Epoxidation Reaction of the Oxoiron(IV) Porphyrin π-Cation Radical Complex: Electron Transfer Coupled Bond Formation Mechanism
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Epoxidation reactions catalyzed by high-valent metal-oxo species are key reactions in various biological and chemical processes. Because the redox potentials of alkenes are higher than those of most high-valent metal-oxo species, the electron transfer (ET
- Fujii, Hiroshi,Hada, Masahiko,Ishimizu, Yuri,Ma, Zhifeng
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supporting information
p. 17687 - 17698
(2021/12/01)
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- Oxoiron(v) mediated selective electrochemical oxygenation of unactivated C-H and CC bonds using water as the oxygen source
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An efficient electrochemical method for the selective oxidation of C-H bonds of unactivated alkanes (BDE ≤97 kcal mol-1) and CC bonds of alkenes using a biomimetic iron complex, [(bTAML)FeIII-OH2]-, as the redox mediator in an undivided electrochemical cell with inexpensive carbon and nickel electrodes is reported. The O-atom of water remains the source of O-incorporation in the product formed after oxidation. The products formed upon oxidation of C-H bonds display very high regioselectivity (75:1, 3°:2° for adamantane) and stereo-retention (RC ~99% for cyclohexane derivatives). The substrate scope includes natural products such as cedryl acetate and ambroxide. For alkenes, epoxides were obtained as the sole product. Mechanistic studies show the involvement of a high-valent oxoiron(v) species, [(bTAML)FeV(O)]- formed via PCET (overall 2H+/2e-) from [(bTAML)FeIII-OH2]- in CPE at 0.80 V (vs. Ag/AgNO3). Moreover, electrokinetic studies for the oxidation of C-H bonds indicate a second-order reaction with the C-H abstraction by oxoiron(v) being the rate-determining step.
- Chandra, Bittu,Gupta, Sayam Sen,Hellan, K. M.,Pattanayak, Santanu
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p. 11877 - 11885
(2020/11/18)
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- Magnetically recoverable porphyrin-based nanocatalysts for the effective oxidation of olefins with hydrogen peroxide: A comparative study
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In this paper, preparation, characterization and catalytic applications of metalloporphyrin-based magnetic nanocatalysts were investigated. meso-Tetrakis(4-carboxyphenyl)porphyrinatoiron(iii) chloride (Fe(TCPP)Cl) and meso-tetrakis(4-carboxyphenyl)porphyrinatomanganese(iii) acetate (Mn(TCPP)OAc) were separately immobilized onto the surface of amine functionalized magnetic nanoparticles (Fe3O4/SiO2/NH2) via covalent attachment. The obtained nanocatalysts were characterized using FT-IR and UV-Vis and atomic absorption spectroscopy, X-ray powder diffraction (XRD), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM). The catalytic efficiency of Fe3O4/SiO2/NH2-Fe(TCPP)Cl and Fe3O4/SiO2/NH2-Mn(TCPP)OAc for the green oxidation of alkenes with H2O2 was investigated in a comparative manner. The Mn-porphyrin based magnetic nanocatalyst shows higher catalytic efficiency compared to the Fe-porphyrin. In addition, the prepared magnetic nanocatalyst exhibited excellent reusability and could be reused at least five times without significant leaching or loss of activity. This journal is
- Rayati, Saeed,Moradi, Dana,Nejabat, Fatemeh
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p. 19385 - 19392
(2020/11/23)
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- A manganese(iii) Schiff base complex immobilized on silica-coated magnetic nanoparticles showing enhanced electrochemical catalytic performance toward sulfide and alkene oxidation
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In this study, a novel Mn(iii)-Schiff base complex was synthesized and characterized. The structure of this complex was determined to be a deformed octahedral coordination sphere by single-crystal X-ray diffraction analysis. The Mn(iii)-Schiff base complex was supported on silica-coated iron magnetic nanoparticlesviaaxial coordination by one-step complex anchoring to produce a heterogenized nanocatalyst. After this, the complex was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), and powder X-ray diffraction (XRD). Moreover, atomic absorption spectroscopy was used to determine the amount of the loaded metal. The heterogenized nanocatalyst effectively catalyzed the oxidation of a broad range of sulfides and alkenes with H2O2in the presence of a glassy carbon electrode, applying voltage to the reaction mixture. The results showed that the application of a potential to the reaction mixture could significantly decrease the reaction time when compared with the case of similar chemical oxidation reactions. In addition, an excellent value of turnover frequency (17?750 h-1) was achieved for the electrochemical oxidation of styrene. Moreover, the nanocatalyst showed good recoverability without significant loss of its activity within six successive runs in the electrochemical oxidation of methyl phenyl sulfide and cyclooctene. The electrochemical properties and stability of Fe3O4?SiO2-[MnL(OAc)] were investigated by cyclic voltammetry measurements and chronoamperometry technique.
