- Reactivity in Z-Philic Displacements in α-Halogenosulfones
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Rates of Z-philic reactions in β-substituted α-bromosulfones have been measured; for displacement-protonation ρ* = 2.9, and isotope fractionation factors close to 2.4 demonstrate extensive C-protonation in the transition structure.
- Vernon, Adam,Stirling, Charles J. M.
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Read Online
- An Oxalate-Functionalized Tetra-ZrIV-Substituted Sandwich-Type Silicotungstate: Hydrothermal Synthesis, Structural Characterization, and Catalytic Oxidation of Thioethers
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A previously unknown inorganic–organic hybrid polyoxidometalate constructed from oxalate-functionalized tetra-ZrIV-substituted dimeric silicotungstate, (NH4)3Na5K6[Zr4(μ3-O)2(μ-OH)2(ox)2(SiW10O37)2]·23H2O (1, ox = oxalate) has been synthesized under mild hydrothermal conditions and characterized by FTIR spectroscopy, elemental analysis, thermogravimetric analysis, single-crystal and powder X-ray diffraction. Compound 1 contains a centrosymmetric polyoxidoanion structure with two [SiW10O37]10– units sandwiching a [Zr4(μ3-O)2(μ-OH)2(ox)2]6+ cluster. The catalytic performances of 1 involving oxygenation reactions of thioethers by H2O2 were evaluated, showing that 1 is an excellent catalyst for the catalytic oxidation of thioethers to sulfoxides/sulfones.
- Wang, Yue-Lin,Zhang, Zhong,Li, Hai-Lou,Li, Xu-Yan,Yang, Guo-Yu
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- Heptamolybdate: A highly active sulfide oxygenation catalyst
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The sulfide oxygenation activities of both heptamolybdate ([Mo7O24]6-, [1]6-) and its peroxo adduct [Mo7O22(O2)2]6- ([2]6-) were examined in this contribution. [Mo7O22(O2)2]6- was prepared in a yield of 65% from (NH4)6[Mo7O24] (1a) upon treatment of 10 equiv. of H2O2 and structurally identified through single crystal X-ray diffraction study. (nBu4N)6[Mo7O22(O2)2] (2b) is an efficient catalyst for the sequential oxygenation of methyl phenyl sulfide (MPS) by H2O2 to the corresponding sulfoxide and subsequently sulfone with a 100% utility of H2O2. Surprisingly, (nBu4N)6[Mo7O24] (1b) is a significantly faster catalyst than 2b for MPS oxygenation under identical conditions. The pseudo-first order kcat constants from initial rate kinetics are 54 M-1 s-1 and 19 M-1 s-1 for 1b and 2b, respectively. Electrospray ionization mass spectrometry (ESI-MS) investigation of 1b under the catalytic reaction conditions revealed that [Mo2O11]2- is likely the main active species in sulfide oxygenation by H2O2.
- Porter, Ashlin G.,Hu, Hanfeng,Liu, Xuemei,Raghavan, Adharsh,Adhikari, Sarju,Hall, Derrick R.,Thompson, Dylan J.,Liu, Bin,Xia, Yu,Ren, Tong
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- A μ-AsO4-Bridging Hexadecanuclear Ni-Substituted Polyoxotungstate
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A novel tetrahedral μ-AsO4-bridging hexadecanuclear Ni-substituted silicotungstate (ST) Na21H10[(AsO4){Ni8(OH)6(H2O)2(CO3)2(A-α-SiW9O34)2}2]·60H2O (1) was made by the reactions of trivacant [A-α-SiW9O34]10- ({SiW9}) units with Ni2+ cations and Na3AsO4·12H2O and characterized by IR spectrometry, elemental analysis, thermogravimetric analysis (TGA), and powder X-ray diffraction (PXRD). 1 contains a novel polyoxoanion [(AsO4){Ni8(OH)6(H2O)2(CO3)2(A-α-SiW9O34)2}2]31- built by four trivacant Keggin [A-α-SiW9O34]10- fragments linked through an unprecedented [(AsO4){Ni8(OH)6(H2O)2(CO3)2}2]9+ cluster, where the tetrahedral AsO4 acts as an exclusively μ2-bridging unit to link multiple Ni centers; such a connection mode appears for the first time in polyoxometalate chemistry. Furthermore, the electrochemical and catalytic oxidation properties of compound 1 have been investigated.
- Lian, Chen,Li, Hai-Lou,Yang, Guo-Yu
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p. 3996 - 4003
(2021/04/07)
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- Primary Alcohols via Nickel Pentacarboxycyclopentadienyl Diamide Catalyzed Hydrosilylation of Terminal Epoxides
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The efficient and regioselective hydrosilylation of epoxides co-catalyzed by a pentacarboxycyclopentadienyl (PCCP) diamide nickel complex and Lewis acid is reported. This method allows for the reductive opening of terminal, monosubstituted epoxides to form unbranched, primary alcohols. A range of substrates including both terminal and nonterminal epoxides are shown to work, and a mechanistic rationale is provided. This work represents the first use of a PCCP derivative as a ligand for transition-metal catalysis.
- Lambert, Tristan H.,Steiniger, Keri A.
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p. 8013 - 8017
(2021/10/25)
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- A sustainable approach towards solventless organic oxidations catalyzed by polymer immobilized Nb(V)-peroxido compounds with H2O2 as oxidant
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New heterogeneous catalysts comprising of peroxidoniobium(V) complexes immobilized on amino acid grafted cross-linked poly(styrene-divinylbenzene) resin has been developed. Results of FTIR, Raman, NMR, XPS, XRD, EDX, SEM, BET, TGA, and elemental analysis confirmed the successful anchoring of triperoxidoniobium(V), [Nb(O2)3]? species to the host polymer via the pendant amino acid groups. The supported catalysts exhibited excellent performance in epoxidation of styrene and a range of cyclic and terpenic compounds under environmentally acceptable solvent-free condition, with aqueous H2O2 as oxidant. The catalytic protocols provided excellent conversion to the desired epoxide (up to 100%) with selectivity > 99%, TON as high as 1000, and high H2O2 utilization efficiency (92–97%). Moreover, the catalysts efficiently facilitated chemoselective solvent-free oxidation of a variety of thioethers to sulfones at room temperature. Simple operational strategy, easy recyclability for multiple reaction cycles with the consistent activity-selectivity profile are the additional significant attributes of the developed catalytic processes.
