A scapolite-hornblende-biotite schist from the Grenville province of the Canadian Shield has been analysed for Tl by an atomic absorption technique with a high sensitivity. K, Rb and some major oxides were determined by wet chemistry. Tl, K/Rb, K/Tl and Tl/Rb were compared to several other rocks and for this report were found to be 432ppb, 429, 4.85x10³ and 88.4x10⁻³ respectively. These values are similar to those quoted for other rocks. / Thesis / Bachelor of Science (BSc)

No description available.

Si en site octaédrique régulier la configuration de spin la plus fréquemment observée pour l'ion Co3+ (3d6) est S=0 (LS), un modèle simple faisant intervenir les énergies d'échangecorrélation et de champ cristallin permet de prévoir qu'un allongement de l'octaèdre favorise les états S=2 (HS) ou S=1 (IS). Une telle distorsion se rencontre dans la structure 1222 des cuprates de thallium. Après une mise au point délicate le composé Tl0.9Sr3LaCo2O8.6 a été préparé et caractérisé. Un équilibre de spin IS-HS ainsi que l'existence d'une valence mixte Co3+ / 2+ jouent un rôle important dans l'interprétation des propriétés électroniques. Le comportement de ce nouveau cobaltite est comparé à celui d'autres oxydes de cobalt 2D en particulier sur la base d'un calcul de structure électronique.

Ce manuscrit traite de la complexation des métaux post-transitionnels de la période 6 par des porphyrines comportant une ou deux anses à acide(s) carboxylique(s) suspendu(s). Celles-ci possèdent des cinétiques rapides d'insertion du Bi permettant d'envisager, de par la complexation et la vectorisation du 213Bi, une application en α-radio-immunothérapie (α-RIT). Dans ce but, trois porphyrines à anse(s) ont été élaborées et le meilleur taux d'insertion du 213Bi a été obtenu avec la porphyrine bis-anse bis-acide grâce à un processus sans précédent de transmétallation Pb«froid»213Bi, il atteint les 80% et est comparable à celui obtenu avec le CHX-DTPA, meilleur chélate du 213Bi. S'agissant de la vectorisation du 213Bi, deux porphyrines bifonctionnelles ont été préparées et les tests de couplage sur anticorps ont montré la formation d'agrégats en raison de leur faible hydrosolubilité. Par ailleurs, une porphyrine hydrosoluble mono-anse monoacide a été synthétisée, mais en absence d'une deuxième anse à acide carboxylique l'insertion du 213Bi reste faible (< 10%). Ce travail permet de conclure que pour atteindre notre objectif d'α-RIT, il faudra élaborer une porphyrine hydrosoluble comportant deux anses à acide carboxylique. Les deux autres parties sont plus fondamentales, d'abord l'accès à un commutateur moléculaire grâce à une double translocation d'ions métalliques au sein de complexes bimétalliques de thallium, déclenchée par un processus d'oxydoréduction TlI↔TlIII. En effet, au sein de nos complexes bimétalliques, deux modes de coordination coexistent, l'un avec un métal M lié à la porphyrine «out of plane» OOP et l'autre avec un métal M' lié à l'anse «hanging atop» HAT. Nous visons un état dans lequel le TlIII serait OOP et le deuxième métal M HAT et un second avec le TlI HAT et M OOP. Les études de coordination du thallium par une porphyrine bis-anse bis-acide ont mis en évidence la formation du 1er exemple de complexe à valence mixte TlIII/TlI par photo-oxydation ou par réduction du HgII. De plus, les deux états du commutateur moléculaire visé ont été obtenus indépendamment : TlIII OOP/PbII HAT et TlI HAT/ PbII OOP. L'utilisation du deuxième phénomène redox pourra permettre le passage de l'un à l'autre constituant un premier pas vers un commutateur moléculaire. Finalement, nous visons de nouveaux complexes supramoléculaires de