- Elmi, Bahareh,Jafarian, Majid,Khodaei, Elham,Nafarieh, Parinaz,Rayati, Saeed,Wojtczak, Andrzej
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p. 17026 - 17036
(2020/05/18)
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- Tri-Manganese(III) Salen-Based Cryptands: A Metal Cooperative Antioxidant Strategy that Overcomes Ischemic Stroke Damage in Vivo
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Oxidative stress is one of the hallmarks of ischemic stroke. Catalase-based (CAT) biomimetic complexes are emerging as promising therapeutic candidates that are expected to act as neuroprotectants for ischemic stroke by decreasing the damaging effects fro
- Du, Yujing,Gao, Song,Huo, Yan,Jiang, Shang-Da,Kang, Lei,Li, Cuicui,Lin, Hengyu,Ning, Yingying,Sedgwick, Adam C.,Sessler, Jonathan L.,Wang, Bing-Wu,Xue, Haozong,Yao, Yuhang,Zhang, Jun-Long
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supporting information
p. 10219 - 10227
(2020/06/27)
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- Promising new catalytic properties of a Co (II)-carboxamide complex and its derived Co3O4 nanoparticles for the Mizoroki-Heck and the Epoxidation reactions
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The new Co(II) - carboxamide complex (1) and Co3O4 nanoparticles (2), by way of thermal decomposition of (1) have been efficiently synthesised in the environment-friendly. X-ray diffraction reveals a slightly distorted octahedral coordination of cobalt (four nitrogens and two oxygens) in (1) and regular octahedral or tetrahedral ones (oxygens only) in (2). The investigation of (1) and (2) in the Mizoroki-Heck and epoxidation of alkens reactions showed them both to be powerful, green and inexpensive catalysts.
- Kiani, Mahsa,Bagherzadeh, Mojtaba,Meghdadi, Soraia,Fadaei-Tirani, Farzaneh,Babaie, Maryam,Schenk-Jo?, Kurt
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- BETA-HYDROXYETHYLAMINES FOR USE IN THE TREATMENT OR PREVENTION OF NON-ALCOHOLIC FATTY LIVER DISEASES
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There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, for use in the treatment of a non-alcoholic fatty liver disease (NAFLD), such as non-alcoholic steatohepatitis (NASH), wherein X, R1, R2, R3 and n have meanings as provided in the description.
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Page/Page column 41; 42
(2019/04/11)
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- Nucleophilic Organic Base DABCO-Mediated Chemospecific Meinwald Rearrangement of Terminal Epoxides into Methyl Ketones
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Nucleophilic organic base DABCO (1,4-diazabicyclo[2.2.2]octane)-mediated Meinwald rearrangement of various epoxides was investigated. 2-Aryl-, alkenyl-, and alkynylepoxides generate the corresponding methyl ketones chemospecifically in good to excellent yields. The current DABCO-mediated Meinwald rearrangement of epoxides features readily accessible starting materials, a wide substrate scope, a transition-metal- and acid-free environment, and chemospecificity in the isomerization of epoxides.
- Li, Siqi,Shi, Yi,Li, Pingfan,Xu, Jiaxi
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p. 4443 - 4450
(2019/04/30)
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- Highly selective and efficient olefin epoxidation with pure inorganic-ligand supported iron catalysts
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Over the past two decades, there have been major developments in the transition iron-catalyzed selective oxidation of alkenes to epoxides; a common structure found in drug, isolated natural products, and fine chemicals. Many of these approaches have enabled highly efficient and selective epoxidation of alkenes via the design of specialized ligands, which facilitates to control the activity and selectivity of the reactions catalyzed by iron atom. Herein, we report the development of the olefin epoxidation with inorganic-ligand supported iron-catalysts using 30% H2O2 as an oxidant, and the mechanism is similar to iron-porphyrin type. With the catalyst 1, (NH4)3[FeMo6O18(OH)6], various aromatic and aliphatic alkenes were successfully transformed into the corresponding epoxides with excellent yields as well as chemo- and stereo-selectivity. This catalytic system possesses the advantages of being able to avoid the use of expensive, toxic, air/moisture sensitive and commercially unavailable organic ligands. The generality of this methodology is simple to operate and exhibits high catalytic activity as well as excellent stability, which gives it the potential to be used on an industrial scale, and maybe opens a way for the catalytic oxidation reaction via inorganic-ligand coordinated iron catalysis.
- Zhou, Zhuohong,Dai, Guoyong,Ru, Shi,Yu, Han,Wei, Yongge
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supporting information
p. 14201 - 14205
(2019/10/02)
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- Mg–Al layered double hydroxide intercalated with manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate as a highly reusable catalyst for epoxidation
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The preparation and characterization are presented of a new catalytic material comprising Mg–Al layered double hydroxide and intercalated manganese(III) 5,10,15,20-tetrakis(4-benzoate)porphyrinacetate. Characterization was realized via various techniques. The prepared composite exhibited excellent catalytic activity in the selective epoxidation of various olefins with tetra-n-butylammonium hydrogen monopersulfate as an oxidant under mild reaction conditions. Furthermore, the catalytic system could be reused nine times without significant reduction in conversion percentage and any special care or additional treatment of the catalyst.
