<p dir="ltr">Vinylidenes are highly reactive intermediates that undergo a variety of chemical reactions. Our group has pioneered the in-situ generation of vinylidenes from bench stable 1,1-dichloroalkenes using transition metal catalysts and an exogenous reductant.</p><p dir="ltr">Herein, we demonstrate the intramolecular insertion of vinylidenes into Si–H bonds for the synthesis of unsaturated silacycles of different ring sizes. It is well known that the replacement of carbon for silicon are of significant interest to medicinal chemists as a strategy for improving the potency or pharmacokinetic properties of biologically active compounds. This method provides convenient access to trisubstituted vinyl silanes which are synthesized intermolecularly, including those that can be used as nucleophilic partners in Hiyama cross-coupling reactions. Finally, deuterium isotope labelling experiments reveal interesting mechanistic features of the reaction.</p><p dir="ltr">The second chapter of the thesis further highlights the reactivity of vinylidenes through utilizing a cobalt catalyst. Vinylidene complexes can be added into an alkyne intramolecularly followed by a cobalt to zinc transmetalation step. The resulting organozinc intermediate can be trapped with various electrophiles. Further, by altering the reaction condition, the cobaltacycle intermediate can be accessed using π systems to form different cycloadducts.</p>

<p dir="ltr">Immunotherapy has revolutionized the field of oncology. While a lot of antibodies and small molecule inhibitors have been developed for this, a lot of targets remain undruggable in humans.</p><p dir="ltr">Targeted protein degradation has opened a new horizon in drug discovery where we can target these undruggable proteins. Proteolysis targeting chimeras using the ubiquitin-proteasomal system is one of the most popular TPD strategies that complement lysosomal degradation strategies to degrade intracellular proteins, typically using bifunctional small molecule degraders. Recently, large biomolecular and antibody conjugates have been developed for degrading membrane and extracellular proteins in cells, such as lysosomal targeting chimeras (LYTACs) and genetically encoded LYTACS, among several others. However, larger molecules have limitations in penetrating solid tumors. This dissertation work focused on the development of bifunctional small molecule degraders for programmed death-ligand 1 (PD-L1), a transmembrane protein ligand for the immune checkpoint programmed cell death 1 (PD-1). PD-L1 is highly expressed on several tumors, such as triple-negative breast cancer (TNBC), non-small cell lung carcinoma, and renal cancer, and is known to suppress cancer-killing immune cells via interaction with PD-1 on T-cells. In addition, PD-L1 is also present on macrophages in the tumor microenvironments leading to further immune suppression and acquired resistance to anti-PD-1 therapy is associated with the upregulation of alternative immune checkpoints, thereby reducing anti-tumor efficacy. We have designed and synthesized bifunctional small molecules as PD-L1 degraders with different recruiters and linkers guided by computational studies with known PD-1/PD-L1 structures to show both cell surface and total protein degradation in human TNBC cells. In a separate project, we also developed small molecule conjugates to degrade an intracellular integral membrane protein of the endoplasmic reticulum with an unknown 3D structure, namely Diglyceride acyltransferase 2 (DGAT2). Recently, our lab identified DGAT2 as a new target for combating Alzheimer’s disease. Specifically, DGAT2 catalyzes triacylglycerol (TAG) synthesis using diacylglycerol and fatty acyl CoA as substrates. The accumulation of TAGs, mechanistically linked to DGAT2, results in “fat” or lipid droplets (LDs) inside the cells. Our lab showed that microglial cells (resident immune cells in the brain) accumulate LDs in the postmortem brains of human patients and mouse models (5xFAD) of Alzheimer’s disease and that the LD accumulation is driven by amyloid-beta (Ab) – a hallmark of Alzheimer’s disease – via DGAT2 pathway. Further, these LD-laden microglia have phagocytic defects and are spared Aβ thereby affecting plaque accumulation and clearance. Inhibiting DGAT2 reduces the amount of TAG in the brain, which in turn reduces LDs and restores microglial ability to phagocytose Ab. However, commercially available DGAT2 inhibitors were unable to reduce LD load in older 5xFAD mice. Using AlphaFold’s models of DGAT2, we designed and identified sites to synthesize bifunctional DGAT2 degraders that resulted in reduced LDs in mouse primary microglial cells and enhanced phagocytosis of Aβ plaques in vivo in aged 5xFAD mice. Our approach shows a framework to develop bifunctional small molecule degraders for membrane proteins to potentially combat immune dysregulation in chronic diseases.</p>

