A preparação de vitrocerâmicas transparentes a base de SiO2-ZrO2 dopado com íons Eu3+ e Er3+ através da metodologia sol-gel foi o objetivo desta dissertação. São apresentados resultados estruturais e óticos deste sistema, em função de temperatura, tempo e composição (variando-se a concentração de zircônia). Os sóis foram preparados em meio ácido e deixados em repouso até evaporação total do solvente, obtendo-se assim monolitos amorfos, os quais foram submetidos a tratamentos a 900, 1000 e 1100ºC durante 2, 4 e 8 horas visando eliminação de resíduos orgânicos, moléculas de água, grupos hidroxilas e densificação do material. O processo de densificação com os tratamentos leva a formação inicial da fase tetragonal de ZrO2. Foi observado o crescimento de nanopartículas de ZrO2 com dimensão dependente do tempo e temperatura de tratamento térmico, além da composição do nanocompósito. As nanopartículas obtidas apresentam tamanho que variam entre 3,1 a 5,5 nm, observadas por microscopia eletrônica de transmissão. A partir da adição de 20% de óxido de zircônio é possível observar uma mistura de fases entre tetragonal e monoclínica, resultado este evidenciado principalmente por espectroscopia Raman. Neste trabalho, o íon Eu3+ foi usado como sonda estrutural e um possível luminóforo na região do vermelho. Íons lantanídeos encontram-se parcialmente distribuídos na rede amorfa à base de sílica, apresentando um tempo de vida do 5D0 de 1,5 ms e em óxido de zircônio, com um tempo de vida de 2,7 ms. À medida que ocorre cristalização, aumenta-se a proporção de íons no óxido de zircônio, sugerindo que os íons lantanídeos preferencialmente encontram-se distribuídos em regiões ricas de ZrO2. Todas as amostras dopadas com íons Er3+ apresentam emissão no infravermelho próximo, na região da banda C utilizada em telecomunicações. A emissão do íon Er3+ em 1532 nm, atribuída à transição 4I13/2 4I15/2, apresentou uma largura a meia altura que variou entre 29 a 56 nm, dependendo da composição e do tratamento térmico realizado. O tempo de vida (1/e) do estado excitado 4I13/2 é de 5,3 ms a 6,5 ms dependendo do tratamento térmico. / The preparation of transparent glass-ceramic based on the SiO2-ZrO2 doped with Eu3+ and Er3+ ions by the sol-gel methodology was the aim of this work. The structural and optical properties of the systems as a function of the time and temperature of annealing and also zirconium concentration are presented. The sol was prepared in acid solution and left in rest until total evaporation solvent, to obtaining the amorphous monoliths. The follow, the growthing of ZrO2 nanoparticles were induced and by the Transmission Electron Microscopy sizes between 3.1 and 5.5 nm were observed to be dependent to the time and temperature of annealing. The densification from the annealing at 900, 1000 and 1100ºC initially takes the formation of the tetragonal phase of ZrO2, and after 20 mol% of zirconium oxide is observed a mixture of phases between the tetragonal and monoclinic phase, result this evidenced by Raman spectroscopy. In this work the Eu3+ ion was used as a structural and possible luminescent material in the red region, displaying a life time value between 1.4 - 2.3 ms, for samples contend 0.3 mol% of Eu3+. The life time values increases as a function of time and temperature of annealing due the increase of the crystallinity of material that decreases the sites number of Eu3+ ions on the system. The Er3+ ions emission assigned to 4I13/2 4I15/2 localized around 1532 nm, showed a full width half maximum between 29 and 56 nm. The lifetime measurements were realized for Er3+ ions. The larger values of lifetime obtained are correspondent to samples with less crystalinity. Samples annealed in less temperatures show 5.3 ms of lifetime while samples annealed in higher temperatures show 6.5 ms of lifetime.

