Sterically encumbered lithium dialkynidoalanates Li[R₂Al(–C≡C–R’)₂] [R=CH(SiMe₃)₂]

Issue title: Papers presented at the ‘Early Main Group Metal Chemistry’ symposium as part of the Pacifichem 2005 conference. Honolulu, Hawaii, December 15th- 20th, 2005.

Article type: Research Article

Authors: Uhl, W. | s, | Er, E. | Matar, M.

Affiliations: Institut für Anorganische und Analytische Chemie der Universität Münster, Münster, Germany

Note: [] Corresponding author. E-mail: [email protected]

Abstract: Bis[bis(trimethylsilyl)methyl]aluminium chloride, [(Me3Si)2CH]2Al–Cl, reacted with two equivalents of the lithium alkynides Li–C≡C–R (R=CMe3, C6H5) and formed the corresponding alanates Li{[(Me3Si)2CH]2Al(–C≡C–R’)2} (1: R=C6H5; 2: R=CMe3), both of which were characterized by crystal structure determinations. Interestingly, a similar ether adduct (3) was formed by the treatment of the trialkylalane Al[CH(SiMe3)2]3 with Li–C≡C–C6H5. The lithium atoms of all compounds are coordinated to both carbon atoms of the triple bonds with the shortest distance to the carbanionic carbon atoms of the alkynido groups. While compounds 1 and 2 form one-dimensional coordination polymers through intermolecular interactions between Li atoms and CH3 groups, an ether molecule attached to the lithium atom of monomeric 3 prevents its polymerization.

Keywords: Aluminium, Alkynides, Lithium

DOI: 10.1080/10241220600833414

Journal: Main Group Chemistry, vol. 5, no. 1, pp. 31-40, 2006