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Lookup NU author(s): Dr Ross Harrington,
Emeritus Professor Bill Clegg
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A series of glutarimide derivatives which has two carbonyl coordination sites for intramolecular pentacoordination at silicon with a X1+nSiC3-nO moiety have been synthesised and characterized. The substituent (leaving group) effects on the Si-O bond exchange between the two coordination sites (resembling a pendulum) have been studied by comparison of the differently substituted (X = F, Cl, OTf, Br and I) structures. The activation parameters for the Si-O bond exchange process were measured by NMR and separately computed and are consistent with the strength of Si-O bond coordination and the nature of the leaving group, X. The temperature-dependent Si-29 NMR spectroscopy is supported by X-ray crystallography and shows that the tetrahedral reactant is converted into pentacoordinate intermediates by intramolecular O-Si association followed by reversion to a tetrahedral geometry by Si-X dissociation. The two association/dissociation patterns offer a model for nucleophilic substitution at a silicon atom. A continuum of structures on the S(N)2 reaction profile from the glutarimide derivatives correlates reasonably well with the structural data obtained from derivatives of lactams, diketopiperazines and quinolones.
Author(s): Sohail M, Panisch R, Bowden A, Bassindale AR, Taylor PG, Korlyukov AA, Arkhipov DE, Male L, Callear S, Coles SJ, Hursthouse MB, Harrington RW, Clegg W
Publication type: Article
Publication status: Published
Journal: Dalton Transactions
Print publication date: 14/08/2013
Online publication date: 22/05/2013
Acceptance date: 21/05/2013
ISSN (print): 1477-9226
ISSN (electronic): 1477-9234
Publisher: Royal Society of Chemistry
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