- Bagherzadeh, Mojtaba,Mesbahi, Elnaz
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- Iron-Decorated, Guanidine Functionalized Metal-Organic Framework as a Non-heme Iron-Based Enzyme Mimic System for Catalytic Oxidation of Organic Substrates
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A novel porous functionalized metal-organic framework (MOF) as a non-heme iron-based enzyme mimic system was achieved via two-step post-synthetic modification of the MIL-101(Cr)-NH2, and characterized by FT-IR, PXRD, TGA, SEM, EDS, CHN, BET surface area, and ICP-OES analyses. This new modified MOF (MIL-101(Cr)-guanidine-Fe) has been demonstrated to be a highly efficient, active, and reusable catalyst for oxidation of various organic substrates, including alcohols, alkenes and alkyl arenes at room temperature using H2O2 as an oxidant. Graphical Abstract: [Figure not available: see fulltext.].
- Shaabani, Ahmad,Mohammadian, Reza,Farhid, Hassan,Karimi Alavijeh, Masoumeh,Amini, Mostafa M.
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p. 1237 - 1249
(2019/03/13)
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- Unified Mechanism of Oxygen Atom Transfer and Hydrogen Atom Transfer Reactions with a Triflic Acid-Bound Nonheme Manganese(IV)-Oxo Complex via Outer-Sphere Electron Transfer
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Outer-sphere electron transfer from styrene, thioanisole, and toluene derivatives to a triflic acid (HOTf)-bound nonheme Mn(IV)-oxo complex, [(N4Py)MnIV(O)]2+-(HOTf)2 (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine), has been shown to be the rate-determining step of different types of redox reactions such as epoxidation, sulfoxidation, and hydroxylation of styrene, thioanisole, and toluene derivatives, respectively, by [(N4Py)MnIV(O)]2+-(HOTf)2. The rate constants of HOTf-promoted epoxidation of all styrene derivatives with [(N4Py)MnIV(O)]2+ and electron transfer from electron donors to [(N4Py)MnV(O)]2+ exhibit a remarkably unified correlation with the driving force of outer-sphere electron transfer in light of the Marcus theory of electron transfer. The same electron-transfer driving force dependence is observed in the oxygen atom transfer from [(N4Py)MnIV(O)]2+-(HOTf)2 to thioanisole derivatives as well as in the hydrogen atom transfer from toluene derivatives to [(N4Py)MnIV(O)]2+-(HOTf)2. Thus, mechanisms of oxygen atom transfer (epoxidation and sulfoxidation) reactions of styrene and thioanisole derivatives and hydrogen atom transfer (hydroxylation) reactions of toluene derivatives by [(N4Py)MnIV(O)]2+-(HOTf)2 have been unified for the first time as the same reaction pathway via outer-sphere electron transfer, followed by the fast bond-forming step, which exhibits the singly unified electron-transfer driving force dependence of the rate constants as outer-sphere electron-transfer reactions. In the case of the epoxidation of cis-stilbene by [(N4Py)MnIV(O)]2+-(HOTf)2, the isomerization of cis-stilbene radical cation to trans-stilbene radical cation occurs after outer-sphere electron transfer from cis-stilbene to [(N4Py)MnIV(O)]2+-(HOTf)2 to yield trans-stilbene oxide selectively, which is also taken as evidence for the occurrence of electron transfer in the acid-catalyzed epoxidation.
- Lee, Yong-Min,Kim, Surin,Ohkubo, Kei,Kim, Kyung-Ha,Nam, Wonwoo,Fukuzumi, Shunichi
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supporting information
p. 2614 - 2622
(2019/03/04)
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- Synthesis of dipyroromethanes in water and investigation of electronic and steric effects in efficiency of olefin epoxidation by sodium periodate catalyzed by manganese tetraaryl and trans disubstituted porphyrin complexes
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Condensation of pyrrole with various aldehydes in the presence of BF3?etherate as an acid catalyst in water provides good yield of some dipyrromethanes. Prolongation of the reaction time with aldehydes substituted by electron-donating (mesityl) or electron-withdrawing (2,6-dichlorophenyl) groups on the ortho positions of the phenyl did not lead to decomposition or scrambling. Manganese trans disubstituted porphyrin complexes which derive from various dipyrromethanes and manganese tetraaryl porphyrin complexes including various substituents with different steric and electronic properties show good catalytic activity in epoxidation of alkenes by NaIO4 in the presence of imidazole (ImH). The study of steric and electronic effects of the catalysts on the epoxidation of olefins shows that Mn-porphyrin complexes with more bulky and electron-releasing groups on meso phenyls could increase the epoxidation yield of most alkenes.
