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This thesis is concerned with the preparation of regiospecifically labelled compounds by homogeneous metal catalysed hydrogen isotope exchange reactions. The features of homogeneous hydrogen isotope exchange reactions are discussed in Chapter 1, along with other exchange methods; acid, base, heterogenous metal, radiation, enzymic and zeolite catalysis. In Chapter 2, homogeneous rhodium trichloride is investigated for regiospecificity of tritium labeling in a wide range of aromatic compounds. High regiospecificity of labelling ortho to carboxyl, carboxamide and methanamide groups is found, with the regiospecificity determined by 3H nmr spectroscopy. Also discussed is a study to determine whether any other Group VIII metal complexes will catalyse the ortho tritiation of benzoic acid, in addition to rhodium trichloride. The results of detritiation studies performed on benzoic acids using ruthenium acetylacetonate as catalyst as a model for rhodium trichloride are presented in Chapter 3, A possible reaction mechanism is also presented. Finally, an application of the rhodium trichloride system to the labelling of biologically useful molecules is discussed in Chapter 4. The deuteration and tritiation of a number of drugs and metabolites containing known ortho directing groups is described. In a large number of cases, the regiospecificity for ortho labelling is very high.

Hydrogen isotope separation systems using palladium (Pd) are currently being designed for both reactor designs with the aim of separating and purifying the reactor exhaust products which contain valuable unspent hydrogen isotopes. Hydrogen isotope exchange in Pd offers an efficient, ambient condition process that can produce pure isotopic species in a process far simpler and less costly than the current state of the art cryogenic distillation processes. The method is applicable whether separating hydrogen (protium), deuterium or tritium and any combination of these. If practical fusion devices are ever to be realised it is essential to produce an economical and efficient fuel cycle capable of separating and purifying hydrogen isotopes. Hydrogen isotope exchange in Pd is also of interest to the waste separation and purification industries, in particular those using hydrogen separation membranes which used Pd and Pd-alloy membranes. Understanding hydrogen isotope exchange, with particular regard to the formation of the intermediate (and often unwanted) hydrogen deuteride (HD), will aid significantly in future designs of hydrogen isotope separation systems. Novel hydrogen isotope exchange experiments involving hydrogen and deuterium at a number of temperatures (208 K, 293 K and 373 K) and pressures (1.3 bar – 8 bar) not yet explored are presented in this thesis. The experiments were carried out on a unique piece of laboratory apparatus provided to and further developed at the University of Bath. Alongside experimentation, a novel comprehensive multidimensional multi-physics model has been created to analyse the experimental data obtained using the new apparatus and elucidate the kinetics and mechanisms of the reactions occurring between hydrogen isotopic species and Pd during hydrogen isotope exchange based on Langmuir-Hinshelwood surface reaction mechanism. The surface reaction rates, kinetic rate constants and heat effects have been examined in detail, and in tandem, for the first time.

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<p> Oxygen and hydrogen isotopic distributions have been studied for rocks from a 100 km transect in the central Superior Province of Ontario, Canada. The transect represents progressively deeper terrains of the Michipicoten Greenstone Belt (MGB), the Wawa Gneiss Terrane (WGT), and the Kapuskasing Structural Zone (KSZ), which correspond to an increase of metamorphic grade and are interpreted as an oblique section through approximately 20 km of crustal thickness. The rocks in the terrains range in age from ~2.76 to ~2.60 Ga, with fewer later intrusions.</p> <p> Equivalent lithologic types have similar δ18O range at middle and lower crustal levels (WGT and KSZ). Tonalitic to granodioritic rocks range from 6.4%o to 9.5o/oo; Dioritic and anorthositic rocks range from 5.5o/oo to 7.6o/oo; a majority of the mafic gneisses (group 1) range from 5.7o/oo to 7.1o/oo, while group 2 mafic gneisses range from 8. 1o/oo to 9.5o/oo. δ18O values of the rocks exhibit a remarkable correlation with SiO2 values, similar to that observed in unaltered plutonic rocks of equivalent composition. Paragneisses have significantly higher δ18O values, 9.3o/oo to 12.2o/oo. Low-grade metavolcanic and metasedimentary rocks of the MGB are 18O-enriched compared to their high-grade equivalents in the KSZ and WGT, 7.4o/oo to 13.3o/oo for mafic to felsic metavolcanic rocks and 11.4o/oo to 14.7o/oo for clastic metasediments.</p> <p> Coexisting minerals from high-grade rocks exhibit 18O-fractionation closely consistent with isotopic equilibrium, suggesting that the isotopic system has not been grossly disturbed. Isotopic thermometers give uniform apparent temperatures, about 553°C to 584°C, across the entire transect, which are lower than the inferred metamorphic temperatures in the highest-grade (KSZ) terrane.</p> <p> The lack of distinctive isotopic differences between equivalent rock types in the KSZ and WGT suggests that there is no significant gradient in δ18O with depth in the crust or with metamorphic grade. The majority of mafic gneisses (Group 1) have δ18O values similar to fresh basalts and appear to have been emplaced either as subaerial extrusives, intrusive sills, or, less likely, as submarine extrusives that were hydrothermally altered at high temperatures. The less abundant Group 2 mafic gneisses have δ18O values typical of greenstones that were altered at low temperature by sea-water, and isotopically resemble low-grade rocks in the Michipicoten and Abitibi belts. In general, no major changes in whole-rock isotopic composition appear to have occurred during granulite facies metamorphism, implying limited flux of water or CO2.</p> <p> The continuous linear gradient in δ18O vs SiO2 in the high-grade rocks cannot be due to differentiation of a mafic source magma. A model involving an association between mantle-derived mafic magma and 18O-enriched crustal materials is more consistent with the oxygen isotopic data.</p> <p> Hydrogen isotope composition of hornblende and biotite has been analyzed from selected rocks. Mafic and anorthositic rocks from the KSZ have δD values from -58 to -62o/oo, suggesting a possible mantle-derived origin of fluid in the system. Two mafic gneisses, which are 18O-enriched, show lower δD values, -89 and -101o/oo. The depletion of deuterium is consistent with the model of low temperature alteration with seawater in a submarine environment. Mafic and tonalitic gneisses from the WGT are also depleted in deuterium, -87 to -109o/oo. Since these rocks intruded into relatively higher level of the crust and commonly contain secondary alteration minerals, it is possible that hydrothermal alteration took place at late- or post-metamorphism stage, and the source of the fluid is likely meteoritic water, The amount of water involved in the exchange was restricted, and was not enough to disturb the oxygen isotopic system in the rocks.</p> / Thesis / Master of Science (MSc)

Grassland bird populations in North America are in steady decline. Despite declining faster and more consistently than any other group of birds, grassland songbird populations are relatively understudied and little is known about factors driving breeding-site philopatry and dispersal. Landscape and habitat composition may influence fidelity of grassland songbirds to a breeding area. As predicted by the theory of the <i>Ideal Free Distribution</i>, high-quality sites are likely to have a higher percentage of return breeders than low-quality sites because higher quality sites should have more or better-quality resources birds need for improved fitness. Using stable hydrogen isotope (äD) analysis, I approximated minimum fidelity rates of two grassland songbirds to two landscape (grass- vs crop-dominated landscapes) and two habitat (native grass vs planted grass) types. I hypothesized that grassland songbirds would return more readily to higher quality sites. For Spragues Pipit (<i>Anthus spragueii</i>), a habitat specialist, this would mean returning more readily to native grass habitat in grass dominated landscapes. I expected no difference in return rate of Savannah Sparrow (<i>Passerculus sandwichensis</i>), a habitat generalist, to either habitat or landscape. However, I found that the proportion of non-returning breeders was not influenced by landscape or habitat for either species. Furthermore, I examined attributes (distance from capture point to nearest crop and to the nearest road, as well as the percentage of native grass, planted grass, water and woody vegetation within landscape and territory buffers around the capture point) of the landscape and territory of each individual to determine if specific landscape or territory characteristics influenced their return rate to a breeding area. Neither species showed an affinity or aversion to any of the landscape or territory characteristics considered.