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Please use this identifier to cite or link to this item: http://hdl.handle.net/10023/695
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Natalie Gooseman PhD thesis.pdf3.89 MBAdobe PDFView/Open
Title: The influence of the C-N⁺ ----- F-C charge dipole interaction in fluoro organic chemistry
Authors: Gooseman, Natalie Elizabeth Jane
Supervisors: O'Hagan, David, 1961-
Keywords: Fluorine
Organo-fluorine
Fluorine gauche effect
Charge dipole
Conformation
Charged nitrogen
Issue Date: 25-Jun-2008
Abstract: Chapter 1 introduces the discovery of elemental fluorine by H. Moissan and some uses of inorganic fluoride. Organo fluoro compounds and their place in pharmaceuticals and agrochemicals are also introduced. The general properties of fluorine and the C-F bond are discussed as well as conformational influences such as the fluorine gauche effect. Chapter 2 describes the C-N⁺------F-C charge dipole interactions within protonated amines and explains the influence of a β fluorine on the conformation on various crystalline structures. A number of systems are synthesised which contain this charge dipole interaction, such as four, five and eight membered aza heterocycles. It was demonstrated that these provided a N⁺-C-C-F gauche torsion angle. This electrostatic effect was also observed in the non-protonated N-ethylpyridinium cations possessing a fluorine β to the charged nitrogen. This clearly showed that hydrogen bonding is not playing a part in the observed N⁺-C-C-F gauche interactions and that it is a purely electrostatic effect. Chapter 3 discusses the effort to explore the C-O⁺-------F-C charge dipole interaction and the synthetic approaches that were taken towards candidate substances. However in the event a Grignard reaction on a fluoro cyclohexanone was found to provide an unexpected product where rearrangement followed by fluorine elimination had occurred. Chapter 4 details the experimental procedures for the compounds synthesised in this thesis and an Appendix outlines the detail of 24 crystal structures that were solved during this research.
URI: http://hdl.handle.net/10023/695
Type: Thesis
Publisher: University of St Andrews
Appears in Collections:Chemistry Theses



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