No processo de craqueamento catalítico fluidizado do petróleo (FCC) ocorre o envenenamento do catalisador pelo V presente sob a forma de complexos, que se decompõem na etapa de regeneração resultando espécies que atacam estruturalmente a zeólita - o principal componente do sistema catalítico. O emprego de terras raras (TR) como passivadores do efeito deletério provocado pelo V neste processo é estudado no presente trabalho. Sob condições similares àquelas encontradas no processo de regeneração, tris-acetilacetonatos TR foram adicionados ao catalisador para craqueamento na presença de V em proporções estabelecidas. Os resultados da interação entre os componentes deste sistema foram analisados e observou-se que as TR têm razoável capacidade de inibir o ataque do V ao catalisador desativado, preservando parcialmente a conversão catalítica do material. Análises de propriedades texturais, luminescência e DRX indicaram que a inserção de TR por meio de complexos é mais efetiva que por meio de óxidos no método empregado, além de não influenciarem as propriedades originais do catalisador na ausência de V. Os resultados dos ensaios realizados por RPE, EFX, RMN 51>/sup>V e MEV-EED revelaram que a capacidade demonstrada pelas TR em neutralizar o V está associada à formação de TRVO4 termo-quimicamente estáveis nas condições estudadas. Em virtude da reduzida capacidade de permeação das TR através das partículas do catalisador, a interação ocorre preferencialmente na superficie das micro-esferas. Todas as TR foram encontradas no catalisador desativado no estado de oxidação (III) e o V no estado de oxidação (V). As TR estudadas apresentaram desempenhos ligeiramente diferentes, no que conceme à neutralização do V no sistema e o Y apresenta o melhor desempenho. Propôs-se, para este sistema um mecanismo que relaciona a capacidade de passivação da TR às propriedades termodinâmicas da reação com V. / In the fluidized catalytic cracking process (FCC process) of petroleum, vanadium complexes present in the FCC feed cause catalyst poisoning. The decomposition of these complexes in the regeneration step produces species that attack the zeolite structure - the main active component in the catalytic system. This work evaluates the employment of rare earths (RE) as passivators to mitigate the deleterious effects ofthe V in the FCC feed. Controlled amounts of tris-acethylacetonate of RE were added to cracking catalyst containing V, under similar conditions to those of the regeneration process. The results of the interaction among the components of this system were analyzed and it was observed that RE have reasonable capacity to inhibit the V attack to the disabled catalyst, partially preserving the material catalytic conversion. Analyses of textural properties, luminescence and XRD indicated that the insertion of RE as complexes is more effective than as oxides in the methods employed. Also, they do not influence the catalyst original properties in the absence of V. The results of the experiments accomplished by EPR, XPS, 51V NMR and SEM-EDS revealed that the capacity demonstrated by RE to neutralize the V is associated with the formation of thermo chemically stable REVO4 at the test conditions. Due to the reduced capacity of RE penetration into the catalyst particles, the interaction happens preferentially in the surface of the micro spheres. All RE found in the catalyst were at the oxidation state (III) and the V at the oxidation state (V). The RE studied presented approximately the same performance in terms of V immobilization on the system and Y presents the best performance. For this system, a mechanism that relates the passivation capacity of RE to the thermodynamic properties of the reaction with V is proposed.

Luminescent lanthanide containing coordination polymers and metal-organic frameworks hold great potential in many applications due to their distinctive spectroscopic properties. While the ability to design coordination polymers for specific functions is often mentioned as a major benefit bestowed upon these compounds, the lack of a meaningful understanding of the crystal engineering and luminescence in lanthanide coordination polymers remains a significant challenge toward functional design. Currently, the study of luminescence attributed to these compounds is based on the antenna effect as derived from molecular systems, where organic antennae are used to facilitate lanthanide-centered luminescence. This molecular based approach does not take into account the unique features of extended network solids, particularly the formation of band structure. By comparing molecular and band-based approaches, it was determined that the band structure of the organic sensitizing linker needs to be considered when evaluating the luminescence of lanthanide coordination polymers. This new model, as well as work on the crystal engineering and sensor applications of these materials will be presented. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

A reação entre nitratos, cloretos e percloratos dos lantanídeos e de ítrio com a 2,6-lutidina-N-óxido (2,6-LNO) conduziu à formação de compostos de adição de composição geral: Ln(NO3)3.4(2,6-LNO), LnCl3.3 (2,6-LNO) e Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er e Y). Os produtos de reação são cristalinos, apresentam as mesmas colorações dos íons lantanídeos hidratados, porém bastante esmaecidas. Os compostos de adição contendo o íon cloreto não fundem até 300ºC. Os compostos de adição contendo os íons nitratos e percloratos são solúveis em acetona, acetonitrila, etanol, metanol, nitrobenzeno e nitrometano, ligeiramente solúveis em clorofórmio. Os compostos de adição contendo o íon cloreto são solúveis em etanol e metanol e praticamente insolúveis em acetona, acetonitrila, clorofórmio, nitrobenzeno e nitrometano. Todos os compostos de adição são praticamente insolúveis em benzeno; tetracloreto de carbono e éter etílico. Os compostos foram caracterizados por meio de análise elementar, espectros na região do infra-vermelho e do visível, medidas de condutância molar em nitrometano, acetonitrila e etanol, e diagramas de raios-x. Para alguns