- Epoxidation of olefins at low temperature using m-chloroperbenzoic acid
-
Epoxidation of olefins using m-chloroperbenzoic acid in dichloromethane without catalyst at low temperature is described.
- Srinivasan,Chandrasekharam,Vani,Chida, A. Seema,Singh
-
-
Read Online
- Transformation of vinyloxirane on Pt-SiO2 and Pd-SiO2
-
The transformation of vinyloxirane and ethyloxirane were studied on Pt-SiO2 and Pd-SiO2 catalysts at 273 and 301 K in a recirculation reactor, in the presence of hydrogen or deuterium. There are significant differences, not only in reaction rates, but also in reaction routes, depending upon the nature of the metal. The main reaction routes are: deoxygenation and hydrogen or deuterium addition on Pt-SiO2; isomerization and hydrogenolysis on Pd-SiO2. The reaction routes leading to the formation of the individual products are interpreted on the basis of the experimental results. In the case of the hydrogenolysis of oxiranes, Pd was shown to exhibit a special reactivity, unlike earlier observations described in the literature.
- Bartok, Mihaly,Fasi, Andras,Notheisz, Ferenc
-
-
Read Online
- Synthesis, crystal structure, and catalytic property of a vanadium(V) complex with mixed ligands
-
With a tridentate hydrazone ligand N′-(3-bromo-2-hydroxybenzylidene)-2-methylbenzohy-drazide (H2L) and a bidentate ligand benzohydroxamic acid (HL′) with VO(Acac)2, a mononuclear vanadium(V) complex was prepared and characterized by elemental analysis, IR spectroscopy and X-ray structure determination (CIF file CCDC no. 1029909). The complex crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 27.870(2), b = 11.4893(5), c = 18.467(2) ?, β = 131.444(1)°, V = 4432.6(6) ?3, Z = 8, R 1 = 0.0350, and wR 2 = 0.0749. Single crystal X-ray diffraction analysis reveals that the V atom is coordinated by the phenolate O, imino N and enolate O atoms of the hydrazone ligand, and the carbonyl O and hydroxy O atoms of benzohydroxamate ligand, and one oxo O group, in an octahedral coordination. Catalytic oxidation of the complex on some olefins was performed.
- Shen,Zhang,Shao,Lian,Liu
-
-
Read Online
- Role of Recrystallization in Alkaline Treatment on the Catalytic Activity of 1-Butene Epoxidation
-
Two alkylol amines, which were ethanolamine (EOA) and triethanolamine (TEOA), were used to posttreat nanosized titanium silicalite-1 (TS-1) to improve its catalytic activity for 1-butene epoxidation. Comparative studies were conducted to clarify the influences of the EOA and TEOA concentrations on the physicochemical properties through detailed characterization. EOA treatment can dissolve the framework Si, [SiO4], on the external surface of TS-1, generating some macropores. TEOA serves as structure-directing agent to form MFI topology other than the dissolution of [SiO4], and promotes the recrystallization of [SiO4], forming new TS-1 particles over the external surface. The two treatments can both improve the catalytic activity of 1-butene epoxidation, but the samples treated with TEOA exhibit better catalytic stability. This can be attributed to the characteristic recrystallization of [SiO4] in the case of TEOA treatment, stabilizing the structure of TS-1 and maintaining more framework Ti and intercrystal space.
- Zuo, Yi,Yang, Liqian,Jiang, Xiao,Ma, Mengtong,Wang, Yanli,Liu, Min,Song, Chunshan,Guo, Xinwen
-
-
Read Online
- Characterization and evaluation of Ag-Pt/SiO2 catalysts prepared by electroless deposition
-
A series of Ag-Pt/SiO2 catalysts have been prepared by the electroless deposition of Ag onto a Pt/SiO2 catalyst. Results indicate that Ag deposition does not readily occur on the SiO2 support, but is essentially restricted
- Schaal, Melanie T.,Pickerell, Anna C.,Williams, Christopher T.,Monnier, John R.
-
-
Read Online
- Deboronation-assisted construction of defective Ti(OSi)3OH species in MWW-type titanosilicate and their enhanced catalytic performance
-
A thorough investigation of the nature of the Ti species in the boron-containing Ti-MWW zeolite has been carried out. It was found that the inactive extra-framework TiO6 species can cover up the zeolite Lewis-acid property through the weak atomic binding forces between the Ti(iv) atom and O atom (TiO6 species). The nitric acid treatment could remove these TiO6 species easily from the as-synthesized Ti-MWW(P), followed by exposure of the zeolite Lewis acidity. Importantly, the formation of new Ti(OSi)3OH species with a strong Lewis-acid strength, is facilitated in the modification process. Thereby, the modified Ti-MWW zeolite has an improved catalytic activity in alkene epoxidation reactions. The removal of framework B(iv) species around the TiO4 species is an essential step because it can accelerate the transformation of perfect Ti(OSi)4 species to the defective Ti(OSi)3OH species in zeolites. Moreover, the strategy to construct Ti(OSi)3OH species was also applied successfully in boron-containing Ti-MCM-56 zeolites. Considering active species environment can be modulated effectively with the removal of framework tetra-coordinate boron, this strategy could also be beneficial for the preparation of other high-performance titanosilicates.
- Chen, Zhen,He, Mingyuan,Liu, Haoxin,Liu, Wei,Liu, Yueming,Tang, Zhimou,Wang, Rui,Wu, Haihong,Yu, Yunkai
-
-
Read Online
- Synthesis, crystal structure and catalytic property of a dinuclear cobalt(III) complex derived from 2-ethyl-2-{[1-(2-hydroxy-5-methylphenyl)methylidene]amino}propane-1,3-diol
-
With a tetradentate Schiff base ligand 2-ethyl-2-{[1-(2-hydroxy-5-methylphenyl)methylidene]amino}propane-1,3-diol (H3L) with cobalt nitrate and ammonium thiocyanate, a dinuclear cobalt(III) complex was prepared and characterized by elemental analysis, IR spectroscopy and X-ray structure determination. The complex crystallizes in the monoclinic space group P21/n with unit cell dimensions a = 17.682(2) ?, b = 22.652(2) ?, c = 18.617(2) ?, β = 99.546(2)°, V = 7,353.5(12) ?3, Z = 4, R1 = 0.0956, and wR2 = 0.2027. Single crystal X-ray diffraction analysis reveals that the asymmetric unit of the compound contains two dinuclear cobalt(III) complex molecules, three methanol molecules and one water molecule of crystallization. The Co???Co distances in the dinuclear cobalt(III) complex molecules are about 2.97 ?. The Co atoms are in octahedral coordination. The complex has effective property on the oxidation of various aliphatic and aromatic olefins.
