- Solid-state rearrangement of sandwich-type polyoxometalate-dopamine nanohybrid to the nanoflower Keggin polyoxometalate: synthesis, characterization, and catalytic efficiency
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Sponge-like inorganic-organic nanohybrid consisting of sandwich-type polyoxometalate of [P2W18Ce3(H2O)2O71]12? (P2W18Ce3) and dopamine (DA) was fabricated by a simple procedure. The DA/P2W18Ce3 sponge-like nanohybrid is turned into a nanoflower by calcination at 300 °C. The results showed a structure rearrangement of sandwich-type polyoxometalate to the Keggin-type polyoxometalate along with this morphology change. The nanomaterials were fully characterized by scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, texture analysis (BET), and X-ray powder diffraction (XPRD). The DA/P2W18Ce3 sponge-like nanohybrid and the Keggin nanoflower showed efficiency toward degradation of methylene blue (MB) and rhodamine B (RhB). Moreover, the catalytic activity of the Keggin nanoflower was examined in the oxidation of sulfides to sulfones with H2O2 as oxidant in water at room temperature. The catalyst was reused at least four times without loss of its catalytic activity.
- Pirdosti, Soleiman Fazeli,Khoshnavazi, Roushan,Naseri, Elham
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p. 723 - 736
(2020/04/28)
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- Sandwich type polyoxometalates encapsulated into the mesoporous material: Synthesis, characterization and catalytic application in the selective oxidation of sulfides
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The A-type sandwich polyoxometalates of [(HOSnIVOH)3(PW9O34)2]12- (P2W18Sn3) and [(OCeIVO)3(PW9O34)2]12- (P2W18Ce3) were immobilized for the first time into the porous metal-organic framework MIL-101(Cr). FT-IR, powder X-ray diffraction, SEM-EDX, ICP analysis, N2 adsorption and thermogravimetric analysis collectively confirmed immobilization and good distribution of polyoxometalates into cages of MIL-101(Cr). The catalytic activities of the homogeneous P2W18Sn3 and P2W18Ce3 and the corresponding heterogeneous catalysts were examined in the oxidation of sulfides to sulfones with H2O2 as the oxidant at room temperature. The effects of different dosages of polyoxometalates, type of solvent, reaction time, amount of catalyst and oxidant in this catalytic system were investigated. The new P2W18Sn3@MIL-101 and P2W18Ce3@MIL-101 nanocomposites exhibited good recyclability and reusability in at least five consecutive reaction cycles without significant loss of activity or selectivity.
- Naseri, Elham,Khoshnavazi, Roushan
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p. 28249 - 28260
(2018/08/16)
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- Fe3O4/PEG-SO3H as a heterogeneous and magnetically-recyclable nanocatalyst for the oxidation of sulfides to sulfones or sulfoxides
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We present below a sulfonated-polyethylene glycol-coated Fe3O4 nanocomposite (Fe3O4/PEG-SO3H) as a greatly effective and ecological nanocatalyst for the selective oxidation of sulfides to sulfoxides or sulfones with brilliant yields under solvent-free conditions by employing 30% hydrogen peroxide as the oxidant. A number of sulfides containing alcohol, ester, and aldehyde functional groups were fruitfully and selectively oxidized without altering the desired characteristics. The magnetic nanocatalyst (Fe3O4/PEG-SO3H) can be conveniently and swiftly retrieved through the utilization of an external magnetic tool and recycled for more than 10 reaction runs without significantly decreasing its catalytic behavior.
- Mirfakhraei, Saeideh,Hekmati, Malak,Eshbala, Fereshteh Hosseini,Veisi, Hojat
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p. 1757 - 1761
(2018/02/09)
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- Immobilized Sandwich-Type Polyoxometalates [Mn4(XW9O34)2]n? on Tb-Doped TiO2 Nanoparticles as Efficient and Selective Catalysts in the Oxidation of Sulfides and Alcohols
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Abstract: Sandwich-type polyoxometalates of [M4(XW9O34)2]n?(M = Mn2+, Cu2+, Zn2+, X = Ge4+, P5+, As5+) supported on Ln-doped TiO2(Ln = Nd3+, Sm3+, Tb3+and Dy3+) nanoparticles were prepared and their catalytic activities examined for oxidation of sulfides and alcohols. Results show that the catalytic activities of new nanocomposites were significantly higher than homogeneous conditions with corresponding sandwich-type polyoxometalates. The best results obtained by [Mn4(XW9O34)2]10?(X = P5+, As5+) supported on Tb/TiO2which were characterized by various techniques. The catalysts can be easily recovered and reused for at least five times without obvious decrease of catalytic activities and the structures of the catalysts remain unchanged after recycling and the yields for catalyst recovery are all above 95%. Graphical Abstract: [Figure not available: see fulltext.]
