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Aluminium Hydrazides: Reactions of tert ‐Butylaluminium Chlorides with Dilithium Bis(trimethylsilyl)hydrazide – Formation of Iminoalanes and their Hydrazido Adducts
Author(s) -
Uhl Werner,
Molter Jens,
Koch Rainer
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199911)1999:11<2021::aid-ejic2021>3.0.co;2-u
Subject(s) - chemistry , dilithium , hydrazide , trimethylsilyl , adduct , medicinal chemistry , ligand (biochemistry) , aluminium chloride , chloride , molecule , aluminium , deprotonation , organic chemistry , ion , biochemistry , receptor
Di( tert ‐butyl)aluminium chloride reacted with dilithium bis(trimethylsilyl)hydrazide with the formation of a novel Al 2 Li 2 N 4 cage compound 1 . Its structure consists of a dimeric iminoalane RAl(μN–SiMe 3 ) 2 AlR (R = CMe 3 ), which is bridged by a dilithiumhydrazido ligand with an intact N–N bond. A heterocubane‐type molecule is formed, in which two vertices are occupied by Al atoms, two by Li atoms and four by N atoms. One face of the cube is strongly distorted due to the short N–N distance of the hydrazido group. A similar compound, 3 , was formed with bis(neopentyl)aluminium chloride but it was isolated in very poor yield. The reaction of Li 2 N 2 (SiMe 3 ) 2 with (Me 3 C) 2 AlCl in the presence of THF yielded an adduct 2 , in which each Li atom of the cage is additionally coordinated via Li–Cl–Al bridges to the ligand (Me 3 Al) 2 Cl · THF. The reaction of dilithium bis(trimethylsilyl)hydrazide with tert ‐butylaluminium dichloride gave, by complete cleavage of the hydrazido groups, a dimeric iminoalane [Me 3 C(THF)AlNSiMe 3 ] 2 ( 4 ), in which each aluminium atom is coordinated to one THF molecule. Its uncoordinated, solvent‐free form 5 was obtained by heating solid 4 to 150 °C in vacuo for several hours. It was identified as the tetrameric iminoalane (Me 3 CAlNSiMe 3 ) 4 , which does not adopt the expected heterocubane‐type structure, but consists of three anellated four‐membered Al 2 N 2 heterocycles in a kind of ladder structure. Remarkably, the cage compound 1 could not be obtained by the reaction of an excess of lithium hydrazide with the iminoalanes 4 and 5 . All compounds 1 – 5 were characterized by crystal structure determinations.