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.
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.
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.
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.
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.
Organosulfur oxidation by hydrogen peroxide using a dinuclear Mn-1,4,7-trimethyl-1,4,7-triazacyclononane complex
Smith, John R. Lindsay,Murray, Jane,Walton, Paul H.,Lowdon, Terry R.
, p. 2005 - 2008 (2006)
A mechanistic study of organosulfide oxidation by H2O 2, using a dinuclear manganese complex as the catalyst, has revealed an unusual switch in the philicity of the oxidant for the first and the second oxygen transfer steps; this switch has been exploited to tune selectivity for each of the products.
Electron transfer reactions of iron(III)-polypyridyl complexes with organic sulfoxides
Adaikalasamy, Kulandai John,Venkataramanan, Natarajan Sathiyamoorthy,Rajagopal, Seenivasan
, p. 3613 - 3619 (2003)
The redox reactions of four iron(III)-polypyridyl complexes with six aryl methyl sulfoxides have been investigated by spectrophotometric technique. The reaction follows clean second order kinetics and proceeds through rate determining electron transfer (ET) from organic sulfoxides to iron(III). The Marcus cross-reaction relation has been applied to obtain the self exchange rate constant for the ArSOR/ArS·+(O)R couple as 1.3×107M-1s-1. The application of Marcus theory to this ET reaction shows that the contribution of inner sphere reorganization energy is 0.4eV. The rate constant and reaction constant values observed with organic sulfoxides are small compared with organic sulfides towards the same oxidant Fe(NN)33+.
Two Ce3+-Substituted Selenotungstates Regulated by N, N-Dimethylethanolamine and Dimethylamine Hydrochloride
Li, Hai-Lou,Lian, Chen,Chen, Li-Juan,Zhao, Jun-Wei,Yang, Guo-Yu
, p. 8442 - 8450 (2019)
Two multi-Ce3+-substituted selenotungstates (STs), [HDMEA][H2N(CH3)2]4H3Na4[Ce2(H2O)6(DMEA)W4O9(α-SeW9O33)3]·26H2O (1) and [H2N(CH3)2]10H4Na10[Ce2W4O9(H2O)7(α-SeW9O33)3]2·63H2O (2), were prepared by the one-pot approach of sodium tungstate, sodium selenite, and lanthanide nitrate in an acidic water solution in the presence of N,N-dimethylethanolamine (DMEA) or dimethylamine hydrochloride (DMAHC). 1 was obained in the presence of DMEA, whereas 2 was synthesized in the presence of DMAHC. The trimeric polyoxoanion of 1 contains an unusual V-shaped [Se3W29O103]20- group embracing a prominent heterometal oxide fragment, [Ce2(H2O)6(DMEA)W2O5]8+, and the hexameric polyoxoanion of 2 is constructed from two equivalent trimeric [Ce2W4O9(H2O)7(SeW9O33)3]2 24- subunits through two -O-W-O-Ce-O- linkages. The most worthy of attention is that the polyoxoanion of 1 can be approximatively viewed as a half of the polyoxoanion of 2 because of the coordination and blocking effect of DMEA. The stability of 1 and 2 in different water pH values was studied by electrospray ionization mass spectroscopy (ESI-MS), and the results manifest that 1 and 2 are stable in pH = 3.5-7.5 and 3.5-7.0, respectively. The oxidation reactions of aromatic sulfides catalyzed by H2O2 were studied when 1 or 2 worked as a catalyst, and experimental results reveal that 1 or 2 can serve as available catalysts for the oxidation of aromatic sulfides under mild conditions.
High Chemoselectivity in the Construction of Aryl Methyl Sulfones via an Unexpected C-S Bond Formation between Sulfonylhydrazides and Dimethyl Phosphite
Liu, Teng,Yu, Shiwen,Shen, Xiang,Li, Yixian,Liu, Jianjun,Huang, Chao,Cheng, Feixiang
, p. 153 - 160 (2021/10/04)
A highly chemoselective route to aryl methyl sulfones via an unexpected C S bond formation between sulfonylhydrazides and dimethyl phosphite catalyzed by NaI under mild conditions has been established. This transformation provides an alternative and metal-free pathway to acquire various aryl methyl sulfones in good to excellent yields. Notably, dimethyl phosphite was employed as a stable and readily available alkyl source.
Sulfoxide and Sulfone Synthesis via Electrochemical Oxidation of Sulfides
Lee, Sunwoo,Park, Jin Kyu
, p. 13790 - 13799 (2021/10/12)
The oxidation of diaryl sulfides and aryl alkyl sulfides to the corresponding sulfoxides and sulfones under electrochemical conditions is reported. Sulfoxides are selectively obtained in good yield under a constant current of 5 mA for 10 h in DMF, while sulfones are formed as the major product under a constant current of 10 or 20 mA for 10 h in MeOH. The oxygen of both the sulfoxide and sulfone function is derived from water.
A μ-AsO4-Bridging Hexadecanuclear Ni-Substituted Polyoxotungstate
Lian, Chen,Li, Hai-Lou,Yang, Guo-Yu
, p. 3996 - 4003 (2021/04/07)
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.