No / The protein O6-alkylguanine-DNA alkyltransferase (Atase) is responsible for the repair of DNA lesions generated by several clinically important anti-cancer drugs; this is manifest as active resistance in those cancer cell lines proficient in Atase expression. Novel O6-substituted guanine analogues have been synthesized, bearing acidic, basic and hydrogen bonding functional groups. In contrast to existing O6-modified purine analogues, such as methyl or benzyl, the new compounds were found to resist repair by Atase even when tested at concentrations much higher than O6-benzylguanine, a well-established Atase substrate active both in vitro and in vivo. The inactivity of the new purines as covalent substrates for Atase indicates that agents to deliver these groups to DNA would represent a new class of DNA-modifying drug that circumvents Atase-mediated resistance.

The potentially most important challenges today are related to energy and the environment. New materials and methods are needed in order to, in a sustainable way, convert and store energy, reduce pollution, and clean the air and water from contaminations. In this, nanomaterials and nanocomposites play a key role, and hence knowledge about the relation between synthesis, structure, and properties of nanosystems is paramount. This thesis demonstrates that solution-chemical synthesis, using amine-modified acetates and nitrates, can be used to prepare widely different nanostructured films. By adjusting the synthesis parameters, metals, oxides, and metal–oxide or oxide–oxide nanocomposites were prepared for two systems based on Co and Zn:Fe, respectively, and the films were characterised using diffraction, spectroscopy, and microscopy techniques, and SQUID magnetometry. A variety of crystalline cobalt films—Co metal, CoO, Co3O4, and composites with different metal:oxide ratios—were synthesised. Heat-treatment parameters and control of the film thickness enabled tuning of the phase ratios. Random and layered Co–CoO composites were prepared by utilising different heating rates and gas flow rates together with a morphology effect associated with the furnace tube. The Co–CoO films exhibited exchange bias due to the ferromagnetic–antiferromagnetic interaction between the Co and CoO, whereas variations in e.g. coercivity and exchange bias field were attributed to differences in the structure and phase distribution. Ordered structures of wurtzite ZnO surrounded by amorphous ZnxFeyO were prepared through controlled phase segregation during the heating, which after multiple coating and heating cycles yielded ZnO–ZnxFeyO superlattices. The amorphous ZnxFeyO was a prerequisite for superlattice formation, and it profoundly affected the ZnO phase, inhibiting grain growth and texture, already from 1% Fe. In addition, ZnO–ZnxFeyO exhibited a photocatalytic activity for the oxidation of water that was higher than results reported for pure ZnO, and comparable to recent results reported for graphene-modified ZnO.

La réévaluation des impacts toxicologique et environnemental des répulsifs synthétiques conduit à reconsidérer les répulsifs d'origine naturelle pour la prévention des maladies transmises par les insectes (dengue, chikungunya, paludisme,…). Cette étude se rapporte aux structures de type bis(oxazolidine) envisagées comme prodrogues de répulsifs naturels par leur conversion avec le tris(hydroxyméthyl)aminométhane (TRIS). Différents protocoles et voies de synthèse ont été étudiés sur une série représentative d'aldéhydes pour définir l'étendue et les limites de l'approche permettant de concentrer deux unités d'un même principe actif au sein de bis(oxazolidines) symétriques et de reproduire un effet synergique avec deux unités différentes formant des bis(oxazolidines) dissymétriques. La fonctionnalisation des bis(oxazolidines) a été également envisagée pour moduler leur balance hydrophile-lipophile. L'étude de la réaction de cyclocondensation met en évidence l'influence des paramètres structuraux sur le procédé de synthèse des bis(oxazolidines), la stabilité des intermédiaires (monooxazolidines) et la stéréosélectivité de la réaction. L'interprétation des résultats est proposée sur la base des effets (stéréo)-électroniques. Cette étude démontre l'intérêt de cette approche chimique pour la production de prodrogues de répulsifs naturels qui peuvent constituer des atouts pour le développement durable. / The more sensitive human and environmental risk assessments of non natural repellents have encouraged the rehabilitation of botanical-based repellents for the prevention of insect-transmitted diseases (dengue, chikungunya, malaria…). This study is related to bis(oxazolidine) structures envisaged as prodrug derivatives of natural repellents by their conversion with tris(hydroxymethyl)aminomethane (TRIS). The scope and limitations of various procedures and pathways have been assessed with structurally diverse aldehydes to concentrate two identical units in the symmetrical structures and to reproduce a synergistic effect with two different units in the unsymmetrical ones. Subsequent functionalization of the heterocyclic derivatives has been achieved to modulate their hydrophilic-lipophilic balance. The study of the cyclocondensation reaction shows evidence for the influence of structural effects not only on the chemical process but also on the relative stability of the monocyclic intermediates and the stereochemical outcomes of the reaction. The results are discussed on the basis of (stereo)-electronic effects. Finally, this study confirms the feasibility of this chemical approach to produce prodrugs of natural repellents which could appear as a contributive effort to sustainable development.