- Ahmed, Kabirun,Gogoi, Sandhya Rani,Islam, Nashreen S.,Saikia, Gangutri,Sultana, Sazida Yasmin,Talukdar, Hiya
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- A {Ti6W4}-Cluster-Substituted Polyoxotungstate: Synthesis, Structure, and Catalytic Oxidation Properties
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A novel Ti-W-O-cluster-substituted tungstoantimonate (TA), [H2N(CH3)2]3Na4H9[{Ti6W4O18(OH)(H2O)3}(B-α-SbW9O33)3]·20H2O (1), has been made by hydrothermal reactions of trivacant [B-α-SbW9O33]9- units, Ti4+ cations, and WO42- anions in the presence of [H2N(CH3)2]·Cl and structurally characterized. Intriguingly, the polyoxoanion of 1 is constructed from three [B-α-SbW9O33]9- units and a previously unobserved decanuclear heterometallic Ti-W-O cluster [Ti6W4O18(OH)(H2O)3]11+ ({Ti6W4}) that is comprised of an octahedral [Ti6WO6(H2O)3]18+ cluster and an edge-sharing [W3O12(OH)]7- fragment via six W-O-Ti/W linkers. Furthermore, studies on the catalytic oxidation properties reveal that 1 possesses good catalytic activity toward the oxidation reactions of various sulfides and cyclooctene based on the environmentally friendly oxidant H2O2.
- Li, Hai-Lou,Lian, Chen,Yang, Guo-Yu
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supporting information
p. 14622 - 14628
(2021/10/01)
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- {Ti6}/{Ti10} Wheel Cluster Substituted Silicotungstate Aggregates
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Two novel Ti-oxo wheel cluster substituted silicotungstates (STs) [H2N(CH3)2]9H9[Ti6O6(SiW10O37)3]·11H2O (1) and [H2N(CH3)2]16H10[Ti10O11(SiW10O37)2(SiW9O35)2]·14H2O (2) have been made by hydrothermal reactions. The polyoxoanion of 1 is a ring-shaped trimer where a Ti6O6 ({Ti6}) wheel cluster is encapsulated by three divacant [SiW10O37]10- (SiW10O37) fragments. However, 2 is built by two divacant SiW10O37 units and two rare trivacant [SiW9O35]12- (SiW9O35) fragments and further installs an unprecedented Ti10O11 ({Ti10}) double-wheel cluster. To the best of our knowledge, 2 is rare in POM chemistry. Studies on the catalytic oxidation properties reveal that 1 exhibits high catalytic activity toward the oxidation of various sulfides using H2O2 as an oxidant. Furthermore, 1 can be facilely recycled and reused for at least five cycles without obvious loss of catalytic activity.
- Li, Hai-Lou,Lian, Chen,Yang, Guo-Yu
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p. 16852 - 16859
(2021/11/13)
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- Sulfoxidation inside a hypercrosslinked microporous network nanotube catalyst
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In the present work, a kind of efficient heterogeneous catalyst was synthesized from amine-functionalized hypercrosslinked bottlebrush copolymers of microporous network nanotubes (amine-MNNs) and Na2WO4. The synthesized tungstate-supported microporous network nanotubes (TMNNs) catalyst was shown to be highly active in the selective H2O2 oxidation of sulfides to sulfoxides or sulfones under mild conditions due to the high specific surface area (800 m2 g-1) and firm structure of the nanotubes. The catalyst was found to be very stable and could be recycled at least 8 times without any significant loss of activity. These results present a new opportunity for the development of efficient green organic catalytic materials with high activity.
- Shi, Zhaocheng,Ying, Zhong,Yang, Liusai,Meng, Xiaoyan,Wu, Lidan,Yu, Leshu,Huang, Sen,Xiong, Linfeng
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supporting information
p. 1542 - 1547
(2020/02/06)
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- Electrochemical radical reactions of alkyl iodides: a highly efficient, clean, green alternative to tin reagents
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An electrochemical ‘redox-relay’ system has been developed which allows the generation of C-centered radicals. Intermolecular ‘tin-like’ radical reactions can subsequently be conducted under the most benign of conditions. The yields and efficiency of the processes are competitive and even superior in most cases to comparable conditions with tributyltin hydride. The use of air and electricity as the promotor (instead of a tin or other reagent) combined with the aqueous reaction media make this a clean and ‘green’ alternative to these classic C-C bond forming processes.
- Li, Diyuan,Ma, Tsz-Kan,Scott, Reuben J.,Wilden, Jonathan D.
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p. 5333 - 5338
(2020/06/04)
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- Three Zr(IV)-Substituted Polyoxotungstate Aggregates: Structural Transformation from Tungstoantimonate to Tungstophosphate Induced by pH
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Three novel Zr-substituted polyoxotungstate aggregates [H2N(CH3)2]7NaH2[Zr2Sb2O3(A-α-PW9O34)2]·16H2O (1), [H2N(CH3)2]6H12[ZrSb4(OH)O2(A-α-PW8O32)(A-α-PW9O34)]2·33H2O (2), and [H2N(CH3)2]4Na11.5H4.5[Zr4W8Sb4P5O49(OH)5(B-α-SbW9O33)2]·53H2O (3) have been made in hydrothermal reactions of the [B-α-SbW9O33]9- precursor with Zr4+ cations and PO43- anions in the presence of dimethylamine hydrochloride and sodium acetate buffer (pH = 4.8) and structurally characterized. Different pH values induce structural transformation from tungstoantimonate (TA) to tungstophosphate (TP). 1 is a di-Zr-substituted sandwich-type TP, the tetranuclear heterometallic [Zr2Sb2O3]8+ entity sandwiched by two [A-α-PW9O34]9- moieties. 2 is a double sandwich-type structure, which can be perceived as two equivalent sandwiched [Sb3(PW8O32)(PW9O34)]11- further sandwiching one [Sb2Zr2(OH)2O4]4+ core to form a novel large-size sandwich-type architecture. Different from 1 and 2, 3 is a tetra-Zr-substituted sandwiched configuration, in which two [B-α-SbW9O33]9- fragments sandwich a unique 21-core Sb-P-W-Zr oxo cluster ({Zr4W8Sb4P5}). Furthermore, the catalytic oxidation of aromatic thioethers by 3 as the heterogeneous catalyst has been investigated, showing high conversion and remarkable selectivity as well as excellent recyclability.
- Li, Hai-Lou,Lian, Chen,Yang, Guo-Yu,Yin, Da-Peng
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p. 12842 - 12849
(2020/09/15)
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- Ionic Liquid Stabilized Niobium Oxoclusters Catalyzing Oxidation of Sulfides with Exceptional Activity
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We present here a new class of niobium oxoclusters that are stabilized effectively by carboxylate ionic liquids. These functionalized ILs are designated as [TBA][LA], [TBA][PA], and [TBA][HPA] in this work, in which TBA represents tetrabutylammonium and LA, PA, and HPA refer to lactate, propionate, 3-hydroxypropionate anions, respectively. The as-synthesized Nb oxoclusters have been characterized by use of elemental analysis, NMR, IR, XRD, TGA, HRTEM. It was found that [TBA][LA]-stabilized Nb oxoclusters (Nb?OC@[TBA][LA]) are uniformly dispersed with an average particle size of 2–3 nm and afforded exceptionally high catalytic activity for the selective oxidation of various thioethers. The turnover number with Nb?OC@[TBA][LA] catalyst was over 56 000 at catalyst loading as low as 0.0033 mol % (1 ppm). Meantime, the catalyst also showed the high activity for the epoxidation of olefins and allylic alcohols by using only 0.065 mol % of catalyst (50 ppm). The characterization of 93Nb NMR spectra revealed that the Nb oxoclusters underwent structural transformation in the presence of H2O2 but regenerated to their initial state at the end of the reaction. In particular, the highly dispersed Nb oxoclusters can absorb a large amount of polar organic solvents and thus were swollen greatly, which exhibited “pseudo” liquid phase behavior, and enabled the substrate molecules to be highly accessible to the catalytic center of Nb oxocluster units.
