2976-30-9Relevant articles and documents
Kinetic studies on the oxidation of aryl methyl sulfides and sulfoxides by dimethyldioxirane; Absolute rate constants and activation parameters for 4-nitrophenyl methyl sulfide and sulfoxide
Hanson, Peter,Hendrickx, Ramon A. A. J.,Lindsay Smith, John R.
, p. XX762-771 (2008)
The oxidations of methyl 4-nitrophenyl sulfide and sulfoxide by dimethyldioxirane, in acetone and mixtures of acetone with water, methanol, acetonitrile and hexane, have been followed by UV-Vis spectroscopy to monitor the decay of the substrates. The data show that, under all the conditions studied, both oxidations obey second-order kinetics. Grunwald-Winstein and Kamlet-Taft analyses of the influence of solvents on the second-order rate constants have been used to obtain mechanistic information on the two reactions. Activation parameters for the two oxidations in acetone and aqueous acetone have been calculated from rate constants for reactions in the temperature range 283-313 K and compared with those from sulfide and sulfoxide oxidations with other oxidants. For sulfoxide oxidations in acetone and 1-20% v/v water in acetone, the results support a concerted nucleophilic displacement by sulfur of oxygen from dimethyldioxirane with the rate being dependent on the solvent's polarity. Sulfide oxidations in acetone and 1-5% v/v water in acetone also proceed by a concerted mechanism. However, in the most polar solvent system studied, 20% v/v water in acetone, the mechanism changes in favour of a two-step reaction involving a betaine intermediate. Importantly, the sulfide oxidation shows a different solvent dependence to that of the sulfoxide, with the rate of oxidation being determined by the hydrogen bond donor capacity and electron-pair donicity of the solvent. This journal is The Royal Society of Chemistry.
Alkylimidazolium/alkylpyridinium octamolybdates catalyzed oxidation of sulfides to sulfoxides/sulfones with hydrogen peroxide
Ye, Jin-Xin,Wang, Jing-Yun,Wang, Xin,Zhou, Ming-Dong
, p. 1 - 3 (2016)
β-Mo8O26 based alkyl imidazolium and pyridinium salts of general formula [Bmim]4Mo8O26 (Bmim = 1-butyl-3-methylimidazolium), [Hmim]4Mo8O26 (Hmim = 1-hexyl-3-methylimidazolium), [Dhmim]4Mo8O26 (Dhmim = 1.2-dimethyl-3-hexylimidazolium) and [Hpy]4Mo8O26 (Hpy = 1-hexylpyridinium) have been used as catalysts for the oxidation of sulfides using 30% hydrogen peroxide as oxidant. The examined β-Mo8O26 salts prove to be highly active and are self-separating. A high selectivity towards either sulfoxides or sulfones can be nicely controlled by variation of the reaction conditions. In both cases, the catalysts can be recycled and reused for several times without significant loss of activity, representing a good stability of the catalysts.
Haloperoxidase activity of oxovanadium(V) thiobisphenolates
Werncke, C. Gunnar,Limberg, Christian,Knispel, Christina,Metzinger, Ramona,Braun, Beatrice
, p. 2931 - 2938 (2011)
By employing the 2,2′-thiobis(2,4-di-tert-butylphenolate) ligand (SL2-) a novel oxovanadium(V) complex, (PPh 4)2[SLV(O)(μ-O)2-O) 2V(O)SL] (1), was synthesised that exhibits haloperoxidase activity: on addition of H2O2 a sequence of successive peroxide formation and intramolecular thioether oxidation events (sulfoxide and sulfone) led to a mixture of five products, which were all identified unambiguously, partly through an independent synthesis and characterisation. It was shown that internal thioether oxidation proceeds through peroxide formation, but the sulfoxidation of external thioether functions requires further activation of the peroxide function by protons or alkyl cations. Consistently, the employment of tBuOOH instead of H2O2 led to a very active system for the catalytic sulfoxidation of thioethers.
