- Magneli-type tungsten oxide nanorods as catalysts for the selective oxidation of organic sulfides
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Selective oxidation of thioethers is an important reaction to obtain sulfoxides as synthetic intermediates for applications in the chemical industry, medicinal chemistry and biology or the destruction of warfare agents. The reduced Magneli-type tungsten oxide WO3?xpossesses a unique oxidase-like activity which facilitates the oxidation of thioethers to the corresponding sulfoxides. More than 90% of the model system methylphenylsulfide could be converted to the sulfoxide with a selectivity of 98% at room temperature within 30 minutes, whereas oxidation to the corresponding sulfone was on a time scale of days. The concentration of the catalyst had a significant impact on the reaction rate. Reasonable catalytic effects were also observed for the selective oxidation of various organic sulfides with different substituents. The WO3?xnanocatalysts could be recycled at least 5 times without decrease in activity. We propose a metal oxide-catalyzed route based on the clean oxidant hydrogen peroxide. Compared to other molecular or enzyme catalysts the WO3?xsystem is a more robust redox-nanocatalyst, which is not susceptible to decomposition or denaturation under standard conditions. The unique oxidase-like activity of WO3?xcan be used for a wide range of applications in synthetic, environmental or medicinal chemistry.
- D?ren, René,Hartmann, Jens,Leibauer, Benjamin,Panth?fer, Martin,Mondeshki, Mihail,Tremel, Wolfgang
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p. 14027 - 14037
(2021/10/19)
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- Accurate Regulating of Visible-Light Absorption in Polyoxotitanate-Calix[8]arene Systems by Ligand Modification
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With use of a macrocyclic polyphenol, tert-butylcalix[8]arene (TBC[8]), as ligands, a series of TBC[8]-stabilized {Ti4O2}clusters, containing penta- and hexacoordinated Ti centers, were synthesized. Such complexes are "core-shell" shaped containing a {Ti4O2} core arranged in a zigzag fashion. While outer walls of the clusters are decorated by deprotonated TBC[8], their upper and lower surfaces can be modified by various O- or N-donor ligands, and the ratio of the penta- and hexacoordinated Ti(IV) centers in the {Ti4O2} core can be precisely regulated from 4:0, to 3:1, to 2:2, to 1:3, and finally to 0:4. The combined coordination of different ligands in the axial direction shows significant influence on the adsorption of the TBC[8]-Ti4 system in the visible-light region, and their absorption edge can be precisely regulated from 600 to 700 nm. The above structural functionalization in the TBC[8]-Ti4 system also tunes their photocatalytic H2 production activities and oxidative desulfurization ability. Thus, for the first time, by confining the polyoxotitanium cluster in macrocyclic molecules, we provide an example of understanding the structure-property relationship of titanium-oxygen materials by ligand modification.
- Liu, Chao,Yang, Xin-Xue,Yi, Xiao-Yi,Yu, Wei-Dong
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- An isotetramolybdate-supported rhenium carbonyl derivative: Synthesis, characterization, and use as a catalyst for sulfoxidation
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A novel isotetramolybdate-supported rhenium carbonyl derivative, [(CH3)4N]4[{Re(CO)3}4(Mo4O16)]·H2O (1), has been successfully synthesized and characterized by single crystal X-ray diffraction crystallography, IR and UV spectroscopy, etc. Results showed that, compound 1 is an efficient catalyst for the oxidation of thioanisole into the corresponding sulfoxide in the presence of hydrogen peroxide with good to excellent conversion (99%) and excellent selectivity (93%). Highly efficient oxygenation of thioanisole can also be achieved with 100% selectivity of sulfone and >99% conversion. Furthermore, optimized conditions were applied to a range of sulfides to obtain the corresponding sulfoxides and sulfones.