- Qiu, Xiao-Yang
-
-
Read Online
- Catalytic Asymmetric Cyclization of Some Bromohydrins with Chiral Cobalt Complex
-
Asymmetric cyclization of a variety of bromohydrins with base was examined in the presence of an optically active cobalt(salen) type complex.Optically active oxiranes of modest optical purities were obtained. erythro-3-Bromo-2-butanol and threo-3-bromo-2-butanol were cyclized similarly, and only trans-2,3-dimethyloxirane and cis-2,3-dimethyloxirane were obtained, respectively, indicating that the cyclization of bromohydrin proceeds by complete SN2 type reaction.
- Takeichi, Tsutomu,Takakura, Teruo,Ishimori, Michihiro,Tsuruta, Teiji
-
-
Read Online
- Structural and dynamical aspects of alkylammonium salts of a silicodecatungstate as heterogeneous epoxidation catalysts
-
The structural and dynamical aspects of alkylammonium salts of a silicodecatungstate [(CH3)4N]4[γ-SiW 10O34(H2O)2] [C1], [(n-C 3H7)4N]4[γ-SiW 10O34(H2O)2] [C3], [(n-C 4H9)4N]4[γ-SiW 10O34(H2O)2] [C4], and [(n-C 5H11)4N]4[γ-SiW 10O34(H2O)2] [C5] were investigated. The results of sorption isotherms, XRD analyses, and solid-state NMR spectroscopy show that facile sorption of solvent molecules, flexibility of structures, and high mobility of alkylammonium cations are crucial to the uniform distribution of reactant and oxidant molecules throughout the bulk solid, which are related to the high catalytic activities for epoxidation of alkenes.
- Uchida, Sayaka,Kamata, Keigo,Ogasawara, Yoshiyuki,Fujita, Megumi,Mizuno, Noritaka
-
-
Read Online
- Liquid- and vapor-phase hydrogenation of 1-epoxy-3-butene using self-assembled monolayer coated palladium and platinum catalysts
-
Alkanethiol self-assembled monolayers (SAMs) have recently been shown to be effective catalyst modifiers for increasing the selectivity of the hydrogenation of 1-epoxy-3-butene (EpB) to 1-epoxybutane in the gas phase. In the results reported here, we demonstrate that SAM coatings can similarly be applied to other supported metals (Pt) and in liquid-phase reaction environments. Coating a Pt/Al2O3 catalyst with n-octadecanethiol resulted in a large improvement in selectivity during vapor-phase EpB hydrogenation, similar to that observed for supported Pd. The liquid phase hydrogenation of EpB using SAM-coated catalysts showed similar selectivity trends in some cases, but interactions of the solvent with the SAM were also important in controlling selectivity. In particular, using a heptane solvent, epoxybutane selectivity increased from 36% with an uncoated Pd/Al 2O3 catalyst to 74% with a thioglycerol SAM-coated catalyst. SAM quality was shown to have a strong impact on the rate of reaction but little effect on selectivity. The results generally indicated that selectivity modification with thiol SAMs is extendable to other supported metals and a variety of reaction environments.
- Kahsar, Karl R.,Schwartz, Daniel K.,Medlin, J. Will
-
-
Read Online
- Discovery of a highly potent anti-inflammatory epoxyisoprostane-derived lactone
-
Epoxyisoprostanes EI (1) and EC (2) are effective inhibitors of the secretion of proinflammatory cytokines IL-6 and IL-12. In detailed studies toward the investigation of the molecular mode of action of these structures, a highly potent lactone (3) derived from 1 was identified. The known isoprostanoids 1 and 2 are most likely precursors of 3, the product of facile intramolecular reaction between the epoxide with the carboxylic acid in 2.
- Egger, Julian,Bretscher, Peter,Freigang, Stefan,Kopf, Manfred,Carreira, Erick M.
-
-
Read Online
- Phosphotungstic acid supported on magnetic nanoparticles as an efficient reusable catalyst for epoxidation of alkenes
-
A new magnetically separable catalyst consisting of phosphotungstic acid supported on imidazole functionalized silica coated cobalt ferrite nanoparticles was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR), and inductively coupled plasma atomic emission spectroscopy (ICP-AES). This immobilized phosphotungstic acid was shown to be an efficient heterogeneous catalyst for the epoxidation of various alkenes using tert-butylhydroperoxide (t-BuOOH) as oxidant. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.
- Kooti,Afshari
-
-
Read Online
- Preparation, characterization, and kinetic evaluation of dendrimer-derived bimetallic Pt-Ru/SiO2 catalysts
-
A series of silica-supported Pt, Ru, and Pt-Ru catalysts has been synthesized using dendrimer-metal nanocomposite (DMN) precursors prepared by both co- and sequential complexation with metal salts. The catalysts have been characterized by several techniqu
- Liu, Dongxia,Lopez-De Jesus, Yaritza M.,Monnier, John R.,Williams, Christopher T.
-
-
Read Online
- Method for preparing epoxybutane by using small organic molecules to catalyze butene in green and efficient manner
-
The invention discloses a method for preparing epoxybutane by using small organic molecules to catalyze butene in a green and efficient manner. The method comprises the following steps of by taking butene as a raw material, adding an organic solvent and a catalyst, taking isobutyraldehyde as a co-reducing agent, and taking oxygen as an oxidizing agent, preparing the epoxybutane at room temperature under the reaction pressure of 0.1-4.5 MPa. The catalyst is selected from at least one of a cyclic organic nitroxide free radical precursor or a compound with the structure as shown in the following formulas (I), (II), (III) or (IV); and R1, R2 and R3 in the formula are independently selected from hydrogen atoms, alkyl groups, cycloalkyl groups, aryl groups, heterocyclic rings, hydroxyl groups, nitryl groups or halogens, or at least two of R2, R3 and R4 form rings. The method has the advantages of simple process, mild conditions, high yield and selectivity of epoxybutane, and good industrial application prospects.
- -
-
Paragraph 0046-0048; 0084
(2021/08/25)
-
- Tris-imidazolinium-based porous poly(ionic liquid)s as an efficient catalyst for decarboxylation of cyclic carbonate to epoxide
-
A series of imidazolinium-based porous poly(ionic liquid)s (PILs) with different anions prepared by free-radical copolymerization of an arene-bridged tris-vinylimidazolium salt and divinylbenzene (DVB) were constructed. The as-prepared PILs were characterized by BET, SEM, TEM, TGA and Elemental Analysis (EA), and the results showed that they had plentiful ionic sites, and abundant and stable mesopores. In particular, the density of ionic sites and pore structure of PILs could be controlled by adjusting the content of DVB. Moreover, the PILs were used as efficient heterogeneous catalysts for the decarboxylation of cyclic carbonates to epoxides for the first time. Results showed that the catalytic activity of PILs was positively correlated with the nucleophilicity of the anions in PILs, and PDVB-[PhTVIM]Cl-1 with a chloride anion-enriched skeleton displayed the best catalytic performance. Without any solvent or cocatalyst, PDVB-[PhTVIM]Cl-1 achieved a TOF value of 108.1 h-1and the yield of butylene oxide of 89.6%, which was even better than the homogeneous IL-based catalysts (TOF value: 8.7 h-1) that had been previously reported. Meanwhile, PDVB-[PhTVIM]Cl-1 also exhibited excellent recyclability and substrate compatibility.