Molybdenum-doped α-MnO2 as an efficient reusable heterogeneous catalyst for aerobic sulfide oxygenation
Uematsu, Tsubasa,Miyamoto, Yumi,Ogasawara, Yoshiyuki,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
, p. 222 - 233 (2016)
Oxygenation of sulfides to sulfoxides and/or sulfones is an important transformation, and the development of efficient heterogeneous catalysts for oxygenation, which can utilize O2 as the terminal oxidant, is highly desired. In this study, we have successfully developed manganese oxide-based efficient heterogeneous catalysts for aerobic oxygenation of sulfides. Firstly, we prepared four kinds of manganese oxides possessing different crystal structures, such as α-MnO2, β-MnO2, γ-MnO2, and δ-MnO2, and their structure-activity relationships were examined for the aerobic oxygenation of thioanisole. Amongst them, α-MnO2 showed the best catalytic performance for the oxygenation. Moreover, α-MnO2 was highly stable during the catalytic oxygenation possibly due to the tunnel K+ ions. In order to further improve the catalytic performance of α-MnO2, substitutional doping of transition metal cations, such as Mo6+, V5+, Cr3+, and Cu2+, into the framework was carried out. Undoped α-MnO2 possessed a fibrous morphology. When high-valent transition metal cations were doped, especially Mo6+, the lengths of the fibers drastically shortened to form grain-like aggregates of ultrafine nanocrystals, resulting in an increase in specific surface areas and the numbers of catalytically active surface sites. In the presence of Mo6+-doped α-MnO2 (Mo-MnO2), various kinds of sulfides could efficiently be oxidized to the corresponding sulfoxides as the major products. The observed catalysis was truly heterogeneous, and Mo-MnO2 could repeatedly be reused while keeping its high catalytic performance. Besides sulfide oxygenation, Mo-MnO2 could efficiently catalyze several aerobic oxidative functional group transformations through single-electron transfer oxidation processes, namely, oxygenation of alkylarenes, oxidative α-cyanation of trialkylamines, and oxidative S-cyanation of benzenethiols.
Oxidation of aryl methyl sulfoxides by oxo(salen)manganese(V) complexes and the reactivity-selectivity principle
Chellamani, Arunachalam,Kulanthaipandi, Periasamy,Rajagopal, Seenivasan
, p. 2232 - 2239 (1999)
The oxidation of various para-substituted phenyl methyl sulfoxides with several substituted oxo(salen)manganese(V) complexes follows an overall second-order kinetics that is first-order in sulfoxide and in oxo(salen)manganese(V) complex. Electron-releasing substituents in sulfoxides and electron-withdrawing substituents in oxo(salen)manganese(V) complexes enhance the rate of oxidation. The less nucleophilic sulfoxides are more sensitive to substituent effect (p = -2.44) compared to the corresponding sulfides (p = -1.86). These results are interpreted with a common mechanism involving the electrophilic attack of the oxidant on the sulfur center of the substrate. Correlation analyses show the presence of an inverse relationship between reactivity and selectivity in the reactions of various sulfoxides with a given oxo(salen)manganese(V) complex and vice versa. Mathematical treatment of the results leads to the conclusion that this redox system falls under strong reactivity-selectivity principle.
A Novel and Efficient Method for Oxidizing Sulfides to Sulfones with the HOF*CH3CN System
Rozen, Shlomo,Bareket, Yifat
, p. 2099 - 2100 (1994)
The HOF*CH3CN complex, made directly by passing fluorine through aqueous acetonitrile, oxidizes all types of sulfides to the corresponding sulfones and also offering a way to make 18O containing sulfone derivatives.
Discovery of a New Family of Polyoxometalate-Based Hybrids with Improved Catalytic Performances for Selective Sulfoxidation: The Synergy between Classic Heptamolybdate Anions and Complex Cations
Zhang, Yin,Yu, Wei-Dong,Li, Bin,Chen, Zheng-Fan,Yan, Jun
, p. 14876 - 14884 (2019)
A series of functional cation-regulated isopolymolybdate-based organic-inorganic hybrid compounds, Na2H2[Mo4O12(C8H17O5N)2]·10H2O (1), Na2[M(Bis-tris)(H2O)]2[Mo7O24]·10H2O [M = Cu, 2; Ni, 3; Co, 4; Zn, 5; Bis-tris = 2,2-Bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol], and (NH4)2[M(Bis-tris)(H2O)]2[Mo7O24]·6H2O (M = Zn, 6; Cu, 7), were synthesized and characterized toward advanced molecular catalyst design. Compound 1 is a covalently bonded adduct, and its self-assembly process can be probed by electrospray ionization mass spectrometry (ESI-MS). Compounds 2-7 are polyoxometalate (POM)-based hybrids containing classic heptamolybdate anions and complex cations with Bis-tris ligands. All of these compounds showed remarkable catalytic effects for selective sulfide oxidation. To the best of our knowledge, compound 5 presents the best catalytic activity so far among the reported hybrid materials with common easily synthesized small-molecule POM clusters and also exhibits outstanding reliability. The conclusion of the catalytic effect is drawn from the results that Zn-based compounds have better catalytic effects than other transition-metal-containing compounds and the compound constructed by Na+ has higher catalytic activity than that constructed by NH4 +. The mechanism studies show that the improvements of the catalytic performance are caused by the synergy between classic heptamolybdate anions and complex cations. ESI-MS data and UV-vis spectra revealed that the POM anions can form intermediate peroxomolybdenum units during catalytic reaction. Further, the combination of the substrate thioanisole with complex cations was characterized by NMR experiments and UV-vis spectra. Thus, a new synergistic mechanism of anions and cations is proposed in which the activated thioanisole is used as a nucleophile to attack the peroxomolybdenum bonds, and this provides a new strategy in the design of reliable POM-based catalysts.