- Lu, Jingkun,Ma, Xinyi,Singh, Vikram,Zhang, Yujiao,Ma, Pengtao,Zhang, Chao,Niu, Jingyang,Wang, Jingping
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p. 5279 - 5285
(2018/04/23)
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- The Polyoxovanadate-Based Carboxylate Derivative K6H[VV17VIV12(OH)4O60(OOC(CH2)4COO)8]·nH2O: Synthesis, Crystal Structure, and Catalysis for Oxidation of Sulfides
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The high-nuclearity polyoxovanadate-based carboxylate derivative K6H[VV17VIV12(OH)4O60(OOC(CH2)4COO)8]·nH2O (1) has been successfully synthesized by conventional aqueous methods and structurally characterized. The [VV17VIV12(OH)4O60(OOC(CH2)4COO)8]7- polyanion is built up from three cages: one {VV17(OH)4O44} cage and two identical [(VIV3O6)2(OOC(CH2)4COO)4]8- cages. Of the three cages, the {VV17(OH)4O44} is a purely inorganic polyoxovanadate cluster, whereas each of the [(VIV3O6)2(OOC(CH2)4COO)4]8- cages is a vanadium-based organic-inorganic hybrid cluster framed via four adipate ligands linking simultaneously to two triangular {V3} units. The two [(VIV3O6)2(OOC(CH2)4COO)4]8- cages are covalently attached to the central {VV17(OH)4O44} cage via V-O-V bonds in a linear arrangement, resulting in a {V29}-based hybrid cluster skeleton. The catalytic properties of compound 1 for the oxidation of sulfides by tert-butyl hydroperoxide were investigated, and the result indicates that 1 exhibits excellent catalytic activity for the oxidation of sulfides under mild conditions.
- Wang, Ke,Niu, Yanjun,Zhao, Dongyan,Zhao, Yanxin,Ma, Pengtao,Zhang, Dongdi,Wang, Jingping,Niu, Jingyang
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p. 14053 - 14059
(2017/11/27)
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- Nano-sized mesoporous sodium iron hydroxyphosphate supported gold: An effective catalyst for the oxidation of sulfides
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New nano-sized mesoporous sodium iron hydroxyphosphate (SIHP, Na4.55Fe(PO4)2H0.45O), synthesized by a microemulsion-hydrothermal synthesis method, with supported gold nanoparticles (AuNPs) could be a very effective catalyst for the selective oxidation of sulfides. The results showed that the SIHP material was an excellent catalyst support due to its special structure and the interactions between the AuNPs and the surface hydroxyl groups.
- Liu, Junhua,Liu, Gui,Liu, Cheng,Li, Wenxiu,Wang, Fang
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p. 2055 - 2059
(2016/04/26)
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- Highly selective and efficient oxidation of sulfide to sulfoxide catalyzed by platinum porphyrins
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Two platinum porphyrins, meso-tetramesitylporphyrinatoplatinum and meso-tetrakis(pentaflourophenyl) porphyrinatoplatinum, are explored for catalytic application in the selective oxidation of sulfide to sulfoxide by iodosylbenzene. The obtained overall turnover number of 90,000 in the oxidation of thioanisole in the presence of meso-tetrakis(pentaflourophenyl) porphyrinatoplatinum indicates the pronounced catalytic activity of the platinum porphyrins. Perfect selectivity toward sulfoxide or sulfone also was achieved via stoichiometric control of reactants.
- Alemohammad, Tahereh,Rayati, Saeed,Safari, Nasser
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p. 1279 - 1283
(2016/02/18)
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- Selective oxidation of sulfides and olefins by a manganese (III) complex containing an N,O-type bidentate oxazine ligand
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A new manganese(III) complex [(N-O)2Mn(OAc)] was synthesized using 2-(2'-hydroxyphenyl)-5,6-dihydro-1,3-oxazine (N-O) as a bidentate O, N donor. The complex has been characterized by elemental analysis, IR, UV-vis spectroscopy, and X-ray structure analysis. Oxidation of sulfides and epoxidation of olefins, respectively, to their corresponding sulfoxides and epoxides were conducted by this catalyst using urea hydrogen peroxide as oxidant at room temperature under air. The catalyst is efficient in oxidation reactions giving high yields and selectivities.