<p> At a larger scale, geographical position within the breeding range may influence dispersal rates of migratory songbirds. Given that environmental factors often change in a clinal manner, central populations presumably experience the most favorable environmental conditions and peripheral populations the least favorable. Therefore, geographically peripheral locations likely occur in ecologically marginal or stressful conditions, resulting in higher dispersal rates of migratory birds. I examined the differences in dispersal rates of two grassland songbirds at two geographically distinct locations; one centrally located in the Spragues Pipit breeding range (Last Mountain Lake area, SK, Canada) and one at the periphery (Bowdoin National Wildlife Refuge, MT, USA). As expected, Spragues Pipits at the Bowdoin National Wildlife Refuge had a significantly larger dispersal rate than at the Last Mountain Lake area. Savannah Sparrow dispersal rates did not differ between locations at the more conservative outlier classification. These results provide some limited evidence that geographical position within the breeding range can influence dispersal rates.<p> Using äD analysis, I found that local amount-weighted growing-season deuterium in precipitation (äDp) at locations within grassland ecosystems differed from those long-term (45+ year) models described by stable hydrogen isotope ratio basemaps, illustrated in Hobson and Wassenaar (1997), Meehan et al. (2004) and Bowen et al. (2005). Therefore, I describe how äDp values were corrected from the long-term isoscape value predicted by Bowen et al. (2005). This method of determining year-specific local weighted growing-season äDp is an improvement upon the currently used Bowen et al. (2005) isoscape that is based on long-term precipitation patterns. To improve assignment of individuals to origins based on their äDf values, future research should incorporate year-to-year variation by applying year-specific corrections to the Bowen et al. (2005) isoscape.<p> More research is needed to determine the factors affecting the philopatry and dispersal of grassland songbirds in order to conserve them.

Grassland bird populations in North America are in steady decline. Despite declining faster and more consistently than any other group of birds, grassland songbird populations are relatively understudied and little is known about factors driving breeding-site philopatry and dispersal. Landscape and habitat composition may influence fidelity of grassland songbirds to a breeding area. As predicted by the theory of the <i>Ideal Free Distribution</i>, high-quality sites are likely to have a higher percentage of return breeders than low-quality sites because higher quality sites should have more or better-quality resources birds need for improved fitness. Using stable hydrogen isotope (äD) analysis, I approximated minimum fidelity rates of two grassland songbirds to two landscape (grass- vs crop-dominated landscapes) and two habitat (native grass vs planted grass) types. I hypothesized that grassland songbirds would return more readily to higher quality sites. For Spragues Pipit (<i>Anthus spragueii</i>), a habitat specialist, this would mean returning more readily to native grass habitat in grass dominated landscapes. I expected no difference in return rate of Savannah Sparrow (<i>Passerculus sandwichensis</i>), a habitat generalist, to either habitat or landscape. However, I found that the proportion of non-returning breeders was not influenced by landscape or habitat for either species. Furthermore, I examined attributes (distance from capture point to nearest crop and to the nearest road, as well as the percentage of native grass, planted grass, water and woody vegetation within landscape and territory buffers around the capture point) of the landscape and territory of each individual to determine if specific landscape or territory characteristics influenced their return rate to a breeding area. Neither species showed an affinity or aversion to any of the landscape or territory characteristics considered.<p> At a larger scale, geographical position within the breeding range may influence dispersal rates of migratory songbirds. Given that environmental factors often change in a clinal manner, central populations presumably experience the most favorable environmental conditions and peripheral populations the least favorable. Therefore, geographically peripheral locations likely occur in ecologically marginal or stressful conditions, resulting in higher dispersal rates of migratory birds. I examined the differences in dispersal rates of two grassland songbirds at two geographically distinct locations; one centrally located in the Spragues Pipit breeding range (Last Mountain Lake area, SK, Canada) and one at the periphery (Bowdoin National Wildlife Refuge, MT, USA). As expected, Spragues Pipits at the Bowdoin National Wildlife Refuge had a significantly larger dispersal rate than at the Last Mountain Lake area. Savannah Sparrow dispersal rates did not differ between locations at the more conservative outlier classification. These results provide some limited evidence that geographical position within the breeding range can influence dispersal rates.<p> Using äD analysis, I found that local amount-weighted growing-season deuterium in precipitation (äDp) at locations within grassland ecosystems differed from those long-term (45+ year) models described by stable hydrogen isotope ratio basemaps, illustrated in Hobson and Wassenaar (1997), Meehan et al. (2004) and Bowen et al. (2005). Therefore, I describe how äDp values were corrected from the long-term isoscape value predicted by Bowen et al. (2005). This method of determining year-specific local weighted growing-season äDp is an improvement upon the currently used Bowen et al. (2005) isoscape that is based on long-term precipitation patterns. To improve assignment of individuals to origins based on their äDf values, future research should incorporate year-to-year variation by applying year-specific corrections to the Bowen et al. (2005) isoscape.<p> More research is needed to determine the factors affecting the philopatry and dispersal of grassland songbirds in order to conserve them.