- Zhou, Qingqing,Ye, Man,Ma, Wenbao,Li, Difan,Ding, Bingjie,Chen, Manyu,Yao, Yefeng,Gong, Xueqing,Hou, Zhenshan
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p. 4206 - 4217
(2019/03/26)
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- Water-soluble polymer anchored peroxotitanates as environmentally clean and recyclable catalysts for mild and selective oxidation of sulfides with H2O2 in water
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Anchoring of peroxotitanium (pTi) species to linear water-soluble acrylic acid based polymers, poly(sodium acrylate) (PA) and poly(sodium methacrylate) (PMA) led to the successful synthesis of a pair of new, water-tolerant and recyclable catalysts of the type [Ti2(O2)2O2(OH)2]4-—L (L = PA or PMA), highly effective in chemoselective sulfoxidation of organic sulfides with 30% H2O2 in aqueous medium at ambient temperature. The catalytic protocol is high yielding (TOF up to 11,280 h?1), operationally simple as well as environmentally clean and safe, being free from halide, or any other toxic auxiliaries. The catalysts are sufficiently stable to afford easy recyclability for at least 10 consecutive reaction cycles of sulfoxidation with consistent activity selectivity profile. Oxidation of dibenzothiophene (DBT) to respective high purity sulfoxide or sulfone could also be accomplished using the same catalysts by variation of reaction conditions.
- Ahmed, Kabirun,Saikia, Gangutri,Paul, Sivangi,Baruah, Satyajit Dey,Talukdar, Hiya,Sharma, Mitu,Islam, Nashreen S.
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- Fe3O4?BNPs?SiO2-SO3H as a highly chemoselective heterogeneous magnetic nanocatalyst for the oxidation of sulfides to sulfoxides or sulfones
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To achieve green chemistry goals and also to reduce the cost of catalysts as well as to avoid producing toxic wastes and show the importance of separation and recycling of catalysts from the reaction medium, in this work, we describe the preparation and characterization of magnetic acidic boehmite nanoparticles as a heterogeneous catalyst, which is called Fe3O4?BNPs?SiO2-SO3H. This catalyst works efficiently in the selective oxidation of sulfides to sulfoxides or sulfones in the presence of H2O2 as a green oxidant. It can easily be separated from the reaction medium by using an external magnet and it was recycled 6 times without loss of magnetic catalytic properties.
- Ghanbari Kermanshahi, Mohammad,Bahrami, Kiumars
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p. 36103 - 36112
(2019/11/20)
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- Efficient molybdenum catalyzed chemoselective, solvent-free oxidation of sulfides to sulfones at room temperature
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An effcient and reusable molybdenum-based catalyst has been prepared by tethering dioxomolybdenumacetylacetonate complex, MoO2(acac)2, via postsynthesis modifcation of zeolite beta. The catalyst has been characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX) and inductively coupled plasma (ICP). The catalyst exhibited very high activity for the selective oxidation of sulfdes to sulfones at room temperature. The catalyst can be recycled and reused four times without signifcant loss of activity.
- Hadigavabar, Ali Dadashi,Tabatabaeian, Khalil,Zanjanchi, Mohammad Ali,Mamaghani, Manouchehr
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p. 3829 - 3833
(2018/05/24)
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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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- Chiral Titanium(IV) Complexes Containing Polydentate Ligands Based on α-Pinene. Catalytic Activity in Sulfoxidation with Hydrogen Peroxide
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The reaction of TiCl4-n(OiPr)n (n = 0, 2, 4) with various terpenoid preligands based on α-pinene, C7H6Me3(OH)(NCH2CH2G) (G = NH2, I; NHMe, II; OH, III), stereoselectively affords a series of new chiral titanium(IV) complexes. Such complexes are either octahedral, [TiCl2X(OC7H6Me3NCH2CH2G-κ3N,N,O)] (X = Cl, G = NH2, 1; X = OiPr, G = NH2, 2; G = NHMe, 3), or trigonal bipyramidal, [Ti(OiPr)3(OC7H6Me3NCH2CH2G-κ2N,O)] (G = NH2, 4; NHMe, 5) and [TiX(OiPr)(OC7H6Me3NCH2CH2O-κ3N,O,O?)] (X = Cl, 6; OiPr, 8), depending on the acidity of titanium, the reaction conditions and the nature of the pendant ending group of the terpenoid ligand. Density functional theory (DFT) calculations have been carried out to assess the stability of the multiple possible diastereoisomers allowing us to propose structural suggestions. The new titanium complexes efficiently catalyze the selective oxidation of various types of sulfides to either sulfoxides or sulfones using aqueous hydrogen peroxide, under mild conditions. All compounds have been characterized by multinuclear NMR spectroscopy and the molecular structure for some of them has been determined by X-ray diffraction.
- Reviejo, Irene,Tabernero, Vanessa,Mosquera, Marta E. G.,Ramos, Javier,Cuenca, Tomás,Jiménez, Gerardo
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p. 3437 - 3449
(2018/10/31)
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- Catalytic Activity of Crystallographically Characterized Organic–Inorganic Hybrid Containing 1,5-Di-amino-pentane Tetrachloro Manganate with Perovskite Type Structure
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Abstract: Layered 2D organic–inorganic hybrid perovskite (OIHS) of the diammonium series, 1,5 di-aminepentane tetrachloro mangenate ([NH3–(CH2)5–NH3] MnCl4) was prepared by slow evaporation and reducing temperature method and characterized by single crystal X-ray diffraction analysis. Its structure consists of organic cation, [NH3(CH2)5NH3]+2 extended in a zigzag fashion and inorganic anion, [MnCl6]?2 where Mn2+ is coordinated by six Cl? ion in octahedral fashion. The organic and inorganic segments are alternately stacked along c-axis where inorganic layer is extended through corner-shared octahedra sandwiched by the di-aminopentane molecules. The layers (organic and inorganic) were connected to each other through N–HCl hydrogen bonds and van-der Waals interaction to build cation–anion–cation cohesion. The hybrid crystal had orthorhombic non-centrosymetric system having I212121 space group with unit cell parameters a = 7.1742(3) ?, b = 7.3817(3) ?, c = 23.9650(10) ?, V = 1269.13 ?3 and Z = 4. The hybrid exhibited excellent catalytic activity towards sulphide and alkene oxidation using aqueous H2O2 as an oxidant. Graphical Abstract: OIHS of the diammonium series [NH3–(CH2)5–NH3] MnCl4; 1,5 di-aminepentane tetrachloro mangenate were prepared by slow evaporation and temperature decrease method, characterized by single crystal X-ray diffraction. This complex exhibits excellent catalytic activity towards sulphide oxidation and alkene oxidation using aqueous H2O2 as an oxidant. [Figure not available: see fulltext.].