- Amini, Mojtaba,Bagherzadeh, Mojtaba,Moradi-Shoeili, Zeinab,Boghaei, Davar M.,Ellern, Arkady,Woo, L. Keith
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p. 464 - 472
(2013/08/24)
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- Iron-catalyzed selective oxidation of sulfides to sulfoxides with the polyethylene glycol/O2 system
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Readily available iron compounds were found to be active catalysts for the selective oxidation of sulfide to sulfoxide with molecular oxygen as the oxidant in polyethylene glycol (PEG). As an indispensable component, PEG had a great promotive effect on the reaction. Notably, high conversion (>99%) along with excellent chemo-selectivity of up to 94% could be attained by using Fe(acac)2 as the catalyst at 100 °C. This methodology was proved to be applicable for the transformation of various aromatic and aliphatic sulfides into the corresponding sulfoxides with high selectivity. PEG is considered to play a crucial role in stablizing the Fe(IV)-oxo species formed in situ which is supposed to be responsible for the sulfide oxidation.
- Li, Bin,Liu, An-Hua,He, Liang-Nian,Yang, Zhen-Zhen,Gao, Jian,Chen, Kai-Hong
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experimental part
p. 130 - 135
(2012/03/26)
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- Factors influencing the catalytic activity of β-tetrabrominated meso-tetra(para-tolyl)porphyrinatomanganese(III) for oxidation of sulfides and olefins with Oxone
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Effect of different reaction parameters on the catalytic activity of β-tetrabrominated meso-tetra(para-tolyl)porphyrinatomanganese(III), MnT(4-CH3P)PBr4(OAc), for oxidation of different sulfides and hydrocarbons with tetra-n-butylammonium hydrogen monopersulfate (TBAHS) has been studied. In oxidation of sulfides, the chemoselectivity of reaction has been significantly changed in THF as the solvent compared with the common organic solvents. Also, using nitrogenous bases bearing electron-withdrawing groups (-Cl or -CN) clearly increased the ratio of sulfoxide to sulfone relative to the electron-donating ones. Catalytic oxidation of olefins with TBAHS was conducted in protic and aprotic solvents and acetonitrile has been found as the best solvent. A significantly large difference was found between the co-catalytic activity of imidazole (ImH) and pyridine in comparison with that observed in dichloromethane. The competitive oxidation of cis- and trans-stilbene suggests the presence of a high valent manganese oxo as well as a six coordinate (ImH)MnT(4-CH3P)PBr4(HSO5) species as the active oxidants in acetonitrile.
- Rayati, Saeed,Zakavi, Saeed,Kalantari, Hossein
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experimental part
p. 131 - 139
(2012/03/22)
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- Nitrogen donor-controlled chemoselectivity of reaction in oxidation of sulfides with tetra-n-butylammonium hydrogen monopersulfate catalyzed by a partially β-brominated meso-tetraphenylporphyrinatomanganese(III) acetate: A clue to the nature of active oxidant
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Highly efficient and rapid oxidation of different sulfides to the corresponding sulfones with tetra-n- butylammonium hydrogen monopersulfate (TBAO) in the presence of catalytic amounts of Mn(TPPBr2)OAc at room temperature is reported. Contrary to other nitrogen donors, using 4-cyanopyridine as co-catalyst leads to an increase in the ratio of sulfoxide to sulfone in the products. Comparison of the chemoselectivity of reaction in the presence of different nitrogen donors as co-catalyst shows the involvement of a high-valent Mn-oxo species as well as the six-coordinate Mn(TPPBr2)(HSO5)(B) (B = nitrogen donors) complex in sulfide oxidation reactions with TBAO.
