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
SMILES
  • 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
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)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
4
1
Flash point −12 °C (10 °F; 261 K)
Related compounds
Related tetraalkylstannanes
Related compounds
  • Tetramethylplumbane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Tetramethyltin is an

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

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

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. ^
    ISBN 0471936235
    .
  3. ^
    hdl:1874/6594
    .
  4. ISBN 9780080450476
    .
  5. doi:10.1021/ja00357a026
    .
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