- Bagherzadeh, Mojtaba,Jonaghani, Mohammad Adineh,Amini, Mojtaba,Mortazavi-Manesh, Anahita
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p. 671 - 678
(2019/04/26)
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- Synthesis, characterization and catalytic activity of supported vanadium Schiff base complex as a magnetically recoverable nanocatalyst in epoxidation of alkenes and oxidation of sulfides
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A new magnetically separable nanocatalyst was successfully synthesized by immobilizing of vanadyl acetylacetonate complex, [VO(acac)2], onto silica coated magnetite nanoparticles previously functionalized with 3-aminopropyltriethoxysilane (3-APTES) and reacted by 5-bromosalicylaldehyde to form Schiff base moiety. The obtained nanocatalyst was characterized by elemental analysis (CHN), FT-IR spectroscopy, Powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), inductively coupled plasma optical emission spectrometry (ICP-OES) and thermogravimetric analysis (TGA). Eventually, the resulting nanoparticles were used as catalyst for epoxidation of alkenes and oxidation of sulfides using tert-butyl hydroperoxide (TBHP) as an oxidant.
- Bagherzadeh, Mojtaba,Bahjati, Mohammad,Mortazavi-Manesh, Anahita
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p. 200 - 206
(2019/07/17)
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- In situ synthesis and encapsulation of copper phthalocyanine into MIL-101(Cr) and MIL-100(Fe) pores and investigation of their catalytic performance in the epoxidation of styrene
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In this work, copper phthalocyanine (CuPc) was encapsulated into mesocages of MIL-101(Cr) and MIL-100(Fe) by assembling CuPc's constitutional fractions using a deep eutectic solvent. The prepared materials, CuPc?MIL-101(Cr) and CuPc?MIL-100(Fe), were characterized by powder X-ray diffraction (PXRD), FT-IR, UV-vis and diffuse reflectance UV (DR-UV) spectroscopies, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ICP-OES spectrometry. The prepared materials were used as heterogeneous catalysts for catalytic epoxidation of styrene with molecular oxygen and also tert-butyl hydroperoxide (TBHP) as oxidants in acetonitrile as a solvent. The impact of MOFs and the role of the CuPc complex as the active species in the MOFs' cages in the epoxidation of styrene were investigated. Among the prepared catalysts, CuPc?MIL-101(Cr) showed the best performance. The heterogeneity of the catalysts was examined by a hot filtration test and ICP-OES of the filtrates after the reaction. Spent catalysts were analyzed by PXRD, FT-IR, UV-DRS, and TEM for reusability investigation and also to further explore the heterogeneous nature of the hybrid materials. Results showed that the prepared catalysts could be recycled and used for several concoctive times without a considerable drop in activity.
- Yeganeh, Ardeshir Dadgar,Amini, Mostafa M.,Safari, Nasser
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p. 1118 - 1131
(2019/11/03)
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- Dearomative [2,3] sigmatropic rearrangement of ammonium ylides followed by 1,4-elimination to form α-(ortho-vinylphenyl)amino acid esters
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A base-induced dearomative [2,3] sigmatropic rearrangement of amino acid ester-derived ammonium salts followed by 1,4-elimination produced α-(ortho-vinylphenyl)amino acid esters. The reaction of azetidine-2-carboxylic acid-derived ammonium salt, (1S,2S,1′R)-3b, proceeded with a perfect N-to-C chirality transfer to afford α-(ortho-vinylphenyl)azetidine-2-carboxylic acid ester, (R)-5 (99% ee). On the other hand, the reaction of glycine-derived ammonium salt (R)-6a, which involves an efficient chirality transfer from a chiral benzylic carbon to an α-carbon of an ester carbonyl giving the optically active α-(ortho-vinylphenyl)glycine ester, (R)-8a (85% ee), was demonstrated. Although this dearomative [2,3] rearrangement followed by 1,4-elimination has limitations with regard to the structures of the substrates, our method provides unique access to substituted α-arylamino acid derivatives.
- Tayama, Eiji,Sotome, Sho
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supporting information
p. 4833 - 4839
(2018/07/15)
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- Regio- and chemoselective rearrangement of terminal epoxides into methyl alkyl and aryl ketones
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The development of the highly active pincer-type rhodium catalyst 2 for the nucleophilic Meinwald rearrangement of functionalised terminal epoxides into methyl ketones under mild conditions is presented. An excellent regio- and chemoselectivity is obtained for the first time for aryl oxiranes.
