The influence of the C-N⁺ ----- F-C charge dipole interaction in fluoro organic chemistry

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

The influence of the C-N⁺ ----- F-C charge dipole interaction in fluoro organic chemistry

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.EThOS - Electronic Theses Online ServiceBiotechnology and Biological Sciences Research CouncilGlaxoSmithKlineGBUnited Kingdo

The fluorine-iminium ion <i>gauche</i> effect: proof of principle and application to asymmetric organocatalysis

The gauche effect that is induced upon reversible formation of an iminium ion (see structure: green F, blue N) provides a powerful method for the preorganization of transient intermediates that are central to secondary amine catalyzed processes. This phenomenon has been exploited in the design of a novel organocatalyst and is showcased in the stereoselective epoxidation of &#945;,&#946;-unsaturated aldehydes

Hunger in the primary school setting: Evidence, impacts and solutions according to school staff in the North East of England, UK

The issue of ‘holiday hunger’ (i.e. food insecurity during school holidays) has received increased attention in recent years, though research in this area is limited. Through qualitative, semi -structured interviews, the current study investigated the views of 12 primary school staff on the existence, impacts and potential solutions to holiday hunger. Thematic analysis revealed holiday hunger forms part of a broader, year -round experience of deprivation and poor nutritional habits. Staff proposed a need for a multi -agency approach to address a range of complex, inter -related needs. Additionally, the findings highlighted a need to address poverty stigma in the development of familial support

The intramolecular β-fluorine⋯ammonium interaction in 4- and 8-membered rings.

The structures of 3-fluoroazetidinium hydrochloride and 3-fluoro-1,5-diazacyclooctane hydrobromide are explored both by X-ray diffraction analysis and DFT calculations, and the conformations of these molecules are shown to be significantly influenced by the through space C–F⋯N+ interaction

The impact of coronavirus disease 2019 on the practice of thoracic oncology surgery: a survey of members of the European Society of Thoracic Surgeons (ESTS)

OBJECTIVES: There is widespread acknowledgement that coronavirus disease 2019 (COVID-19) has disrupted surgical services. The European Society of Thoracic Surgeons (ESTS) sent out a survey to assess what impact the COVID-19 pandemic has had on the practice of thoracic oncology surgery. METHODS: All ESTS members were invited (13-20 April 2020) to complete an online questionnaire of 26 questions, designed by the ESTS learning affairs committee. RESULTS: The response rate was 23.0% and the completeness rate was 91.2%. The number of treated COVID-positive cases per hospital varied from fewer than 20 cases (30.6%) to more than 200 cases (22.7%) per hospital. Most hospitals (89.1%) postponed surgical procedures. All hospitals performed patient screening with a nasopharyngeal swab, but only 6.7% routinely tested health care workers. A total of 20% of respondents reported that multidisciplinary meetings were completely cancelled and 66%, that multidisciplinary decisions were not different from normal practice. Trends were recognized in prioritizing surgical patients based on age (younger than 70), type of surgery (lobectomy or less), size of tumour (T1-2) and lymph node involvement (N1). Sixty-three percent of respondents reported that surgeons were involved in daily care of COVID-19-positive patients. Fifty-three percent mentioned that full personal protective equipment was available to them when treating a COVID-19-positive patient. CONCLUSIONS: The COVID-19 pandemic has created issues for the safety of health care workers, and surgeons have been forced to change their routine practice. However, there was no consensus about surgical priorities in lung cancer patients, demonstrating the need for the production of specific guidelines.status: publishe