coordination à partir de sous-unités bimétalliques dont l'assemblage métal-dirigé via l'anse sera modulé par la nature des métaux sur la porphyrine. Trois nouvelles porphyrines ont été synthétisées avec une ou deux anses à acide carboxylique suspendu dont la position α est substituée par une seconde fonction acide carboxylique ou par une fonction cyano. La métallation de celles-ci par le PbII, le HgII ou le CdII a été étudiée et deuxstructures RX de complexes dinucléaires de CdII et de PbII ont été obtenues avec une porphyrine bis-anse bis-cyano. Elles montrent l'influence de la nature du métal sur l'orientation des groupements coordinants. / This manuscript is related to the complexation of the period 6 main group and late transition metals by porphyrins bearing one or two straps with overhanging carboxylic acid. These porphyrins possess fast metal ion insertion rate allowing us to consider, through 213Bi-α-emitter complexation and vectorization, an application in α-radio-immunotherapy (α-RIT). For that purpose, we designed 3 strapped-porphyrins with one or 2 overhanging carboxylic acid. The best 213Bi insertion rate of 80% was obtained with the bis-acid bis-strapped porphyrin thanks to an unprecedented transmetallation “cold” Pb213Bi process; which is close to that of the CHX-DTPA, best known 213Bi chelate. Regarding 213Bi vectorization, 2 BFC porphyrins were synthetized and immunoconjugation experiments proved aggregate formation due to their poor water-solubility. Furthermore, a water-soluble mono-acid and mono-strapped porphyrin was realised but without the 2nd carboxylic acid the 213Bi insertion was very low (<10%). This work provided the conclusion that to achieve the α-RIT objective we have to design a new porphyrin water-soluble with 2 straps bearing one overhanging carboxylic acid. The 2 last chapters are related to fundamental applications, Firstly, a molecular switch through thallium heterobimetallic complexes in which a double translocation of metallic ions will take place thanks to Tl(I)↔Tl(III) redox process. In fact, in our heterobimetallic porphyrin complexes 2 coordination modes can coexist, one M metal is out of the porphyrin plane (OOP) while the other M’ metal is bound to the strap and hanging atop the porphyrin (HAT). So, we considered a state in which the Tl(III) will be OOP while the other metal M will be HAT and in the 2nd the Tl(I) will be HAT and the M metal will be OOP. Thallium coordination studies were implemented with a bis-acid bis-strapped porphyrin and they evidenced the sunlight-driven and redox-driven formation the 1st example of a mixed-valence Tl(III)/Tl(I) porphyrin complex. Moreover, 2 states of the targeted molecular switch have been independently obtained the OOP Tl(III)/HAT Pb(II), and the HAT Tl(I)/OOP Pb(II). Using the 2nd phenomenon, we can consider obtaining transition between those 2 complexes to move towards an eventual molecular switch. Finally, we aim new supramolecular coordination complexes from bimetallic and dynamic porphyrin sous-units of which the metal-directed self-assembly through the strap could be modulated by the nature of metals bound to the porphyrin. 3 new porphyrins were designed with strap(s) bearing overhanging carboxylic acid of which α-position is occupied by either one other carboxylic acid or a cyano group. Metalation studies of those porphyrins was performed with Pb(II), Bi(III), Hg(II) or Cd(II) and 2 Xray structures of binuclear complexes of Cd(II) and Pb(II) was obtained with a bis-cyanoacid bis-strapped porphyrin. They proved the influence of the metallic ion nature on the coordinating group orientation.

No description available.

