Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: Wm. Randall Babbitt. Includes bibliographical references (leaves 250-257).

Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on June 9, 2010). "Department of Chemistry." Includes bibliographical references.

Many of the world's economic rare earth element (REE) deposits are formed from, or have been subsequently upgraded by, hydrothermal fluids. Some of the most important REE minerals are the light REE (LREE) enriched fluorocarbonates and carbonates, which are commonly found in carbonatites. Textural and mineralogical evidence from these and other sites point towards wall rock composition as a major control on the observed REE mineralisation, with the supply of carbonate, and possibly fluoride, thought to be the limiting factor. Despite theoretical and experimental studies focussed on REE speciation in hydrothermal fluids, and a few on REE mineral solubility, there remains a lack of understanding of the processes occurring at the uid-rock interface during REE carbonate and fluorocarbonate mineralisation. Many of the issues surrounding this topic stem from the difficulty of working at elevated temperatures, low REE concentrations, and with the corrosive fluoride ion. The synthesis of REE carbonates under simple, low temperature conditions is a useful starting point for understanding REE mineralisation, and as such has been the focus of research for decades. Despite this, cross-series trends are rarely assessed together under the same conditions, and multi-REE-bearing systems - useful for assessing REE fractionation - have scarcely been explored. Furthermore, wall rock experiments, whereby REE-rich fluids are reacted directly with carbonate rocks, are absent from the literature. The same is true for systems containing fluoride, necessary for studying the formation of fluorocarbonates. A fuller understanding of REE mineralisation cannot be achieved until empirical experimental results can be compared with theoretical data and field observations. This thesis documents the laboratory synthesis of single- and multiple-REE-bearing carbonates and fluorocarbonates, and compares the findings with a mineralogical and textural study of two REE-bearing carbonatite deposits. The REEs La, Nd, Gd, Er and Yb were investigated as representatives of the entire series. The experiments constituted titrations of REE chloride solutions with sodium carbonate, and `wall rock reactions' of REE chloride with dolomite, or dolomite plus fluorite. Batch and flow-through setups were used, and the experiments were performed, or the products aged, at temperatures ranging from ambient to 200 °C. Products were characterised by techniques such as PXRD and SEM to document their structure and morphology as a function of temperature, and assess the influence of single vs multiple REE on the final material (whether mixed or separate phases formed). Results showed that in titration experiments, the LREEs crystallised easily and at low temperatures (as low as room temperature), HREEs either do not crystallise (in some cases even at 200 °C) or are more diffcult to crystallise, and mixed LREE + HREE precipitates behaved more like HREE-only examples. The HREEs and LREEs + HREEs mostly produced X-ray amorphous materials, identified as carbonates using FTIR. These were analysed by XAS (XANES and EXAFS) to assess whether they possessed the same short-range structure as the crystalline phase into which are known to form, thus adding to the non-classical nucleation pathway argument as previously suggested for these materials. Results suggested the short-range order of most phases analysed were similar to known bulk phases, but that these were probably different to the earlier precipitates formed in solution. Additionally, in the mixed LREE + HREE systems (Nd+Er), REEs were well dispersed (as opposed to Nd- and Er-rich clusters). In contrast to the titration results were those of wall rock reactions, in which excellent crystallisation was observed for almost every REE configuration (single- or up to five- REE mix), or ageing duration. All but three of the phases produced were previously described natural or synthetic minerals. When fluorite was included in batch reactions the results were more varied: REE carbonates, fluorides and fluorocarbonates were all observed, but never together in the same sample (except in one example). A textural and mineralogical assessment of two carbonatite deposits, Bayan Obo, China and Tundulu, Malawi, which were analysed by EMPA, revealed multiple stages of hydrothermal activity, some of which related to REE fluorocarbonate mineralisation. REE fluorocarbonates, identified at both sites, were typically LREE enriched. No REE carbonates or fluorides were observed, despite the presence of fluorite (REE-barren) and carbonates at Bayan Obo, and carbonates (low REE content) at Tundulu. However, at both sites apatite contained considerable REE. The REE fluorocarbonates were not solely associated with carbonate wall rocks, although the Ca-REE fluorocarbonate synchysite was only observed in the significantly more carbonate-rock-rich Tundulu samples. At Bayan Obo, bastnasite and huanghoite (Ba-REE fluorocarbonate) were observed, the latter of which is reportedly replacing earlier Ca-REE fluorocarbonates. The results demonstrate the varying behaviour of REEs during precipitation under different conditions, and highlights the influence of dissolved carbonate supply rate to morphology, structure and crystallinity of the products. The occurrence of only one class of REE mineral (carbonate, fluoride or fluorocarbonate) in the synthetic experiments with fluoride may help explain the lack of natural REE carbonates and fluorides - and predominance of REE fluorocarbonates - in hydrothermal systems, as was observed in the natural samples studied. In addition, the lack (absence?) of naturally occurring HREE carbonates and fluorocarbonates in the studied carbonatites (and the literature) is suggested to result not from factors such as structural constraints, but instead from the relative crustal abundances of the individual REEs. It is shown that HREE carbonates and fluorocarbonates are valid species under certain conditions, but that these are not likely to occur naturally.

Magister Scientiae - MSc (Physics) / Rare-earth intermetallic compounds continue to draw considerable attention, due to their fundamental importance in understanding physical properties and potential applications based on a variety of phenomena. The focus of this project is to employ two family of rare-earth intermetallic compounds: RE2Pt2In (RE = Pr, Nd) and RE8Pd24Ga (RE = Gd, Tb, Dy) ternary intermetallic systems as a model candidate to uncover the underlying ground state properties that result in a strong coupling between the conduction electron and the 4f-electron of the rare-earth ions.

Orientador: Gilbert Bannach / Banca: Eder Tadeu Gomes Cavalheiro / Banca: Flavio Junior Caires / O Programa de Pós Graduação em Ciência e Tecnologia de Materiais, PosMat, tem caráter institucional e integra as atividades de pesquisa em materiais de diversos campi / Resumo: A síntese e caracterização de complexos do fármaco anti-inflamatório não esteroide sulindaco (sulin) com os íons lantanídeos (Ln3+) La3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+ e Ho3+ no estado sólido são descritas neste trabalho. A caracterização dos complexos foi realizada empregando a termogravimetria-calorimetria exploratória diferencial simultânea acoplada ao espectrômetro de FTIR (TG-DSC-FTIR), DSC-fotovisual, titulação complexométrica com EDTA e análise elementar, além de utilização de difração de raios X pelo método do pó e espectroscopia vibracional de refletância na região do infravermelho com transformada de Fourier (FTIR). Os métodos termoanalíticos foram utilizados para verificar a decomposição térmica, estabilidade térmica, entalpia de desidratação, entre outras propriedades e juntamente com a titulação complexométrica e a análise elementar, foi possível determinar a estequiometria dos complexos como [Ln(sulin)3]XH2O. Através do espectro de infravermelho pode-se sugerir que o sulindaco está coordenado aos íons lantanídeos de modo bidentado e em ponte pelo grupo carboxilato. Os testes de citotoxicidade e de atividades anti-inflamatória dos compostos sintetizados demonstraram que os complexos, em geral, possuem comportamento muito semelhante ao do fármaco. Contudo, os resultados, sugerem que complexo [Gd(sulin)3] apresenta potencial para um melhoramento farmacológico / Abstract: Synthesis and characterization of complexes of the anti-inflammatory drug nonsteroidal sulindac (sulin) with the lanthanide ions (Ln3+) La3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+ and Ho3+ in the solid state area described in this work. The characterization of the pharmaceutical and the complexes was performed using simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC), differential scanning calorimetry-photovisual (DSC-photovisual), coupled thermogravimetry-infrared spectroscopy (TG-FTIR) analyses, complexometric titranion with EDTA and elemental analysis, and also use of X-ray diffraction by the powder method and vibrational spectroscopy reflectance in the infrared Fourier transform spectroscopy (FTIR). The thermal analysis results provided information concerning the thermal stability, dehydration and the thermal behavior of the compounds and along with the compleximetric titration and elemental analysis, it was possible to determine the stoichiometry of the complex as [Ln(sulin)3]XH2O. The spectroscopic results suggest that the ligand sulindac coordinates through the carboxylate group to the metals as a bidentatebrinding ligand. Tests for cytotoxicity and anti-inflammatory activity of the synthesized compounds demonstrated tha the complexes in general have very similar behavior in comparison to the drug. However, the results suggest that [Gd(sluin)3] has potential for pharmacological improvement / Mestre

Made available in DSpace on 2016-01-13T13:27:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-07-28. Added 1 bitstream(s) on 2016-01-13T13:32:38Z : No. of bitstreams: 1 000855142.pdf: 2602801 bytes, checksum: 3d3b585e85a9cfc362e0b0d136af6d71 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A síntese e caracterização de complexos do fármaco anti-inflamatório não esteroide sulindaco (sulin) com os íons lantanídeos (Ln3+) La3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+ e Ho3+ no estado sólido são descritas neste trabalho. A caracterização dos complexos foi realizada empregando a termogravimetria-calorimetria exploratória diferencial simultânea acoplada ao espectrômetro de FTIR (TG-DSC-FTIR), DSC-fotovisual, titulação complexométrica com EDTA e análise elementar, além de utilização de difração de raios X pelo método do pó e espectroscopia vibracional de refletância na região do infravermelho com transformada de Fourier (FTIR). Os métodos termoanalíticos foram utilizados para verificar a decomposição térmica, estabilidade térmica, entalpia de desidratação, entre outras propriedades e juntamente com a titulação complexométrica e a análise elementar, foi possível determinar a estequiometria dos complexos como [Ln(sulin)3]XH2O. Através do espectro de infravermelho pode-se sugerir que o sulindaco está coordenado aos íons lantanídeos de modo bidentado e em ponte pelo grupo carboxilato. Os testes de citotoxicidade e de atividades anti-inflamatória dos compostos sintetizados demonstraram que os complexos, em geral, possuem comportamento muito semelhante ao do fármaco. Contudo, os resultados, sugerem que complexo [Gd(sulin)3] apresenta potencial para um melhoramento farmacológico / Synthesis and characterization of complexes of the anti-inflammatory drug nonsteroidal sulindac (sulin) with the lanthanide ions (Ln3+) La3+, Ce3+, Pr3+, Nd3+, Gd3+, Tb3+ and Ho3+ in the solid state area described in this work. The characterization of the pharmaceutical and the complexes was performed using simultaneous thermogravimetry-differential scanning calorimetry (TG-DSC), differential scanning calorimetry-photovisual (DSC-photovisual), coupled thermogravimetry-infrared spectroscopy (TG-FTIR) analyses, complexometric titranion with EDTA and elemental analysis, and also use of X-ray diffraction by the powder method and vibrational spectroscopy reflectance in the infrared Fourier transform spectroscopy (FTIR). The thermal analysis results provided information concerning the thermal stability, dehydration and the thermal behavior of the compounds and along with the compleximetric titration and elemental analysis, it was possible to determine the stoichiometry of the complex as [Ln(sulin)3]XH2O. The spectroscopic results suggest that the ligand sulindac coordinates through the carboxylate group to the metals as a bidentatebrinding ligand. Tests for cytotoxicity and anti-inflammatory activity of the synthesized compounds demonstrated tha the complexes in general have very similar behavior in comparison to the drug. However, the results suggest that [Gd(sluin)3] has potential for pharmacological improvement / FAPESP: 13/04096-2

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Neste trabalho foram estudadas duas composições vítreas, a saber: 30PbF2 - 15InF3 - 20GaF3 - 15ZnF2 - 20CaF2, chamada fluoroindogalato e 41,5Al2O3 - 47,4CaO - 7SiO2 - 4,1MgO, chamada LSCA ( do inglês Low Silica content Calcium Aluminate). A matriz de fluoroindogalato foi dopada com dois conjuntos de íons terras-raras: Tm3+ + Ho3+ e Er3++Yb3+, enquanto que a matriz LSCA foi dopada apenas com os íons Er3+:Yb3+. O objetivo do trabalho foi a caracterização destas matrizes como possíveis meios ativos para laser de estado sólido nas regiões de 2,0 µm (Ho3+) e 2,8µm (Er3+). Neste sentido, foram realizados os experimentos de absorção óptica, fotoluminescência e tempo de vida. A partir dos dados obtidos, foram calculados os parâmetros de intensidade de Judd-Ofelt, os microparâmetros de transferência de energia e o coeficiente de ganho óptico das transições eletrônicas 5I7→ 5I8 (Ho3+) e 4I11/2→ 4I13/2 (Er3+). A contribuição deste trabalho a espectroscopia de terras-raras em vidros está na caracterização destes íons em termos dos parâmetros de transferência de energia via os modelos de Dexter e Yokota e Tanimoto. Haja vista que tais dados não se encontram disponíveis na literatura especializada. Os resultados mostraram que ocorrem processos de transferência de energia de ordem mais alta que dipolo-dipolo nas interações Tm3+→ Tm3+ e Tm3+→ Ho3+. A transição 5I7 → 5I8 do Ho3+ apresenta coeficiente de ganho óptico positivo a partir da densidade de excitação de 1,2 kW/cm2. Os processos de transferência de energia Er3+→ Er3+ e Er3+→ Yb3+ ocorrem via mecanismo de dipolo-dipolo e a transição 4I11/2→ 4I13/2 do Er3+ não é auto-terminada na matriz de fluoroindogalato. O coeficiente de ganho óptico para esta transição é sempre positivo para qualquer densidade de excitação. . A matriz LSCA apresenta auto-terminação da transição 4I11/2→ 4I13/2 do Er3+, sendo portanto, necessária a inserção dos mecanismos de upconversion para a observação de ganho óptico nesta transição eletrônica / In this work two vitreous compositions were studied, that are: fluoroindogalate (30PbF2 - 15InF3 - 20GaF3 - 15ZnF2 - 20CaF22) and LSCA (41,5Al2O3 - 47,4CaO - 7SiO2 - 4,1MgO) - Low Silica Content Calcium Aluminates. The fluoroindogalate host was doped with two sets of rare earth ions: Tm3+ + Ho3+ and Er3++Yb3+, whereas the LSCA host was only doped with Er3+ and Yb3+ ions. The aim of the work was the characterization of these hosts as possible active media for solid state lasers in the spectral regions of 2,0 µm (Ho3+) and 2,8µm (Er3+). In this sense, optical absorption, photoluminescence and lifetime experiments were performed. From the resulting data, Judd-Ofelt intensity parameters, energy transfer microparameters and the electronic transitions 5I7→ 5I8 (Ho3+) and 4I11/2→ 4I13/2 (Er3+) optical gain coefficients were calculated. This work\'s contribution to the rare earth spectroscopy lies in the characterization of such ions in terms of the energy transfer parameters using the Dexter, and Yokota and Tanimoto models considering that these data are not available in the specialized literature. The results have shown that higher than dipole-dipole order processes occur in the interactions Tm3+→ Tm3+ and Tm3+→ Ho3+. The Ho3+ 5I7→ 5I8 transition presents positive optical gain coefficient starting from the excitation density of 1.2 kW/cm2. The energy transfer processes Er3+→ Er3+ and Er3+→ Yb3+ occur via dipole-dipole mechanism and the Er3+ 4I11/2→ 4I13/2 transition is not auto terminated in the fluoroindogalate host. The optical gain coefficient for this transition is always positive for any excitation density. The LSCA host presents auto termination of the Er3+ 4I11/2→ 4I13/2 making it necessary the insertion of upconversion mechanisms for the observation of the optical gain in this electronic transition

