Dimethylaluminium chloride

Dimethylaluminium chloride is an organoaluminium compound with the chemical formula [(CH3)2AlCl]2. It behaves similarly to diethylaluminium chloride but is more expensive. Hence, it is less commonly used.[2]

Dimethylaluminium chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.013.335 Edit this at Wikidata
EC Number
  • 214-668-8
UNII
  • InChI=1S/2CH3.Al.ClH/h2*1H3;;1H/q;;+1;/p-1
    Key: JGHYBJVUQGTEEB-UHFFFAOYSA-M
  • C[Al](C)Cl
Properties
C4H12Al2Cl2
Molar mass 185.00 g·mol−1
Appearance colorless liquid
Density 0.996 g cm−3
Melting point −21 °C (−6 °F; 252 K)
Boiling point 126–127 °C (259–261 °F; 399–400 K)
Hazards
GHS labelling:[1]
GHS02: FlammableGHS05: Corrosive
Danger
H225, H250, H260, H314
P210, P222, P223, P231, P231+P232, P233, P240, P241, P242, P243, P260, P264, P280, P301+P330+P331, P302+P335+P334, P302+P361+P354, P303+P361+P353, P304+P340, P305+P354+P338, P316, P321, P363, P370+P378, P402+P404, P403+P235, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Like other organoaluminium chlorides, dimethylaluminium chloride is a Lewis acid. This property is exploited by the use of dimethylaluminium chloride to induce some Diels-Alder reactions.[3]

Structure and bonding

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Compounds of the empirical formula AlR2Cl (R = alkyl, aryl) usually exist as dimers with the formula (R2Al)2(μ-Cl)2. The bridging ligands, indicated by the prefix "μ-", are halides, not the organic substituents. The aluminium adopts a tetrahedral geometry and follows the octet rule.[4][5] By contrast, triethylaluminium and trimethylaluminium feature bridging alkyl groups and these compounds violate the octet rule.

Safety

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Dimethylaluminium chloride is not only flammable but pyrophoric.

References

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  1. ^ "Aluminum, chlorodimethyl-". pubchem.ncbi.nlm.nih.gov.
  2. ^ Snider, Barry B. (2001). "Dimethylaluminum Chloride". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rd297. ISBN 0-471-93623-5.
  3. ^ Danheiser, Rick L.; Renslo, Adam R.; Amos, David T.; Wright, Graham T. (2003). "Preparation of Substituted Pyridines Via Regiocontrolled [4 + 2] Cycloadditions of Oximinosulfonates: Methyl 5-Methylpyridine-2-Carboxylate". Organic Syntheses. 80: 133. doi:10.15227/orgsyn.080.0133.
  4. ^ Brendhaugen, Kristen; Haaland, Arne; Novak, David P.; Østvold, Terje; Bjørseth, Alf; Powell, D. L. (1974). "The Molecular Structure of Dimethylaluminium Chloride Dimer, [(CH3)2AlCl]2 Redetermined by Gas Phase Electron Diffraction". Acta Chemica Scandinavica. 28a: 45–47. doi:10.3891/acta.chem.scand.28a-0045.
  5. ^ McMahon, C. Niamh; Francis, Julie A.; Barron, Andrew R. (1997). "Molecular Atructure of [(tBu)2Al(μ-Cl)]2". Journal of Chemical Crystallography. 27 (3): 191–194. doi:10.1007/BF02575988. S2CID 195242291.