Tetramethyltin

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Tetramethyltin
Stereo structural formula of tetramethyltin
Ball-and-stick model of the tetramethyltin molecule
Names
Preferred IUPAC name
Tetramethylstannane[1]
Other names
Tin tetramethyl
Identifiers
3D model (JSmol)
3647887
ChEBI
ChemSpider
ECHA InfoCard 100.008.941 Edit this at Wikidata
EC Number
  • 209-833-6
1938
RTECS number
  • WH8630000
UNII
UN number 3384
  • InChI=1S/4CH3.Sn/h4*1H3; checkY
    Key: VXKWYPOMXBVZSJ-UHFFFAOYSA-N checkY
  • C[Sn](C)(C)C
Properties
C4H12Sn
Molar mass 178.850 g·mol−1
Appearance Colorless liquid
Density 1.291 g cm−3
Melting point −54 °C (−65 °F; 219 K)
Boiling point 74 to 76 °C (165 to 169 °F; 347 to 349 K)
Hazards
GHS labelling:
GHS02: FlammableGHS06: ToxicGHS09: Environmental hazard
Signal word
 Danger
H225, H300, H310, H330, H410
P210, P233, P240, P241, P242, P243, P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P303+P361+P353, P304+P340, P310, P320, P321, P322, P330, P361, P363, P370+P378, P391, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)
3
4
1
Flash point −12 °C (10 °F; 261 K)
Related compounds
Related tetraalkylstannanes
 Tetrabutyltin

Tetraethyltin

Related compounds
 Neopentane

Tetramethylsilane

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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. It is volatile and toxic, so care should be taken when using it in the laboratory.

Synthesis and structure[]

Tetramethyltin is synthesized by reaction of the Grignard reagent methylmagnesium iodide, with tin tetrachloride,[2] which is synthesized by reacting tin metal with chlorine gas.[3]

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.

Applications[]

Precursor to methyltin compounds[]

Tetramethyltin is a precursor to trimethyltin chloride (and related methyltin halides), which are precursors to other organotin compounds. These methyltin chlorides are prepared via the so-called Kocheshkov redistribution reaction. Thus, (CH3)4Sn and SnCl4 are allowed to react at temperatures between 100 °C and 200 °C to give (CH3)3SnCl as a product:

SnCl4 + 3 (CH3)4Sn → 4 (CH3)3SnCl

A second route to trimethyltin chloride utilizing tetramethyltin involves the reaction of mercury(II) chloride to react with (CH3)4Sn.[2]

4 HgCl2 + 4 (CH3)4Sn → 4 Me3SnCl + 4 MeHgCl

A variety of methyltin compounds are used as precursors for stabilizers in PVC. Di- and trimercaptotin compounds are used to inhibit the dehydrochlorination, which is the pathway for photolytic and thermal degradation of PVC.[3]

Surface functionalization[]

Tetramethyltin decomposes in the gas phase at about 277 °C; (CH3)4Sn vapor reacts with silica to give a (CH3)3Sn-grafted solid.

(CH3)4Sn + ≡SiOH → ≡SiOSn(CH3)3 + 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.[4]

Applications in organic synthesis[]

In organic synthesis, tetramethyltin undergoes palladium-catalyzed coupling reactions with acid chlorides to give methyl ketones:[5]

SnMe4 + RCOCl → RCOMe + Me3SnCl

References[]

  1. ^ "Tetramethyltin | C4H12Sn". ChemSpider. Retrieved 2013-09-15.
  2. ^ a b Scott, W. J.; Jones, J. H.; Moretto, A. F. (2002). "Tetramethylstannane". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rt070. ISBN 0471936235.
  3. ^ 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 (13): 2145–2157. doi:10.1016/j.jorganchem.2004.03.027. hdl:1874/6594.
  4. ^ Davies, A. G. (2008). "Tin Organometallics". In Robert H. Crabtree; D. Michael P. Mingos (eds.). Comprehensive Organometallic Chemistry III. Elsevier. pp. 809–883. doi:10.1016/B0-08-045047-4/00054-6. ISBN 9780080450476.
  5. ^ Labadie, J. & Stille, J. (1983). "Mechanisms of the palladium-catalyzed couplings of acid chlorides with organotin reagents". J. Am. Chem. Soc. 105 (19): 6129. doi:10.1021/ja00357a026.
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