Methylmagnesium chloride is an
organometallic
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 so ...
compound with the general formula . This highly flammable, colorless, and moisture sensitive compound is the simplest
Grignard reagent and is commercially available, usually as a solution in
tetrahydrofuran
Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is ...
.
Synthesis and reactions
Relative to the more commonly encountered methylmagnesium bromide and methylmagnesium iodide, methylmagnesium chloride offers the advantages of low equivalent weight and low cost. It is prepared by the reaction of
methyl chloride and magnesium in
ethyl ether.
left, Structure of , which is representative of the species in donor solvents.
As with most Grignard reagents, methylmagnesium chloride is highly solvated by
ether solvents via
coordination from two oxygen atoms to give a
tetrahedrally bonded magnesium center.
Like
methyllithium
Methyllithium is the simplest organolithium reagent, with the empirical formula LiCH3. This s-block organometallic compound adopts an oligomeric structure both in solution and in the solid state. This highly reactive compound, invariably used i ...
, it is the synthetic equivalent to the
methyl carbanion
synthon. It reacts with water,
alcohols and other
protic reagents to give methane, e.g.,:
:
When treated with
dioxane, ether solutions of methylmagnesium chloride reacts to give the insoluble
coordination polymer with the formula . Remaining in the solution is the dioxane adduct of
dimethylmagnesium. This conversion exploits the
Schlenk equilibrium, which is driven to the right by the precipitation of the magnesium halide:
:
See also
*
Methylation
Further reading
*{{cite journal, doi=10.1021/ja00378a047, title=Ab initio study of the structure and vibrational frequencies of the Grignard reagent methylmagnesium chloride, year=1982, last1=Sakai, first1=Shogo, last2=Jordan, first2=K. D., journal=
Journal of the American Chemical Society, volume=104, issue=14, page=4019
References
Organomagnesium compounds
Methylating agents
Methyl complexes