Synthesis and crystal structures of organometallic compounds containing the ligands C(SiMe3)2(SiMe2H) and C(SiMe2Ph)2(SiMe2H)

Asadi, Ashrafolmolouk, Avent, Anthony G, Coles, Martyn P, Eaborn, Colin, Hitchcock, Peter B and Smith, David J (2004) Synthesis and crystal structures of organometallic compounds containing the ligands C(SiMe3)2(SiMe2H) and C(SiMe2Ph)2(SiMe2H). Journal of Organometallic Chemistry, 689 (7). 1238 - 1248. ISSN 0022-328X

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Abstract

Metallation of (HMe2Si)(Me3Si)2CH (1) by LiMe gave the organolithium compound Li(THF)2C(SiMe3)2(SiMe2H) (2a), which exists in toluene solution as a mixture of covalent species and ion pairs [Li(THF)4][Li{C(SiMe3)2(SiMe2H)}2] (2b). Treatment of a mixture of 1 and LiMe with KOBut gave KC(SiMe3)2(SiMe2H) (3). This reacted with AlMe2Cl in hexane/THF to give Al(THF)Me2{C(SiMe3)2(Si Me2H)} (4). Treatment of (HMe2Si)(PhMe2Si)2CH (5) with LiMe in Et2O/THF gave the THF adduct [Li(THF)2C(SiMe2Ph)2(SiMe2H)] (6); in the presence of KOBut the solvent-free [K][C(SiMe2Ph)2(SiMe2H)] (7) was obtained. Crystal structure determinations showed that 6 crystallizes in a molecular lattice and 7 in an ionic lattice in which the coordination sphere of the potassium comprises phenyl groups and hydrogen atoms attached to silicon, as well as the central carbon of the bulky carbanion. Compound 7 reacted with an excess of AlMe2Cl to give [AlClMe{C(SiMe2Ph)2(SiMe2H)}]2 (8) and AlMe3. A small amount of the methoxo derivative [Al(OMe)Me{C(SiMe2Ph)2(SiMe2H)}]2 (9) was obtained as a byproduct, presumably after the accidental admission of traces of air. X-ray structural determinations showed that 8 forms halogen-bridged dimers, with the bulky ligands in the anti-configuration, and 9 forms methoxo-bridged species in which the bulky ligands are syn.

Item Type: Article
Schools and Departments: School of Life Sciences > Chemistry
Depositing User: Martyn Coles
Date Deposited: 06 Feb 2012 18:45
Last Modified: 30 Nov 2012 17:01
URI: http://sro.sussex.ac.uk/id/eprint/18191
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