compostos de adição contendo o íon nitrato foram obtidos os espectros Raman. Os dados obtidos nos espectros na região do infravermelho indicam que a coordenação da 2,6-LNO ao ion lantanídeo ocorre pelo oxigênio do grupo N-O. Foram observadas cinco bandas que podem ser atribuídas ao íon nitrato, nos correspondentes compostos de adição, indicando que estes íons estão coordenados aos íons lantanídeos. As bandas atribuídas aos íons percloratos indicaram que os mesmos não estão coordenados. Os espectros eletrônicos dos compostos de adição contendo o íon perclorato, no estado sólido e em solução de nitrometano são muito semelhantes, sugerindo que a simetria em torno do íon central, é a mesma em ambos os casos. Os dados de condutância eletrolítica indicaram que os nitratos comportam-se como não-eletrólitos em nitrometano e acetonitrila e como eletrólito 1:1 em metanol. É interessante notar que os percloratos comportam-se como eletrólitos 1:3 em nitrometano e acetonitrila, mas em metanol, provavelmente devido a existência de pares iônicos, comportam-se como eletrólitos 1:2. Os dados para os cloretos em metanol estão de acordo com aqueles para eletrólitos 1:1. Todos os compostos preparados foram caracterizados por meio de diagramas de raios-X. De acordo com os dados três séries diferentes foram obtidas para os nitratos: (a) para o composto de La, (b) para os compostos de Pr, Nd and Gd, que são isomorfos, (c) para os compostos de Ho, Er and Y, que também são isomorfos. Para os percloratos duas séries de substâncias são observadas: a primeira série contém os compostos de Y, Pr, Gd, Ho e Er, e a segunda série os compostos de La e Nd. Para os cloretos duas séries diferentes foram também obtidas: (a) para os compostos de La, Pr e Nd, (b) para os compostos de Y, Gd, Ho e Er. / The reaction between hydrated lanthanide and ytrium nitrates, chlorides and perchlorates with 2,6-lutidine-N-oxide (2,6-LNO) provided adducts of general composition: Ln(NO3)3.4(2,6-LNO), LnCl3.3(2,6-LNO) and Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er and Y). The products are crystalline, present the same, but less intense colors of the hydrated lanthanide ions. The chloride adducts do not melt up to 300ºC. The nitrate and perchlorate adducts are solube in acetone, acetonitrile, ethanol, methanol, nitrobenzene and nitromethane, slightly soluble in chloroform. The chloride adducts are soluble in ethanol and methanol and practically insoluble in acetone, acetonitrile, chloroform, nitrobenzene and nitromethane. All the adducts are practically insoluble in benzene, carbon tetrachloride and ethyl eter. The compounds were characterized by elemental analyses, infrared and visible spectra, molar conductance measurements in nitromethane, acetonitrile and methanol, and X-ray powder patterns. For some of the nitrate adducts the Raman spectra were obtained. Infrared data indicate that the 2,6-LNO is coordinated to the lanthanide ions through of oxygen. Five bands attributed to the nitrate ions were observed for the corresponding adducts, indicating these ions are coordinated to the lanthanides ions. The bands due to perchlorate ions indicate that they are not coordinated to the lanthanides ions.The electronic spectra of the perchlorates adducts in the solid state and in nitromethane solution indicate the existence of the same symmetry around the central ions in both cases. The electrolytic conductance data indicate that the nitrates behave as non-electrolytes in nitromethane and acetonitrile and 1:1 electrolytes in methanol. It is interesting to note that the perchlorates behave as 1:3 electrolytes in nitromethane and acetonitrile, but in methanol, probably due to the existence of ions pairs, they behave as 1:2 electrolytes. The data for the chlorides in methanol are in accordance of 1:1 electrolytes. to that All the compounds prepared were characterized by X-ray powder patterns. According to the data three different patterns were obtained for the nitrates: (a) for the compounds of La; (b) for the compounds of Pr, Nd and Gd, that are isomorphous, (c) for the oompounds of Ho, Er and Y, that are also isomorphous. For the perchlorates two series of isomorphous substances were observed: the first series contains the compounds of Y, Pr, Gd, Ho and Er, and the second series the adducts of La and Nd. For the chlorides two different patterns were also obtained: (a) for the compounds of La, Pr and Nd, (b) for the compounds of Y, Gd, Ho and Er.

Le transfert d'énergie par résonance de type Förster (FRET) est un transfert d'énergie non radiatif d'un donneur à un accepteur à proximité. En raison de sa dépendance de la distance extrêmement sensible entre env. 1 et 20 nm, FRET joue un rôle important dans la nanobiotechnologie. Ainsi FRET peut être utilisé comme système de transduction du signal, mais aussi pour l'estimation de la distance entre le donneur et l'accepteur.Les accepteurs de FRET utilisés dans ce travail étaient des nanocristaux semi-conducteurs (quantum dots, QD). Ce type de luminophore est bien connu pour ses propriétés photophysiques supérieures. Leur absorption forte et spectralement large, et leur photoluminescence (PL) brillante et spectralement fine et de l'accordabilité spectrale de la PL sont idéalement adaptés aux applications de FRET. La combinaison des QDs comme accepteurs de FRET avec des complexes luminescents de terbium (CLT) comme donneurs permet des grandes distances de FRET (> 10 nm). La distance de FRET est caractéristique d'une paire FRET et décrit la distance à laquelle l'efficacité de FRET est égale à 50%. CLT sont idéal comme donneurs de FRET parce qu'ils fournissent des longues durées de vie des états excités à l'ordre de la milliseconde. Cette longue période de décroissance de PL permet de mesurer en temps décalé pour une répression d’autofluorescence et la PL des QDs directement excités, ce qui augmente fortement la sensibilité de détection. Les bandes d'émission de PL structurés de CLT et la PL accordable de QDs sont idéales pour l'application dans le diagnostic multiplexé.La thèse se compose de deux parties. Dans la première le couple FRET CLT-QD a été utilisé dans des immunodosages de