- Li, Yang,Wang, Liguo,Cao, Yan,Xu, Shuang,He, Peng,Li, Huiquan,Liu, Hui
-
p. 14193 - 14202
(2021/04/22)
-
- Ionic liquid, polyionic liquid and preparation methods and application thereof
-
The invention provides an ionic liquid, a polyionic liquid and preparation methods and application thereof. The structure of the ionic liquid is as shown in formula I, and the polyionic liquid is obtained by polymerizing the ionic liquid. The preparation method of the ionic liquid comprises the following steps: mixing N-vinyl imidazole, a compound X-R-X and an organic solvent, and conducting reacting to obtain the ionic liquid. The ionic liquid and the polyionic liquid have the advantages of high activity and easiness in separation when being used as catalysts, and can be applied to synthesis of epoxy compounds.
- -
-
Paragraph 0078-0080; 0094-0095
(2021/09/15)
-
- Synthesis, crystal structures and catalytic activity of oxidovanadium(V) complexes with tridentate ONO aroylhydrazone ligands
-
Two oxidovanadium(V) complexes, [VOL1(OEt)] (1) and [V2O2(L2)2(OEt)2] (2), where L1 and L2 are the anions of 2-amino-N′-(2-hydroxybenzylidene)benzohydrazide (H2L1) and N′-(2-hydroxybenzylidene)-4-hydroxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and 1H NMR spectra. Structures of the complexes were further confirmed by single-crystal X-ray determination. The V atom in the mononuclear complex 1 is in square pyramidal coordination, and those in the dinuclear complex 2 are in octahedral coordination. Both aroylhydrazone ligands coordinate to the V atoms through the phenolate O, imino N, and enolate O atoms. The ethanol ligand in complex 1 is in terminal coordination mode, while that in complex 2 is in bridging coordination mode. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Liang, Min,Zou, Dong-Hui,Chen, Wei,Kan, Wei,Tian, Zhi-Ming
-
-
- Synthesis, X-Ray crystal structures and catalytic epoxidation of oxidovanadium(V) complexes with aroylhydrazone and ethyl maltolate ligands
-
Two oxidovanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2) (L = ethyl maltolate), derived from the aroylhydrazones 4-bromo-N'-(2-hydroxy-5-methylbenzylidene)benzohydrazide (H2L1) and N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectroscopy. Structures of the complexes were further confirmed by single crystal X-ray determination. The V atoms in the complexes are coordinated by the ONO donor atoms of the aroylhydrazone ligand, OO donor atoms of the ethyl maltolate ligand, and one oxido O atom, forming octahedral coordination. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Chen, Wei,Liang, Min,Zou, Dong-Hui
-
p. 441 - 446
(2021/06/25)
-
- Method for epoxidizing small-molecular olefin
-
The invention relates to a micromolecular olefin epoxidation method, which is characterized by comprising the following steps: contacting micromolecular olefin, an organic peroxide and a titanium-silicon composite oxide under epoxidation reaction conditions of at least two reaction temperatures of A and B to obtain an alkylene oxide-containing product, wherein the A is 80-95 DEG C, the B is 100-120 DEG C, the titanium-silicon composite oxide is of an amorphous structure, is formed by aggregation of nano-particles and has mesopores in the range of 16-50 nm, the ratio of the volume of the mesopores to the total pore volume is larger than or equal to 80%, and the volume of the mesopores is larger than or equal to 0.5 cm/g. According to the method, the amorphous titanium-silicon-titanium-silicon composite oxide is taken as the catalyst, and at least two sections of conditions with different reaction temperatures are combined, so that compared with the prior art, the catalyst is stable in structure, low in cost, high in olefin epoxidation reaction activity and good in product selectivity.
- -
-
Paragraph 0172-0173; 0200-0215; 0217-0232
(2021/06/06)
-
- Oxidovanadium(V) and dioxidomolybdenum(VI) Complexes of N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide: Synthesis, characterization, crystal structures and catalytic property
-
N'-(3,5-Dichloro-2-hydroxybenzylidene)-4-fluorobenzohydrazide (H2L) was used to prepare oxidovanadium(V) complex [VOL(OEt)(MeOH)] (1) and dioxidomolybdenum(VI) complex [MoO2L(OH2)]·[MoO2L(EtOH)] (2). The complexes were characterized by IR, UV-Vis, NMR spectroscopy, and single crystal X-ray diffraction. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydroperoxide as oxidant.
- Liu, Huan-Yu,Yang, Luo-Ju,Ye, Ya-Fang,Yin, Yi-Shu,Zou, Xiao-Ling
-
p. 130 - 136
(2020/03/30)
-
- Method for catalyzing epoxidation of olefin
-
The invention discloses a method for catalyzing epoxidation of olefin. According to the method, an olefin compound is used as a raw material, hydrogen peroxide, peracetic acid, tert-butyl hydroperoxide and m-chloroperoxybenzoic acid are used as oxidants, a metalloporphyrin-based super-cross-linked polymer is used as a catalyst, and a catalytic reaction is carried out at a reaction temperature of 25-80 DEG C to obtain an epoxide at high selectivity. The method has the advantages of simple process, high yield, catalyst recyclability, mild conditions and the like.
- -
-
Paragraph 0029-0030
(2020/04/17)
-
- Enantioselective Resolution Copolymerization of Racemic Epoxides and Anhydrides: Efficient Approach for Stereoregular Polyesters and Chiral Epoxides
-
Herein we report an efficient strategy for preparing isotactic polyesters and chiral epoxides via enantioselective resolution copolymerization of racemic terminal epoxides with anhydrides, mediated by enantiopure bimetallic complexes in conjunction with a nucleophilic cocatalyst. The chirality of both the axial linker and the diamine backbones of the ligand are responsible for the chiral induction of this kinetic resolution copolymerization process. The catalyst systems exhibit exceptional levels of enantioselectivity with a kinetic resolution coefficient exceeding 300 for various racemic epoxides, affording highly isotactic copolymers (selectivity factors of more than 300) with a completely alternating structure and low polydispersity index. Most of the produced isotactic polyesters are typical semicrystalline materials with melting temperatures in the range from 77 to 160 °C.
