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Ch1 The X-ray structural determinations of the neutral 1',2',1'",2'"-tetranaphthylmethyl- and the 1', 3', 1', 3'-tetranaphthylmethyl- biferrocenium triiodide have been determined. Our Mossbauer measurement for 1.34 and 1.35 indicate that the intramolecular electron transfer rates are quite sensitive to the environmental perturbations caused by the grinding of the sample. An interesting finding is that the Mossbauer results indicate that the unground diffusing sample of 1.34 is valence delocalized on the Mossbauer time scale above 180K. However, the ground diffusing sample of 1.34 exhibits a Mossbauer spectrum characteristic of a valence-trapped cation which remains valence-trapped electronic state at 300K. The effects of grinding of samples are also observed in the EPR and XRD measurements. Ch2 A great deal of research has concentrated on long range electron and energy transport in transition metal- based system and conducting polymer. We have synthesis a new bis-terpyridine bridging ligand (2.40) which the spacer is biferrocene moiety. Incorporating of the Ruthenium (II) subunits via redox-active spacer group promote to construction polynuclear transition metal complexes (i.e. multicomponent system). Cyclic voltammetric analysis indicated that there are Fe-Fe electronic coupling in the bridging ligand, and the degree of Fe-Ru electronic coupling is weak. In addition to dominant UV absorption near 240 and 280 nm from terpyridinyl and MLCT absorption from Ru to terpyridine around 480 nm, the complexes containing ferrocene or biferrocene as endgroup exhibit an unusual absorption band around 560 nm which is due to a feccocene moiety to terpyridine MLCT transition.

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Thesis (M.S.)--University of Michigan, 1963.

Thesis (M.S.)--University of Michigan, 1963.

Thesis (M.S.)--University of Michigan, 1944.

Made available in DSpace on 2014-06-11T19:27:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-23Bitstream added on 2014-06-13T20:16:11Z : No. of bitstreams: 1 moreira_rhs_me_guara.pdf: 1620956 bytes, checksum: e70dbaf4dfb1c01921ef51fc17d1cb18 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fios ortodônticos são fabricados com uma série de materiais como aço inoxidável, metais, cerâmicas e polímeros. No meio bucal, eles estão sujeitos a fluídos corrosivos e variação de pH podendo levar a liberação de íons níquel nos tecidos e fluídos corpóreos. Neste estudo in vitro, filmes de carbono amorfo hidrogenado A-C:H foram depositados em fios ortodônticos empregando a técnica de PECVD para inibir a liberação de íons. O arranjo estrutural dos fios foi estudado a partir de Espectroscopia Raman e a molhabilidade avaliada medindo-se o ângulo de contato da superfície. Para avaliar a liberação de íons, os arcos ortodônticos (com e sem filme) foram montados em modelos confeccionados com resina e imersos em solução fisiológica a 37°C por 30 dias. Durante o tempo de imersão as amostras foram lavadas e/ou imersas em colutórios diariamente. Espectrofotometria de absorção atômica foi usada para medir a liberação de elementos a partir de amostras. Os resultados mostraram que o revestimento previne a liberação de Ni dos fios. O tratamento de superfície alterou o comportamento mecânico dos fios avaliados / Orthodontics wires are made from a variety of metals such as stainless steel, metals, ceramics and polymers. In oral environment, they are subjected to aggressive fluids and pH variation that can lead to nickel ions releasing to body tissues and fluids. In this in vitro study, A:C-H films were deposited on orthodontics wires by radio-frequency plasma-enhanced chemical vapour deposition (PECVD) from inhibited nickel ions release. The structural arrangement of films was probed by Raman spectroscopy and contact angle measurements were carried out in order to evaluate the wettability of surface. To evaluate ions release, orthodontics wires (coated and uncoated) were mounted in resin mould and immersed inn physiological serum for 30 days at 37°C. During the immersion time the samples were brushed and/or immersed in mouthwashes daily. Atomic absorption spectrophotometry was used to measure the release of elements from the samples in solution. Results showed that the coating prevents Ni release of orthodontics wires. Surface treatment change mechanical properties of orthodontics wires

Made available in DSpace on 2014-10-09T12:51:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:17Z (GMT). No. of bitstreams: 1 11307.pdf: 4388306 bytes, checksum: c125267132b30edad3f63953bc6e68a5 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP