- 33S NMR spectra of sulfonium salts: Calculated and experimental
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33S NMR chemical shifts were calculated by the scaled DFT and EMPI approaches for the fluoride, chloride and bromide of trimethylsulfonium ion (1) and S-methyltetrahydrothiophenium ion (2), in addition to the free cations. Experimental values were obtained for the iodides of 1 (δ +48, CS 2 = 0 ppm) and 2 (δ +95), and were found to agree with the calculated values well within the standard deviation of 35 ppm (3.5% of the shielding range) established in earlier work for a great variety of sulfur compounds. An earlier literature value of δ +750 for the iodide of 2 is therefore to be replaced. Calculations provide a shift of δ +68 for S-methylthianium ion with equatorial methyl, indicating that the reported value of δ +670 for the iodide is also incorrect. Copyright
- Dickinson, L. Charles,Chesnut, Donald B.,Quin, Louis D.
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- Novel cyclic sulfonium-based ionic liquids: Synthesis, characterization, and physicochemical properties
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A new series of ionic liquids composed of three cyclic sulfonium cations and four anions has been synthesized and characterized. Their physicochemical properties, including their spectroscopic characteristics, ion cluster behavior, surface properties, phase transitions, thermal stability, density, viscosity, refractive index, tribological properties, ion conductivity, and electrochemical window have been comprehensively studied. Eight of these salts are liquids at room temperature, at which some salts based on [NO3]- and [NTf2]- ions exhibit organic plastic crystal behaviors, and all the saccharin-based salts display relatively high refractive indices (1.442-1.594). In addition, some ionic liquids with the [NTf2] - ion exhibit peculiar spectroscopic characteristics in FTIR and UV/Vis regions, whilst those salts based on the [DCA]- ion show lower viscosities (34.2-62.6 mPa s at 20°C) and much higher conductivities (7.6-17.6 mS cm-1 at 20°C) than most traditional 1,3-dialkylimidazolium salts.
- Zhang, Qinghua,Liu, Shimin,Li, Zuopeng,Li, Jian,Chen, Zhengjian,Wang, Ruifeng,Lu, Liujin,Deng, Youquan
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- SULFONIUM SALT, ELECTROLYTIC SOLUTION, AND LITHIUM ION SECONDARY BATTERY
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PROBLEM TO BE SOLVED: To provide a sulfonium salt superior in high temperature durability, electrolytic solution and a lithium ion secondary battery. SOLUTION: There is provided a sulfonium salt shown by a chemical formula (1). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0047
(2017/12/01)
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- SULFONIUM SALT, ELECTROLYTIC SOLUTION FOR LITHIUM SECONDARY BATTERY, AND LITHIUM SECONDARY BATTERY THEREWITH
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PROBLEM TO BE SOLVED: To provide a sulfonium salt having low viscosity, electrolytic solution for a lithium secondary battery and a lithium secondary battery. SOLUTION: There is provided a sulfonium salt shown by a chemical formula (1). SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0074
(2018/02/20)
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- Catalytic (asymmetric) methylene transfer to aldehydes
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[Chemical equation presented] An investigation Into the poor activity of sulfides as catalysts for sulfonium-ylide-mediated methylene transfer to aldehydes has indicated that ylide formation is the problematic catalytic cycle step. Alkylation with traditional electrophiles does not proceed with sufficient efficiency to allow the sulfide to be used catalytically. Methyl triflate rapidly alkylates cyclic thiolanes under mild conditions, allowing their use in efficient aldehyde epoxidation reactions (in conjunction with phosphazene bases) at loadings as low as 10 mol %.
- Piccinini, Alessandro,Kavanagh, Sarah A.,Connon, Paul B.,Connon, Stephen J.
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supporting information; scheme or table
p. 608 - 611
(2010/05/18)
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- The unprecedented reaction of dimethylsulfonium methylide with Michael acceptors: Synthesis of 1-substituted vinyl silanes and styrenes
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Rather than the usual cyclopropanation, conditions for an unprecedented elimination reaction from the adduct of dimethylsulfonium methylide and various Michael acceptors have been established leading to functionalized 1-substituted alkenes. In silyl substituted substrates (2a and 2h), where a facile Peterson-type olefination is possible from the adduct; elimination took place instead to give functionalized 1 -substituted vinyl silanes. Aryl substituted Michael acceptors (2b-e, 2g and 2i-k) also underwent a similar kind of olefination to give 1-substituted styrene derivatives with moderate yields along with a side product, which arose by nucleophilic demethylation from the adduct of dimethylsulfonium methylide and arylidene malonates. Hammett studies revealed that selectivity for olefination vs. demethylation increases as the aryl substituent becomes more electron deficient. Alkylidene malonates (2f and 2l) with a β-alkyl substituent did not favour the olefination process. Sequential addition of Michael acceptors and alkyl halides to a mixture of dimethylsulfonium methylide and sodium dimsylate provided olefination followed by alkylation on the active methine group. A mechanistic pathway has been formulated from the studies of a few sulfonium methylides. The Royal Society of Chemistry 2005.
- Date, Sonali M.,Singh, Rekha,Ghosh, Sunil K.
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p. 3369 - 3378
(2007/10/03)
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- Organic-Soluble Lanthanide Nuclear Magnetic Resonance Shift Reagents for Sulfonium and Isothiuronium Salts
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Lanthanide complexes of the formula 4>- (fod, 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione) are effective organic-soluble nuclear magnetic resonance shift reagents for sulfonium and isothiuronium salts.The shift reagent is formed in solution from Ln(fod)3 and Ag(fod) or K(fod).The selection of Ag(fod) or K(fod) in forming the shift reagent is dependent on the anion of the organic salt.Ag(fod) is more effective with halide salts, whereas K(fod) is preferred with tetrafluoroborate salts.Resolution of diastereotopic hydrogen atoms was observed in the shifted spectra of certain substrates.Enantiomeric resolution was obtained in the spectrum of sec-butylisothiuronium chloride with a chiral shift reagent.The reagents can be employed in solvents such as chloroform and benzene.
- Wenzel, Thomas J.,Zaia, Joseph
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p. 562 - 567
(2007/10/02)
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- Aspects of the Chemistry of Dehydromethionine
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Dehydromethionine is shown to be a useful intermediate for the preparation of methyl-labelled methionines via its base-catalysed exchange in methanol or methanol.However, it is not possible to effect stereoselective exchange of protons at C-5 of dehydromethionine using sodiummethoxide-methanol.A complete analysis of the 1H n.m.r. spectrum of dehydromethionine has been achieved by computer-assisted simulation and by comparison with the spectra of 2H-labelled dehydromethionines.Dehydromethionine is converted , by treatment with aqueous sodium hydroxide, mainly into the (S,S)-sulphoxide of methionine.This result can be rationalised by postulating a trigonal bipyramidal intermediate having in-line OH and NH attached to sulphur.Syntheses of stereochemically distinct methionines are described.
- Billington, David C.,Golding, Bernard T.
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p. 1283 - 1290
(2007/10/02)
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