FRET homogènes pour la détection de marqueurs biologiques antigène prostatique spécifique (TPSA), énolase specifique des neurones (NSE), antigène carcino-embryonnaire (CEA), et le récepteur du facteur de croissance épidermique (EGFR). La sensibilité du dosage immunologique a été optimisé en utilisant des différents types d'anticorps IgG, F (ab')2, F (ab), et pour EGFR un anticorps de chaîne lourde unique. Des limites de détection picomolaires étaient réalisées en utilisant des échantillons de sérum de petit volume et des mesures sur des lecteurs de microplaques cliniques. Une étude détaillée des différents systèmes de FRET en utilisant la spectroscopie résolue en temps a été réalisée pour étudier l'influence des différents anticorps sur la distance, la fonctionnalité, et la sensibilité des immunodosages. L'étude a été complétée par la mesure de NSE et CEA dans un format duplexé et des échantillons réels de patients.Dans la deuxième partie le FRET pour des mesures de distance nanométriques (réglette moléculaire ou spectroscopique) étaient étudiés. FRET en résolution temporelle a permis de calculer la distance entre le donneur et l’accepteur. Par conséquent, deux stratégies de liaisons différentes ont été étudiées pour établir une proximité entre le CLT et le QD : la reconnaissance biotine-streptavidine et l’auto-assemblage médié par polyhistidine. Une étude en résolution temporelle détaillée a été effectuée avec des QDs de différentes tailles, formes et revêtements de surface combiné avec des CLT liés à trois différentes biomolécules. L'analyse des courbes de décroissance multiexponentielle des donneurs et accepteurs permettait à obtenir des informations sur la taille, la forme et la biofonctionnalité des bioconjugués CLT-QD. Les résultats étaient en accord avec d'autres méthodes d'analyse de structure, telles que la microscopie électronique à transmission (MET) ou la diffusion de lumière dynamique (DLS), mais avec l'avantage d'une mesure homogène à la résolution 3-dimensionelle (impossible pour le MET), sans l'inclusion d'une couche d'hydratation (l’inconvénient de DLS) et en faible concentration dans le même environnement que celui utilisé pour l'application biologique. / Förster resonance energy transfer (FRET) is a non-radiative energy transfer from a donor to an acceptor in close proximity. Due to its extremely sensitive distance dependence in the 1 – 20 nm range, FRET plays an important role in nanobiotechnology. Thereby FRET can be used as signal transduction system but also for the distance estimation between donor and acceptor. The selected FRET acceptors in this work were semiconductor nanocrystals (quantum dots, QDs). This type of luminophore is well known for its superior photophysical properties. Their strong and broad absorption and their bright, narrow-band, and size-tunable photoluminescence (PL) emission make QDs ideally suited for FRET application. Combing QDs as FRET acceptors with luminescent terbium complexes (LTC) as FRET donors offers exceptionally large Förster distances of more than 10 nm. The Förster distance is characteristic of a FRET pair and is the distance at which the FRET efficiency equals 50 %. A large Förster distance is desirable as it offers the detection of biological interactions over large distances. LTC are suitable FRET donors for QDs because they provide long excited-state lifetimes in the millisecond range. This long PL decay time enables time-gated measurements for the suppression of autofluorescence and PL of directly excited QDs, which strongly increases the detection sensitivity. Additionally, the structured PL emission bands of LTCs together with the size-tunable PL emission bands of QDs make this FRET pair ideal for the application in multiplexed diagnostics, which is the measurement of multiple biomarkers in a single sample.The PhD thesis consists of two parts. In the first part the LTC-QD FRET pair was used within homogeneous FRET immunoassays for the detection of the biomarkers prostate specific antigen (TPSA), neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), and epidermal growth factor receptor (EGFR). The immunoassay sensitivity was optimized using different types of antibodies IgG, F(ab’)2,F(ab), and for EGFR single heavy chain antibodies, which differ largely in their size. The use of small-volume serum samples and measurements on clinical as well customized fluorescence plate readers result in picomolar detection limits for all measured biomarkers. In addition to these QD-based in vitro diagnostic tests, a detailed study of the different FRET-systems using time-resolved spectroscopy was performed. The investigation revealed the influence of the different antibodies on distance, functionality, and sensitivity of the FRET immunoassays. The study was completed by the measurement of NSE and CEA in a duplexed format and real patient samples were investigated.The second part was to use FRET for nanometric distance measurements as molecular or spectroscopic ruler. Time-resolved FRET measurements enabled the calculation of the distance between donor and acceptor. Therefore two different binding strategies were investigated to establish a close proximity between the LTC-donor to the QD-acceptor, namely biotin-streptavidin recognition and polyhistidine mediated self-assembly. A detailed time-resolved study was performed of QDs with different sizes, shapes, and surface coatings in combination with LTC bound to three different host biomolecules, which also possessed different sizes, shapes, orientations, and binding conditions. The analysis of the multi-exponential decay curves of donor and acceptor allowed to obtain information about the size, shape, and biofunctionality of the investigated QD bioconjugates. The results were in agreement with other structural analysis methods, such as transmission electron microscopy (TEM) or dynamic light scattering (DLS), but with the advantage of a homogeneous measurement with three-dimensional resolution (not possible for TEM), without the inclusion of a hydration shell (drawback for DLS), and at low concentration in the same environment as used for the biological application.