- Tian, Yingying,Jürgens, Eva,Kunz, Doris
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supporting information
p. 11340 - 11343
(2018/10/31)
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- Axial base-controlled catalytic activity, oxidative stability and product selectivity of water-insoluble manganese and iron porphyrins for oxidation of styrenes in water under green conditions
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A series of water-insoluble iron(III) and manganese(III) porphyrins, FeT(2-CH3)PPCl, FeT(4-OCH3)PPCl, FeT(2-Cl)PPCl, FeTPPCl, MnT(2-CH3)PPOAc, MnT(4-OCH3)PPOAc, MnT(2-Cl)PPOAc and MnTPPOAc, in the presence of imidazole (ImH), F?, Cl?, Br? and acetate were used as catalysts for the aqueous-phase heterogeneous oxidation of styrenes to the corresponding epoxides and aldehydes with sodium periodate. Also, the effect of various reaction parameters such as reaction time, molar ratio of catalyst to axial base, type of axial base, molar ratio of olefin to oxidant and nature of metal centre on the activity and oxidative stability of the catalysts and the product selectivity was investigated. Higher catalytic activities were found for the iron complexes. Interestingly, the selectivity towards the formation of epoxide and aldehyde (or acetophenone) was significantly influenced by the type of axial base. Furthermore, Br? and ImH were found to be the most efficient co-catalysts for the oxidation of olefins performed in the presence of the manganese and iron porphyrins, respectively. The optimized molar ratio of catalyst to axial base was different for various axial bases. Also, the order of co-catalyst activity of the axial bases obtained in aqueous medium was different from that reported for organic solvents. The use of a convenient axial base under optimum reaction catalyst to co-catalyst molar ratio in the presence of the manganese porphyrin gave the oxidative products with a conversion of ca 100% in a reaction time of less than 3?h. However, the catalytic activity of the iron porphyrins could not be effectively improved by increasing the catalyst to co-catalyst molar ratio.
- Zakavi, Saeed,Hashemi-Amiri, Akbar,Asadi, Fatemeh
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- Copper based coordination polymers based on metalloligands: Utilization as heterogeneous oxidation catalysts
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This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.
- Kumar, Gulshan,Hussain, Firasat,Gupta, Rajeev
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p. 16985 - 16994
(2019/01/03)
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- The synthesis, characterization and catalytic application of manganese porphyrins bonded to novel modified SBA-15
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In the presented research, a highly ordered mesoporous silica material (SBA-15) was functionalized with imidazole as a functionalizing reagent (SBA-TMSIm) and then characterized via FT-IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffra
- Rayati, Saeed,Nafarieh, Parinaz,Amini, Mostafa M.
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p. 6464 - 6471
(2018/04/23)
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- Kinetics and mechanistic studies on the formation and reactivity of high valent MnO porphyrin species: Mono-: ortho or para -substituted porphyrins versus a di- ortho -substituted one
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The high valent MnV(O) (λmax ≈ 407 nm) and MnIV(O) (λmax ≈ 421 nm) species of a series of electron-rich and electron-deficient meso-tetra(aryl)porphyrins (aryl = phenyl, 2-chlorophenyl, 2-nitrophenyl, 2-methylphenyl, 2-bromophenyl, 2,6-dichlorophenyl 4-methoxyphenyl, 4-methylphenyl, 4-chlorophenyl and 4-pyridyl) were prepared through the reaction of their corresponding manganese porphyrins with oxone in dichloromethane at a relatively low temperature (273 K). While the high valent Mn(O) intermediates of the para-substituted porphyrins were significantly degraded under reaction conditions, the corresponding species of the ortho substituted porphyrins showed high oxidative stability up to 20 min. Interestingly, the high valent Mn(O) of the mono-ortho-substituted meso-tetra(phenyl)porphyrins were as stable as that of meso-tetra(2,6-dichlorophenyl)porphyrin. The presence of imidazole (ImH) was found to play crucial roles in the formation and reactivity of the high valent Mn(O) species. The kinetics and mechanism of the oxidation of olefins with the high valent MnV(O) porphyrin intermediate were studied and the second order rate constants were evaluated under pseudo-first-order conditions. Also, the MnIV(O) species showed a reactivity comparable with that of the corresponding MnV(O) species. The observation of a Hammet constant of ρ = -0.48 in the oxidation of para-substituted styrenes is in accord with an electrophilic mechanism.
- Nasrollahi, Rahele,Zakavi, Saeed
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supporting information
p. 1806 - 1815
(2018/02/09)
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- Preparation, Characterization and Reactivity of a Bis-hypochlorite Adduct of a Chiral Manganese(IV) Salen Complex
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A bis-hypochlorite adduct of a manganese(IV) salen complex having a chiral (R,R)-cyclohexane-1,2-diamine linkage (2-tBu) is successfully prepared and characterized by various spectroscopic methods. The reactions of 2-tBu with various organic substrates show that 2-tBu is capable of sulfoxidation, epoxidation, chlorination, and hydrogen abstraction reactions. However, the enantioselectivity of the epoxidation reactions by 2-tBu is much lower than that reported for the catalytic reactions by Jacobsen's catalyst. The low enantioselectivity is consistent with a planar conformation of the salen ligand, which is suggested by circular dichroism spectroscopy. This study suggests that 2-tBu is not a reactive intermediate of Jacobsen's enantioselective epoxidation catalysis.