- Li, Jie,Ren, Bai-Hao,Wan, Zhao-Qian,Chen, Shi-Yu,Liu, Ye,Ren, Wei-Min,Lu, Xiao-Bing
-
supporting information
p. 8937 - 8942
(2019/06/11)
-
- Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
-
Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
- Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
-
supporting information
p. 513 - 518
(2019/01/14)
-
- Synthesis, Characterization and Crystal Structures of Oxidovanadium(V) and Dioxidomolybdenum(VI) Complexes Derived from 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide with Catalytic Property
-
Abstract: A hydrazone compound 2-bromo-N'-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (H2L) was prepared and characterized by IR, UV-Vis and NMR spectra. Based on the hydrazone compound, a new oxidovanadium(V) and a new dioxidomolybdenum(VI) complexes, [VO(L)(OEt)(EtOH)] (I) and [MoO2(L)(OH2)] (II), were prepared and characterized by IR, UV-Vis, NMR spectra, and single crystal X-ray diffraction (CIF files nos. 1866755 (I) and 1866756 (II)). Complex I crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 12.8733(12), b = 13.5088(13), c = 11.9262(11) ?, β = 91.765(2)°, V = 2073.0(3) ?3, Z = 4, R1 = 0.0524, wR2 = 0.1329, GOOF = 1.245. Complex II crystallizes as the monoclinic space group P21/c with unit cell dimensions a = 8.1140(9), b = 16.2975(19), c = 13.4318(15) ?, β = 106.456(2)°, V = 1703.4(3) ?3, Z = 4, R1 = 0.0296, wR2 = 0.0728, GOOF = 1.046. X-ray analysis indicates that the complexes are mononuclear species with the metal atoms in octahedral coordination. The complexes were studied for catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zou,Yang,Ye,Yang
-
p. 809 - 816
(2019/11/11)
-
- Synthesis and Crystal Structures of Oxidovanadium(V) Complexes Derived from Hydrazones with the Catalytic Property
-
Two new structurally similar oxidovanadium(V) complexes [VOL1L] (1) and [VOL2L] (2) (L = acetohydroxamate) derived from N′-(5-bromo-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L1) and N′-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) hydrazones are prepared and characterized by elemental analyses, FT-IR, 1H NMR, and single crystal X-ray diffraction (CIF files CCDC Nos. 1859442 (1) and 1859446 (2)). The V atoms in the complexes are in the octahedral coordination, with hydrazones behaving as binegative donors and acetohydroxamate acting as a mononegative ligand. The complexes function as effective olefin epoxidation catalysts.
- Zou,Sun,Chen
-
p. 1101 - 1109
(2019/08/12)
-
- Diastereoselective Desymmetrization of p-Quinamines through Regioselective Ring Opening of Epoxides and Aziridines
-
A highly diastereoselective desymmetrization of p-quinamines via regioselective ring opening of epoxides and aziridines under mild conditions has been developed. A chairlike six-membered transition state with minimized 1,3-diaxial interactions explains the relative stereoselectivity of the cyclization reaction. This transition-metal free [3 + 3] annulation reaction provides rapid access to fused bicyclic morpholines and piperazines with a tetrasubstituted carbon center in high yields. In addition, it also allows the synthesis of enantioenriched products by using easily accessible chiral nonracemic epoxides and aziridines.
- Jadhav, Sandip B.,Chegondi, Rambabu
-
supporting information
p. 10115 - 10119
(2019/12/24)
-
- OXYSTEROLS AND METHODS OF USE THEREOF
-
Compounds are provided according to Formula (I): and pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof; wherein R2, R3, R4, R5, and and R6 are as defined herein. Compounds of the present invention are contemplated useful for the prevention and treatment of a variety of conditions.
- -
-
Paragraph 00647
(2018/05/16)
-
- Synthesis, Characterization, and Crystal Structures of Dioxomolybdenum(VI) Complexes Derived from Similar Tridentate Hydrazone Compounds with Catalytic Property
-
Abstract: Two hydrazone compounds 2-chloro-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (H2L1) and N'-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide (H2L2) were prepared and characterized by IR, UV-Vis and 1H NMR spectra. Based on the hydrazone compounds, two new structurally similar dioxomolybdenum(VI) complexes, [MoO2L1(CH3OH)] (I) and [MoO2L2(CH3OH)] (II), were prepared and characterized by IR and UV-Vis spectra, and single crystal X-ray diffraction (CIF files nos. 1566491 (I) and 1566492 (II)). Complex I crystallizes as the triclinic space group (Formula presented.) with unit cell dimensions a = 8.0750(5), b = 10.5223(7), c = 10.8110(7) ?, α = 96.975(2)°, β = 97.909(2)°, γ = 104.497(2)°, V = 869.2(1) ?3, Z = 2, R1 = 0.0323, wR2 = 0.0620, GOOF = 1.089. Complex II crystallizes as the monoclinic space group P21/n with unit cell dimensions a = 11.680(1), b = 10.496(2), c = 14.879(2) ?, β = 98.862(2)°, V?= 1802.2(4) ?3, Z = 4, R1 = 0.0270, wR2 = 0.0675, GOOF = 1.111. X-ray analysis indicates that the complexes are mononuclear dioxomolybdenum(VI) species with the Mo atoms in octahedral coordination. The complexes were studied for their catalytic oxidation property on some olefins with tert-butyl hydrogen peroxide as oxidant.
- Liu,Yang,Diao,Ye,Zou
-
p. 572 - 578
(2018/09/11)
-
- Synthesis, crystal structures and catalytic property of oxidovanadium(V) complexes with similar aroylhydrazones
-
A pair of new oxidovanadium(V) complexes, [VOL1L]·EtOH (1) and [VOL2L]·EtOH (2) (L = acetohydroxamate), derived from the aroylhydrazones N’-(5-bromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide (H2L1) and N’-(5-bro-mo-2-hydroxybenzylidene)-4-methylbenzohydrazide (H2L2), have been prepared and characterized by elemental analyses, FT-IR,1H and13C NMR spectroscopy and single-crystal structural X-ray diffraction. The complexes have octahedral structures in which the aroylhydrazone ligands behave as binegative donors. Single-crystal structure analyses reveal that the V centers are coordinated by the donor atoms of the aroylhydrazone ligands, the acetohydroxamate ligands and the oxido groups. Crystal structures of the complexes are stabilized by hydrogen bonds. The complexes function as effective olefin epoxidation catalysts.
- Liang, Min,Sun, Nan,Zou, Dong-Hui
-
p. 964 - 969
(2019/02/15)
-
- Oxidation of lower alkenes by Α-oxygen (FeIII–O??)Α on the FeZSM-5 surface: The epoxidation or the allylic oxidation?
-
Reactions of anion-radical α-oxygen (FeIII–O??)α with propylene and 1-butene on sodium-modified FeZSM-5 zeolites were studied in the temperature range from ?60 to 25 °C. Products were extracted from the zeolite surface and identified. It was found that main reaction pathway was the epoxides formation. Selectivity for epoxides at ?60 °C was 59–64%. Other products were formed as a result of secondary transformations of epoxides on the zeolite surface. According to IR spectroscopy, the oxidation of propylene over the entire temperature range and 1-butene at ?60 °C were not accompanied by the formation of (FeIII–OH)α groups, in distinction to methane oxidation. This testifies that hydrogen abstraction does not occur. In case of 1-butene reaction with α-oxygen at 25 °C, hydrogen abstraction occurred but was insignificant, ca 7%. According to DFT calculation ferraoxetane intermediate formation is preferable over hydrogen abstraction. Following decomposition of this intermediate leads to the propylene oxide (PO) formation. The results may be relevant to the low selectivity problem of the silver catalyst in propylene epoxidation and raise doubts about the presently accepted mechanism explaining an adverse effect of allylic hydrogen.
- Starokon, Eugeny V.,Malykhin, Sergei E.,Parfenov, Mikhail V.,Zhidomirov, Georgy M.,Kharitonov, Alexander S.
-
-
- Synthesis, x-ray structural characterization, and catalytic property of binuclear oxidovanadium(V) complex with 2,4-dibromo-6-(5-methylamino-[1,3,4]thiadiazol-2-yl) phenol
-
A novel binuclear oxidovanadium(V) complex [V2O2(μ-O)L2(OEt)2], where L is the deprotonated form of 2,4-dibromo-6-(5-methylamino-[1,3,4]thiadiazol-2-yl)phenol (HL), was prepared by the reaction of 2-(3,5-dibromo-2-hydroxybenzylidene)-N-methylhydrazinecarbothioamide (HL’) and VO(acac)2 in ethanol. The ligand L’ underwent a cyclization during the coordination, to form a new ligand L. Structure of the complex was characterized by physicochemical methods and single-crystal X-ray determination. Crystal of the complex crystallizes in hexagonal space group R-3, with a = b = 33.302(3) ?, c = 15.308(2) ?, α = β = 90°, γ = 120°, V = 14702(3) ?3, Z = 18, R1 = 0.0823, wR2 = 0.2064, S = 1.011. X-ray analysis indicates that the V atom in the complex is in an octahedral coordination environment, constructed by the phenolate O and thiadiazol N atoms of L, one oxido O atom, one bridging O atom, and one deprotonated ethanol O atom. The distance between the two V atoms is 3.365(1) ?. The complex has an effective catalytic property for the oxidation of several olefins.
- Lei, Yan,Yang, Qiwen
-
p. 526 - 530
(2017/08/10)
-
- A dioxidomolybdenum(VI) complex of tridentate ONO aroylhydrazone ligand: Synthesis, crystal structure and catalytic activity
-
A new dioxidomolybdenum complex with the formula [MoO2L(MeOH)], derived from the tridentate aroylhydrazone 2-amino-N?-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide (H2L), has been prepared and characterized by elemental analysis, FTIR, 1H NMR, and single-crystal structural X-ray diffraction. The complex has a distorted octahedral structure in which the aroylhydrazone ligand behaves as a binegative donor one, leaving the amino-N uncoordinated toward the metal center. Single-crystal structure analysis reveals that the Mo(VI) center is coordinated by the donor atoms of the binegative aroylhydrazone ligand, two oxido groups and one oxygen atom of a methanol ligand. Crystal of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a cocatalyst.
- Liang, Min,Zou, Dong-Hui
-
p. 110 - 115
(2017/08/10)
-
- Synthesis, crystal structures, and catalytic properties of two oxidovanadium(V) complexes with tridentate Schiff bases
-
Two new oxidovanadium(V) complexes, [VO2L1] (I) and [VO2L2] (II), where L1 and L2 are the deprotonated forms of 4-methyl-2-[(2-morpholin-4-ylethylimino)methyl]phenol (HL1) and 2-[(2-isopropylaminoethylimino) methyl]-4-trifluoromethoxyphenol (HL2), respectively, have been prepared and characterized by physico chemical methods and single crystal X-ray diffraction (CIF files CCDC nos. 1443671 (I), 1443672 (II)). The V atom in each complex is coordinated by the phenolate oxygen, imino nitrogen and amino nitrogen of the Schiff base ligand, and two oxo groups, forming trigonal-bipyramidal geometry. The oxidation of olefins with the complexes as catalyst was evaluated, which indicated that both complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates by using tert-butyl hydrogen peroxide as oxidant.
- Peng
-
p. 404 - 410
(2017/06/19)
-
- Application of homochiral alkylated organic cages as chiral stationary phases for molecular separations by capillary gas chromatography
-
Molecular organic cage compounds have attracted considerable attention due to their potential applications in gas storage, catalysis, chemical sensing, molecular separations, etc. In this study, a homochiral pentyl cage compound was synthesized from a condensation reaction of (S,S)-1,2-pentyl-1,2-diaminoethane and 1,3,5-triformylbenzene. The imine-linked pentyl cage diluted with a polysiloxane (OV-1701) was explored as a novel stationary phase for high-resolution gas chromatographic separation of organic compounds. Some positional isomers were baseline separated on the pentyl cage-coated capillary column. In particular, various types of enantiomers including chiral alcohols, esters, ethers and epoxides can be resolved without derivatization on the pentyl cage-coated capillary column. The reproducibility of the pentyl cage-coated capillary column for separation was investigated using nitrochlorobenzene and styrene oxide as analytes. The results indicate that the column has good stability and separation reproducibility after being repeatedly used. This work demonstrates that molecular organic cage compounds could become a novel class of chiral separation media in the near future.
- Xie, Shengming,Zhang, Junhui,Fu, Nan,Wang, Bangjin,Hu, Cong,Yuan, Liming
-
-
- Azidolysis of epoxides catalysed by the halohydrin dehalogenase from Arthrobacter sp. AD2 and a mutant with enhanced enantioselectivity: an (S)-selective HHDH
-
Halohydrin dehalogenase from Arthrobacter sp. AD2 catalysed azidolysis of epoxides with high regioselectivity and low to moderate (S)-enantioselectivity (E?=?1–16). Mutation of the asparagine 178 to alanine (N178A) showed increased enantioselectivity towards styrene oxide derivatives and glycidyl ethers. Conversion of aromatic epoxides was catalysed by HheA-N178A with complete enantioselectivity, however the regioselectivity was reduced. As a result of the enzyme-catalysed reaction, enantiomerically pure (S)-β-azido alcohols and (R)-α-azido alcohols (ee???99%) were obtained.
- Mikleu?evi?, Ana,Primo?i?, Ines,Hrenar, Tomica,Salopek-Sondi, Branka,Tang, Lixia,Elenkov, Maja Majeri?
-
p. 930 - 935
(2016/09/13)
-
- Method for co-production of epoxide and dicumyl peroxide
-
The invention relates to a method for co-production of epoxide and dicumyl peroxide to mainly solve the problems of the prior art that a large amount of wastewater and offscum containing chlorine and sulphur is generated, pollution is serious, product quality is poor, energy consumption is high, production efficiency is low, and labor intensity is high. The method comprises the steps that a, cumyl hydroperoxide and olefin react, and reaction products are separated to obtain epoxide and alpha, alpha-dimethyl benzyl alcohol; b, cumyl hydroperoxide reacts with alpha, alpha-dimethyl benzyl alcohol generated in the step a to generate dicumyl peroxide. The method can be used for industrial co-production of epoxide and dicumyl peroxide.