- Gholamyan, Sahar,Khoshnavazi, Roushan,Rostami, Amin,Bahrami, Leila
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- hydrogen fluorine ether sulphone class compound and its preparation method, the electrolyte of the lithium battery (by machine translation)
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The invention provides a hydrofluoroether sulfones compound and a preparation method thereof as well as lithium-ion battery electrolyte. The lithium-ion battery electrolyte comprises a lithium salt, a solvent and the hydrofluoroether sulfones compound shown as the formula (I). Compared with the prior art, the hydrofluoroether sulfones compound is added into the hydrofluoroether sulfones compound shown as the formula (I) contains a hydrofluoroether radical. Firstly, the hydrofluoroether sulfones compound shown as the formula (I) keeps the high voltage resistance advantage of the sulfones compound and the high voltage resistance of the electrolyte can be improved; the hydrofluoroether radical is good for overcoming the disadvantages of the sulfones compound that the smelting point and the viscosity are high and has high conductivity; then, the hydrofluoroether sulfones compound, an electrolyte common solvent and the lithium salt have good compatibility and a homogeneous solution is easy to form; finally, the hydrofluoroether sulfones compound shown as the formula (I) has the advantages of hydrofluoroether compounds and is good for improving the flashing point of the electrolyte, so that the electrolyte has good fire resistance.
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Paragraph 0070
(2017/03/28)
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- A highly efficient, green, rapid, and chemoselective oxidation of sulfides using hydrogen peroxide and boric acid as the catalyst under solvent-free conditions
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We report boric acid as a highly efficient and eco-friendly catalyst for the selective oxidation of sulfides to sulfoxides or sulfones, in excellent yields under solvent-free conditions, using 30% hydrogen peroxide as an oxidant. Various sulfides possessing functional groups such as alcohol, ester, and aldehyde are successfully and selectively oxidized without affecting sensitive functionalities.
- Rostami, Amin,Akradi, Jamal
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experimental part
p. 3501 - 3503
(2010/08/20)
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- Tetra-(tetraalkylammonium)octamolybdate catalysts for selective oxidation of sulfides to sulfoxides with hydrogen peroxide
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Tetra-(tetraalkylammonium)octamolybdate catalysts are successfully applied in the selective oxidation of various sulfides to sulfoxides with 30% aqueous hydrogen peroxide as oxidant under mild reaction conditions in 94-100% yield and 95-100% selectivity. The octamolybdate catalysts show high catalytic activity in a high ratio of substrate to catalyst (up to 10000:1) and are recyclable, with actively functional groups, including hydroxyl group and CC bonds, tolerated in the oxidation. The Royal Society of Chemistry 2009.
- Yang, Chuanbo,Jin, Qingping,Zhang, Hua,Liao, Jian,Zhu, Jin,Yu, Bin,Deng, Jingen
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supporting information; experimental part
p. 1401 - 1405
(2010/05/02)
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- Synthesis of β-hydroxy sulfones via opening of hydrophilic epoxides with zinc sulfinates in aqueous media
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Reaction of hydrophilic epoxides (ethylene oxide and propylene oxide) with readily accessible zinc sulfinates in aqueous solution under essentially neutral conditions afforded β-hydroxy sulfones in good yields. This method avoids the need for organic solvents and produces ZnO as the only major reaction byproduct. 2-(Methylsulfonyl)ethanol, a common reagent for the protection of various functional groups, was obtained by this methodology from ethylene oxide in 78% yield. Reaction of various simple zinc alkane- and benzenesulfinates with propylene oxide proceeded regioselectively in 63-67% yield. The corresponding opening of these epoxides with zinc 1,3-butadiene-1-sulfinate afforded 1-butadienyl β-hydroxyalkyl sulfones in 30% yield. Mechanistic studies revealed that the yields of these products were limited by their consumption in competing intra- and intermolecular Michael addition processes.