Chemistry of Oxaziridines. 7. Kinetics and Mechanism of the Oxidation of Sulfoxides and Alkenes by 2-Sulfonyloxaziridines. Relationship to the Oxygen-Transfer Reactions of Metal Peroxides
Davis, Franklin A.,Billmers, Joanne M.,Gosciniak, Donald J.,Towson, James C.,Bach, Robert D.
, p. 4240 - 4245 (1986)
A kinetic investigation of the oxidation of sulfoxides to sulfones and the epoxidation of 1-methylcyclohexene by a series of aryl-substituted 2-sulfonyloxaziridines, 5 and 9, are described.On the basis of linear free energy relationships and a qualitative frontier molecular orbital analysis, an SN2-type mechanism is proposed that involves displacement of a substituted sulfonylimine from the oxaziridine functional group by the lone pair on the sulfur or the ?-bond of the alkene.The reaction rates are subject to both steric and electronic effects with only a minor amount of negative charge residing on the leaving group.The relationship and similarity of oxygen-transfer mechanisms for 2-sulfonyloxaziridines, metal peroxides such as the Sharpless reagent, dioxiranes, and peracids is discussed.
Fluorous biphasic catalytic oxidation of sulfides by molecular oxygen/2,2-dimethylpropanal
Colonna, Stefano,Gaggero, Nicoletta,Montanari, Fernando,Pozzi, Gianluca,Quici, Silvio
, p. 181 - 186 (2001)
The use of perfluoroalkyl-substituted cobalt complexes as catalysts for the oxidation of alkyl aryl sulfides with molecular oxygen/2,2-dimethypropanal has been studied in a fluorous organic biphasic system. The addition of very small amounts of a Co11-tetraarylporphyrin (Co-4) led to increased substrate conversions (67-100%). Sulfoxide was generally obtained as the main product, together with variable quantities of sulfone (0-100%), depending on the nature of the substrate. A perfluoroalkyl-substituted Co11-phthalocyanine (Co-6) proved to be less efficient with regard to substrate conversion (40-78%), but afforded sulfoxides selectively. Although the mechanism has not been investigated in detail, the reaction probably proceeds through a free-radical oxidative process, initiated by the Co11 complexes. The attempts at recycling the catalysts through phase separation were partly ineffectual owing to their instability under the reaction conditions, which is more pronounced in the case of Co-6.
Electron transfer reactions of organic sulfoxides with photochemically generated ruthenium(III)-polypyridyl complexes
Ganesan, Muniyandi,Sivasubramanian, Veluchamy Kamaraj,Rajagopal, Seenivasan,Ramaraj, Ramasamy
, p. 1921 - 1929 (2004)
The electron transfer (ET) reaction of aryl methyl sulfoxides with ruthenium(III)-polypyridine complexes is sensitive to the change of substituent in the aryl moiety of ArS(O)CH3 and ligand of Ru(III) complex. The detection of sulfoxide radical cation as the transient by conventional flash photolysis confirms ET in the rate-controlling step. The successful application of Marcus cross relation of ET leads to the evaluation of self-exchange rate constant of ArS+(O)CH3/ArS(O)CH3 as 4.0×105M-1s-1 similar to organic sulfides. Comparison with the reactivity of iron(III)-polypyridyl complexes points out that both reactivity and ρ values are higher with Ru(III) complexes.