This work was initially launched to study the synthesis of low-valent group 13 compounds bearing the bis(imino)pyridine ligand framework. Since its inception, this project has grown beyond the boundaries of group 13 to include low valent tin, silver, and rhenium. Alongside the reports of novel coordination compounds, we utilized computational chemistry to uncover unprecedented interactions which challenge conventional concepts of bonding. Synthesis, characterization, and complimentary computational studies are presented herein. Chapter 1 presents a historical overview of the bis(imino)pyridine ligand as well as our synthetic methodology and characterization of new ligand variants we have contributed to the literature. Chapter 2 presents the synthesis of a series of In(I) and In(III) bis(imino)pyridine complexes with varied sterics. Ligand-metal interaction and effect of ligand steric bulk on complex stability, as well as computational studies highlighting weak covalent interactions will be discussed. Chapter 3 presents the synthesis of Ga(III) bis(imino)pyridine complexes. Reactivity with “GaI” synthon as well as varied-stoichiometry one-pot synthesis attempts to generate low valent Ga-bis(imino)pyridine complexes will be discussed. Chapter 4 presents the synthesis of a series of Tl(I) bis(imino)pyridine complexes with varied sterics analogous to the approach taken with indium(I). Unprecedented weak ligand-metal as well as Tl-arene interactions will be discussed. Chapter 5 presents the synthesis of a series of Sn(II) bis(imino)pyridine complexes with varied sterics and halide substituents. Preferential cation-anion pair formation and attempted reactivity will be discussed. Chapter 6 presents the synthesis of a series of Ag(I) bis(imino)pyridine complexes with varied sterics. Resulting ligand-metal interactions as well as reactivity towards Lewis basic donor ligands will be discussed. Chapter 7 presents the synthesis of first crystallographically authenticated examples of rhenium(I) pincer complexes utilizing the bis(imino)pyridine ligand. Chapter 8 presents a general conclusion to the work.

Esta tese apresenta um estudo sobre a contração de anel de olefinas e cetonas cíclicas promovida por sais de tálio(III). A reação de uma série de cicloexanonas e cis e trans-2-decalonas com TTN em CH2Cl2 levou aos correspondentes produtos de contração em rendimentos muito bons, desde que não houvesse um grupo metila em &#945;-carbonila. A reação de 3- e 4-alquilcicloexanonas, bem como de trans-2-decalonas, ocorreu com alto grau de seletividade. As diastereosseletividades observadas estão de acordo com o mecanismo proposto por McKillop. O sistema indânico, resultante da contração de um dos anéis do sistema bicíclico[4.4.0], foi construído de três maneiras diferentes. A reação de 1-tetralonas com TTN/K-10 em pentano forneceu 1-indanocarboxilatos de metila em rendimentos razoáveis, enquanto que o tratamento de 1,2-diidronaftalenos com TTN em MeOH levou aos correspondentes produtos de contração em bons rendimentos, quando não havia grupos alquílicos ligados à dupla ligação. Finalmente, a reação de dois álcoois homoalílicos, contendo a dupla ligação endocíclica, com TTN em uma mistura 1:1 de AcOH e H2O, levou às correspondentes 1-(2,3-diidro-1H-1-indanil)-3-hidroxi-1- propanonas em rendimentos excelentes. / This thesis presents studies toward the ring contraction of ketones and olefins promoted by thallium(III) The reaction of alkylcyclohexanones and cis and trans-2-decalones with TTN in CH2Cl2 led to the corresponding ring contraction products in very good yields, providing there is no methyl group at &#945;-carbonyl position. The reaction of 3- and 4-alkylcyclohexanones, as well as trans-2-decalones, occurred with high degree of selectivity. The observed diastereoselectivities agree with the McKillop\'s mechanism. The indan ring system was constructed by three different protocols. The reaction of 1-tetralones with TTN/K-10 in pentane afforded methyl 1-indanecarboxylates in reasonable yields, while treatment of 1,2-dihydronaphathlenes with TTN in MeOH furnished the corresponding ring contraction products in good yields, as long as there is no alkyl group at the double bond. Finally, the reaction of two homoallylic alcohols, bearing an endocyclic double bond, with TTN in a 1:1 mixture of AcOH and H2O, led to 1-(2,3-dihydro-1H-1-indenyl)-3-hydroxypropan-1-ones in excellent yields.

