Anions are involved in fundamental processes in all living things. Recognition,transport and concentration control of anions such as chloride, phosphate and sulfate iscarried out by biological systems on a perpetual basis. Fluoride, nitrate and pertechnetate are potentially dangerous contaminants that can gain access to our watersystems by various means. Fluorosis, toxicity due to high levels of fluoride in drinkingwater, is a serious human health concern in many parts of the world Synthetic chemistsseek to mimic nature’s level of sophistication in designing and making chemosensorscapable of determining the concentration of a target anion in any medium.
Beginning with a review of anion sensor chemistry with a particular focus ondevelopments over the past 15 years, this thesis documents research into novelmolecular sensors that target the differential sensing of fluoride and chloride anions.The design of these sensors has focussed on an optical signalling event based onelectronic changes on binding but in addition, by virtue of a significant change instructural 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 thisclass of molecule to various anions. One example designed to fit our proposed modelshows interesting and unusual fluorescence quenching response to chloride anion. Inaddition, the synthesis of a related carbamate species and a range of oxygen bridgedboron macrocycles are reported.
Results and Discussion II discloses our approaches to more synthetically demandingconstructs, obeying the model but trying to overcome the challenges met previously.An interesting, highly selective ratiomeric response to fluoride is observed with anisolated target molecule. Fluoride binding behaviour of a previously unexamined sp2boron centre is examined.
|Date of Award||1 Jan 2010|
|Supervisor||Tony James (Supervisor) & Matthew Davidson (Supervisor)|