- Mondal, Paramita,Abdel-Aal, Seham Kamal,Das, Debasis,Islam, Sk Manirul
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p. 2332 - 2339
(2017/08/22)
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- Catalyst-free oxidation of sulfides to sulfoxides and diethylamine catalyzed oxidation of sulfides to sulfones using Oxone as an oxidant
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Abstract: We describe here our journey from the failure of our attempts in controlled oxidation of sulfides to sulfoxides using an Oxone–KBr combination to our success in the development of a catalyst-free protocol for the oxidation of sulfides to sulfoxides using Oxone as an oxidant. We also describe the failure of our attempts at the oxidation of sulfides to sulfones using an excess of Oxone–KBr as well as Oxone, and our success towards the development of a rapid, scalable and chromatography-free protocol for the oxidation of sulfides to sulfones using diethylamine–Oxone as an unprecedented catalyst–oxidant combination.
- Kupwade,Khot,Lad,Desai,Wadgaonkar
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p. 6875 - 6888
(2017/10/06)
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- 1,1,2,2-Tetrahydroperoxy-1,2-diphenylethane as new oxidant for chemoselective and catalyst free oxidation of sulfides to sulfoxides and sulfones
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A catalyst free and chemoselective oxidation of sulfides to sulfoxides or sulfones was developed using 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane as a new oxidant. This scope has shown the achievement of various sulfoxides and sulfones which were obtained selectively in high yields at room temperature.
- Khosravi, Kaveh,Naserifar, Shirin,Mahmoudi, Boshra,Khalaji, Kobra
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p. 316 - 321
(2017/02/18)
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- A chemoselective oxidation of sulfides to sulfoxides and sulfones using urea-2,2-dihydroperoxypropane as a novel oxidant
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Background: Sulfoxides and sulfones have been in the center of attention due to their wide range of promises in various approaches. The functional groups presented in these compounds serve as important building blocks in numerous natural, pharmeceutical and agricultural compounds. These deriatives have been prepared through a multitude of routes which were accompanied by several drawbacks. Therefore, there has been an ever-increasing interest to find a new methodology that leads to the production of these compounds via an environmentally benign path bringing about high yields. Recently, gem-dihydroperoxides have attracted much attention due to their oxidizing power and they have been utilized in several oxidation processes. Methods: We carried out a chemoselective oxidation of sulfides to sulfoxides and sulfones on treatment with urea-2,2-dihydroperoxypropane, a solid oxidant composed of equal amounts of 2,2-dihydroperoxypropane and urea, using THF as the solvent under catalyst-free conditions at room temprature. Results: Sulfides possessing a variety of substitutions namely dialkyl, diaryl, ally l and alkyl-aryl were subjected to the optimized reaction conditions and they could successfully afford different amounts of sulfoxides and sulfones depending on the amount of the oxidant utilized. Based on the results, electron-donating groups accelerated the reaction while electron-withdrawing substituents lowered the reactivity. Conclusion: Urea-2,2-dihydroperoxypropane as a solid oxidant which can be stored for several months without any loss in its activity has proved its capability to oxidize sulfides to sulfoxides and sulfones under catalyst-free and mild conditions. This approach is a cost-effective and environmentally benign methodology via which the products have been synthesized in high yields and short reaction times.
- Khosravi, Kaveh,Naserifar, Shirin,Asgari, Atefeh
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p. 749 - 756
(2017/02/05)
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- Synthesis and characterization of insoluble cobalt(II), nickel(II), zinc(II) and palladium(II) Schiff base complexes: Heterogeneous catalysts for oxidation of sulfides with hydrogen peroxide
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The condensation reaction of 1,2-bis(2'-aminophenoxy)benzene with 2-pyridinecarbaldehyde in a mole ratio of 1:2 gives a new Schiff base ligand (L). Four Schiff base complexes, CoL(NO3)2 (1), NiLCl2 (2), ZnL(NO3)2 (3) and Pd2LCl4 (4) have been prepared by direct reaction of the ligand (L) and appropriate metal salts. The Schiff base ligand (L) has been characterized by IR, 1H NMR and 13C NMR spectroscopy and elemental analysis. Also, all complexes have been characterized by IR and XRD spectroscopy techniques and elemental analysis. The synthesized complexes have very poor solubility in all polar and non-polar solvents such as: H2O, MeOH, EtOH, CH3CN, DMSO, DMF, CHCl3, CH2Cl2, THF, etc; therefore, they have been used as heterogeneous catalysts. Catalytic performance of the complexes was studied in oxidation of thioanisole using hydrogen peroxide (H2O2) as the oxidant. Various factors including the reaction temperature, amount of oxidant and catalyst amount were optimized. The palladium Schiff base complex, Pd2LCl4 (4), shows better catalytic activity than other complexes. Therefore, the Pd(II) Schiff base complex has been used as a catalyst for oxidation of different sulfides to their corresponding sulfones in acetonitrile with hydrogen peroxide as the oxidant. The palladium Schiff base complex, Pd2LCl4 (4), has shown a very good recyclability, up to five times, without any appreciable decreases in catalytic activity and selectivity.
- Menati, Saeid,Amiri Rudbari, Hadi,Askari, Banafshe,Riahi Farsani, Mostafa,Jalilian, Fariba,Dini, Ghasem
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p. 347 - 356
(2016/04/20)
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- Peroxo-dimolybdate catalyst for the oxygenation of organic sulfides by hydrogen peroxide
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The reaction between Na2MoO4 and hydrogen peroxide at pH around 6.5 resulted in a novel peroxo-dimolybdate anion [{MoO(O2)2}2(μ-O)]2-, which was isolated as a tetrabutylammonium salt (1). X-ray single crystal diffraction study of 1 revealed that there are two η2-peroxo ligands for each Mo center and a single μ-oxo bridge linking two Mo(VI) centers. Compound 1 can function as a stoichiometric oxidant for the oxygenation of organic sulfides and donate up two active oxygen atoms. Furthermore, 1 catalyzes organic sulfide oxygenation by hydrogen peroxide with 100% utility. The catalytic proficiency of 1 was examined with the oxygenation reactions of substrates including benzyl phenyl sulfide, methyl phenyl sulfide and 4-bromo thioanisole with TOF of 240, 550 and 740 h-1, respectively. Based on the initial rate study of several para-substituted thioanisoles, a reactivity constant (ρ) of -1.06 was obtained, which implies an electron deficient transition state. The initial rate study using thioanisole as the substrate also revealed that the reaction is first order in catalyst but zero order in hydrogen peroxide. Based on these results, a mechanism for the activation of hydrogen peroxide is proposed. The DFT calculations of model catalyst and substrate resulted in an activation energy of 75 kJ mol-1 for the transition state, and a reaction free energy of -69 kJ mol-1.
- Thompson, Dylan J.,Cao, Zhi,Judkins, Eileen C.,Fanwick, Phillip E.,Ren, Tong
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p. 103 - 109
(2015/09/15)
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- Diruthenium(II,III) tetracarboxylates catalyzed H2O2 oxygenation of organic sulfides
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Diruthenium(II,III) tetracarboxylates, Ru2(OAc)4Cl (A), Ru2(esp)2Cl (B, esp = tetramethyl-1,3-benzenedipropionate) and Ru2(3-HB)4Cl (C, 3-HB = 3-hydroxybenzoate) were investigated for activating hydrogen peroxide in organic sulfide oxygenation. The speciation of the substrate and potential products, sulfoxide and sulfone, were investigated for each catalyst. With methyl phenyl sulfide as the substrate, A simultaneously produces sulfoxide and sulfone, B yields the highest turnover with complete conversion to sulfoxide at 6 min before sulfone appears, and C facilitates complete conversion to sulfoxide in 20 min but little subsequent conversion to sulfone. The dependence of the initial reaction rate on catalyst and H2O2 concentrations were investigated. A small set of other sulfides were subjected to catalytic reactions with C, and all reactions resulted in near quantitative conversion. Finally, the sulfide oxygenation activity and stability towards hydrogen peroxide of the diphosphonate complex Na4[Ru2(hedp)2(H2O)Cl] (D, hedp = 1-hydroxyethylidenediphosphonate) was investigated, and D was found to be an effective catalyst, which retains its activity over an extended period of time due to its robustness at the (III,III) oxidation state.
- Thompson, Dylan J.,Barker Paredes, Julia E.,Villalobos, Leslie,Ciclosi, Marco,Elsby, Rachel J.,Liu, Bin,Fanwick, Phillip E.,Ren, Tong
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p. 150 - 155
(2015/02/02)
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- Polyoxomolybdate-Calix[4]arene Hybrid: A Catalyst for Sulfoxidation Reactions with Hydrogen Peroxide
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An easily accessible polyoxomolybdate-calix[4]arene hybrid 1 has been synthesized and applied as a heterogeneous catalyst in the sulfoxidation of thioethers to sulfoxides and to sulfones under strictly stoichiometric amounts of 30% H2O2 in CH3CN as the solvent. This study represents the first promising example of successful employment of calixarenes-polyoxometalate (POM) hybrid materials in the area of catalytic oxidations.
- Meninno, Sara,Parrella, Alessandro,Brancatelli, Giovanna,Geremia, Silvano,Gaeta, Carmine,Talotta, Carmen,Neri, Placido,Lattanzi, Alessandra
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supporting information
p. 5100 - 5103
(2015/11/03)
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- Peroxoniobium(v)-catalyzed selective oxidation of sulfides with hydrogen peroxide in water: A sustainable approach
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An efficient and eco-compatible route for the selective oxidation of a variety of thioethers to the corresponding sulfoxide or sulfone with 30% aqueous H2O2 in water, using newly synthesized peroxoniobium (pNb) complexes as catalysts, is described. The catalysts with formulas Na2[Nb(O2)3(arg)]·2H2O (arg = arginate) (NbA) and Na2[Nb(O2)3(nic)(H2O)]·H2O (nic = nicotinate) (NbN) have been synthesized from the reaction of sodium tetraperoxoniobate with 30% H2O2 and the respective organic ligand in an aqueous medium, and these have been comprehensively characterized by elemental analysis, spectral studies (FTIR, Raman, 1H NMR, 13C NMR and UV-vis), EDX analysis and TGA-DTG analysis. The density functional theory (DFT) method has been used to investigate the structure of the synthesized pNb complexes. The catalysts are physiologically safe and can be reused for at least six reaction cycles without losing their activity or selectivity. The oxidation is chemoselective for sulfides or sulfoxides leaving the C=C or alcoholic moiety unaffected. The developed methodologies, apart from being high yielding and straightforward, are completely free from halogen, organic co-solvent, or co-catalysts.
- Gogoi, Sandhya Rani,Boruah, Jeena Jyoti,Sengupta, Gargi,Saikia, Gangutri,Ahmed, Kabirun,Bania, Kusum K.,Islam, Nashreen S.
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p. 595 - 610
(2015/02/02)
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- Selective sulfoxidation with hydrogen peroxide catalysed by a titanium catalyst
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A moisture-tolerant cyclopentadienyl-silsesquioxane titanium complex efficiently catalyses the selective oxidation of various types of sulfides to either sulfoxides (TOFs up to 32 530 h-1) or sulfones with H2O2 (30% in water) under mild conditions.
- Postigo, Lorena,Ventura, Maria,Cuenca, Toms,Jimnez, Gerardo,Royo, Beatriz
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p. 320 - 324
(2015/02/02)
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- Carbon-supported metal-modified lacunary tungstosilicic polyoxometallates used as catalysts in the selective oxidation of sulfides
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Lacunary tungstosilicic polyoxometallates modified with transition metal ions [SiW11O39M(H2O)]6-, where M = Mn2+, Fe2+, Co2+or Cu2+, were synthesized and supported on activated carbon to obtain the SiW11MC catalysts. The samples were characterized by FT-IR, XRD, N2 adsorption-desorption measurements, and the acidic properties were determined using the isopropanol dehydration test reaction. The activity and selectivity of the catalysts were evaluated in the selective oxidation of a series of sulfides to sulfoxides or sulfone. The reaction was carried out in acetonitrile as solvent using H2O2 35% p/V as a clean oxidant. The conversion values decreased in the following order: SiW11MnC > SiW11FeC > SiW11CuC > SiW11CoC. The catalysts were reused without appreciable loss of their catalytic activity. It was found that the activity of the catalysts decreases in parallel with the increment in the reduction temperature values. The most easily reducible catalyst displayed the highest conversion values. We found a convenient and selective procedure for oxidizing sulfides to sulfoxides or sulfones using aqueous hydrogen peroxide and a catalytic amount of lacunary tungstosilicic polyoxometallates supported on carbon at low temperatures (20-50 °C) in a reasonably short reaction time
- Frenzel, Romina,Sathicq, ángel G.,Blanco, Mirta N.,Romanelli, Gustavo P.,Pizzio, Luis R.
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- Epoxidation of alkenes and oxidation of sulfides catalyzed by a new binuclear vanadium bis-oxazoline complex
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Bis(oxazoline) ligand, [2,2′-(1,3-phenylene)bis(oxazole-4,2-diyl)]-dimethanol, derived from dicyanobenzene was applied as ligand for complexation with vanadium.The catalyst was characterized by FT-IR, UV-Vis, 1H NMR spectroscopic methods, CHNS, ICP and thermal analyses, and magnetic susceptibility. The catalytic activity of this complex was then studied in the epoxidation of alkenes with TBHP (tert-butyl hydroperoxide), in acetonitrile. The effect of reaction parameters such as kind of solvent and oxygen donors was studied in the epoxidation of cyclooctene. The catalytic activity of this catalyst was also investigated in the oxidation of sulfides with H2O2 in ethanol and the corresponding sulfoxides and sulfones were produced.
