Aluminium hydrazides - Formation of a dimeric di(tert-butyl)aluminium hydrazide containing a four-membered Al2N2 heterocycle and reaction of dialkylaluminium chloride with dilithium bis(trimethylsilyl)hydrazide

The reaction of di(tert-butyl)aluminium chloride with tert-butylhydrazine y ielded an adduct (1) which was isolated in a pure form and characterized by crystal structure determination. 1 reacted with n-butyllithium by deproton ation and salt elimination to give the corresponding di(tert-butyl)aluminiu m hydrazide (2), which is a dimer in solution and in the solid state and po ssesses a four-membered Al2N2 heterocycle with two exocyclic N-N bonds. The structure of 2 differs from that of other di(tert-butyl)aluminium hydrazid es which have four- or five-membered heterocycles. Treatment of impure samp les of 1 with n-butyllithium yielded by the cleavage of the N-N bonds a mix ture of several un-known products, from which the dimeric, centrosymmetric aluminium amide [(Me3C)(2)AlN(H)CMe3](2) (3) was isolated. A similar produc t (4) was obtained in a low yield by the reaction of (Me3SiCH2)(2)AlCl with the dilithium hydrazide Li2N2(SiMe3)(2). An intact N-N bond was neither fo und in the second product isolated from this reaction. Instead a tricyclic compound was formed by C-H activation which has two five-membered AlNSiC2 h eterocycles bridged by Al-N bonds.