- -
-
Paragraph 0099; 0100; 0104; 0105
(2016/10/08)
-
- A 1, 2 - epoxy butane synthetic method
-
The invention discloses a synthetic method for 1,2-epoxybutane. The method mainly comprises the step that the 1,2-epoxybutane is prepared through an one-step oxidation method, wherein an oxidizing agent is hydrogen peroxide. The synthetic method is simple in technological process, high in reaction yield, relatively low in preparation cost, and environmentally friendly in the whole process.
- -
-
Paragraph 0019-0020
(2017/05/27)
-
- Recyclable, green and efficient epoxidation of olefins in water with hydrogen peroxide catalyzed by polyoxometalate nanocapsule
-
A practical method for the selective epoxidation of alkenes was discovered using HxPMo12O40 H4Mo72Fe30(CH3COO)15O254 as a catalyst in the presence of H2O2 as a green oxidant. However, the simple catalyst system involving polyoxometalates and H2O2 exercised the most successful system in obtaining high to excellent yields of epoxide products for different alkenes, including aromatic and aliphatic alkenes at room temperature in water. The effectiveness of this catalyst is evidenced by 99% selectivity to epoxide and 97-99% efficiency of H2O2 utilization. The stability of PMo > Mo72Fe30 under a catalytic reaction has been confirmed by XRD, FT-IR and Raman spectroscopies.
- Fareghi-Alamdari, Reza,Hafshejani, Shahrbanou Moradpour,Taghiyar, Hamid,Yadollahi, Bahram,Farsani, Mostafa Riahi
-
-
- Synthesis, crystal structure and catalytic activity of dioxidomolybdenum(VI) complex with tridentate ono aroylhydrazone ligand
-
A novel dioxidomolybdenum complex, [MoO2L], derived from the tridentate aroylhydrazone 2-amino-N'-(2-hydroxy-3-methylbenzylidene)benzohydrazide (H2L), has been prepared and characterized by elemental analysis, FT-IR, 1H NMR, and single crystal structural X-ray diffraction. The complex has distorted square pyramidal structure in which the aroylhydrazone ligand behaves as a binegative donor, leaving the amino-N group uncoordinated towards the metal center. Single crystal structure analysis reveals that the Mo(VI) center is coordinated by the donor atoms of the binegative aroylhydrazone ligand and two oxido groups. Crystal structure of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.
- Liang, Min,Zou, Dong-Hui
-
p. 180 - 185
(2016/03/19)
-
- A method for preparing epoxy butane
-
The invention relates to a method for preparing epoxy butane, which comprises the following step: in an isopropyl benzene solution containing 25 wt% of cumene hydroperoxide solute, preparing epoxy butane from butylene oxide by using the cumene hydroperoxide solute as an oxidizer and a titanium-silicon molecular sieve with three-dimensional pore canal structure as a catalyst, wherein the fixed bed reaction conditions are as follows: the mole ratio of butylene to the cumene hydroperoxide solute is (5.0-12.0):1, the weight hourly space velocity of the cumene hydroperoxide is 1.0-5.0 h, the reaction pressure is 1.0-6.0 MPa, and the temperature is 60.0-120.0 DEG C. The catalyst is the titanium-silicon molecular sieve with three-dimensional pore canal structure; the molecular sieve has hysteresis loop on the low-temperature nitrogen adsorption and desorption isotherm; the average pore size is 2.0-8.0nm, and the specific area is 650.0-1100.0 m/g; and the catalyst has the advantages of favorable activity and high epoxy butane selectivity, and can be widely popularized and applied to industrial production of epoxy butane by butylene epoxidation.
- -
-
Paragraph 0025; 0026
(2017/03/08)
-
- A 1,2-epoxy butane cleaning preparation method of
-
The invention discloses a clean method for preparing 1,2-epoxybutane. The method comprises the following step: carrying out epoxidation reaction on a solvent, 1-butene, hydrogen peroxide and a surfactant in a reactor filled with a catalyst at a mass ratio of (20-50) to (1.0-10) to (0.5-1.0) to (0.08-0.15) to (0.5-1.2) under certain conditions to obtain 1,2-epoxybutane, wherein the reaction conditions are that the reaction temperature is 50-80 DEG C, the reaction pressure is 0.4-1.0MPa and the reaction time is 2-4h. The process is simple, the reaction conditions are mild, the environment friendliness is achieved, the energy consumption in separation of the product is reduced and the method can be used for industrial production.
- -
-
Paragraph 0020
(2017/03/17)
-
- Chiral oligomers of spiro-salencobalt(III)X for catalytic asymmetric cycloaddition of epoxides with CO2
-
Several new chiral oligomers of spiro-salenCo(III)X (spiro = 1.1′-spirobiindane-7.7′-diol) complexes have been designed, synthesized, and characterized by nuclear magnetic resonance (NMR), infrared (IR), and elemental analyses, in which, the chiral spiro moieties are first introduced into a scaffold of chiral salenCo catalysts. They were used to catalyze the asymmetric cycloaddition of epoxides with carbon dioxide. Under very mild reaction conditions, a kinetic resolution of racemic epoxides with CO2 was smoothly initiated by these chiral oligomer catalysts with good enantioselectivities, which can be attributed to the match effect between chiral backbones of salen and spiro. High stability and easy recyclability are their major advantages.
- Zhu, Zhouhe,Zhang, Yuqian,Wang, Kai,Fu, Xiying,Chen, Fengjuan,Jing, Huanwang
-
-
- A comprehensive test set of epoxidation rate constants for iron(IV)-oxo porphyrin cation radical complexes
-
Cytochrome P450 enzymes are heme based monoxygenases that catalyse a range of oxygen atom transfer reactions with various substrates, including aliphatic and aromatic hydroxylation as well as epoxidation reactions. The active species is short-lived and difficult to trap and characterize experimentally, moreover, it reacts in a regioselective manner with substrates leading to aliphatic hydroxylation and epoxidation products, but the origin of this regioselectivity is poorly understood. We have synthesized a model complex and studied it with low-pressure Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry (MS). A novel approach was devised using the reaction of [FeIII(TPFPP)]+ (TPFPP = meso-tetrakis(pentafluorophenyl)porphinato dianion) with iodosylbenzene as a terminal oxidant which leads to the production of ions corresponding to [FeIV(O)(TPFPP+a?￠)]+. This species was isolated in the gas-phase and studied in its reactivity with a variety of olefins. Product patterns and rate constants under Ideal Gas conditions were determined by FT-ICR MS. All substrates react with [FeIV(O)(TPFPP+a?￠)]+ by a more or less efficient oxygen atom transfer process. In addition, substrates with low ionization energies react by a charge-transfer channel, which enabled us to determine the electron affinity of [FeIV(O)(TPFPP+a?￠)]+ for the first time. Interestingly, no hydrogen atom abstraction pathways are observed for the reaction of [FeIV(O)(TPFPP+a?￠)]+ with prototypical olefins such as propene, cyclohexene and cyclohexadiene and also no kinetic isotope effect in the reaction rate is found, which suggests that the competition between epoxidation and hydroxylation - in the gas-phase - is in favour of substrate epoxidation. This notion further implies that P450 enzymes will need to adapt their substrate binding pocket, in order to enable favourable aliphatic hydroxylation over double bond epoxidation pathways. The MS studies yield a large test-set of experimental reaction rates of iron(iv)-oxo porphyrin cation radical complexes, so far unprecedented in the gas-phase, providing a benchmark for calibration studies using computational techniques. Preliminary computational results presented here confirm the observed trends excellently and rationalize the reactivities within the framework of thermochemical considerations and valence bond schemes.
