Methylmagnesium bromide
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| Names | |
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| IUPAC name
bromido(methyl)magnesium | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.000.768 |
| EC Number |
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PubChem CID |
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| UNII | |
| UN number | 1928 |
CompTox Dashboard (EPA) |
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| Properties | |
| CH3MgBr | |
| Molar mass | 119.244 g·mol−1 |
| Appearance | colorless solid |
| 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: | |
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| Danger | |
| H225, H250, H260, H314 | |
| 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) | |
| Flash point | −17 °C (1 °F; 256 K) |
| Related compounds | |
Related compounds |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Methylmagnesium bromide is an organomagnesium compound described with the general formula CH3MgBr. It is a colorless and moisture-sensitive compound. It is one of the simplest Grignard reagents.[1] It is commercially available as a solution in tetrahydrofuran (thf).
Synthesis and reactions
[edit]It is prepared by the reaction of methyl bromide and magnesium in ethyl ether.[2] and methylmagnesium iodide, methylmagnesium chloride offers the advantages of low equivalent weight and low cost. [3]
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.,:
- CH3MgBr + ROH → CH4 + "ROMgBr"
When treated with dioxane, ether solutions of methylmagnesium bromide 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:[4]
- 2 CH3MgBr + 2 dioxane → (CH3)2Mg + MgBr2(dioxane)2
Structure
[edit]As with most Grignard reagents, methylmagnesium bromide is usually deployed as a complex containing ether or thf as ligands. In these etherial solutions multiple species may coexist.[1] The trigonal bipyramidal complex CH3MgBr(thf)3 has been crystallized and identified by X-ray crystallography.[5]
See also
[edit]References
[edit]- 1 2 Seyferth, Dietmar (2009). "The Grignard Reagents". Organometallics. 28 (6): 1598–1605. doi:10.1021/om900088z.
- ↑ Raymond Paul; Olivier Riobé; Michel Maumy (1976). "(E)-4-Hexen-1-ol". Org. Synth. 55: 62. doi:10.15227/orgsyn.055.0062.
- ↑ E. R. Coburn (1947). "3-Penten-2-ol". Org. Synth. 27: 65. doi:10.15227/orgsyn.027.0065.
- ↑ Fischer, Reinald; Görls, Helmar; Meisinger, Philippe R.; Suxdorf, Regina; Westerhausen, Matthias (2019). "Structure–Solubility Relationship of 1,4-Dioxane Complexes of Di(hydrocarbyl)magnesium". Chemistry – A European Journal. 25 (55): 12830–12841. doi:10.1002/chem.201903120. PMC 7027550. PMID 31328293.
- ↑ Vallino, Maurice (1969). "Structure cristalline de CH3MgBr·3 C4H8O". Journal of Organometallic Chemistry. 20: 1–10. doi:10.1016/S0022-328X(00)80080-7.
