Tetramethyltin is an

organometallic compound Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and s ...

with the formula (CH₃)₄Sn. This liquid, one of the simplest

organotin compound Organotin compounds or stannanes are chemical compounds based on tin with hydrocarbon substituents. Organotin chemistry is part of the wider field of organometallic chemistry. The first organotin compound was diethyltin diiodide (), discovered ...

s, 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 Methylmagnesium chloride is an organometallic compound with the general formula CH3MgCl. This highly flammable, colorless, and moisture sensitive material is the simplest Grignard reagent and is commercially available, usually as a solution in tet ...

, with tin tetrachloride, which is synthesized by reacting tin metal with chlorine gas. :4 CH₃MgI + SnCl₄ → (CH₃)₄Sn + 4 MgICl In tetramethyltin, the metal surrounded by four

methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ...

groups in a tetrahedral structure is a heavy analogue of

neopentane Neopentane, also called 2,2-dimethylpropane, is a double-branched-chain alkane with five carbon atoms. Neopentane is a flammable gas at room temperature and pressure which can condense into a highly volatile liquid on a cold day, in an ice bat ...

Applications

Precursor to methyltin compounds

Tetramethyltin is a precursor to

trimethyltin chloride Trimethyltin chloride is an organotin compound with the formula . It is a white solid that is highly toxic and malodorous. It is susceptible to hydrolysis. Synthesis Trimethyltin chloride can be prepared by the redistribution reaction of tetramet ...

(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 Mercury(II) chloride (or mercury bichloride, mercury dichloride), historically also known as sulema or corrosive sublimate, is the inorganic chemical compound of mercury and chlorine with the formula HgCl2. It is white crystalline solid and is ...

to react with (CH₃)₄Sn. :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.

Surface functionalization

Tetramethyltin decomposes in the gas phase at about 277 °C; (CH₃)₄Sn vapor reacts with

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...

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

zeolite Zeolites are microporous, crystalline aluminosilicate materials commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. These p ...

s at temperatures as low as −90 °C.

Applications in organic synthesis

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

, tetramethyltin undergoes

palladium-catalyzed coupling reactions In organic chemistry, a cross-coupling reaction is a reaction where two fragments are joined together with the aid of a metal catalyst. In one important reaction type, a main group organometallic compound of the type R-M (R = organic fragment, M = ...

with acid chlorides to give methyl ketones:{{cite journal , author1=Labadie, J. , author2=Stille, J. , name-list-style=amp , title =Mechanisms of the palladium-catalyzed couplings of acid chlorides with organotin reagents , journal =

J. Am. Chem. Soc. The ''Journal of the American Chemical Society'' is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytical ...

, volume = 105 , issue = 19 , page = 6129 , year = 1983 , doi = 10.1021/ja00357a026 :SnMe₄ + RCOCl → RCOMe + Me₃SnCl

References

Organotin compounds Tin(IV) compounds Methyl complexes