Secondary Amine Stabilized Aluminum Hydrides Derived from N'N-Di-tert-butylethylenediamines

Michael G. Gardiner, Stacey M. Lawrence, Colin L. Raston

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The metalation of substituted N,N'-di-tert-butylethylenediamines by various aluminum hydride sources has been investigated. HN(t-Bu)CH(t-Bu)CH2N(H)(t-Bu) forms a dimeric lithium chelated adduct of LiAlH4 [{HN(t-Bu)CH(t-Bu)CH2N(H)(t-Bu)]Li(μ-H)2AlH 2}2], 4, which thermally decomposes to yield the tetrameric lithium diamidoaluminum hydride [{Li[N(t-Bu)CH(t-Bu)CH2N(t-Bu)]AlH2}4], 5. The same diamine reacts with AlH3·-NMe3 or AlH3 diethyl etherate to give the secondary amine stabilized amidoaluminum hydride species [{HN(t-Bu)CH(t-Bu)CH2N(t-Bu)}AlH2], 2. Similarly, the same aluminum hydride sources react with the diamine racHN(t-Bu)CH(Me)CH(Me)N(H)(t-Bu) to yield [{rac-HN(t-Bu)CH(Me)CH(Me)N(t-Bu)}AlH2], 3. Compounds 2 and 3 are stable with respect to elimination of hydrogen to form diamidoaluminum hydrides, but can be converted to the alane rich species, [H2Al{N(t-Bu)CH(t-Bu)CH2N(t-Bu)}AlH2], 6, and [H2Al{rac-N(t-Bu)CH(Me)CH(Me)N-(t-Bu)}AlH2], 7, by reaction with AlH3·NMe3 under special conditions. The varying reactivity of the three aluminum hydride sources in these reactions has enabled mechanistic information to be gathered, and the effect of the different steric requirements in the diamines on the stability of the complexes is discussed. Crystals of 3 are monoclinic, space group P21/n (No. 14), with a = 8.910(4), b = 14.809(1), and c = 12.239(6) Å, β= 109.76(2)°, V = 1520(1) Å3, and Z = 4. Crystals of 4 are orthorhombic, space group Pbca (No. 61), with a = 15.906(9), b = 24.651(7), and c = 9.933(7) Å, V = 3895(3) Å3, and Z = 4. Crystals of 6 are monoclinic, space group P21/c (No. 14), with a = 8.392(1), b= 17.513(2), and c = 12.959(1) Å, β= 107.098(8)°, V= 1820.4(3) Å3, and Z = 4.

Original languageEnglish
Pages (from-to)1349-1354
Number of pages6
JournalInorganic Chemistry
Volume35
Issue number5
DOIs
Publication statusPublished - 1 Dec 1996
Externally publishedYes

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