abstract: Hydrogen isotope compositions of the martian atmosphere and crustal materials can provide unique insights into the hydrological and geological evolution of Mars. While the present-day deuterium-to-hydrogen ratio (D/H) of the Mars atmosphere is well constrained (~6 times that of terrestrial ocean water), that of its deep silicate interior (specifically, the mantle) is less so. In fact, the hydrogen isotope composition of the primordial martian mantle is of great interest since it has implications for the origin and abundance of water on that planet. Martian meteorites could provide key constraints in this regard, since they crystallized from melts originating from the martian mantle and contain phases that potentially record the evolution of the H2O content and isotopic composition of the interior of the planet over time. Examined here are the hydrogen isotopic compositions of Nominally Anhydrous Phases (NAPs) in eight martian meteorites (five shergottites and three nakhlites) using Secondary Ion Mass Spectrometry (SIMS). This study presents a total of 113 individual analyses of H2O contents and hydrogen isotopic compositions of NAPs in the shergottites Zagami, Los Angeles, QUE 94201, SaU 005, and Tissint, and the nakhlites Nakhla, Lafayette, and Yamato 000593. The hydrogen isotopic variation between and within meteorites may be due to one or more processes including: interaction with the martian atmosphere, magmatic degassing, subsolidus alteration (including shock), and/or terrestrial contamination. Taking into consideration the effects of these processes, the hydrogen isotope composition of the martian mantle may be similar to that of the Earth. Additionally, this study calculated upper limits on the H2O contents of the shergottite and nakhlite parent melts based on the measured minimum H2O abundances in their maskelynites and pyroxenes, respectively. These calculations, along with some petrogenetic assumptions based on previous studies, were subsequently used to infer the H2O contents of the mantle source reservoirs of the depleted shergottites (200-700 ppm) and the nakhlites (10-100 ppm). This suggests that mantle source of the nakhlites is systematically drier than that of the depleted shergottites, and the upper mantle of Mars may have preserved significant heterogeneity in its H2O content. Additionally, this range of H2O contents is not dissimilar to the range observed for the Earth’s upper mantle. / Dissertation/Thesis / Masters Thesis Geological Sciences 2015

α-Epimerisation has been found to be absent in the reactions of threo-1,2-diphenyl-1-propyltrimethylammonium ion and its -2-d₁ analogue with t-butoxide ion in t-butyl alcohol at 30ºC. The formation of trans-α-methylstilbene, cis-α-methylstilbene and threo-N,N-dimthyl-1,2-diphenyl-1-propylamine has been associated with anti-elimination, syn-elimination and with nucleophilic substitution at a N-methyl carbon atom, respectively, and interpreted in terms of structural and medium features of the reactions. The β-hydrogen isotope effects for anti- and syn-elimination have been associated with reactant-like and product-like transition states, respectively, for these reaction modes. / Thesis / Master of Science (MSc)