- Araki, Ikuko,Fukui, Kaoru,Fujii, Hiroshi
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supporting information
p. 1685 - 1688
(2018/02/27)
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- Mn(III)-porphyrin/graphene oxide nanocomposite as an efficient catalyst for the aerobic oxidation of hydrocarbons
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In this study, manganese porphyrin was grafted on the surface of graphene oxide nanosheets via covalent bonding to produce a heterogeneous catalyst. The prepared nanocomposite was characterized using X-ray diffraction, UV–vis spectroscopy, scanning electron microscopy, Fourier transform infrared, and thermogravimetric analysis. Atomic absorption spectroscopy was also used to determine the amount of the loaded catalyst. The catalytic efficiency of the immobilized Mn-porphyrin was investigated for the aerobic oxidation of alkenes and saturated alkanes in acetone under mild reaction conditions. The prepared heterogenized catalyst displays superior catalytic performance as compared to the homogeneous catalyst. Moreover, the excellent turnover number (more than 31,767) achieved for the oxidation of styrene indicates the high longevity of the supported catalyst. The catalyst structure is preserved well after the oxidation reaction and is simply reused at least five times, without any significant loss of the catalytic efficiency.
- Rayati, Saeed,Rezaie, Saghar,Nejabat, Fatemeh
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p. 696 - 703
(2018/04/20)
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- Heterogenization of manganese porphyrin via hydrogen bond in zeolite imidazolate framework-8 matrix, a host-guest interaction, as catalytic system for olefin epoxidation
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A heterogenized meso-tetrakis(2,3-dihydroxyphenyl)porphyrinatomanganese(III) acetate at zeolite imidazolate framework-8 (T(2,3-OHP)PorMn@ZIF-8) is investigated for the catalytic olefin epoxidation reactions at room temperature. Heterogenization is accompl
- Bagherzadeh, Mojtaba,Mesbahi, Elnaz
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p. 972 - 980
(2018/09/12)
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- Efficient epoxidation reaction of terminal olefins with hydrogen peroxide catalyzed by an iron (II) complex
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A highly active iron (II) complex that catalyzed epoxidation of terminal olefins with hydrogen peroxide was described. The catalytic system displayed excellent catalytic ability for the selective oxidation of terminal olefins to epoxides with high selecti
- Li, Lu,Song, Hong-Jin,Meng, Xiang-Guang,Yang, Ren-Qiang,Zhang, Ni
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supporting information
p. 2436 - 2439
(2018/05/24)
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- COMPOUNDS FOR THE TREATMENT OF HYPERGLYCAEMIA
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There is herein provided a compound of formula (I) or a pharmaceutically acceptable salt thereof, for use in the treatment of hyperglycaemia or a disorder characterized by hyperglycaemia, such as type 2 diabetes, wherein X, R1, R2, R3 and n have meanings as provided in the description.
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Page/Page column 45
(2017/09/28)
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- Regioselective hydrosilylation of epoxides catalysed by nickel(II) hydrido complexes
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Bench-stable nickel fluoride complexes bearing NNN pincer ligands have been employed as precursors for the regioselective hydrosilylation of epoxides at room temperature. A nickel hydride assisted epoxide opening is followed by the cleavage of the newly formed nickel oxygen bond by σ-bond metathesis with a silane.
- Wenz, Jan,Wadepohl, Hubert,Gade, Lutz H.
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supporting information
p. 4308 - 4311
(2017/04/21)
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- Synthesis method for ethylene oxide derivative
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The invention discloses a synthesis method for an ethylene oxide derivative, which is an important intermediate for pesticides and medicines. The synthesis method includes the steps of performing a reaction to alkoxy phenyl sulfide (IV) with a methylation reagent at 70-90 DEG C to synthesize sulfonium salt (III); and then performing a reaction to the sulfonium salt (III) with a carbonyl compound (II) under alkali condition to generate the ethylene oxide derivative (I). In the method, sulfur ylide is synthesized by using the alkoxy phenyl sulfide, which is difficult to volatilize and is low in odor, instead of dimethyl sulfide, which is toxic and malodorous, in a conventional method, so that a problem of malodorous odor generated during production is solved from the source, and environment stress is greatly alleviated. Meanwhile, the alkoxy phenyl sulfide can be recycled, so that industrial cost is reduced and production efficiency is increased. The method is environment-friendly and high-effectively and can be used for synthesizing various ethylene oxide derivatives as pesticide and medicine intermediates.
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Paragraph 0079; 0080; 0081
(2018/01/11)
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- Reductive activation of O2 by a bioinspired Fe complex for catalytic epoxidation reactions
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Aerobic epoxidation of olefins catalyzed by iron complexes without the use of a sacrificial coreductant is unknown. We report the reductive activation of O2 by a bioinspired [(bTAML)FeIII(H2O)]- (1) complex to catalyze the epoxidation of alkenes with TONs of up to 80. Spectroscopic and kinetic evidence indicates the involvement of FeV(O) as the active oxidant during the reaction.