A reação entre nitratos, cloretos e percloratos dos lantanídeos e de ítrio com a 2,6-lutidina-N-óxido (2,6-LNO) conduziu à formação de compostos de adição de composição geral: Ln(NO3)3.4(2,6-LNO), LnCl3.3 (2,6-LNO) e Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er e Y). Os produtos de reação são cristalinos, apresentam as mesmas colorações dos íons lantanídeos hidratados, porém bastante esmaecidas. Os compostos de adição contendo o íon cloreto não fundem até 300ºC. Os compostos de adição contendo os íons nitratos e percloratos são solúveis em acetona, acetonitrila, etanol, metanol, nitrobenzeno e nitrometano, ligeiramente solúveis em clorofórmio. Os compostos de adição contendo o íon cloreto são solúveis em etanol e metanol e praticamente insolúveis em acetona, acetonitrila, clorofórmio, nitrobenzeno e nitrometano. Todos os compostos de adição são praticamente insolúveis em benzeno; tetracloreto de carbono e éter etílico. Os compostos foram caracterizados por meio de análise elementar, espectros na região do infra-vermelho e do visível, medidas de condutância molar em nitrometano, acetonitrila e etanol, e diagramas de raios-x. Para alguns compostos de adição contendo o íon nitrato foram obtidos os espectros Raman. Os dados obtidos nos espectros na região do infravermelho indicam que a coordenação da 2,6-LNO ao ion lantanídeo ocorre pelo oxigênio do grupo N-O. Foram observadas cinco bandas que podem ser atribuídas ao íon nitrato, nos correspondentes compostos de adição, indicando que estes íons estão coordenados aos íons lantanídeos. As bandas atribuídas aos íons percloratos indicaram que os mesmos não estão coordenados. Os espectros eletrônicos dos compostos de adição contendo o íon perclorato, no estado sólido e em solução de nitrometano são muito semelhantes, sugerindo que a simetria em torno do íon central, é a mesma em ambos os casos. Os dados de condutância eletrolítica indicaram que os nitratos comportam-se como não-eletrólitos em nitrometano e acetonitrila e como eletrólito 1:1 em metanol. É interessante notar que os percloratos comportam-se como eletrólitos 1:3 em nitrometano e acetonitrila, mas em metanol, provavelmente devido a existência de pares iônicos, comportam-se como eletrólitos 1:2. Os dados para os cloretos em metanol estão de acordo com aqueles para eletrólitos 1:1. Todos os compostos preparados foram caracterizados por meio de diagramas de raios-X. De acordo com os dados três séries diferentes foram obtidas para os nitratos: (a) para o composto de La, (b) para os compostos de Pr, Nd and Gd, que são isomorfos, (c) para os compostos de Ho, Er and Y, que também são isomorfos. Para os percloratos duas séries de substâncias são observadas: a primeira série contém os compostos de Y, Pr, Gd, Ho e Er, e a segunda série os compostos de La e Nd. Para os cloretos duas séries diferentes foram também obtidas: (a) para os compostos de La, Pr e Nd, (b) para os compostos de Y, Gd, Ho e Er. / The reaction between hydrated lanthanide and ytrium nitrates, chlorides and perchlorates with 2,6-lutidine-N-oxide (2,6-LNO) provided adducts of general composition: Ln(NO3)3.4(2,6-LNO), LnCl3.3(2,6-LNO) and Ln(ClO4)3.8(2,6-LNO) (Ln= La, Pr, Nd, Gd, Ho, Er and Y). The products are crystalline, present the same, but less intense colors of the hydrated lanthanide ions. The chloride adducts do not melt up to 300ºC. The nitrate and perchlorate adducts are solube in acetone, acetonitrile, ethanol, methanol, nitrobenzene and nitromethane, slightly soluble in chloroform. The chloride adducts are soluble in ethanol and methanol and practically insoluble in acetone, acetonitrile, chloroform, nitrobenzene and nitromethane. All the adducts are practically insoluble in benzene, carbon tetrachloride and ethyl eter. The compounds were characterized by elemental analyses, infrared and visible spectra, molar conductance measurements in nitromethane, acetonitrile and methanol, and X-ray powder patterns. For some of the nitrate adducts the Raman spectra were obtained. Infrared data indicate that the 2,6-LNO is coordinated to the lanthanide ions through of oxygen. Five bands attributed to the nitrate ions were observed for the corresponding adducts, indicating these ions are coordinated to the lanthanides ions. The bands due to perchlorate ions indicate that they are not coordinated to the lanthanides ions.The electronic spectra of the perchlorates adducts in the solid state and in nitromethane solution indicate the existence of the same symmetry around the central ions in both cases. The electrolytic conductance data indicate that the nitrates behave as non-electrolytes in nitromethane and acetonitrile and 1:1 electrolytes in methanol. It is interesting to note that the perchlorates behave as 1:3 electrolytes in nitromethane and acetonitrile, but in methanol, probably due to the existence of ions pairs, they behave as 1:2 electrolytes. The data for the chlorides in methanol are in accordance of 1:1 electrolytes. to that All the compounds prepared were characterized by X-ray powder patterns. According to the data three different patterns were obtained for the nitrates: (a) for the compounds of La; (b) for the compounds of Pr, Nd and Gd, that are isomorphous, (c) for the oompounds of Ho, Er and Y, that are also isomorphous. For the perchlorates two series of isomorphous substances were observed: the first series contains the compounds of Y, Pr, Gd, Ho and Er, and the second series the adducts of La and Nd. For the chlorides two different patterns were also obtained: (a) for the compounds of La, Pr and Nd, (b) for the compounds of Y, Gd, Ho and Er.

