N-bridged and H-bridged aminoalanes: Single-crystal X-ray structure determinations for the planar dimer {[(Me3Si)(2)N](2)Al(mu-H)}(2) and the puckered four-membered ring compound (Me3Si)(2)N(Me2N)Al(mu-NMe2)(2)Al(H)N(SiMe3)(2)

摘要

The known bis(bis(trimethylsilyl)amino)alane ([(Me3Si)(2)N](2)Al(mu-H))(2), (1) is obtained from disproportionation of the base-stabilized monomeric bis(trimethylsilyl)aminoalane [(Me3Si)(2)NAlH2]. NMe3 in refluxing toluene. The single-crystal X-ray structure determination for 1 provides a II-bridged planar dimer with exo-cyclic N(SiMe3)(2) groups. The combination of 1 with HNMe2 in a I:1 ratio results in competing aminolysis at the AIlH site and transamination at the Al-N(SiMe3)(2) site of 1, as illustrated by the molecular structure of (Me3Si)(2)N(Me2N)Al(mu-NMe2)(2)Al(H)N(SiMe3)(2) (2) which is isolated from this system. The characteristic structural feature of 2 is a puckered (Al-N-Al-N) ring with different ligands on two aluminum atoms. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 38]