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Z. Naturforsch. 2012, 67b, 1081 – 1090
doi:10.5560/ZNB.2012-0145
The Methylene-bridged Dialuminium Compound R2Al-CH2-AlR2 [R = CH(SiMe3)2] as an Effective Chelating Lewis Acid – Adducts with Halides, Perchlorate and Isopropylamide
Werner Uhl, Christian Rösener, Christina Stefaniak, Tim Choy, Beate Jasper-Peter, Jutta Kösters, Marcus Layh, and Alexander Hepp
Institut für Anorganische und Analytische Chemie der Universität Münster, Corrensstraße 30, 48149 Münster, Germany
Reprint requests to Prof. Werner Uhl. E-mail: uhlw@uni-muenster.de
Received May 24, 2012 / published online October 8, 2012
Dedicated to Professor Heribert Offermanns on the occasion of his 75th birthday
The new methylene-bridged dialuminium compound Aryl2Al-CH2-AlAryl2 1b was synthesised from Cl2Al-CH2-AlCl2 and four equivalents of LiAryl [Aryl = C6H2(2,4,6-i-Pr)3]. A 1 : 2 stoichiometric ratio of the starting compounds afforded the dimeric aluminium halide (Aryl2AlCl)2 (2) by dismutation. The coordination behaviour of the related, but more easily available dialuminium compound R2Al-CH2-AlR2 [R = CH(SiMe3)2] 1a was explored. It yields the Lewis acid base adducts [M][R2Al-CH2-AlR2(μ-X)] [3a, M = Li(TMEN)2, X = Cl; 3b, M = Li(TMEN)2, X = Br; 3c, M = K(18-crown-6), X = ClO4; 3d, M = Li(TMEN)2, X = NH(i-Pr)] with X residing in a bridging position between the two Al atoms as evident from NMR spectroscopy and X-ray crystallography (3b, 3c, 3d). Compound 3c is a unique example of a stable, in organic solvents soluble adduct that features a ClO4 anion coordinated by an alkylaluminium compound via two of its oxygen atoms.
Key words: Aluminium, Lithium, Chelating Lewis Acids, Anion Receptors, Perchlorate
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