Trimethylsulfonium
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| Names | |
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| Other names
Trimesium
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C3H9S+ | |
| Molar mass | 77.17 g/mol |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Trimethylsulfonium (systematically named trimethylsulfanium and trimethylsulfur(1+)) is an organic cation with the chemical formula (CH3)3S+ (also written as C
3H
9S+
). It is the simplest sulfonium cation.
Compounds
Several salts of trimethylsulfonium are known:
| Salt | Molecular formula | Chemical formula | Molecular weight (g/mol) | Properties[1] |
|---|---|---|---|---|
| Trimethylsulfonium chloride | (CH3)3SCl | C3H9ClS | 112.5 | Colorless crystals, decompose at 100 °C, very soluble in ethanol, very hygroscopic.[2] |
| Trimethylsulfonium bromide | (CH3)3SBr | C3H9BrS | 157 | Colorless crystals from H2O. Decomposes at 172 °C, melts in a sealed tube at 201-201 °C, reacts in neutral aqueous solution.[3] |
| Trimethylsulfonium iodide | (CH3)3SI | C3H9IS | 204 | Colorless crystals from ethanol, decomposes at 203-207 °C.[3][4] crystal structure monoclinic a=5.94 b=8.00 c=8.92 μm β=126°32′ 2 formulas per unit cell density=1.958[5] |
| Trimethylsulfonium tetrafluoroborate | (CH3)3SBF4 | C3H9BF4S | 163.97 | mp 205-210°[6] |
| Trimethylsulfonium methylsulfate | (CH3)3SSO4CH2 | C4H12O4S2 | 188.27 | mp 92-94°[7] Crystal structure orthorhombic a=12.6157 b=8.2419 μm c=7.540 cell volume 784.0 2 formulas per unit cell |
Preparation
Sulfonium compounds can be synthesised by treating a suitable alkyl halide with a thioether. For example, the reaction of dimethyl sulfide with iodomethane yields trimethylsulfonium iodide:
- CH3–S–CH3 + CH3–I → (CH3)3SI
Related
An extra oxygen atom can bond to the sulfur atom to yield the trimethylsulfoxonium ion.
Use
Glyphosate herbicide is often supplied as a trimethylsulfonium salt. When mixed with aluminium bromide, or aluminium chloride or even hydrogen bromide, trimethylsulfonium bromide forms an ionic liquid, which melts at temperatures below standard conditions.[8]
References
- ^ Heilbron's Dictionary of Organic Compounds, volume 4, revised edition published in 1953. Published in Great Britain
- ^ Blättler, H. (1919). "Über Trimethylsulfoniumverbindungen". Monatshefte für Chemie und verwandte Teile anderer Wissenschaften. 40 (8): 417–429. doi:10.1007/BF01559085.
- ^ a b Steinkopf, W.; Müller, S. (1923). "Über die Einwirkung von Jodmethyl auf Disulfide". Chem. Ber. 56 (8): 1926–1930. doi:10.1002/cber.19230560834.
- ^ Mussgnug, F. (1941). "Trimethylammoniumjodid und Trimethylsulfoniumjodid". Naturwissenschaften. 29 (17): 256. doi:10.1007/BF01479158.
- ^ Zuccaro, D. Ε.; McCullough, J. D. (1 January 1959). "The crystal structure of trimethylsulfonium iodide". Zeitschrift für Kristallographie - Crystalline Materials. 112 (1–6). doi:10.1524/zkri.1959.112.jg.401.
- ^ "Trimethylsulfonium tetrafluoroborate". Sigma-Aldrich. Retrieved 23 September 2016.
- ^ "Trimethylsulfonium methyl sulfate". Sigma-Aldrich. Retrieved 23 September 2016.
- ^ Ma, M.; Johnson, K.E. (April 1995). "Some physicochemical characteristics of molten salts derived from trimethylsulfonium bromide". Canadian Journal of Chemistry. 73 (4): 593–598. doi:10.1139/v95-076.