A reação entre a N,N,N\',N\'-tetrametilmalonamida e os iodetos de lantanídeos e ítrio em acetona conduziu a formação dos compostos de adição de fórmula geral LnI3.xTMMA (x = 5, Ln= La, Ce; x = 4, Ln = Pr - Lu, V). Os produtos da reação são cristalinos e apresentam a coloração característica dos correspondentes íons lantanídeos , porém bem menos pronunciadas; não são, em geral, higroscópicos; são bastante solúveis em água, nitrometano e acetonitrila, menos solúveis em metanol e etanol, fracamente solúveis em nitrobenzeno, acetona e praticamente insolúveis em benzeno, tetracloreto de carbono e clorofórmio. Fundem com decomposição na faixa entre 200 e 2500 C°. Os compostos obtidos foram caracterizados por análise elementar, espectros na região do infra-vermelho, difração de raios-X (método do pó), condutância molar. Foram obtidos espectros na região do visível dos compostos de neodímio, hólmio e érbio, em solução; o espectro do composto de neodímio foi também obtido no estado sólido em temperaturas diferentes. Foi registrado o espectro de fluorescência do composto de eurôpio , no estado sólido, em temperatura do nitrogênio líquido. Os espectros na região do infra-vermelho indicaram que a coordenação do ligante se efetua através dos átomos de oxigênio da carbonila. Os difratogramas de raios-X permitiram a identificação de quatro tipos de estruturas: o primeiro e constituído dos compostos de lantânio e cério; o segundo forma uma série isomorfa que se estende do composto de praseodímio ao do disprósio, o terceiro é constituído do composto de hôlmio e o último tipo é formado pelos compostos de érbio a lutécio, incluíndo ítrio. Os valores obtidos para as medidas de condutância molar mostram que os compostos comportam-se como eletrólitos 1: 3 em acetonitrila e nitrometano e como eletrólitos 1:2 em metanol. Os espectros de absorção eletrônicos dos compostos de neodímio, hólmio e érbio em solução de acetonitrila, não são essencialmente modificados nas diferentes concentrações em que os mesmos foram registrados. O estudo do espectro do composto de neodímio permitiu mostrar que a interação entre o ligante e o Nd3+ é essencialmente eletrostática. Os valores do parâmetro nefelauxético, β e do fator de covalência, b1/2 e de SINHA, δ, indicaram este fato. A força do oscilador foi calculada em solução de nitrometano e comparada com os valores obtidos para outros compostos O espectro de fluorescência do composto de európio sugere simetria D2d para o Eu3+, Foi admitida esta mesma simetria para os compostos que apresentam estruturas cristalinas iguais. Um estudo comparativo sobre espectroscopia de absorção e emissão na região do visivél foi realizado utilizando-se de compostos de adição contendo perclorato, hexafluorfosfato, nitrato, isotiocianato e cloreto de neodímio e európio com a N,N,N\',N\'-tetrametilmalonamida. Dados sobre os parâmetros nefelauxéticos, fatores de covalência e forças do oscilador foram determinados para cada composto de neodímio. As simetrias possíveis e os poliedros de coordenação para os compostos de európio foram sugeridos. / Addition compounds of formula Lni3.xTMMA (x = 5 for Ln = La, Ce and x = 4 for Ln = Pr - Lu, Y) were prepared by reaction of N,N.N\',N\'-tetramethylmalonamide (TMMA) and lanthanide iodides in acetone. The crystalline adducts present the same, but fainter colors of the corresponding lanthanide ions; they are in general practically not hygroscopic and melt with decomposition between 200-250°. They are soluble in water, nitromethane, acetonitrile, slightly soluble in methanol, ethanol, nitrobenzene, acetone and practically insoluble in benzene, carbon tetrachloride and chloroform. The compounds were characterized by elemental analysis, infrared spectra, X-ray powder patterns, electrolytic molar conductance, visible spectra of neodymium, holmium and erbium in acetonitrile, absorption spectrum of the solid neodymium compound at different temperatures and emission spectrum of the solid europium compound at liquid nitrogen temperature. lnfrared spectra indicate that coordination of the ligand occurs through the carbonyl oxygens. X-ray patterns show four types of structures: the first contains the lanthanum and cerium compounds; the second the adducts for praseodymium to dysprosium, the third the holmium compound and the fourth type the adducts from erbium to lutecium and yttrium. Conductance data indicate a behaviour of 1:3 electrolytes in acetonitrile and nitromethane, and 1:2 electrolytes in methanol. The visible spectra of neodymium, holmium and erbium adducts in acetonitrile are not essentially modified at different concentrations. The nephelauxetic parameter, β, the covalency factor, b1/2 and the SINHA\'s parameter, δ, were determined from the neodymium spectrum. The values obtained show that the interaction between Nd3+ and the ligand is essentially electrostatic. The oscillator strenght was calculated from the neodymium spectrum in nitromethane solution and the value was compared with those obtained for other neodymium adducts. The number of bands and shape of the emission spectrum of the europium compound may suggest the D2d symmetry for the adducts of the same isomorphous series. A comparative study concerning absorption and emission spectra of the perchlorate, hexafluorphosphate, nitrate, isothiocyanate and chloride neodymium and europium adducts with TMMA was realized. The parameters, β, b1/2 and δ and the oscillator strenghts. P, were determined for the neodymium adducts. The emission spectra of the corresponding europium compounds were also determined. Suggestions concerning symmetry and geometry of the adducts are given.