- Javadi, Maedeh Moshref,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah
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p. 477 - 485
(2015/02/05)
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- Cobalt(II), copper(II), zinc(II) and palladium(II) Schiff base complexes: Synthesis, characterization and catalytic performance in selective oxidation of sulfides using hydrogen peroxide under solvent-free conditions
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An asymmetric bidentate Schiff-base ligand (HL: 2-tert-butyliminomethyl-phenol) was prepared from the reaction of salicylaldehyde and tert-butylamine. Cobalt(II), copper(II), zinc(II) and Pd(II) complexes, CoL2, CuL2, ZnL2 and PdL2, were synthesized from the reaction of CoCl2·6H2O, CuCl2·2H2O, Zn(NO3)2·6H2O and PdCl2 with the bidentate Schiff base ligand HL in methanol. The ligand and its metal complexes were characterized by elemental analysis (CHN), FT-IR and UV-Vis spectroscopy. In addition, 1H and 13C NMR techniques were employed for characterization of the ligand (HL) and the diamagnetic complexes (ZnL2 and PdL2). The molecular structures of all the complexes were determined by the single crystal X-ray diffraction technique. The crystallographic data reveal that in all the complexes the metal centers are four-coordinated by two phenolate oxygen and two imine nitrogen atoms of two Schiff base ligands. The geometry around the metal center in the CoL2, CuL2 and ZnL2 complexes is a distorted tetrahedral and for PdL2 it is square-planar. The catalytic activity of these complexes has been evaluated for the selective oxidation of sulfides with the green oxidant 35% aqueous H2O2 under solvent free conditions. For all the catalysts, using optimized reaction conditions, different sulfides were converted to the corresponding sulfones. ZnL2 showed a higher catalytic performance for the oxidation of the different sulfides to the corresponding sulfones.
- Khorshidifard, Mahsa,Rudbari, Hadi Amiri,Askari, Banafshe,Sahihi, Mehdi,Farsani, Mostafa Riahi,Jalilian, Fariba,Bruno, Giuseppe
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- Selective hydrogen peroxide oxidation of sulfides to sulfoxides or sulfones with MWW-type titanosilicate zeolite catalyst under organic solvent-free conditions
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Selective oxidation of sulfides to sulfoxides and sulfones with hydrogen peroxide under organic solvent-free conditions was demonstrated by the MWW-type titanosilicate zeolite catalyst. Sulfides were oxidized smoothly to give sulfoxides with good selectivities at ambient temperature using 1.0-1.2 equiv of hydrogen peroxide with the MWW-type titanosilicate zeolite catalyst. Especially, the Ti-MWW with an interlayer-expanded structure (Ti-IEZ-MWW) catalyst showed high activity with good chemoselectivity for the oxidation of various sulfides. The catalyst is recyclable for at least five cycles, and the only byproduct is water. Sulfides were directly oxidized to give sulfones in high yields by 2.5 equiv of hydrogen peroxide with the MWW-type titanosilicate zeolite catalyst under organic solvent-free conditions.
- Kon, Yoshihiro,Yokoi, Toshiyuki,Yoshioka, Masato,Tanaka, Shinji,Uesaka, Yumiko,Mochizuki, Takehisa,Sato, Kazuhiko,Tatsumi, Takashi
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p. 7584 - 7592
(2014/12/10)
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- Synergistic combination of multi-ZrIV cations and lacunary keggin germanotungstates leading to a gigantic Zr24-cluster- Substituted Polyoxometalate
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Synergistic directing roles of six lacunary fragments resulted in an unprecedented Zr24-cluster substituted poly(polyoxotungstate) Na 10K22[Zr24O22(OH) 10(H2O)2(W2O10H) 2(GeW9O34)4(GeW8O 31)2]·85H2O (Na10K 22·1·85H2O), which contains the largest [Zr24O22(OH)10(H2O)2] (Zr24) cluster in all the Zr-based poly(polyoxometalate)s to date. The most remarkable feature is that the centrosymmetric Zr24-cluster- based hexamer contains two symmetry-related [Zr12O 11(OH)5(H2O)(W2O10H) (GeW9O34)2(GeW8O31)] 16- trimers via six μ3-oxo bridges and was simultaneously trapped by three types of different segments of B-α-GeW9O34, B-α-GeW8O 31, and W2O10. The other interesting characteristic is that there are two pairs of intriguing triangular atom alignments: one is composed of the Zr(2,4,6,8,11) and W21 atoms and the other contains the Ge(1-3), Zr(3,5,7,9,10,12) and W26 atoms, and the Zr5 atom is inside the triangle; a linking mode is unobserved. The oxygenation reactions of thioethers by H2O2 were evaluated when Na 10K22·1·85H2O served as a catalyst. Results show that it is an effective catalyst for oxygenation of thioethers by H2O2. The unique redox property of oxygen-enriched polyoxotungstate fragments and Lewis acidity of the Zr cluster imbedded in Na10K22·1·85H2O provide a sufficient driving force for the catalytic conversion from thioethers to sulfoxides/sulfones.
- Huang, Ling,Wang, Sa-Sa,Zhao, Jun-Wei,Cheng, Lin,Yang, Guo-Yu
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supporting information
p. 7637 - 7642
(2014/06/10)
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- Highly efficient selective oxidation of sulfides to sulfoxides by montmorillonite-immobilized metalloporphyrins in the presence of molecular oxygen
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Highly efficient and selective oxidation of sulfides to sulfoxides with dioxygen catalyzed by cationic meso-tetrakis (1-methyl-4-pyridyl) (TM4PyP) metalloporphyrins immobilized into montmorillonite (MT) interlayer was achieved. Manganese (II) porphyrin (MnTM4PyP-MT) presented excellent activity for the oxidation of sulfides under ambient conditions. In the model oxidation, thioanisole was converted completely and the selectivity towards sulfoxide was up to 95%. This catalyst also showed high activity and selectivity for the most sulfides. The catalyst could be reused consecutively five times without significant loss of activity.
- Zhou, Xian-Tai,Ji, Hong-Bing
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-
- Oxidation of alkenes and sulfides catalyzed by a new binuclear molybdenum bis-oxazoline complex
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A novel bis(oxazoline) ligand derived from 1,3-dicyanobenzene was prepared and applied as a ligand for the preparation of a new binuclear molybdenyl complex. This ligand was characterized by UV-Vis, mass, 1H NMR, and FT-IR spectroscopic methods, thermal and elemental analysis and X-ray diffraction. The molybdenum complex was prepared by the reaction of this ligand with MoO2(acac)2. The catalyst was also characterized by FT-IR, UV-Vis, and ICP spectroscopy, elemental and thermal analysis. This catalytic system was efficiently used for the oxidation of alkenes and sulfides in the presence of TBHP. The effect of different solvents and kind of oxygen donor was also studied in the oxidation reactions.