- Singh, Kundan K.,Gupta, Sayam Sen
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supporting information
p. 5914 - 5917
(2017/07/11)
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- Au-Carbon Electronic Interaction Mediated Selective Oxidation of Styrene
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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
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p. 3483 - 3488
(2017/06/09)
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- Cu-Schiff base complex grafted onto graphene oxide nanocomposite: Synthesis, crystal structure, electrochemical properties and catalytic activity in oxidation of olefins
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Copper(II) Schiff base complex has been immobilized onto graphene oxide (GO) via covalent bonding. The nanocomposite was characterized using powder X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV–visible spectroscopies, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA) and the energy-dispersive X-ray spectroscopy (EDX). The amount of catalyst loading on the solid support was determined by atomic absorption spectroscopy. The thermogravimetric analysis (TGA) demonstrated that the nanocatalyst was stable up to almost 220?°C, exhibiting high thermostability. Highly active and selective catalyst was found with excellent turnover numbers (up to 47,000 for oxidation of styrene) for the epoxidation of olefins in ethanol using aqueous hydrogen peroxide as oxidant. It could be readily reused for successive ten times without discernible activity and selectivity deterioration, which displays potential for practical applications.
- Rayati, Saeed,Khodaei, Elham,Shokoohi, Saeedeh,Jafarian, Majid,Elmi, Bahareh,Wojtczak, Andrzej
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p. 520 - 528
(2017/07/22)
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- Catalytic activity and electrochemical properties of Cu(II)-Schiff base complex encapsulated in the nanocavities of zeolite-Y for oxidation of olefins and sulfides
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Copper(II) complex of a Schiff base ligand (H2L) was synthesized, characterized, and encapsulated in the cavities of zeolite-Y by a fixed ligand method. The zeolite encapsulated metal complex (CuL-Y) was characterized using FT-IR, UV–Vis and atomic absorption spectroscopy, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), scanning electron microscopy images (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET). The catalytic activity and electrochemical behavior of the encapsulated complex has been studied in the oxidation of a wide range of sulfides and olefins using H2O2 in ethanol. This heterogeneous catalytic system shows a dramatic increase in total turnover number (46,500) for oxidation of styrene. It could be readily reused for at least eight successive times without discernible activity and selectivity deterioration, which displays potential for practical applications.
- Rayati, Saeed,Khodaei, Elham,Jafarian, Majid
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p. 2736 - 2750
(2017/09/06)
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- Synthesis, characterization, and X-ray structure of n′-(2-hydroxy- 5-methylbenzylidene)-4-trifluoromethylbenzohydrazide and its dioxidomolybdenum(vi) complex with catalytic property
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A new hydrazone compound N′-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L) was prepared. Based on H2L, a new dioxidomolybdenum(VI) complex [cis-MoO2L(MeOH)], was obtained. Single crystals of H2
- Liang, Peng,Hong, Zhe
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p. 950 - 955
(2017/08/10)
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- Selective photocatalytic hydroxylation and epoxidation reactions by an iron complex using water as the oxygen source
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The iron complex [(bTAML)FeIII-OH2]- (1) selectively catalyses the photocatalytic hydroxylation and epoxidation reactions of alkanes and alkenes, respectively, using water as the oxygen-atom source. Upon the oxidation of unactivated alkanes, which included several substrates including natural products, hydroxylation was observed mostly at the 3° C-H bonds with 3° :2° selectivity up to ~100:1. When alkenes were used as the substrates, epoxides were predominantly formed with high yields. In the presence of H218O, more than 90% of the 18O-labelled oxygen atoms were incorporated into the hydroxylated and epoxide product indicating that water was the primary oxygen source. Mechanistic studies indicate the formation of an active [{(bTAML)FeIV}2-μ-oxo]2- (2) dimer from the starting complex 1via PCET. The subsequent disproportionation of 2 upon addition of substrate, leading to the formation of FeV(O), renders the high selectivity observed in these reactions.
- Chandra, Bittu,Singh, Kundan K.,Gupta, Sayam Sen
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p. 7545 - 7551
(2017/10/30)
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- Synthesis, structure characterization and study of a new molybdenum Schiff base complex as an epoxidation catalyst with very high turnover numbers
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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
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- Indium(III) Chloride Promoted Highly Efficient Tandem Rearrangement-α-Addition Strategy towards the Synthesis of α-Hydroxyamides
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A new tandem process is reported that provides access to α-hydroxyamides from epoxides for the first time. Herein, we explore InCl3-mediated tandem rearrangement of epoxides to aldehydes and α-addition of TosMIC to in situ derived aldehydes. An unprecedented C-C bond-forming reaction is disclosed that features mild conditions, high yields, and shorter reaction times.
- Lingaswamy, Kadari,Mohan, Dumpala,Krishna, Palakodety Radha,Prapurna, Y. Lakshmi
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supporting information
p. 1693 - 1698
(2016/07/06)
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- Facile access to α-acyloxyamides via epoxide rearrangement/three-component domino reaction catalyzed by indium(III) chloride
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A simple and efficient Passerini reaction of epoxides involving highly regioselective rearrangement of epoxide to aldehyde/three-component Passerini reaction catalyzed by indium(III) chloride is described. In the present protocol, epoxides served as wonderful substrates to furnish a library of α-acyloxyamides under mild reaction conditions in shorter reaction times and in good yields.