- Rayati, Saeed,Zakavi, Saeed,Noroozi, Vahid
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experimental part
p. 89 - 95
(2010/10/20)
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- Controlled oxidation of organic sulfides to sulfoxides under ambient conditions by a series of titanium isopropoxide complexes using environmentally benign H2O2 as an oxidant
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Controlled oxidation of organic sulfides to sulfoxides under ambient conditions has been achieved by a series of titanium isopropoxide complexes that use environmentally benign H2O2 as a primary oxidant. Specifically, the [N,N′-bis(2-oxo-3-R1-5-R2- phenylmethyl)-N,N′-bis(methylene-R3)-ethylenediamine]Ti(O iPr)2 [R1 = t-Bu, R2 = Me, R 3 = C7H5O2 (1b); R1 = R2 = t-Bu, R3 = C7H5O2 (2b); R1 = R2 = Cl, R3 = C7H 5O2 (3b) and R1 = R2 = Cl, R 3 = C6H5 (4b)] complexes efficiently catalyzed the sulfoxidation reactions of organic sulfides to sulfoxides at room temperature within 30 min of the reaction time using aqueous H2O 2 as an oxidant. A mechanistic pathway, modeled using density functional theory for a representative thioanisole substrate catalyzed by 4b, suggested that the reaction proceeds via a titanium peroxo intermediate 4c′, which displays an activation barrier of 22.5 kcal mol-1 (ΔG?) for the overall catalytic cycle in undergoing an attack by the S atom of the thioanisole substrate at its σ*-orbital of the peroxo moiety. The formation of the titanium peroxo intermediate was experimentally corroborated by a mild ionization atmospheric pressure chemical ionization (APCI) mass spectrometric technique. The Royal Society of Chemistry 2010.
- Panda, Manas K.,Shaikh, Mobin M.,Ghosh, Prasenjit
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experimental part
p. 2428 - 2440
(2010/06/18)
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- Catalytic oxidation of organosulfides to sulfoxides using two novel Cu(II) and Ni(II) complexes with aqueous H2O2: Effect of TMAO promoter on oxidation of organosulfides
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Two new copper(II) and nickel(II) complexes [Cu(MeOH)(O-NO 2)(L)](NO3)·CH3OH (1) and [Ni(L) 2(NO3)2]·H2O (2) derived from the 4′-(2-thienyl)-2,2′,6′,2″-terpyridine (L) were synthesized. The ligand and complexes were characterized with elemental analysis, 1H and 13C NMR, IR spectroscopy and finally the solid structure of complexes were determined by X-ray crystallography. Complexes (1) and (2) were tested as homogenous catalysts for sulfoxidation of a variety of organosulfide substrates utilizing hydrogen peroxide in the presence of a catalytic amount of trimethylamine N-oxide (TMAO). Addition of TMAO to the reaction mixture enhanced the conversion and selectivity.
- Kharat, Ali Nemati,Bakhoda, Abolghasem,Hajiashrafi, Taraneh
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scheme or table
p. 94 - 99
(2011/02/23)
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- Observed and calculated 1Hand 13C chemical shifts induced by the in situ oxidation ofmodel sulfides to sulfoxides and sulfones
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A series of model sulfides was oxidized in the NMR sample tube to sulfoxides and sulfones by the stepwise addition of meta-chloroperbenzoic acid in deuterochloroform. Various methods of quantum chemical calculations have been tested to reproduce the observed 1H and 13C chemical shifts of the starting sulfides and their oxidation products. It has been shown that the determination of the energy-minimized conformation is a very important condition for obtaining realistic data in the subsequent calculation of the NMR chemical shifts. The correlation between calculated and observed chemical shifts is very good for carbon atoms (even for the 'cheap' DFT B3LYP/6-31G* method) and somewhat less satisfactory for hydrogen atoms. The calculated chemical shifts induced by oxidation (the δd values) agree even better with the experimental values and can also be used to determine the oxidation state of the sulfur atom (-S-, -SO-, -SO2 -). Copyright
- Dracinsky, Martin,Pohl, Radek,Slavetinska, Lenka,Budesinsky, Milos
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experimental part
p. 718 - 726
(2011/05/15)
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- Selective oxidation of sulfides to sulfoxides and sulfones using n-butyltriphenylphosphonium dichromate (BunPPh3) 2Cr2O7 in the presence of aluminium chloride in solution and under microwave irradiation
