Affiliations: Department of Chemistry and Chemical Biology,
University of New Mexico, Albuquerque, NM, USA | Department of Chemistry, University of Munich, Munich,
Germany
Note: [] Corresponding author: Robert T. Paine, Department of Chemistry
and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA.
E-mail: rtpaine@vnm.edu
Abstract: 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-iPr_{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}.