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Nowadays the necessity for designing and synthesizing novel imaging agents increases rapidly. The long wavelength, and thus, low energy, of excitation and emission, and the good specificity and stability are examples of essential characteristics of ideal diagnostic and therapeutic agents. In this work, the synthesis and photophysical studies of metal complexes for biological applications were performed and evaluated, and it contained the development of (a) a porphyrin probe for imaging and treatment and (b) a tripodal thermal sensor for imaging. The research and study of the two cases of complex is analyzed in the second and third chapters, respectively, which follow the introduction or literature review to the diagnostic and/ or therapeutic agents which is given with examples in the first chapter. The scope of the main project, which is analysed in the second chapter, was the development and synthesis of a porphyrin-based bio-probe capable of bacterial fluorescence imaging. The porphyrin moiety of a complex is also able to generate singlet oxygen and this effect can be used for treatment purposes (PDT, Photodynamic Therapy). Thus, the complex can act as a diagnostic and therapeutic (anti-bacterial in this case) agent simultaneously. A probe with such a dual capability is known as theranostic agent. A theranostic agent is crucial for the enhancement and expansion of personalised medicine. The studies and physical measurements of the proposed, synthesised porphyrin complex have proved its capability to be used as a theranostic probe. Furthermore, after coupling the porphyrin moiety firstly with a small protein part (ampetoid: antimicrobial peptoid) and secondly with a radionuclide (Gallium-68), the in vitro and in vivo studies have to be performed. The aim of the project analysed in the third chapter was the development of a thermal sensor. Coordination of a tripodal ligand with a mixture of two lanthanides in various ratios was achieved and the photophysical measurements of the resulted complexes were evaluated. Lanthanide metals were chosen due to their unique photophysical properties that they offer when they are connected to an organic chomophoric ligand. Additionally, the preferred final luminophore product would obey a thermostable structure over a wide temperature range and it would be capable of effectively sensing the alterations in temperature. These properties were true for the ratio 99.5:0.5 for Terbium: Europium, and thus, the complex with such a consistency clarified the final product. Furthermore, the highly promising results after repeatedly photophysical (especially emission) measurements could conclude that the complex can be served as an ideal thermal sensor. Additional emission measurements at higher temperatures have to be done in order to confirm the ability of the proposed thermal sensor to be used for bio-imaging purposes. In conclusion, two-kind of metal complexes for biological applications were synthesized and their photophysical properties were assessed. Both the bulky porphyrin complex and the smaller tripodal ligand have shown promising results for their proposed applications. Of course, a more detailed assessment is required to verify their capability.