Issue 2, 1988

Some sterically hindered lithium alkylbromo- and alkylchloro-magnesates, -cadmates, and -manganates. Crystal and molecular structures of [Li(thf)2(µ-Br)2Mg{C(SiMe3)3}(thf)], [Li(thf)4][{Cd[C(SiMe3)3]}3(µ-Br)33-Br)]·0.5C6H12, [{Li(thf)}33-Br)33-OSiMe3)Cd{C(SiMe3)3}], and [Li(thf)4][{Mn[C(SiMe3)3]}3(µ-Cl)4(thf)](thf = tetrahydrofuran)

Abstract

Tris(trimethylsilyl)methyl-lithium reacts with anhydrous magnesium(II) bromide to give the magnesate [Li(thf)2(µ-Br)2Mg{C(SiMe3)3}(thf)](1), which has been shown by an X-ray study to have a structure with two bridging bromine atoms between lithium and magnesium. With cadmium(II) bromide, Li{C(SiMe3)3} gives the tricadmate [Li(thf)4][{Cd[C(SiMe3)3]}3(µ-Br)33-Br)]·0.5C6H12(2)(C6H12= cyclohexane), in which the anion has a structure based on a Cd3Br4 cube with one corner missing. In the presence of traces of moisture, the neutral compound [{Li(thf)}33-Br)33-OSiMe3)Cd{C(SiMe3)3}](3), also with a cage structure, is obtained. Both (2) and (3) can be converted into CdBr{C(SiMe3)3}, and Cd(OH){C(SiMe3)3}. The chloride CdCl{C(SiMe3)3} is dimeric in the gas phase. The reaction between tris(dimethylphenylsilyl)methyl-lithium and cadmium(II) bromide yields the cadmate Li(thf)2CdBr2{C(SiMe2Ph)3} which can be converted into Cd(OH){C(SiMe2Ph)3}, CdBr{C(SiMe2Ph)3}, or Cd(OMe){C(SiMe2Ph)3}. The reaction between Li{C(SiMe3)3} and anhydrous manganese(II) chloride gives the trimanganate [Li(thf)4][{Mn[C(SiMe3)3]}3(µ-Cl)4(thf)], in which the anion has been shown by X-ray diffraction to have a cage structure related to that of the anion in (2). In each C(SiMe3)3 group the three SiMe3 fragments are twisted from fully staggered positions so the group as a whole is chiral. In some tris(trimethylsilyl)methylmetal compounds left- and right-handed C(SiMe3)3 groups alternate in the crystal lattice; in other chiralities are arranged randomly.

Article information

Article type
Paper

J. Chem. Soc., Dalton Trans., 1988, 381-391

Some sterically hindered lithium alkylbromo- and alkylchloro-magnesates, -cadmates, and -manganates. Crystal and molecular structures of [Li(thf)2(µ-Br)2Mg{C(SiMe3)3}(thf)], [Li(thf)4][{Cd[C(SiMe3)3]}3(µ-Br)33-Br)]·0.5C6H12, [{Li(thf)}33-Br)33-OSiMe3)Cd{C(SiMe3)3}], and [Li(thf)4][{Mn[C(SiMe3)3]}3(µ-Cl)4(thf)](thf = tetrahydrofuran)

N. H. Buttrus, C. Eaborn, M. N. A. El-Kheli, P. B. Hitchcock, J. D. Smith, A. C. Sullivan and K. Tavakkoli, J. Chem. Soc., Dalton Trans., 1988, 381 DOI: 10.1039/DT9880000381

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements