Tetramethyltin
From Wikipedia, the free encyclopedia
| Tetramethyltin | |
|---|---|
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| IUPAC name | tetramethyltin |
| Other names | Tin tetramethyl tetramethylstannane |
| Identifiers | |
| CAS number | [594-27-4] |
| Properties | |
| Molecular formula | C4H12Sn |
| Molar mass | 178.85 g/mol |
| Appearance | colorless liquid |
| Density | 1.291 g/cm3 |
| Melting point |
-54 °C (219 K) |
| Boiling point |
74-75 °C (347-348 K) |
| Hazards | |
| R-phrases | R26/27/28, R50/53 |
| S-phrases | S26, S27, S28, S45, S60, S61 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Tetramethyltin is an organometallic compound with the formula (CH3)4Sn. This liquid, one of the simplest organotin compounds, is useful for transition-metal mediated conversion of acid chlorides to methyl ketones and aryl halides to aryl methyl ketones.
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[edit] Synthesis and structure
Tetramethyltin is synthesized by reaction of the Grignard reagent methylmagnesium iodide, with SnCl4, [1] which is synthesized by reacting tin metal with chlorine gas.[2]
- 4 CH3MgI + SnCl4 → (CH3)4Sn + 4 MgICl
In tetramethyltin, the metal surrounded by four methyl groups in a tetrahedral structure is a heavy analogue of neopentane.
[edit] Applications
[edit] Precursor to methyltin compounds
Tetramethyltin is a precursor to trimethyltin chloride (and related methyltin halides), which are precursors to orther organotin compounds. These methyltin chlorides are prepared via the so-called Kocheshkov redistribution reaction. Thus, SnMe4 and SnCl4 are allowed to react at temperatures between 100 °C and 200 °C to give Me3SnCl as a product:
- SnCl4 + 3 SnMe4 → 4 Me3SnCl
A second route to trimethyltin chloride utilizing tetramethyltin involves the reaction of mercury (II) chloride to react with SnMe4.[1]
- 4 HgCl2 + 4 SnMe4 → 4 Me3SnCl + 4 MeHgCl
A variety of methyltin compounds are used as precursors for stabilizers in PVC. Di- and trimercapto tin compounds are used to inhibit the dehydrochlorination, which is the pathway for photolytic and thermal degradation of PVC.[2]
[edit] Surface functionalization
Tetramethyltin decomposes in the gas phase at about 277 °C (550 K) Me4Sn vapor reacts with silica to give Me3Sn-grafted solid.
- Me4Sn + ≡SiOH → ≡SiOSnMe3 + MeH
This reaction is also possible with other alkyl substituents. In a similar process, tetramethyltin has been used to functionalize certain zeolites at temperatures as low as -90 °C.[3]
[edit] Applications in organic synthesis
In organic synthesis, tetramethyltin undergoes palladium-catalyzed coupling reactions with acid chlorides to give methyl ketones:[4]
- SnMe4 + RCOCl → RCOMe + Me3SnCl
[edit] References
- ^ a b Scott, W. J.; Jones, J. H.; Moretto, A. F. (2002). "Tetramethylstannane". Encyclopedia of Reagents for Organic Synthesis. doi:.
- ^ a b Thoonen, S. H. L.; Deelman, B.; van Koten, G; (2004). "Synthetic Aspects of Tetraorganotins and Organotin(IV) Halides". Journal of Organometallic Chemistry 689: 2145&ndash2157.
- ^ Davies, A. G. "Tin Organometallics." Comprehensive Organometallic Chemistry III. Elsevier B. V.:2008. pg 809-883 doi: 10.1016/B0-08-045047-4/00054-6
- ^ Labadie, J. and Stille, J. "Mechanisms of the palladium-catalyzed couplings of acid chlorides with organotin reagents." J. Am. Chem. Soc. 105(19). 6129. (1983). Doi: 10.1021/ja00357a026