- Lingaswamy, Kadari,Krishna, Palakodety Radha,Prapurna, Y. Lakshmi
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supporting information
p. 1275 - 1282
(2016/08/16)
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- Three powerful dinuclear metal-organic catalysts for converting CO2 into organic carbonates
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Developing efficient catalysts for converting carbon dioxide (CO2) into varied organic carbonates is an important scientific goal. By using the NH2-functionalized tripodal ligand 2-((bis(2-aminoethyl)amino)methyl)phenol (HL), three dinuclear metal-organic complexes [Zn(L)]2·2ClO4 (1), [Cu(L)]2·2ClO4·2H2O (2) and [Cd(L)]2·2ClO4 (3) have been successfully isolated and structurally characterized using single-crystal X-ray diffraction analyses. Considering the dinuclear metal centers and the NH2-functional groups in the structures, 1-3 were investigated as catalysts for converting CO2 into organic carbonates, and the results show that 1-3 exhibit an outstanding ability for converting CO2 into varied organic carbonates at atmospheric pressure (0.1 MPa). The catalytic system also displays a wide substrate scope and high catalytic activity, and the reaction mechanism has been proposed herein.
- Zhao, Dan,Liu, Xiao-Hui,Shi, Zhuang-Zhi,Zhu, Chen-Dan,Zhao, Yue,Wang, Peng,Sun, Wei-Yin
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p. 14184 - 14190
(2016/11/05)
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- Catalyst structure and substituent effects on epoxidation of styrenics with immobilized Mn(tmtacn) complexes
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Monomeric and dimeric complexes of Mn 1,4,7-trimethyl-1,4,7-triazacyclononane (tmtacn) were immobilized under reaction conditions onto solid supports to create heterogeneous catalysts for epoxidation with H2O2. These solid supports consist of activated carbon or silica grafted or co-condensed with benzoic or C3/C4 acids that function both as tethering points and as required co-catalysts. Immobilized catalysts were as much as 50-fold faster than the analogous soluble system, and an immobilized, dimeric Mn(tmtacn) complex with a solid benzoic acid co-catalyst gave the highest yields to epoxide. A Hammett study on the catalytic epoxidation of a series of styrenes showed weak increases in yield for more electron-withdrawing p-substituents reactants for both immobilized complexes, which runs counter to previous observations with analogous homogeneous catalysts, and which appears to reflect a previously unappreciated tradeoff between the intrinsic epoxidation reactivity and strong catalyst inhibition by styrene oxides and glycols. Finally, these catalysts were tested with a variety of solid-co-catalysts, and were successfully utilized in the challenging epoxidation of divinylbenzene to industrially-useful divinylbenzene dioxide using a cascade of two catalyst charges.
- Ignacio-De Leon, Patricia Anne A.,Contreras, Christian A.,Thornburg, Nicholas E.,Thompson, Anthony B.,Notestein, Justin M.
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- Pd(II) anchored to modified Fe3O4 nanoparticles as a new magnetically recoverable catalyst for epoxidation of styrene
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A new support for Pd(II) was synthesized via the functionalization of Fe3O4 nanoparticles with N-(2-aminoethyl)acetamide. PdCl2 was anchored to the support for obtaining a heterogeneous magnetically recoverable catalyst fo
- Keshipour, Sajjad,Khalteh, Nastaran Kalam
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p. 1977 - 1982
(2016/09/16)
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- Spectroscopy and catalytic activity study of gold supported on barium titanate nanotubes for styrene epoxidation
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Gold (0.5-5 wt.%) supported on barium titanate nanotubes (Au/BaTNT) were prepared, characterized and for the first time, investigated as catalysts for selective oxidation of styrene with oxygen (O2 or H2 + O2) and peroxides (H2O2 or TBHP). Conversion of styrene enhanced when H2 was co-added to O2 in the reactions. Au/BaTNT activated O2 and H2 and produced H2O2 in situ for use in oxidations. Peroxides were found better oxidants than O2. At optimized conditions, styrene oxide selectivity of 80.1 wt.% at styrene conversion of 60.5 wt.% was achieved over Au(1 wt.%)/BaTNT using TBHP. Au particles (5.0-7.4 nm) were dispersed and decorated on the walls of BaTNT. They exhibited superior performance to the known Au catalysts in styrene oxidation. Reactive oxygen species formed during oxidation reactions were followed with in situ spectral characterizations (diffuse reflectance UV-vis and FT-Raman). Au/BaTNT was reusable in four recycles with little loss in catalytic activity.
- Nepak, Devadutta,Srinivas, Darbha
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- Catalytic properties of the homologous series of the β-brominated-pyrrole manganese(III) tetraphenylporphyrins
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A homologous series of β-brominated Mn-porphyrins were prepared and their catalytic activities were investigated in the oxidation of cyclooctene with urea hydrogen peroxide (UHP). The highest conversion of cyclooctene with UHP in ethanol was obtained in t
- Rayati, Saeed,Nejabat, Fatemeh
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- 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
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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
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p. 105 - 113
(2016/07/06)
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