Por ser um semicondutor de elevado número atômico, elevada densidade de massa e largo gap de energia, o brometo de tálio (TlBr) é um material promissor para a detecção da radiação à temperatura ambiente. Entretanto, existem poucos trabalhos relacionados ao estudo deste material sob forma de filme fino policristalino para produção em grandes áreas como desejado para aplicações médicas. Neste trabalho, as técnicas de spray pyrolysis e evaporação térmica foram avaliadas como métodos alternativos para a deposição de filmes de TlBr policristalinos. Ambas as técnicas apresentam relativo baixo custo e podem facilmente ser expandidas para grandes áreas. O objetivos deste trabalho é o estudo da influência das principais condições de crescimento nas propriedades (estruturais, ópticas e elétricas) finais dos filmes de TlBr. Para os filmes produzidos por spray pyrolysis água mili-Q foi utilizada como solvente. A solução (0,10 g de TlBr dissolvidos em 100 g de água) foi agitada à temperatura de 70ºC. Cada deposição foi realizado mantendo os substratos (1cm x 1cm) à temperatura de 100ºC, com um fluxo de nitrogênio (N2) de 8 1/min e um fluxo de solução de aproximadamente 1/90 (ml/s). A distância bico de spray-substrato utilizada foi de 19 cm. Os filmes de TlBr evaporados foram crescidos pela evaporação térmica do material a partir de um cadinho de tungstênio. Um sistema de aquecimento dos substratos foi implantado e permitiu a variação da temperatura destes durante a deposição desde a temperatura ambiente até 200ºC. A separação substrato-superfície de evaporação, h, e o número de deposições por filme, n, também foram variados no intervalo de 3 a 9 cm e 1 a 4, respectivamente. A estrutura dos filmes foi investigada por Difração de Raio-x, a morfologia por Microscopia Eletrônica de Verredura e a composição através da Espectroscopia de Dispersão de Energia (EDS). Experimentos ópticos de transmitância em função do comprimento de ondas foram realizados para estimar o gap ótico dos filmes.As resistividades foram medidas a partir de experimentos de corrente em função da voltagem aplicada fluorescente (20 watts). Por fim, algumas amostras selecionadas foram expostas aos raios-X na faixa de diagnóstico mamográfico. As melhores propriedades foram obtidas para os filmes crescidos por evaporação térmica. A maior compactação e o maior gap óptico foram encontrados para os filmes produzidos a partir de h= 9 cm, os quais garantiram a maior sensibilidade para estes filmes quando expostos aos raios-X. Para os filmes produzidos pela deposição sequencial de várias camadas, a estrutura colunar dos filmes foi mantida para camadas superiores e resultados semelhantes para todas as amostras foram obtidos em relação ao gap óptico e à resistividade elétrica. Além disso, a sensibilidade a partir da utilização de raio-X na faixa mamográfica foi quadruplicada para o filme mais espesso. O aumento da temperatura do substrato resultou na maior compactação e homogeneidade no recobrimento do substrato. Entretanto, uma perda significativa de material durante a evaporação determinou filmes menos espessos em relação aos depósitos à temperatura ambiente. Variações cristalográficas e morfológicas foram obtidas entre os filmes depositados a diferentes temperaturas. Maiores valores gap foram obtidos para 150 e 200ºC. A caracterização elétrica dos filmes depositados a diferentes temperaturas foi limitada, neste trabalho, pela baixa pureza do pó utilizado para produção destes filmes. / Due to its high atomic number, high mass density and intrinsic band gap, thallium bromide (TlBr) is a promising semiconductor for room temperature operation for ionizing radiation detection. However, there are few works related to the study of this material in the polycrystalline thin film form for production in large areas (~ 40 x 40 cm2 ), as desired by medical applications. In this work, spray pyrolysis and thermal evaporation were used as alternative methods for the deposition of polycrystalline TlBr films. Both techniques present relative low cost and can be expanded for large areas. The aim of this work is to investigate the influence of the main growth conditions on the final structural, optical and electrical TlBr films properties. Films produced by spray pyrolysis used mili-Q water as solvent. The solution (0,10g of TlBr dissolved in 100g of water) was stirred at 70o C. Each deposition was performed maintaining the substrates (1cm2 ) at 100o C, the nitrogen rate at 8l/min and the solution flow at 1/90 ml/s approximately. The nozzle-spray to substrate distance was 19 cm. Evaporated TlBr films were grown by resistive thermal evaporation of purified material from a tungsten crucible. The substrate temperature was evaluated from room temperature to 200°C. The separation between evaporation source and substrates, h, and the number of depositions, n, were also varied from 3 cm up to 9 cm and from 1 up to 4, respectively. The structure of the crystals was investigated by X-ray Diffraction, the morphology by Scanning Electron Microscopy and the composition by Energy Dispersive X-Ray Spectroscopy. Optical experiments of absorbance as a function of wavelength were performed to estimate the optical gap of the TlBr films. Electrical resistivities were measured using current versus voltage experiments. The dark current was compared to the current under illumination with a fluorescent lamp (20 watts). Finally, some selected samples were exposed to X-ray in the range of mammography diagnosis. The best properties were obtained for films produced by resistive thermal evaporation. This technique allowed the production of films with thickness of approximately 28 µm, for a unique deposition of 12 minutes. However, bromine has lower vapor pressure than the thallium, what leads to a Br loss of about 10% in the composition of evaporated films. The smallest distribution of cracks and the largest optical gap were obtained for films produced at the lowest deposition rates. This leads also to a higher increase of the ratio between current under irradiation and in the dark, when the films were exposed to X-rays. For films produced at room temperature using sequential depositions, the columnar structure was kept for the superior layers and similar results for all samples were obtained in relation to optical gap and electrical resistivity. Moreover, for the thicker film, an increase of a factor 4 was observed for the ratio between current under irradiation using X-rays in the mammography range in relation to the dark. The higher substrate temperature leads to significant material loss during the evaporation and determined less thick films in relation to the ones deposited at room temperature. Structural and morphological variations were verified for films deposited at different temperatures. Larger gap values were found for 150 and 200ºC. For the electrical characterization of the films deposited at different temperatures an original powder with higher purity would be necessary. Moreover, due to the significant difference between bromine and thallium vapor pressures, better results would probably be obtained by a change to the hot-wall evaporation technique.

Neste trabalho, os cristais de TlBr foram crescidos pelo método de Bridgman, a partir de materiais purificados pela técnica de fusão zonal. A eficiência da purificação e avaliação da superfície cristalina em relação ao desempenho como detectores de radiação foi observada. Bons resultados foram obtidos com os aprimoramentos realizados nos processos de purificação, crescimento de cristais e na fabricação dos detectores. A resposta à radiação foi verificada excitando os detectores com fontes de raios gama: 241Am (59 keV), 133Ba (80 e 355 keV), 57Co (122 keV), 22Na (511 keV) e 137Cs (662 keV) à temperatura ambiente. Os valores de resolução em energia mais satisfatórios encontrados nesse trabalho foram a partir de detectores mais puros. Os melhores valores de resolução em energia obtidos foram de 10keV (16%), 12keV (15%), 12keV (10%), 28 keV (8%), 31keV (6%) e 36keV (5%) para as energias de 59, 80, 122, 355, 511 e 662 keV, respectivamente. Também foi realizado um estudo da resposta à detecção a uma temperatura de -20ºC e da estabilidade desses detectores. Nos detectores desenvolvidos não houve diferença significativa na resolução tanto em temperatura ambiente quanto na reduzida. Em relação à estabilidade foi observada uma degradação das características espectrométricas sob operação contínua do detector a temperatura ambiente e esta instabilidade variou para cada detector. Ambas características também foram observadas por outros autores. A viabilidade de utilização do cristal de TlBr como fotodetector para acoplamento em cintiladores também foi estudada neste trabalho. TlBr é um material promissor para ser utilizado como fotodetector devido a sua adequada eficiência quântica