- Moshref Javadi, Maedeh,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Kargar, Hadi,Tahir, Muhammad Nawaz
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-
- Highly selective and efficient oxidation of sulfides with hydrogen peroxide catalyzed by a chromium substituted Keggin type polyoxometalate
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The catalytic oxidation of sulfides into the corresponding sulfones by a chromium substituted Keggin type polyoxometalate, (TBA)4[PW 11CrO39]·3H2O, was achieved using mild reaction conditions. Excellent yields were obtained using four equivalents of 30% H2O2. Under these reaction conditions, the sulfide group was highly reactive and other functional groups such as hydroxyl or a double bond were unaffected. Using a commercially available, eco-friendly, and cheap oxidant, mild reaction conditions, operational simplicity, practicality, short reaction times, high to excellent yields, and excellent chemoselectivity are some of the advantages of this catalytic system.
- Afrasiabi, Roozbeh,Farsani, Mostafa Riahi,Yadollahi, Bahram
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supporting information
p. 3923 - 3925
(2014/07/08)
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- Solvent free oxidation of sulfides to sulfones by H2O2 in the presence of chromium substituted polyoxometalate as catalyst
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Solvent-free oxidation of sulfides into sulfones by 30% hydrogen peroxide has been achieved using chromium substituted Keggin type polyoxometalate under mild reaction conditions in 94-100% yield. This catalytic system showed excellent activity in the oxidation of sulfide groups. The other active functional groups such as hydroxyl and C=C bond have been tolerated.
- Afrasiabi, Roozbeh,Jalilian, Fariba,Yadollahi, Bahram,Farsani, Mostafa Riahi
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p. 113 - 116
(2015/02/19)
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- Selectivity adjustment of SBA-15 based tungstate catalyst in oxidation of sulfides by incorporating a hydrophobic organic group inside the mesochannels
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A novel heterogeneous catalyst system comprising tungstate ions embedded into the hydrophobic mesochannels of SBA-15 was found to exhibit significant selectivity enhancement in oxidation of sulfides in water or water/CH 3CN using 30% H2O2. Our studies demonstrated that the presence of an n-octyl group in the interior of nanospaces of our catalyst system provides a hydrophobic/hydrophilic region in the mesochannels of the catalyst where the active tungstate species are located and in turn results in at least three distinct important features. First of all, the catalyst comprising the n-octyl group shows much better water tolerance than the catalysts not having hydrophobic organic moieties. Moreover, the nonproductive decomposition of H2O2 was significantly inhibited in the present catalyst system. The present catalyst system also offers an unprecedented selectivity changeover depending on the hydrophobic nature of the initial sulfides and/or the utilized solvent mixture. While high yields and excellent selectivities toward the corresponding sulfoxide were obtained in the oxidation of less hydrophobic sulfides in H2O as a reaction solvent, the selectivity pattern was shifted toward sulfones in the case of using more hydrophobic sulfides as substrates. On the other hand, in CH3CN/ H2O (1:1) as the reaction solvent, almost all of the studied sulfides were selectively oxidized to the corresponding sulfoxide in high yields. On the basis of several compelling observations, we have proposed a synergistic model to explain the origin of the observed selectivities. The catalyst was respectively recovered and reused in five and seven successive reaction runs in water and water/CH3CN, respectively, with only a slight decrease of reactivity.
- Karimi, Babak,Khorasani, Mojtaba
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p. 1657 - 1664
(2013/07/26)
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- Merrifield resin supported peroxomolybdenum(vi) compounds: Recoverable heterogeneous catalysts for the efficient, selective and mild oxidation of organic sulfides with H2O2
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We have generated new heterogeneous catalysts by immobilizing dioxomonoperoxomolybdenum(vi) on amino acid functionalized Merrifield resin, which exhibit excellent activity, stability and selectivity for the oxidation of thioethers and dibenzothiophene (DBT) to the corresponding sulfoxides or sulfones by H2O2 at ambient temperature. The synthetic protocols are high-yielding, halogen-free, environmentally clean and safe, and operationally simple. The catalysts, [MoO2(O2)(L) 2]2--MR [L = valine (MRVMo) or alanine (MRAMo) and MR = Merrifield resin] were prepared by reacting H2MoO4 with 30% H2O2 and the respective amino acid functionalized resin, at near neutral pH. The compounds were characterized by elemental analysis, spectral studies (FTIR, Raman, 13C NMR and 95Mo NMR, diffuse reflectance UV-Vis and XPS), SEM, EDX, XRD, Brunauer-Emmett-Teller (BET) and TGA-DTG analysis. The easy recyclability of the catalysts for several catalytic cycles without change in activity and selectivity, their complete chemoselectivity towards the sulfur group of substrates bearing other oxidation prone functional groups, are important "green" attributes of these catalysts.
- Boruah, Jeena Jyoti,Das, Siva Prasad,Ankireddy, Seshadri Reddy,Gogoi, Sandhya Rani,Islam, Nashreen S.
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p. 2944 - 2959
(2013/10/08)
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- Imidazolium perrhenate ionic liquids as efficient catalysts for the selective oxidation of sulfides to sulfones
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A series of imidazolium perrhenate ionic liquids (IPILs) have been synthesized and used as efficient catalysts for the oxidation of sulfides to sulfones with aqueous hydrogen peroxide under mild conditions. Various sulfones are obtained in good to excellent yields. IPILs are stable and can be reused at least ten times without detectable activity loss. Furthermore, this system provides a reasonably environmentally benign chemical process in terms of potential industrial application.
- Zhang, Bo,Li, Su,Yue, Shuang,Cokoja, Mirza,Zhou, Ming-Dong,Zang, Shu-Liang,Kühn, Fritz E.
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p. 108 - 112
(2013/10/01)
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- TiCl4 hiocarbonyls and oxidation of sulfides in the presence of H2O2
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H2O2 in combination with TiCl4 proved to be a highly reactive reagent system for the desulfurization of thioamide and thioketone derivatives in excellent yields and short reaction times with high purity. Sulfides were also found to undergo oxidation to sulfones under similar reaction conditions. In most cases, these reactions are highly selective, simple, and clean, affording products in high yields and purity.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Shakibaian, Vida,Khaledian, Donya,Yousefi, Behrooz H.
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experimental part
p. 155 - 163
(2012/06/01)
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- Selective oxidation of organic sulfides by mononuclear and dinuclear peroxotungsten(VI) complexes
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Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone could be achieved in high yields at room temperature using mononuclear as well as dinuclear diperoxo complexes of tungsten as oxidants, by a variation of reaction conditions. The compounds could also effectively catalyze oxidation of sulfides by H2O2 to selectively yield sulfone with reasonably good turnover frequency (TOF).
- Das, Siva Prasad,Boruah, Jeena Jyoti,Chetry, Hiran,Islam, Nashreen S.
