Methylmagnesium chloride

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

Methylmagnesium chloride

Names
IUPAC name chlorido(methyl)magnesium
Other names (chloromagnesio)methane
Identifiers
CAS Number	676-58-4 Y 75-16-1 (bromide) Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:51492 Y
ChemSpider	10610396 Y
ECHA InfoCard	100.010.573
EC Number	211-629-7
PubChem CID	12670
UNII	M5E1132G4W Y 22CW9773DF (bromide) Y
CompTox Dashboard (EPA)	DTXSID7052365
InChI InChI=1S/CH3.ClH.Mg/h1H3;1H;/q;;+1/p-1 Y Key: RQNMYNYHBQQZSP-UHFFFAOYSA-M Y InChI=1/CH3.ClH.Mg/h1H3;1H;/q;;+1/p-1/rCH3Mg.ClH/c1-2;/h1H3;1H/q+1;/p-1 Key: RQNMYNYHBQQZSP-OWCPXFRBAR
SMILES [Cl-].[Mg+]C
Properties
Chemical formula	CH3MgCl
Molar mass	74.79 g·mol−1
Appearance	colorless solid
Solubility in water	Reacts with water
Solubility	soluble in diethyl ether and THF
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Flammable, reacts violently with water, severe skin burns and serious eye damage
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H225, H250, H260, H314
Precautionary statements	P210, P222, P223, P231+P232, P233, P240, P241, P242, P243, P260, P264, P280, P301+P330+P331, P302+P334, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P335+P334, P363, P370+P378, P402+P404, P403+P235, P405, P422, P501
NFPA 704 (fire diamond)	3 3 2 W
Flash point	−17 °C (1 °F; 256 K)
Related compounds
Related compounds	Phenylmagnesium bromide Dimethylmagnesium Dibutylmagnesium
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Synthesis and reactions

Relative to the more commonly encountered methylmagnesium bromide^[1] 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.^[2]

Structure of CH₃MgCl(THF)₂, 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, it is the synthetic equivalent to the methyl carbanion synthon. It reacts with water, alcohols and other protic reagents to give methane, e.g.,:

CH₃MgCl + ROH → CH₄ + ROMgCl

When treated with dioxane, ether solutions of methylmagnesium chloride reacts to give the insoluble coordination polymer with the formula MgCl₂(dioxane)₂. 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:^[3]

2 CH₃MgCl + 2 dioxane → (CH₃)₂Mg + MgCl₂(dioxane)₂

See also

• Methylation

Further reading

• Sakai, Shogo; Jordan, K. D. (1982). "Ab initio study of the structure and vibrational frequencies of the Grignard reagent methylmagnesium chloride". Journal of the American Chemical Society. 104 (14): 4019. doi:10.1021/ja00378a047.