Anions are involved in fundamental processes in all living things. Recognition, transport and concentration control of anions such as chloride, phosphate and sulfate is carried out by biological systems on a perpetual basis. Fluoride, nitrate and pertechnetate are potentially dangerous contaminants that can gain access to our water systems by various means. Fluorosis, toxicity due to high levels of fluoride in drinking water, is a serious human health concern in many parts of the world Synthetic chemists seek to mimic nature’s level of sophistication in designing and making chemosensors capable of determining the concentration of a target anion in any medium. Beginning with a review of anion sensor chemistry with a particular focus on developments over the past 15 years, this thesis documents research into novel molecular sensors that target the differential sensing of fluoride and chloride anions. The design of these sensors has focussed on an optical signalling event based on electronic changes on binding but in addition, by virtue of a significant change in structural conformation. Fluorescent molecules have been utilised and as such, fluorescence emission changes investigated in the presence of a variety of anions. Results and Discussion I outlines our conformational model and discusses the design, synthesis and sensory behaviour of phenyl(boronates). UV, electrochemical, fluorescence and NMR techniques are brought together to elucidate the response of this class of molecule to various anions. One example designed to fit our proposed model shows interesting and unusual fluorescence quenching response to chloride anion. In addition, the synthesis of a related carbamate species and a range of oxygen bridged boron macrocycles are reported. Results and Discussion II discloses our approaches to more synthetically demanding constructs, obeying the model but trying to overcome the challenges met previously. An interesting, highly selective ratiomeric response to fluoride is observed with an isolated target molecule. Fluoride binding behaviour of a previously unexamined sp2 boron centre is examined.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:518289 |
| Date | January 2010 |
| Creators | Galbraith, Ewan |
| Contributors | James, Tony ; Davidson, Matthew |
| Publisher | University of Bath |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0015 seconds