Diethylaluminium cyanide

Diethylaluminium cyanide
Skeletal formula of diethylaluminium cyanide
Names
IUPAC name
diethylalumanylformonitrile
Other names
  • Cyanodiethyl aluminium
  • (Cyano-κC)diethyl-aluminium
  • (Cyano-C)diethyl-aluminium
  • Cyanodiethyl-(7CI,8CI) aluminium
  • Cyanodiethylallane
  • Cyanodiethylaluminium
  • Diethylaluminium Cyanide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.024.873 Edit this at Wikidata
EC Number
  • 227-359-8
  • InChI=1S/2C2H5.CN.Al/c3*1-2;/h2*1H2,2H3;;
    Key: KWMUAEYVIFJZEB-UHFFFAOYSA-N
  • CC[Al](CC)C#N
Properties
(CH3CH2)2AlCN
Molar mass 111.124 g·mol−1
Appearance Dark brown, clear liquid (1.0 mol/L in toluene)[1]
Density 0.864 g/cm3 at (25 °C) (liquid)
Boiling point 162 °C (324 °F; 435 K) at 0.02 mmHg
Reacts with water
Solubility Benzene, Toluene, diisopropyl ether
Hazards
GHS labelling:[1]
GHS06: ToxicGHS09: Environmental hazard
Danger
H300, H310, H330, H400
P260, P262, P264, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P316, P320, P321, P330, P361+P364, P391, P403+P233, P405, P501
Flash point 7 °C (45 °F; 280 K) closed cup[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Diethylaluminium cyanide ("Nagata's reagent")[2] is the organoaluminium compound with formula ((C2H5)2AlCN)n. This colorless compound is usually handled as a solution in toluene. It is a reagent for the hydrocyanation of α,β-unsaturated ketones.[1][3][4][5][6]

Synthesis

Diethylaluminium cyanide was originally generated by treatment of triethylaluminium with a slight excess of hydrogen cyanide. The product is typically stored in ampoules because it is highly toxic. It dissolves in toluene, benzene, hexane and isopropyl ether. It undergoes hydrolysis readily and is not compatible with protic solvents.

n Et3Al + n HCN → (Et2AlCN)n + n EtH

Structure

Diethylaluminium cyanide has not been examined by X-ray crystallography, although other diorganoaluminium cyanides have been. Diorganylaluminium cyanides have the general formula (R2AlCN)n, and they exist as cyclic trimers (n = 3) or tetramers (n = 4). In these oligomers, one finds AlCN---Al linkages. One compound similar to diethylaluminium cyanide is bis[di(trimethylsilyl)methyl]aluminium cyanide, ((Me3Si)2CH)2AlCN, which has been shown crystallographically to exist as a trimer with the following structure:[4]

trimeric bis[di(trimethylsilyl)methyl]aluminium cyanide

Bis(tert-butyl)aluminium cyanide, tBu2AlCN exists as a tetramer in the crystalline phase:[7][8]

tetrameric bis(tert-butyl)aluminium cyanide

Uses

Diethylaluminium cyanide is used for the stoichiometric hydrocyanation of α,β-unsaturated ketones. The reaction is influenced by the basicity of the solvent. This effect arises from the Lewis acidic qualities of the reagent.[9] The purpose of this reaction is to generate alkylnitriles, which are precursors to amines, amides, carboxylic acids esters and aldehydes.

References

  1. ^ a b c "MSDS - 276863". Sigma-Aldrich. Retrieved December 9, 2012.
  2. ^ Nagata, W (1988). "Diethylaluminum cyanide". Organic Syntheses. VI: 307. doi:10.15227/orgsyn.052.0090.
  3. ^ Nagata, W. (1966). "Alkylaluminum cyanides as potent reagents for hydrocyanation". Tetrahedron Lett. 7 (18): 1913–1918. doi:10.1016/S0040-4039(00)76271-X.
  4. ^ a b Uhl, Werner; Schütz, Uwe; Hiller, Wolfgang; Heckel, Maximilian (1995). "Synthese und Kristallstruktur des trimeren [(Me3Si)2CH]2Al—CN". Z. anorg. allg. Chem. 621 (5): 823–828. doi:10.1002/zaac.19956210521.
  5. ^ Wade, K.; Wyatt, B. K. (1969). "Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide". J. Chem. Soc.: 1121–1124. doi:10.1039/J19690001121.
  6. ^ Coates, G. E.; Mukherjee, R. N. (1963). "35. Dimethylaluminium cyanide and its gallium, indium, and thallium analogues; beryllium and methylberyllium cyanide". J. Chem. Soc.: 229–232. doi:10.1039/JR9630000229.
  7. ^ Uhl, W.; Matar, M. (2004). "Hydroalumination of nitriles and isonitriles" (PDF). Z. Naturforsch. B. 59 (11–12): 1214–1222. doi:10.1515/znb-2004-11-1239. S2CID 99001626.
  8. ^ Uhl, W.; Schütz, U.; Hiller, W.; Heckel, M. (2005). "Synthese und Kristallstruktur des trimeren [(Me3Si)2CH]2Al—CN" (PDF). Z. Naturforsch. B. 60 (2): 155–163.
  9. ^ Nagata, W.; Yoshioka, M. (1988). "Diethylaluminum cyanide". Organic Syntheses; Collected Volumes, vol. 6, p. 436.