- Sainna, Mala A.,Kumar, Suresh,Kumar, Devesh,Fornarini, Simonetta,Crestoni, Maria Elisa,De Visser, Sam P.
-
p. 1516 - 1529
(2015/03/04)
-
- Synthesis, structure, and catalytic oxidation of a molybdenum(VI) complex [MoO2(CH3OH)L]
-
A new molybdenum(VI) complex, [MoO2(CH3OH)(L)] (L = N′-(4-diethylamino-2-hydroxybenzylidene)-4-hydroxybenzohydrazide), was prepared and characterized by spectroscopy methods and single crystal X-ray diffraction (CIF file CCDC no. 1038153). The crystal of the complex, C19H23MoN3O6, crystallizes in the triclinic space group P1 with unit cell dimensions a = 6.9824(9), b = 10.206(1), c = 15.302(2) ?, α = 94.399(2)°, β = 101.877(2)°, γ = 104.062(2)°, V = 1025.9(2) ?3, Z = 2, R1 = 0.0317, wR2 = 0.0796, S = 1.060. The Mo atom in the complex is in an octahedral coordination with phenolate O, imino N, enolate O atoms of the ligand L, and one oxo O in the equatorial plane, and with one methanol O and the other oxo O in the axial sites. Crystals of the complex are stabilized by hydrogen bonds. The complex was studied for its catalytic oxidation property on some olefins, with tert-butyl hydrogen peroxide as oxidant.
- Liu,Zang,Lv
-
p. 451 - 455
(2015/07/01)
-
- Synthesis, x-ray structural characterization, and catalytic property of dioxomolybdenum(VI) Complexes with N-(3-Bromo-2-hydroxybenzylidene)-2- hydroxybenzohydrazide and N-(5-Chloro-2-hydroxybenzylidene)-4- nitrobenzohydrazide
-
Two new dioxomolybdenum(VI) complexes [MoO2(Bhbz) (CH3OH)] (1) and [MoO2(Cnbz)(CH3OH)] (2) with the benzohydrazone ligands H2Bhbz and H2Cnbz derived from 5-chlorosalicylaldehyde with 4-nitrobenzohydrazide and 3-bromosalicylaldehyde with 2-hydroxybenzohydrazide, respectively, have been synthesized and structurally characterized by physicochemical methods and single crystal X-ray determination. The crystal of (1) crystallizes in triclinic space group P-1, with a = 8.0014(9), b = 9.6294(10), c = 11.4204(12) A, = 89.193(2), β = 87.833(2), γ = 89.110(2)°, V = 879.11(16) A3, Z = 2, R 1 = 0.0464, wR 2 = 0.1185, S = 1.051. The crystal of (2) crystallizes in monoclinic space group P21/c, with a = 7.4108(3), b = 18.7901(7), c = 12.6293(5) A, β = 104.4850(10)°, V = 1702.72(12) A3, Z = 4, R 1 = 0.0236, wR 2 = 0.0576, S = 1.061. X-ray analysis indicates that the structures of both complexes are similar to each other. The molybdenum atom in each complex is in an octahedral coordination environment, constructed by two oxo groups and NO2 donor set of the ligand, and one methanol O atom. The complexes have effective catalytic property for the oxidation of several olefins.
- Lei, Yan,Yang, Qiwen,Chen, Gangcai,Yang, Qingling
-
p. 590 - 597
(2014/01/06)
-
- Vanadium(V) complexes with hydrazone and benzohydroxamate ligands: Synthesis, structures and catalytic epoxidation
-
Two structurally similar vanadium(V) complexes, [VOL1L] (1) and [VOL2L] (2), where L1 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)-4-methoxybenzohydrazide, L2 is the dianionic form of N'-(3,5-dibromo-2-hydroxybenzylidene)nicotinohydrazide, and L is benzohydroxamate, were prepared and characterized by elemental analysis, infrared spectra, and single crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 12.0262(7), b = 16.5629(9), c = 12.3449(8) A, β = 105.160(2)°, V = 2373.4(2) A3, Z = 4, R1 = 0.0376, wR2 = 0.0844, GOOF = 1.058; 2 crystallizes in the monoclinic space group P2 1/c, with unit cell dimensions a = 10.6439(7), b = 16.1968(9), c = 13.1108(8) A, β = 104.180(2)°, V = 2191.4(2) A3, Z = 4, R1 = 0.0521, wR2 = 0.1142, GOOF = 1.018. X-ray analysis indicates that vanadium in the complexes are coordinated by phenolate oxygen, imino nitrogen, and enolate oxygen of the hydrazone, two oxygens of the benzohydroxamate, and one oxo, generating octahedral coordination. Oxidations of olefins with the complexes as catalysts were evaluated. The complexes showed effective catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
-
p. 2076 - 2085
(2014/08/18)
-
- Synthesis and structures of two molybdenum(VI) complexes derived from similar benzohydrazone ligands with catalytic properties
-
Two new structurally similar molybdenum(VI) complexes, [MoO 2L1(CH3OH)] (1) and [MoO2L 2(CH3OH)] (2), where L1 is the dianionic form of N′-(2-hydroxy-5-nitrobenzylidene)-2-methylbenzohydrazide and L 2 is the dianionic form of N′-(2-hydroxy-4-methoxybenzylidene)- 2-methylbenzohydrazide, were prepared and structurally characterized by elemental analysis, infrared spectra, and single-crystal X-ray diffraction. 1 crystallizes in the monoclinic space group P21/c, with unit cell dimensions a = 7.941(1), b = 14.337(2), c = 15.141(2) A, β = 92.782(2)°, V = 1721.8(4) A3, Z = 4, R1 = 0.0286, wR2 = 0.0650, GOOF = 1.028. 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 8.003(1), b = 10.608(1), c = 10.880(1) A, α = 95.745(2)°, β = 97.627(2)°, γ = 105.762(2)°, V = 872.0(2) A3, Z = 2, R1 = 0.0226, wR2 = 0.0595, GOOF = 1.116. X-ray analysis indicates that Mo in the complexes are coordinated by the phenolate oxygen, imino nitrogen, and enolate oxygen of the benzohydrazone, methanol, and two oxo groups, generating octahedral coordination. The oxidation of olefins with the complexes as catalysts was evaluated, indicating that the complexes showed excellent catalytic efficiency in oxidation of most aliphatic and aromatic substrates under mild conditions using tert-butyl hydrogen peroxide as oxidant. 2014
- Li, An-Mei
-
p. 1022 - 1031
(2014/05/20)
-
- N′-(3-Bromo-2-hydroxybenzylidene)isonicotinohydrazide and its oxovanadium(V) complex: Synthesis, structures, and catalytic properties
-
A new hydrazone N′-(3-bromo-2-hydroxybenzylidene)isonicotinohydrazide (H2L) and its oxovanadium(V) complex, [VOLL′]·2H2O (L′ = 2-hydroxybenzohydroxamate), were prepared and structurally characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. The hydrazone coordinates to V through the phenolate oxygen, imino nitrogen, and enolate oxygen. The hydroxamate coordinates to V through the carbonyl oxygen and deprotonated hydroxyl oxygen. Vanadium in the complex is octahedral. The oxidation of olefins with the complex as catalyst was evaluated, which indicated that the complex showed catalytic efficiency in oxidation of several aliphatic and aromatic substrates under mild conditions, using tert-butyl hydrogen peroxide as oxidant.