No processo de craqueamento catalítico fluidizado do petróleo (FCC) ocorre o envenenamento do catalisador pelo V presente sob a forma de complexos, que se decompõem na etapa de regeneração resultando espécies que atacam estruturalmente a zeólita - o principal componente do sistema catalítico. O emprego de terras raras (TR) como passivadores do efeito deletério provocado pelo V neste processo é estudado no presente trabalho. Sob condições similares àquelas encontradas no processo de regeneração, tris-acetilacetonatos TR foram adicionados ao catalisador para craqueamento na presença de V em proporções estabelecidas. Os resultados da interação entre os componentes deste sistema foram analisados e observou-se que as TR têm razoável capacidade de inibir o ataque do V ao catalisador desativado, preservando parcialmente a conversão catalítica do material. Análises de propriedades texturais, luminescência e DRX indicaram que a inserção de TR por meio de complexos é mais efetiva que por meio de óxidos no método empregado, além de não influenciarem as propriedades originais do catalisador na ausência de V. Os resultados dos ensaios realizados por RPE, EFX, RMN 51>/sup>V e MEV-EED revelaram que a capacidade demonstrada pelas TR em neutralizar o V está associada à formação de TRVO4 termo-quimicamente estáveis nas condições estudadas. Em virtude da reduzida capacidade de permeação das TR através das partículas do catalisador, a interação ocorre preferencialmente na superficie das micro-esferas. Todas as TR foram encontradas no catalisador desativado no estado de oxidação (III) e o V no estado de oxidação (V). As TR estudadas apresentaram desempenhos ligeiramente diferentes, no que conceme à neutralização do V no sistema e o Y apresenta o melhor desempenho. Propôs-se, para este sistema um mecanismo que relaciona a capacidade de passivação da TR às propriedades termodinâmicas da reação com V. / In the fluidized catalytic cracking process (FCC process) of petroleum, vanadium complexes present in the FCC feed cause catalyst poisoning. The decomposition of these complexes in the regeneration step produces species that attack the zeolite structure - the main active component in the catalytic system. This work evaluates the employment of rare earths (RE) as passivators to mitigate the deleterious effects ofthe V in the FCC feed. Controlled amounts of tris-acethylacetonate of RE were added to cracking catalyst containing V, under similar conditions to those of the regeneration process. The results of the interaction among the components of this system were analyzed and it was observed that RE have reasonable capacity to inhibit the V attack to the disabled catalyst, partially preserving the material catalytic conversion. Analyses of textural properties, luminescence and XRD indicated that the insertion of RE as complexes is more effective than as oxides in the methods employed. Also, they do not influence the catalyst original properties in the absence of V. The results of the experiments accomplished by EPR, XPS, 51V NMR and SEM-EDS revealed that the capacity demonstrated by RE to neutralize the V is associated with the formation of thermo chemically stable REVO4 at the test conditions. Due to the reduced capacity of RE penetration into the catalyst particles, the interaction happens preferentially in the surface of the micro spheres. All RE found in the catalyst were at the oxidation state (III) and the V at the oxidation state (V). The RE studied presented approximately the same performance in terms of V immobilization on the system and Y presents the best performance. For this system, a mechanism that relates the passivation capacity of RE to the thermodynamic properties of the reaction with V is proposed.

