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Energy transfer in lanthanide complexesClarkson, Ian Michael January 1999 (has links)
This thesis details investigations into the photophysical properties of lanthanide ions in a number of different systems. The preparation and characterisation of lanthanide containing surfactant salts of the type Ln(A0T)(_3) (Ln = Tb, Nd, Eu, AOT = bis-(2-ethylhexyl) sulfosuccinate) is described. Small angle neutron scattering experiments have been used to determine the size and shape of reverse micelles formed by these surfactants in water/cyclohexane microemulsions. The luminescence lifetimes of the lanthanide ions have been used to investigate the solvation environment within reverse micelle systems as a function of water content. The use of lanthanide complexes based on 1,4,7,10-tetraazacyclododecane bearing phenanthridine antenna in luminescence microscopy has been explored. Samples such as silica particles, onion skin cells and guinea pig heart cells have been imaged. Time- resolved measurements have allowed time gating of the sample from a fluorescent background and lifetime maps of the images have been obtained. The preparation and characterisation of deuteriated complexes of dota (1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid) with lanthanide ions is described. Selective deuteriation of both the ring and arm sites allow the relative quenching effects of C-H/D oscillators to be determined for various lanthanides in a series of structurally well defined complexes. Finally, investigations into the distance dependence of the energy transfer between aromatic chromophores and lanthanide ions have been undertaken. The synthesis of a model system linking a phenanthridine donor to a europium complex by poly(valine) spacer units is described. Preliminary photophysical results show that the quantum yield of emission by europium decreases as the distance between the donor acceptor pair is increased.
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The development of new and improved deuterium/tritium labeling procedures relevant to biomaterialsGetvoldsen, Gareth Simon January 2000 (has links)
This thesis is concerned with the development of new and improved labeling procedures for introducing deuterium and tritium into organic compounds with the intention that some of the methods can be applied to more complex compounds such as biomaterials. The thesis consists of 6 chapters. In the first of these the necessary background information relating to biomaterials and the currently used methods of preparing deuteriated/tritiated compounds is presented, whilst in the second chapter various aspects of the use of our Tri-Sorber unit, unique to universities, are presented. The instrument allows H2, D2 and T2 to be stored on uranium beds and does away with the many problems associated with the use of a glass gas line; this is especially true for T2. In Chapter 3 the advantages of using microwaves in the area of aromatic dehalogenations are explored. The use of solid formates (DCOO-K+) in preference to D2 gas, combined with microwave irradiation, greatly increases the rates of these reactions although there are still instances where reactions do not proceed satisfactorily. In Chapter 4 it is shown for the first time how the pattern of microwave-enhanced Raney nickel isotope exchange reactions can be influenced, depending on the deuteriated solvent employed. General labeling through to specific labeling is reported. In Chapter 5 the benefits of using microwave and solid donors in hydrogenation reactions are explored; some examples of microwave-enhanced hydrogenations in the absence of solvent, as well as in the presence of solvent, are reported. Finally, in the last, brief chapter some of the new developments reported in the earlier chapters are applied to the attempted deuteriation of a biocompatible polymer and a model compound.
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