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A wide variety of sulfides are efficiently oxidized to their corresponding sulfoxides and sulfones in excellent yields using n-butyltriphenylphosphonium dichromate (BTPPDC) in the presence of aluminium chloride in acetonitrile solution and under microwave irradiation. In addition, selective oxidation of sulfides in the presence of functional groups such as a carbon-carbon double bond, ketone, oxime, aldehyde, ether, and acetal can be considered as a noteworthy advantage of this method. Copyright Taylor & Francis Inc.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid Reza,Bahrami, Kiumars,Esmayilpour, Karim
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p. 2751 - 2766
(2007/10/03)
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- 3-Carboxypyridinium chlorochromate - aluminium chloride - An efficient and inexpensive reagent system for the selective oxidation of sulfides to sulfoxides and sulfones in solution and under microwave irradiation
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3-Carboxypyridinium chlorochromate (CPCC) in the presence of aluminium chloride is a very efficient reagent for the selective oxidation of sulfides to sulfoxide and sulfones in solution and under microwave irradiation. It is noteworthy that different functional groups including carbon-carbon double bonds, ketones, oximes, aldehydes, ethers, and acetals were tolerated under these reaction conditions.
- Mohammadpoor-Baltork, Iraj,Memarian, Hamid R.,Bahrami, Kiumars
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p. 115 - 121
(2007/10/03)
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- Mechanisms of hydrogen-, oxygen-, and electron-transfer reactions of cumylperoxyl radical
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Rates of hydrogen-transfer reactions from a series of para-substituted N,N-dimethylanilines to cumylperoxyl radical and oxygen-transfer reactions from cumylperoxyl radical to a series of sulfides and phosphines have been determined in propionitrile (EtCN) and pentane at low temperatures by use of ESR. The observed rate constants exhibit first-order and second-order dependence with respect to concentrations of N,N-dimethylanilines. This indicates that the hydrogen- and oxygen-transfer reactions proceed via 1:1 charge-transfer (CT) complexes formed between the substrates and cumylperoxyl radical. The primary kinetic isotope effects are determined by comparing the rates of N,N-dimethylanilines and the corresponding N,N-bis(trideuteriomethyl)anilines. The isotope effect profiles are quite different from those reported for the P-450 model oxidation of the same series of substrates. Rates of electron-transfer reactions from ferrocene derivatives to cumylperoxyl radical have also been determined by use of ESR. The catalytic effects of Sc(OTf)3 (OTf = triflate) on the electron-transfer reactions are compared with those of Sc(OTf)3 on the hydrogen- and oxygen-transfer reactions. Such comparison provides strong evidence that the hydrogen- and oxygen- transfer reactions of cumylperoxyl radical proceed via a one-step hydrogen atom and oxygen atom transfer rather than via an electron transfer from substrates to cumylperoxyl radical.
- Fukuzumi, Shunichi,Shimoosako, Kanji,Suenobu, Tomoyoshi,Watanabe, Yoshihito
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p. 9074 - 9082
(2007/10/03)
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- Reactions of chlorine dioxide with organic compounds: Selective oxidation of sulfides to sulfoxides by chlorine dioxide
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A novel method for the selective oxidation of various types of sulfides to sulfoxides using chlorine dioxide as the oxidant is proposed.
- Kutchin,Rubtsova,Loginova
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p. 432 - 435
(2007/10/03)
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- Oxidation of organic sulphides by heteropolyvanadomolybdate-hydrogen peroxide system
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The reactivity of unsubstituted and V/Ti substituted heteropoly compounds for the homogeneous oxidation of organic sulphide has been evaluated and the results are compared with those obtained for substituted silicalites.
