Dimethylzinc

Dimethylzinc
IUPAC name

dimethylzinc
Identifiers
CAS number 544-97-8 Y
ChemSpider 10254473 Y
ChEBI CHEBI:51497 Y
Jmol-3D images Image 1
Properties
Molecular formula Zn(CH3)2
Molar mass 95.478 g/mol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dimethylzinc, also known as Zinc methyl, DMZ, or DMZn is a colorless mobile liquid Zn(CH3)2, formed by the action of methyl iodide on zinc at elevated temperature or on zinc sodium alloy.

2Zn + 2CH3I → Zn(CH3)2 + ZnI2

The sodium assists the reaction of the zinc with the methyl iodide. Zinc iodide is formed as a byproduct.

It has a disagreeable odor, and is spontaneously flammable in air. It has been of great importance in the synthesis of organic compounds. It is soluble in alkanes and often sold as a solution in hexanes. It belongs to the large series of similar compounds such as diethylzinc.

Contents

History

This substance was first prepared by Edward Frankland during his work with Robert Bunsen in 1849 at the University of Marburg. After heating a mixture of zinc and methyl iodide in an airtight vessel a flame bursted out after the seal was broken.[1] In laboratory scale the synthesis method did not change till today, except that copper or copper compounds are used to activate the zinc.

Uses

Dimethyl zinc was used for a long time to introduce methyl groups into organic molecules or to synthesize organometallic compounds containing methyl groups. Grignard reagents, (organo-magnesium compounds), which are easier to handle and less flammable replaced organo-zinc compounds in most laboratory syntheses. Due to differences in reactivity (as well as in reaction by-products) between organo-zinc compounds and Grignard reagents, organo-zinc compounds may be preferred in some syntheses.[2] Its high vapor pressure has led to extensive uses in metalorganic chemical vapor deposition (MOCVD) for the preparation of wide band gap II–VI semiconducting films (e.g. ZnO, ZnS, ZnSe, ZnTe) and as p-dopant precursors for III–V semiconductors (e.g. GaAs, InP, [[AlxGa1-xAs]]), which have many electronic and photonic applications. [3]

Structure

In the solid state the compound exists in two modifications. The monoclinic high-temperature phase shows a two-dimensional disorder, while the low-temperature phase which is also monoclinic is ordered. The molecules are linear with Zn-C bond lengths measuring 1.927(6) pm.[4] The structure of the gas-phase shows a very similar Zn-C distance of 193.0(2) pm.[5]

References

  1. ^ E. Frankland (1849). "Notiz über eine neue Reihe organischer Körper, welche Metalle, Phosphor u. s. w. enthalten". Liebig's Annalen der Chemie und Pharmacie 71 (2): 213–216. doi:10.1002/jlac.18490710206. 
  2. ^ Erdik, Ender (1996). Organozinc reagents in organic synthesis. Boca Raton: CRC Press. ISBN 0-84939151-2. 
  3. ^ Mohammad Afzaal, Mohammad A. Malik, Paul O’Brien (2007). "Preparation of zinc containing materials". New Journal of Chemistry 31: 2029–2040. doi:10.1039/b712235g. 
  4. ^ John Bacsa, Felix Hanke, Sarah Hindley, Rajesh Odedra, George R. Darling, Anthony C. Jones and Alexander Steiner (2011). "The Solid State Structures of Dimethylzinc and Diethylzinc". Angewandte Chemie International Edition 50: 11685–11687. doi:10.1002/anie.201105099. 
  5. ^ A. Haaland, J. C. Green, G. S. McGrady, A. J. Downs, E. Gullo, M. J. Lyall, J. Timberlake, A. V. Tutukin, H. V. Volden, K.-A. Østby (2003). "The length, strength and polarity of metal–carbon bonds: dialkylzinc compounds studied by density functional theory calculations, gas electron diffraction and photoelectron spectroscopy". Dalton Transactions: 4356–4366. doi:10.1039/B306840B.