Polymerverkapselte magnetische Nanopartikel versprechen, in der Zukunft sehr erfolgreich bei Anwendungen in der Biologie und der Medizin eingesetzt werden zu können z. B. in der Krebstherapie und als Kontrastmittel bei der magnetischen Kernspinresonanztomographie. Diese Arbeit zeigt, dass durch die interdisziplinäre Kombination verschiedener Techniken Herstellungsverfahren und Eigenschaften solcher Partikel verbessert werden können. <br /> <br /> Unter Miniemulsionen versteht man wässrige Dispersionen relativ stabiler Öltröpfchen, zwischen 30 und 50 nm Größe. Ein Nanometer (nm) ist der 1.000.000.000ste Teil eines Meters. Ein Haar ist ungefähr 60.000 Nanometer breit.<br /> <br /> Hergestellt werden Miniemulsionen durch Scherung eines Systems bestehend aus Öl, Wasser, Tensid (Seife) und einer weiteren Komponente, dem Hydrophob, das die Tröpfchen stabilisieren soll. Die Polymerisation von Miniemulsionen ermöglicht die Verkapselung anorganischer Materialen z. B. magnetischer Teilchen oder Gadolinium-haltiger Komponenten. Zu Optimierung des Verkapselung, ist es notwendig, die richtige Menge eines geeigneten Tensids zu finden. <br /> <br /> Die magnetischen polymerverkapselten Nanopartikel, die in einer wässrigen Trägerflüssigkeit dispergiert sind, zeigen in Abhängigkeit von Partikelgröße, Zusammensetzung, elektronischer Beschaffenheit, etc. ein sogenanntes superpara- oder paramagnetisches Verhalten. Superpara- oder paramagnetisches Verhalten bedeutet, dass die Flüssigkeiten in Anwesenheit äußerer Magnetfeldern ihre Fließfähigkeit beibehalten. Wenn das Magnetfeld entfernt wird, haben sie keine Erinnerung mehr daran, unter dem Einfluss eines Magnetfeldes gestanden zu haben, d. h., dass sie nach Abschalten des Magnetfeldes selbst nicht mehr magnetisch sind. <br /> <br /> Die Vorteile des Miniemulsionsverfahrens sind der hohe Gehalt und die homogene Verteilung magnetischer Teilchen in den einzelnen Nanopartikeln. Außerdem ermöglicht dieses Verfahren nanostrukturierte Kompositpartikel herzustellen, wie z. B polymerverkapselte Nanopartikel mit Nanoschichten bestehend aus magnetischen Molekülen. / Combining the magnetic properties of a given material with the tremendous advantages of colloids can exponentially increase the advantages of both systems. This thesis deals with the field of magnetic nanotechnology. Thus, the design and characterization of new magnetic colloids with fascinating properties compared with the bulk materials is presented. <br /> <br /> Ferrofluids are referred to either as water or organic stable dispersions of superparamagnetic nanoparticles which respond to the application of an external magnetic field but lose their magnetization in the absence of a magnetic field. <br /> <br /> In the first part of this thesis, a three-step synthesis for the fabrication of a novel water-based ferrofluid is presented. The encapsulation of high amounts of magnetite into polystyrene particles can efficiently be achieved by a new process including two miniemulsion processes. The ferrofluids consist of novel magnetite polystyrene nanoparticles dispersed in water which are obtained by three-step process including coprecipitation of magnetite, its hydrophobization and further surfactant coating to enable the redispersion in water and the posterior encapsulation into polystyrene by miniemulsion polymerization. It is a desire to take advantage of a potential thermodynamic control for the design of nanoparticles, and the concept of &quot;nanoreactors&quot; where the essential ingredients for the formation of the nanoparticles are already in the beginning. The formulation and application of polymer particles and hybrid particles composed of polymeric and magnetic material is of high interest for biomedical applications. Ferrofluids can for instance be used in medicine for cancer therapy and magnetic resonance imaging.<br /> <br /> Superparamagnetic or paramagnetic colloids containing iron or gadolinium are also used as magnetic resonance imaging contrast agent, for example as a important tool in the diagnosis of cancer, since they enhance the relaxation of the water of the neighbouring zones. New nanostructured composites by the thermal decomposition of iron pentacarbonyl in the monomer phase and thereafter the formation of paramagnetic nanocomposites by miniemulsion polymerization are discussed in the second part of this thesis. In order to obtain the confined paramagnetic nanocomposites a two-step process was used. In the first step, the thermal decomposition of the iron pentacarbonyl was obtained in the monomer phase using oleic acid as stabilizer. In the second step, this iron-containing monomer dispersion was used for making a miniemulsion polymerization thereof. <br /> <br /> The addition of lanthanide complexes to ester-containing monomers such as butyl acrylate and subsequent polymerization leading to the spontaneous formation of highly organized layered nanocomposites is presented in the final part of this thesis. By an one-step miniemulsion process, the formation of a lamellar structure within the polymer nanoparticles is achieved. The magnetization and the NMR relaxation measurements have shown these new layered nanocomposites to be very apt for application as contrast agent in magnetic resonance imaging.

Les propriétés thermodynamiques standard (PTS) des lanthanides (Ln3+) sont nécessaires pour prévoir leur transport dans les fluides hydrothermaux.<br />De nouvelles PTS (volumes et capacités calorifiques molaires apparentes) des Ln3+ ont été déterminées jusqu'à 300°C et 300 bars à l'aide d'un densimètre à tube vibrant et d'un calorimètre différentiel à écoulement, en utilisant des solutions de triflates de (La3+, Nd3+, Gd3+, Yb3+). L'anion triflate (CF3SO3), stable à haute température, ne complexe pas avec Ln3+. Les PTS de HCF3SO3 et de NaCF3SO3 sont mesurées pour obtenir les PTS de CF3SO3.<br />D'autre part la solubilité du pôle pur de la monazite (NdPO4) étudiée entre 300°C et 800°C, à 2 kbars, dans H20 et H20+NaCl, par perte de masse et par dilution isotopique, est prograde pour des pH neutres. L'étude de la spéciation de Nd3+ à 650°C et à 300°C, à 2 kbars, montre que seules les espèces hydroxylées sont présentes.<br />Ces données permettent la révision des paramètres de Ln3+ dans le modèle HKF.