Dimethylmagnesium

Dimethylmagnesium
Names
IUPAC name
Dimethylmagnesium
Identifiers
3D model (JSmol)
ChemSpider
Properties
C2H6Mg
Molar mass 54.38 g·mol−1
Density 0.96 g/cm3
Reacts
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

Dimethylmagnesium is an organomagnesium compound. It is a white pyrophoric solid.

Preparation

Like other dialkylmagnesium compounds, it is prepared by adding at least one equivalent of dioxane to a solution of methylmagnesium halide:[1][2]

2 CH3MgX + dioxane ⇌ (CH3)2Mg + MgX2(dioxane)

The complex of magnesium dihalide and dioxane precipitates as a solid, driving the Schlenk equilibrium to give the dialkylmagnesium compound, which remains in solution.

It can also be prepared by reacting calcium, magnesium and methyl iodide in diethyl ether or by reacting dimethyl mercury with magnesium.[3][4]

Properties

The structure of this compound has been determined by X-ray crystallography. The material is a polymer with the same connectivity as silicon disulfide, featuring tetrahedral magnesium centres, each surrounded by bridging methyl groups. The Mg-C distances are 224 pm.[5] Dimethylberylium adopts the same structure.[6]

References

  1. ↑ Cope, A. C. (1935). "The Preparation of Dialkylmagnesium Compounds from Grignard Reagents". J. Am. Chem. Soc. 57 (11): 2238–2240. doi:10.1021/ja01314a059.
  2. ↑ Anteunis, M. (1962). "Studies of the Grignard Reaction. II. Kinetics of the Reaction of Dimethylmagnesium with Benzophenone and of Methylmagnesium Bromide-Magnesium Bromide with Pinacolone". J. Org. Chem. 27 (2): 596–598. doi:10.1021/jo01049a060.
  3. ↑ (in German) [, p. 215, at Google Books Houben-Weyl Methods of Organic Chemistry Vol. XIII/2a, 4th Edition Organometallic Compounds of Group II of the Periodic Table (except mercury)], Georg Thieme Verlag, 2014, p. 215, ISBN 3-13-180654-0, , p. 215, at Google Books
  4. ↑ Jane E. Macintyre (1994) (in German), [, p. 2273, at Google Books Dictionary of Organometallic Compounds], CRC Press, p. 2273, ISBN 978-0-412-43060-2, , p. 2273, at Google Books
  5. ↑ Weiss, E. (1964). "Die Kristallstruktur des Dimethylmagnesiums". J. Organomet. Chem. 2 (4): 314–321. doi:10.1016/S0022-328X(00)82217-2.
  6. ↑ Snow, A.I.; Rundle, R.E. (1951). "Structure of Dimethylberyllium". Acta Crystallographica. 4: 348–52. doi:10.1107/S0365110X51001100.
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