- Viswanathan, B.,Athilakshmi
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p. 1186 - 1188
(2007/10/03)
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- Nature of 2?/1?* Three-Electron-Bonded Chlorine Adducts to Sulfoxides
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Reaction of sulfoxide radical cations, R2SO.+, with chloride ions in acidic aqueous solutions (pH * electron.The same species is formed upon oxidation of sulfoxides by Cl2*, although only with relatively low rate constants.The measured λmax are 390, 400, and 410 nm for the R2SO...Cl species with R = Me, Et, and n-Pr, respectively.Equilibrium constants for R2SO.+ + Cl- R2SO...Cl have been determined to be 560, 600, and 575 M-1, for the same respective series of species (error limit +/- 20percent).It is considered that our three-electron-bonded species is identical with an electronically not further specified chlorine-atom adduct to sulfoxide, R2SO(Cl)., observed earlier in sulfoxide-containing solutions of carbon tetrachloride and dichloromethane.The R2SO...Cl exhibit oxidizing properties and are shown to oxidize, for example organic sulfides and disulfides (rate constants on the order of 108 M-1 s-1) or SCN- (rate constants on the order of 109 M-1 s-1).The optical and kinetic results are discussed in light of the electronic properties of the radical species.
- Kishore, Kamal,Asmus, Klaus-Dieter
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p. 7233 - 7239
(2007/10/02)
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- Radical Cations from One-electron Oxidation of Aliphatic Sulphoxides in Aqueous Solution. A Radical Chemical Study
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Sulphoxide radical cations, (R2SO)+., have been observed upon one-electron oxidation of simple aliphatic sulphoxides by strongly oxidizing radicals with redox potentials >/=+2 V, e.g.SO4-., (CH3I)+., (CH3IICH3)+, or Ti2+ in pulse-irradiated aqueous solutions.They exhibit optical absorptions in the u.v. with λmax depending on the substituent (e.g. 300, 320, and 330 nm for R=Me, Et, and Pr, respectively).Extinction coefficients are of the order of 103 mol-1dm-3cm-1.The sulphoxide radical cations exist only at low pH and are probably best formulated in terms of an adduct with one water molecule, (R2SOOH2)+.The pK values for the equilibrium (R2SOOH2)+R2SO(OH). + H+ have been estimated to be 5.6, 6.1, and 6.5, for R=Me, Et, and Pr, respectively, from yield measurements.The neutral R2SO(OH). is identical with the hydroxyl radical adduct to sulphoxides formed at any pH in the reaction of R2SO + .OH, and decays irreversibly into R. + RSO2- + H+.The sulphoxide radical cationsare very good oxidants.Absolute rate constants have been measured for their reactions with a variety of electron donors, namely, organic sulphides, dithia compounds, disulphides, Br-, I-, and SCN-.The optical and kinetic results are discussed in the light of the electronic properties of the radical species.
- Kishore, Kamal,Asmus, Klaus-Dieter
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p. 2079 - 2084
(2007/10/02)
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- Mechanism of the Reaction of Dialkyl Sulphides with Bromamine T in Alkaline Medium
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Bromamine T (p-MeC6H4SO2NBr-K+) reacts readily with dialkyl sulphides (R2S) to yield sulphoxides (R2SO) and sulphimides (R2SNTs).The kinetics of the reaction were investigated in buffered alkaline water-methanol solutions.In rate-determining steps HOBr and p-MeC6H4SO2NHBr formed in equilibrium reactions convert dialkyl sulphides into bromosulphonium (R2SBr+) intermediates (ρ* -1.22 and 1.11, ρI -13.3 and -14.4, respectively.).Electrophilic additions of Br+ to sulphur atom are significantly hindered by the steric effect of S-alkyl groups (δ 0.713 and 0.765, ρs 0.766 and 0.792, respectively).Products are rapidly formed from bromosulphonium ions by nucleophilic displacement with OH- and p-MeC6H4SO2NH- nucleophiles.Product distribution depends on pH and the concentration of p-MeC6H4SO2NH2 but is not influenced markedly by S-alkyl groups in sulphides.Results are compared with those obtained earlier for chloramine T.
- Ruff, Ferenc,Kucsman Arpad
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p. 1075 - 1080
(2007/10/02)
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