Picture of a black hole

Strathclyde Open Access research that creates ripples...

The Strathprints institutional repository is a digital archive of University of Strathclyde's Open Access research outputs. Strathprints provides access to thousands of research papers by University of Strathclyde researchers, including by Strathclyde physicists involved in observing gravitational waves and black hole mergers as part of the Laser Interferometer Gravitational-Wave Observatory (LIGO) - but also other internationally significant research from the Department of Physics. Discover why Strathclyde's physics research is making ripples...

Strathprints also exposes world leading research from the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Structural chemistry of monodentate donor-solvated mixed lithium-magnesium secondary amide complexes

Forbes, G.C. and Kennedy, A.R. and Mulvey, R.E. and Rodger, P.J.A. and Rowlings, R.B. (2001) Structural chemistry of monodentate donor-solvated mixed lithium-magnesium secondary amide complexes. Journal of the Chemical Society, Dalton Transactions, 2001 (9). pp. 1477-1484. ISSN 0300-9246

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

The monodentate donor-solvated intermetallic lithium-magnesium amide complexes [Mg(HMDS)(3)Li . (THF)] 1 [HMDS=N(SiMe3)(2)], [Mg(HMDS)(3)Li . (Pyr)] 2 and [Mg{N(Cy)(2)}(3)Li . (THF)] 3 [N(Cy)(2)=dicyclohexylamide] have been prepared and characterised by NMR spectroscopy and X-ray crystallography. Synthesis was achieved by the reaction of equimolar amounts of n-BuLi and n,sec-Bu2Mg with three equivalents of the appropriate amine in hexane/donor solution. The molecular structures of 1, 2 and 3 are essentially isostructural containing a central, planar LiNMgN four-membered ring: two amide units bridge to the metal centres whilst the third binds exclusively to magnesium in the terminal position to complete a three-coordinate distorted trigonal planar geometry. The lithium achieves a similar geometry with solvation from a single monodentate donor molecule. Three co-crystalline by-products were also isolated from solution and are included for completeness: [Mg(HMDS)(2)(Bu)Li . Pyr] 4, [(LiHMDS . Pyr)(2)] 5 and [Mg(HMDS)(2). (Pyr)(2)] 6. Complex 4 exhibits a similar structure to 1, 2 and 3 with an alkyl group (consisting of disordered n- and sec-butyl groups) replacing the terminal amido functionality. Complex 4 is produced by a similar method to 2 via incomplete amination in the presence of two equivalents of hexamethyldisilazane (HMDS(H)). In contrast, 5 and 6 are simple homometallic amides formed when an excess of pyridine is introduced into the reaction system. To conclude the study a series of reactions were undertaken in which the stoichiometry of both amine and donor was altered systematically. The results from this study imply that intermetallic aggregation is hindered by the presence of excess donor solvent.