The 1:1 combination of
(Me
$_{3}$
Si)
$_{3}$
Al
• OEt
$_{2}$
with the primary aryl
amine, aniline, in hexane at 23°C shows no evidence for
the generation of an acid-base adduct. However, under reflux, the combination
produces Me
$_{3}$
SiH and a mixture of cis and
trans isomers of a dimeric aminoalane,
[(Me
$_{3}$
Si)
$_{2}$
AlN(H)(C
$_{6}$
H
$_{5})$
]
$_{2}$
(1). In refluxing toluene, the same reagent combination evolves
Me
$_{3}$
SiH with formation of a cubane-like iminoalane,
[(Me
$_{3}$
Si)AlNPh]
$_{4}$
(2). In
contrast, the 1:1 combination of
(Me
$_{3}$
Si)
$_{3}$
Al
• OEt
$_{2}$
with sterically more
crowded 2,6-diisopropylaniline in hexane at 23°C leads
to an adduct, (Me
$_{3}$
Si)
$_{3}$
Al
• N(H)
$_{2}$
(2,6-iPr
$_{2}$
C
$_{6}$
H
$_{3}$
)
(3). Reflux of a toluene solution of 3 results in
Me
$_{3}$
SiH elimination with formation of a trimeric
iminoalane,
[(Me
$_{3}$
Si)AlN(2,6-
$i$
Pr
$_{2}$
C
$_{6}$
H
$_{3}$
)]
$_{3}$
(4). A low level impurity of 2,4-diisopropylaniline in
2,6-diisopropylaniline gives a dimeric aminoalane,
[(Me
$_{3}$
Si)
$_{2}$
AlN(H)(2,4-i Pr
$_{2}$
C
$_{6}$
H
$_{3}$
)]
$_{2}$
(5). The molecular structures of 1, 2, 4 and 5
were determined by single crystal X-ray diffraction methods, and the reaction
pathways are compared with the reactions of
(Me
$_{3}$
Si)
$_{3}$
Al • OEt
$_{2}$
and the primary
borazinylamine,
(H
$_{2}$
N)B
$_{3}$
(Me)
$_{2}$
N
$_{3}$
Me
$_{3}$
.
