Reactions of organoaluminium compounds with cyanides. Part III. Reactions of trimethylaluminium, triethylaluminium, dimethylaluminium hydride, and diethylaluminium hydride with dimethylcyanamide

Abstract

Dimethylcyanamide reacts with trimethyl- and triethyl-aluminium to form adducts, Me₂NC⋮N,AlR₃, the i.r. spectra of which show that co-ordination occurs through the cyanide nitrogen. At 115° in a sealed tube, Me₂NC⋮N,AlMe₃ suffers extensive decomposition to methane, (Me₂AlNMe₂)₂, and polymeric materials, whereas Me₂NC⋮N,AlEt₃ loses ethylene and rearranges to the dimeric formamidino-derivative (Me₂NCH:NAlEt₂)₂. This last, like its methyl analogue (Me₂NCH:NAlMe₂)₂, is better prepared from Me₂NC⋮N +⅓(R₂AlH)₃, and is believed to have a structure based on an (AlN)₂ four-membered ring. Features of the i.r. and ¹H n.m.r. spectra of the dimethylcyanamide adducts and formamidino-derivatives are discussed.