- Xiong, Yan,Li, Wen-Hui
-
p. 3279 - 3287
(2015/10/20)
-
- Syntheses, crystal structures, and catalysis by polymeric dioxomolybdenum(VI) complexes with similar (iso)nicotinohydrazones
-
Polymeric dioxomolybdenum(VI) complexes, [MoO2L]n(L= L1= N'-(2-hydroxybenzylidene) nicotinohydrazide for 1, L=L 2= N'-(2-hydroxy-5-methoxybenzylidene)isonicotinohydrazide for 2), were prepared and characterized by physico-chemical, spectroscopic methods, and single-crystal X-ray determination. Complex 1 crystallizes in the orthorhombic space group P212121with a=7.6568(4), b =11.6315(7), c = 15.2211(9)A, V= 1355.59(13) A3, Z = 4, R1= 0.0181, wR2= 0.0464, and S = 1.097. Complex 2 crystallizes in the monoclinic space group P21/n with a=11.2516(6), b=11.8134(7), c= 12.4371(6) A, β = 116.2210(10)°, V=1483.02(14) A3, Z= 4, R1= 0.0399, wR2= 0.0874, and S=1.096. X-ray analysis indicates that Mo in each complex is octahedral with two oxo groups and N2O2donor set of the nicotinohydrazone or isonicotinohydrazone. The complexes are efficient catalysts for oxidation of olefins.
- Xu, Wei-Xiu,Yuan, Yong-Mei,Li, Wen-Hui
-
p. 2726 - 2735
(2014/02/14)
-
- Synthesis, x-ray crystal structure, and oxidation catalytic property of a dioxomolybdenum(VI) complex derived from 5-diethylamino-2-[(2-hydroxyethylimino) methyl]phenol
-
A new dioxomolybdenum(VI) complex, [MoO2L(CH3OH)], where L is the dianion of 5-diethylamino-2-[(2-hydroxyethylimino) methyl]phenol, was prepared and structurally characterized by physicochemical and spectroscopic methods and single-crystal X-ray determination. The Mo atom in the complex is in octahedral coordination. The crystal of the complex is stabilized by hydrogen bonds. The complex functions as an effective olefin epoxidation catalyst with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a cocatalyst under air atmosphere at room temperature.
- Ding, Shao-Bing
-
p. 877 - 881
(2013/05/22)
-
- Routes for reactions of alkylene oxides with R-β-hydroxyalkyl sulfides: Unusual exchange of functional groups
-
Possible routes of the previously unknown exchange reaction of alkylene oxides with R-β-hydroxyalkyl sulfides have been considered. Each route has intermediates and transition states of its own, but all the directions in the final stage lead to the formation of a single intermediate cyclic bipolar ion with intramolecular hydrogen bonding, which determines the common nature and composition of end products for all routes. The features of the reaction have been analyzed. The quantitative description of each route has been given. Pleiades Publishing, Ltd., 2012.
- Malievskii
-
experimental part
p. 194 - 203
(2012/10/18)
-
- Self-assembly approach toward chiral bimetallic catalysts: Bis-urea-functionalized (Salen)cobalt complexes for the hydrolytic kinetic resolution of epoxides
-
A series of novel bis-urea-functionalized (salen)Co complexes has been developed. The complexes were designed to form self-assembled structures in solution through intermolecular urea-urea hydrogen-bonding interactions. These bis-urea (salen)Co catalysts resulted in rate acceleration (up to 13atimes) in the hydrolytic kinetic resolution (HKR) of rac-epichlorohydrin in THF by facilitating cooperative activation, compared to the monomeric catalyst. In addition, one of the bis-urea (salen)CoIII catalyst efficiently resolves various terminal epoxides even under solvent-free conditions by requiring much shorter reaction time at low catalyst loading (0.03-0.05amol %). A series of kinetic/mechanistic studies demonstrated that the self-association of two (salen)Co units through urea-urea hydrogen bonds was responsible for the observed rate acceleration. The self-assembly study with the bis-urea (salen)Co by FTIR spectroscopy and with the corresponding (salen)Ni complex by 1HaNMR spectroscopy showed that intermolecular hydrogen-bonding interactions exist between the bis-urea scaffolds in THF. This result demonstrates that self-assembly approach by using non-covalent interactions can be an alternative and useful strategy toward the efficient HKR catalysis.
- Park, Jongwoo,Lang, Kai,Abboud, Khalil A.,Hong, Sukwon
-
supporting information; experimental part
p. 2236 - 2245
(2011/03/22)
-
- METHODS OF PRODUCING EPOXIDES FROM ALKENES USING A TWO-COMPONENT CATALYST SYSTEM
-
Methods for the epoxidation of alkenes are provided. The methods include the steps of exposing the alkene to a two-component catalyst system in an aqueous solution in the presence of carbon monoxide and molecular oxygen under conditions in which the alkene is epoxidized. The two-component catalyst system comprises a first catalyst that generates peroxides or peroxy intermediates during oxidation of CO with molecular oxygen and a second catalyst that catalyzes the epoxidation of the alkene using the peroxides or peroxy intermediates. A catalyst system composed of particles of suspended gold and titanium silicalite is one example of a suitable two-component catalyst system.
- -
-
Page/Page column 3-4
(2011/05/16)
-
- A flexible nonporous heterogeneous catalyst for size-selective oxidation through a bottom-up approach
-
Size does matter: The nonporous tetra-n-butylammonium salt of silicodecatungstate, synthesized through a bottom-up approach, heterogeneously catalyzes the size-selective oxidation of various organic compounds, including olefins, sulfides, and organosilanes, with aqueous H2O2 in ethyl acetate. The catalyst can be easily separated by filtration and reused several times with retention of high catalytic activity. Copyright
- Mizuno, Noritaka,Uchida, Sayaka,Kamata, Keigo,Ishimoto, Ryo,Nojima, Susumu,Yonehara, Koji,Sumida, Yasutaka
-
supporting information; experimental part
p. 9972 - 9976
(2011/03/18)
-
