4731-36-6Relevant articles and documents
Crystal structures of tris(tert-butyl)boron, -aluminum, -gallium, and -indium: Nonplanarity of the AlC3 skeleton and evidence of inter- and intramolecular agostic or hyperconjugative interactions
Cowley, Andrew R.,Downs, Anthony J.,Marchant, Sarah,Macrae, Victoria A.,Taylor, Russell A.,Parsons, Simon
, p. 5702 - 5709 (2005)
X-ray crystal structures determined at low temperatures (150-220 K) for the tris(tert-butyl) derivatives of boron, aluminum, gallium, and indium (M) reveal essentially monomeric molecular units throughout with consistently longer M-C bonds than in the corresponding monomeric trimethyl derivatives. Comparison of the three structures shows a significant strengthening of intermolecular M...β-CH3 binding in the order M = B ～ Ga a distinctly nonplanar MC3 skeleton with the M atom displaced 0.25 A above the plane of the quaternary C atoms in the case where M = Al. Tilting of the tert-butyl groups about the M-C bonds, which is concerted when M = B or Al, appears to reflect the influence of intramolecular hyperconjugation or agostic bonding.
Hydroaluinination and hydrogallation of 1,2-bis(trimethylsilylethynyl) benzene: Formation of molecular capsules and C-C bond activation
Uhl, Werner,Hepp, Alexander,Westenberg, Hauke,Zemke, Sarina,Wuerthwein, Ernst-Ulrich,Hellmann, Johannes
, p. 1406 - 1412 (2010/05/01)
Treatment of l,2-bis(trimethylsilylethynyl)benzene with di-tert-butylaluminum and di-tert-butylgallium hydrides afforded the simple addition products 1,2-[(Me3Si)(R2E)C-C(H)] 2C6H4 (R = CMe3; E = Al (1), Ga (2)), which could, not be isolated in a pure crystalline form but have been characterized unambiguously by spectroscopic methods. Addition of the Lewis base ethyldimethylamine initiated condensation reactions which gave cage compounds (3 and 4) by the release of the corresponding tri-tert-butyl element derivatives. These cages contain two aluminum or gallium atoms which are bridged by three l,2-bis(trimethylsilylethenyi)benzene spacers to form molecular capsules. The metal atoms are further coordinated by terminal amino groups. The amino ligands could not be removed from the dialuminum compound 4 without decomposition, but the ligand-free gallium, compound 5 was obtained upon heating of 3 (E = Ga) to 80 °C under vacuum. Thermolysis of the aluminum compound 1 in boiling n-hexane gave a unique reaction by the release of tri-tert-butylaluminum and the formal elimination of trimethylsilylethyne (decarbalumination). The product 6 is dimeric in the solid, state via Al-C-Al bridges and has a pentacyclic molecular structure.
Aluminium and gallium compounds of salicylic and anthranilic acids: Examples of weak intra-molecular hydrogen bonding
Branch,Lewinski,Justyniak,Bott,Lipkowski,Barron
, p. 1253 - 1258 (2007/10/03)
Reaction of M(tBu)3 with anthranilic, salicylic and ortho-toluic acids yields [(tBu)2M(μ-O2CC6 H4-2-NH2)]2, M = Al (1), Ga (2), [(tBu)2Ga(μ-O2CC6 H4-2-OH)]2 (3), and [(tBu)2Ga(μ-O2CC6 H4-2-Me)]2 (4), respectively. Reaction of anthranilic acid with two equivalents of Al(tBu)3 allows for the isolation of (tBu)2Al(μ-O2CC6 H4-2-NH2)Al(tBu)3 (5). Compounds 1-5 have been characterized by NMR and IR spectroscopy, mass spectrometry, and X-ray crystallography. The presence of intra-molecular hydrogen bonding, in compounds 1-3, is probed by the orientation of the aromatic rings. Compound 5 is proposed to be a Lewis acid stabilized complex of the intermediate in the synthesis of compound 1.
