Tetramethyltin

Chembox new
ImageFile=Tetramethltin.svg
ImageSize=150px
Name = Tetramethyltin
IUPACName = tetramethyltin
OtherNames = Tin tetramethyl tetramethylstannane
Section1 = Chembox Identifiers
CASNo = 594-27-4
Section2 = Chembox Properties
Formula = C₄H₁₂Sn
MolarMass = 178.85 g/mol
Appearance = colorless liquid
Density = 1.291 g/cm³
MeltingPt = -54 °C (219 K)
BoilingPt = 74-75 °C (347-348 K)
Section7 = Chembox Hazards
RPhrases = R26/27/28, R50/53
SPhrases = S26, S27, S28, S45, S60, S61

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.

ynthesis and structure

Tetramethyltin is synthesized by reaction of the Grignard reagent methylmagnesium iodide, with SnCl₄, cite journal
author = Scott, W. J.; Jones, J. H.; Moretto, A. F.
title = Tetramethylstannane
journal = Encyclopedia of Reagents for Organic Synthesis
date = 2002
doi = 10.1002/047084289X.rt070 ] which is synthesized by reacting tin metal with chlorine gas.cite journal
author = Thoonen, S. H. L.; Deelman, B.; van Koten, G; | title = Synthetic Aspects of Tetraorganotins and Organotin(IV) Halides
journal = Journal of Organometallic Chemistry
volume =689
date = 2004
pages = 2145–2157
doi = 10.1016/j.jorganchem.2004.03.027] :4 CH₃MgI + SnCl₄ → (CH₃)₄Sn + 4 MgIClIn 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 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. :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.

urface 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. [cite book | author = Davies, A. G. | chapter = Tin Organometallics | editor = Robert H. Crabtree and D. Michael P. Mingos | title = Comprehensive Organometallic Chemistry III | publisher = Elsevier | year = 2008.| pages = 809-883 | doi = 10.1016/B0-08-045047-4/00054-6]

Applications in organic synthesis

In organic synthesis, tetramethyltin undergoes palladium-catalyzed coupling reactions with acid chlorides to give methyl ketones: [cite journal | author = Labadie, J. and Stille, J. | title =Mechanisms of the palladium-catalyzed couplings of acid chlorides with organotin reagents | journal = J. Am. Chem. Soc. | volume = 105 | issue = 19 | pages = 6129 | year = 1983 | doi = 10.1021/ja00357a026] :SnMe₄ + RCOCl → RCOMe + Me₃SnCl

References