- Sulfonium
A sulfonium ion, also known as sulphonium ion and sulfanium ion, is a positively charged
sulfur ion carrying threealkyl groups as substituents (S+R3).Ionic compound s consisting of a positively charged sulfoniumcation and a negatively chargedanion are called sulfonium salts.Sulfonium compounds can be synthesized from the reaction of dialkylsulfides with
alkyl halide s:: CH3-S-CH3 + CH3-I → (CH3)3S+ I− (trimethylsulfonium iodide)
In the above reaction, the alkylation of a sulfide, the sulfur atom has two lone electron pairs. Using those lone pairs, the sulfide acts as a nucleophile, and attacks the carbon of iodomethane. At the same time, as part of a concerted nucleophilic substitution mechanism (SN2), the iodide leaving group comes off; this leaves a positively charged trimethylsulfonium ion. This cation is attracted to the negatively charged iodide, so the two form an ionic bond, giving trimethylsulfonium iodide. [Dan Rather]
See also
*
Sulfide R-S-R
*Sulfate R-SO4-R
*Sulfite R-SO3-R
*Sulfonate R-SO3−
*Onium compounds References
External links
* [http://www.iupac.org/goldbook/S06121.pdf IUPAC definition] (short pdf)
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