N-Bridged and H-Bridged Aminoalanes: Single-Crystal X-ray Structure Determinations for the Planar Dimer .(Me3Si)2N2Al(mu-H).2 and the Puckered Four- Membered Ring Compound (Me3Si)2N(Me2N)Al (mu-NMe2)2Al(H)N(SiMe3)2

摘要

The known bis(bis(trimethylsilyl)amino)alane .(Me3Si)2N2Al(mu-H).2 (1) is obtained from disproportionation of the base-stabilized monomeric bis(trimethylsilyl)aminoalane (Me3Si)2NAlH2.NMe3 in refluxing toluene. The single-crystal X-ray structure determination for 1 provides a H-bridged planar dimer with exo-cyclic N(SiMe3)2 groups. The combination of 1 with HNMe2 in a 1: ratio results in competing aminolysis at the Al-H site and transamination at the Al-N(SiMe3)2 site of 1, as illustrated by the molecular structure of (Me3Si) 2N(Me2N)Al(mu-NMe2)2Al(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.