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.