na região de 350 a aproximadamente 500 nm. Como uma aplicação para este trabalho foram iniciados estudos para fabricação de sondas cirúrgicas utilizando cristais de TlBr como o meio detector. / In this work, TlBr crystals were grown by the Bridgman method from zone melted materials. The influence of the purification efficiency and the crystalline surface quality on the crystal were studied, evaluating its performance as a radiation detector. Due to significant improvement in the purification and crystals growth, good results have been obtained for the developed detectors. The spectrometric performance of the TlBr detector was evaluated by 241Am (59 keV), 133Ba (80 e 355 keV), 57Co (122 keV), 22Na (511 keV) and 137Cs (662 keV) at room temperature. The best energy resolution results were obtained from purer detectors. Energy resolutions of 10keV (16%), 12keV (15%), 12keV (10%), 28keV (8%), 31keV (6%) and 36keV (5%) to 59, 80, 122, 355, 511 and 662 keV energies, respectively, were obtained. A study on the detection response at -20ºC was also carried out, as well as the detector stability in function of the time. No significant difference was observed in the energy resolution between measurements at both temperatures. It was observed that the detector instability causes degradation of the spectroscopic characteristics during measurements at room temperature and the instability varies for each detector. This behavior was also verified by other authors. The viability to use the developed TlBr crystal as a photodetector coupled to scintillators crystals was also studied in this work. Due to its quantum efficiency in the region from 350 to 500 nm, TlBr shows to be a promising material to be used as a photodetector. As a possible application of this work, the development of a surgical probe has been initiated using the developed TlBr crystal as the radiation detector of the probe.

Esta tese apresenta a primeira aplicação sintética da metodologia desenvolvida em nosso grupo de pesquisa, que se trata da contração de anel de 1,2-diidronaftalenos promovida por trinitrato de tálio (TTN) para fornecer derivados indânicos. A molécula-alvo da abordagem sintética é o Mutisiantol, um sesquiterpeno fenólico, que foi isolado da Mutisia homoeantha em 1979, e que possui substituintes nas posições 1 e 3 do anel ciclopentânico, com uma relação estereoquímica trans entre os mesmos. A rota proposta foi otimizada primeiramente na síntese de um composto modelo e depois aplicada na síntese total do Mutisiantol. O material de partida escolhido para a síntese do Mutisiantol foi o 2-metil-anisol, que é um composto comercial e bastante acessível economicamente. A etapa chave da seqüência envolveu a contração de anel do 1,6-dimetil-7-metóxi-1,2-diidronaftaleno promovida por TTN, que forneceu um derivado indânico com bom rendimento e elevada diastereosseletividade. Três etapas posteriores completaram a seqüência sintética, fornecendo o Mutisiantol em um total de 12 etapas. Descrevemos também o estudo de contração de anel de uma série de 1- tetralonas e 1,2-diidronaftalenos promovida por TTN, visando à obtenção de outros indanos e à complementação de estudos iniciados anteriormente. / This thesis presents the first synthetic application of the methodology developed in our research group, which involves the ring contraction of 1,2- dihydronaphthalenes promoted by thallium trinitrate (TTN) to afford indane derivatives. The target molecule of the synthetic approach is Mutisianthol, a phenolic sesquiterpene, isolated from Mutisia homoeantha in 1979, which embodies a trans-1,3-disubstituted cyclopentyl unit. The proposed route was first optimized in the synthesis of a model compound and then applied to the total synthesis of Mutisianthol. The starting material chosen for the Mutisianthol synthesis was the commercially available and cheap 2-methyl-anisol. The key step of the sequence involved the ring contraction of the 1,6-dimethyl-7-methoxy-1,2-dihydronaphthalene promoted by TTN, which furnished a functionalized indan with good yield and with high diastereoselectivity. The indan derivative was transformed into the final product in 3 steps. Overall, the total synthesis of Mutisianthol was accomplished in 12 steps. The TTN- promoted ring contraction of a series of 1-tetralones and of 1,2- dihydronaphthalenes was also studied in this thesis, with the aim to prepare other indanes and to extend earlier studies.