- Chumachenko, Nataliya,Sampson, Paul
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p. 4540 - 4548
(2007/10/03)
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- The Preparation of 9-Oxo-10-oxaprostanoids by the Conjugate Addition of (E)-1-(Phenylthio)oct-2-enyllithium to γ-Crotonolactone and the Direct Alkylation of the Derived Enolate with Methyl 7-Bromohept-5-ynoate and Related Electrophiles
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The conjugate addition of (E)-1-(phenylthio)oct-2-enyllithium in tetrahydrofuran containing hexamethylphosphoric triamide to γ-crotonolactone (but-2-en-4-olide) followed by treatment of the resulting lactone enolate with either methyl 7-bromohept-5-ynoate or 7-bromohept-5-ynenitrile gave the corresponding enolate trapped products in yields of 50-55percent from the octenyllithium reagent.Use of 7-iodohept-5-ynoate gave a slightly higher yield than the first electrophile.Treatment of the enolate with triphenyltin chloride prior to addition of the electrophiles resulted in approximately 5-10percent enhancement of the yields of the products.The products obtained from the methyl 7-halohept-5-ynoates were converted into the 9-oxo-10-oxaprostanoids through the corresponding sulfoxides and the allylically transposed alcohols by a standard sequence of reactions.In an attempt to convert the lactone ring of the enolate-trapped products into the fully carbocyclic nucleus of primary prostaglandins, the nucleophilic ring opening of the lactone nucleus with the lithiated carbanion derived from t-butyl methyl sulfone in the presence of N,N,N',N'-tetramethylethylenediamine was carried out.However, attempts to oxidize the resulting hemiacetals to the requisite diketone precursors of the carbocyclic prostaglandins were unsuccessful.
- Haynes, Richard K.,Schober, Paul A.
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p. 1249 - 1265
(2007/10/02)
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- Elimination Reactions of α-Substituted Thymines Derived from Tautomeric Heterocyclic Thiols and Selenols
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Tautomeric heterocyclic thiols are readily alkylated by 5-(halomethyl)uracils, giving both S- and N-substituted products.S derivatives such as 19 undergo rapid elimination of thiolate anion in base, whereas the isomeric 6-substituted uracil drivatives such as 3 show no elimination.Kinetic and 13C NMR studies are consistent with an elimination mechanism involving heterocyclic quinone methide intermediate, which can arise from the 5-substituted uracil derivatives but not from the 6-substituted series.The proposed mechanism is further supported by studies of the pH dependency of the elimination reaction and of the effect of substitution in the uracil ring (see Table I and Scheme II).N-Substituted (thione) derivatives such as 36 also undergo base-catalyzed elimination, but a rates some 105 to 106 times slower than those for the corresponding S derivatives when the uracil is unsubstituted on nitrogen.The high sensivity of elimination rate to changes in the leaving group atom is attributed to a transition state in which the connecting methylene group has considerable carbocation character (see Scheme VI).Analogous derivatives (such as 42) of tautomeric heterocyclic selenols have also been prepared, and their elimination kinetics further support this interpretation.
- Bartles-Keith, James R.,Mahoney, J. Barry,Puttick, Anthony J.
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p. 980 - 987
(2007/10/02)
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- Effects of Volume and Surface Property in Hydrolysis by Acetylcholinesterase. The Trimethyl Site
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β-Substituted ethyl acetates, XCH2CH2OCOCH3, have been prepared, and their hydrolysis by acetylcholinesterase has been studied.Log of enzymic reactivity, normalized for intrinsic reactivity in hydrolysis by hydroxide, log(kcat/Km)n, rises linearly with increasing refraction volume, MR (or RD25), for substrates with β-X = H, Cl, Br, CH3CH2, (CH3)2CH, (CH3)2S+, (CH3)3N+, and (CH3)3C.Larger substituents may by accommodated, (CH3)3Si and (CH3CH2)3N+, with no further increase in rate.Substrates with β-substituents CH3S, CH3S(O), (CH3)3N+(OH), and CH3S(O2) are less reactive than consistent with the relation with MR by factors of 5-40, indicating that hydrophobic surface and desolvation of the substrate-enzyme interface may be necessary for maximum reactivity correlated with MR.Values of log (kcat/Km)n for substrates with β-substituents X = CH3S, Cl, Br, CH3CH2, (CH3)2CH, (CH3)3C, and (CH3)3Si rise linearly with increasing hydrophobicity, ?, but reactivity of substrates with X = (CH3)3N+ and (CH3)2S+ are more reactive than consistent with a relation to ? by factors of 300 and 40 and with X = CH3S(O2), CH3S(O), and (CH3)2N+(OH), by factors of 7-100.Reactivity appears related to (i) volume of the β-substituent and its fit in its subsite, which is trimethyl rather than anionic, and (ii) the hydrophobicity of its surface.
- Cohen, Saul G.,Elkind, Jerome L.,Chishti, S. Bano,Giner, Jose-L. P.,Reese, Heide,Cohen, Jonathan B.
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p. 1643 - 1647
(2007/10/02)
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