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experimental part
p. 1163 - 1168
(2012/03/26)
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- New polymer-immobilized peroxotungsten compound as an efficient catalyst for selective and mild oxidation of sulfides by hydrogen peroxide
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A new polymer-bound peroxotungstate(VI) catalyst of the type [W(O) 2(O2)(CN)2]-PAN [PAN = poly(acrylonitrile)] (PANW) has been prepared by reacting H2WO4 with 30% H 2O2 and the macromolecular ligand, PAN at pH 5.0. The compound was characterized by elemental analysis, SEM, EDX, TGA and spectral studies (FTIR and 13C NMR). Clean conversion of a variety of sulfides and dibenzothiophene (DBT) to the corresponding sulfoxide or sulfone, using H2O2 as oxidant, could be achieved in the presence of the heterogeneous catalyst PANW, by a versatile variation of reaction conditions. The reactions proceed under mild conditions to afford the resulting products with impressive turn over frequency (TOF). The catalyst exhibit complete chemoselectivity toward sulfur group of substituted sulfides with other oxidation prone functional groups. Easy regeneration and reusability of the catalyst for at least up to seven catalytic cycles with consistent activity and selectivity is an important attribute of the catalyst.
- Das, Siva Prasad,Boruah, Jeena Jyoti,Sharma, Niharika,Islam, Nashreen S.
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experimental part
p. 36 - 45
(2012/04/17)
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- Polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3): Highly efficient catalyst for chemoselective oxygenation of sulfides to sulfones by H2O2
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A highly efficient method for the oxidation of sulfides to sulfones using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3) in the presence of (35%) hydrogen peroxide has been developed. This procedure cleanly oxidizes dialkyl and alkyl aryl sulfides to the corresponding sulfones in excellent yields at room temperature.
- Mokhtary, Masoud,Lakouraj, Moslem Mansour,Niaki, Masoumeh Rastegar
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experimental part
p. 321 - 326
(2012/03/27)
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- Host (aluminum incorporated mesocellulous silica foam (Al-MCF))-guest (tungsten polyoxometalate) nanocomposite material: An efficient and reusable catalyst for selective oxidation of sulfides to sulfoxides and sulfones
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A green, efficient and selective approach for the oxidation of sulfides to sulfoxides and sulfones with H2O2 at room temperature is reported. The reaction is performed in the presence of tungstophosphoric acid (PW12) supported on an aluminum incorporated mesocellulous silica foam (Al-MCF) (via both: the impregnation and encapsulation methods), as heterogeneous and reusable catalysts. The structural and textural characterizations of these catalysts were done using FTIR, X-ray diffraction, N2 adsorption-desorption and TEM.
- Fazaeli, Razieh,Aliyan, Hamid,Ahmadi, Mohammad Ali,Hashemian, Saeedeh
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- Cyanuric chloride as promoter for the oxidation of sulfides and deoxygenation of sulfoxides
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This Letter discusses the use of cyanuric chloride as an efficient promoter for the chemoselective oxidation of sulfides to the corresponding sulfones in the presence of H2O2 as the terminal oxidant. Sulfoxides were also found to undergo deoxygenation to sulfides with cyanuric chloride and potassium iodide system. The reaction is broad in scope and easy to perform.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Sohrabnezhad, Samira
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experimental part
p. 6420 - 6423
(2011/12/21)
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- Keggin heteropolycompounds as catalysts for liquid-phase oxidation of sulfides to sulfoxides/sulfones by hydrogen peroxide
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H4PMo11VO40, H5PMo 10V2O40 and H9PMo6V 6O40 acids and an acidic pyridinium salt of H 4PMo11VO40 were synthesized. They were characterized by FT-IR and the variations of their acid properties were determined by titration with n-butylamine. They proved to be highly active and selective catalysts for the hydrogen peroxide oxidation of methyl phenyl sulfide to the corresponding sulfoxide or sulfone. The conversion and selectivity results may be explained in terms of the co-existence of acidic and oxidative properties in the catalysts. On the other hand, a convenient catalytic homogeneous procedure has been found to oxidize different sulfides to sulfoxides or sulfones, with 35% aqueous H2O2, using (PyH)H 3PMo11VO40 as catalyst. The oxidation reaction is carried out at room temperature for sulfoxides or 40 °C for sulfones and requires a short time. The sulfoxides or sulfones were obtained with excellent yields by controlling the amount of H2O2.
- Romanelli, Gustavo P.,Villabrille, Paula I.,Cáceres, Cármen V.,Vázquez, Patricia G.,Tundo, Pietro
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p. 726 - 730
(2013/01/09)
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- Cyanuric chloride promoted oxidation of sulfides to sulfoxides or sulfones in the presence of hydrogen peroxide
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Aromatic and aliphatic sulfides are readily oxidized to sulfoxides or sulfones in high yield with 35% hydrogen peroxide in the presence of cyanuric chloride (CC) as an efficient activator. The oxidation of sulfides proceeds at room temperature and the corresponding sulfoxides or sulfones was selectively obtained by controlling the amounts of H2O2 and CC. Various sulfides possessing functional groups such as hydroxyl, methoxy, nitrile, aldehyde and olefinic double bond were successfully and selectively oxidized without affecting sensitive functionalities. [image omitted].
- Lakouraj, Moslem Mansour,Abdi, Hamid,Hasantabar, Vahid
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experimental part
p. 435 - 441
(2012/06/16)
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- TiO2 nanoparticles and Preyssler-type heteropoly acid modified nano-sized TiO2: A facile and efficient catalyst for the selective oxidation of sulfides to sulfones and sulfoxides
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A new and efficient synthetic method has been developed for the selective conversion of sulfides into their corresponding sulfones and sulfoxides using H2O2 in the presence of neat or Preyssler-type heteropoly acid modified nano-sized TiO2 as catalyst, respectively. The reaction was performed at room temperature with quantitative yields. The catalyst is reusable without significant loss of activity for the next oxidation reaction.
- Rahimizadeh, Mohammad,Rajabzadeh, Ghadir,Khatami, Seyed-Mola,Eshghi, Hossein,Shiri, Ali
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scheme or table
p. 59 - 64
(2010/09/04)
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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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- Simple and Friendly Sulfones Synthesis Using Aqueous Hydrogen Peroxide with a Reusable Keggin Molybdenum Heteropolyacid, Immobilized on Aminopropyl-Functionalized Silica
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Keggin molybdenum heteropolyacid (H3PMo12O 40), immobilized on aminopropyl-functionalized silica catalysts, were made using two immobilization methods: incipient wetness and equilibrium adsorption. The material prepared for the equilibrium adsorption technique was found to be a highly efficient, ecofriendly, and recyclable heterogeneous catalyst for the selective oxidation of sulfides to sulfones in excellent yields, under mild reaction condition using 35% w/v aqueous hydrogen peroxide as the oxidant.
- Palermo, Valeria,Romanelli, Gustavo P.,Vazquez, Patricia G.
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scheme or table
p. 3258 - 3268
(2010/04/26)
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