[pt] Nanocompósitos de cobre com nanotubos de carbono (Cu-CNT) são considerados promissores para aplicações em materiais eletrônicos, trocadores de calor e como elementos estruturais. Espera-se que com a adição de CNTs, a matriz de cobre possa melhorar as propriedades mecânicas e de transporte. No presente estudo foram produzidos materiais nanocompósitos de matriz de cobre reforçados 0,5, 2 e 5,0 por cento em massa de MWCNT. O procedimento parte da funcionalização dos MWCNTS por método de oxidação convencional e microondas, e sua posterior incorporação na solução de nitrato de cobre, dispersão, dissociação e redução in-situ, com atmosfera de hidrogênio. Foram avaliadas soluções dispersantes como a água e THF no processo da síntese. Técnicas de compactação a frio com posterior sinterização convencional e Spark Plasma Sintering (SPS) foram usadas para produção de pastilhas. Os CNTs funcionalizados pelo método convencional se mostram efetivos para dispersão e decoração quando utilizado THF como solução dispersante. Análises por TEMEELS indicam a presença de cobre metálico na interface Cu-MWCNT. As pastilhas produzidas por sinterização convencional apresentaram tamanho de grão entre 50 nm e 4 um, com boa distribuição dos CNTs, assim como uma diminuição na resistividade elétrica em 98 por cento usando 5wt por cento MWCNT. Por outro lado, as pastilhas produzidas por SPS apresentaram tamanho de grão entre 50nm e 2 um, com alta segregação e modificação dos MWCNTs nos contornos de grão da matriz, assim como o aumento na resistividade elétrica. Aumento de 139 por cento na dureza e 65.5 por cento no módulo de elasticidade foi observado na amostra contendo 0.5 wt por cento MWCNTs produzida por SPS, enquanto valores similares ou inferiores foram observados nas outras frações em massa de MWCNTs. / [en] Copper- multiwall carbon nanotube nanocomposites (Cu-MWCNT) are been considered as a promising material for applications in electronic materials, heat exchanger and structural elements. It is expected that MWCNT addition in a copper matrix can improve the mechanical and transport properties. In this work Cu matrix nanocomposites reinforced with 0,5 wt percent; 2 wt percent; and 5,0 wt percent MWCNT were produced. The procedure starts from the MWCNTs functionalization by conventional oxidation and microwave methods and subsequent incorporation into the copper nitrate solution, dispersion, dissociation, and in-situ reduction in hydrogen atmosphere. Also, it was evaluated water and THF solutions for MWCNTs dispersants. Cold compaction follow by conventional sintering and Spark Plasma Sintering (SPS) techniques were used to produce pellets. CNTs functionalized by conventional method are shown effective for dispersing and decorating CNTs when THF was used as dispersant solution. TEM-EELS analyses indicate the presence of metallic copper in the Cu- MWCNT interface. Pellets produced by conventional sintering were in the 50nm - 4 um grain size, with good CNT distribution and decreasing in 98 per cent the electrical resistivity using 5wt percent MWCNT. Meanwhile, pellets produced by SPS were in the 50nm - 2um grain size with high segregation and modification of MWCNTs at the grain boundaries, as well as the increase in electrical resistivity. Increase of hardness 139 percent and 65.5 percent in elastic modulus were observed in the sample containing 0.5 wt percent MWCNTs produced by SPS, while similar or lower values were observed in the other MWCNTs fractions.

Les nanoparticules (NPs) de métaux nobles ont de nombreuses applications grâce à leurs propriétés optiques, chimiques et électriques extraordinaires. Les propriétés optiques résultent de plasmons localisés de surface, exaltant l’absorption et la diffusion de la lumière aux longueurs d’onde de résonance dans le domaine du visible. Les propriétés optiques, dépendantes de la taille et de la forme exacte de la NP, sont mises à profit dans l’objectif de créer un absorbant parfait en couche mince. Les applications de ces couches minces concernent, parmi d’autres, les photodétecteurs, le solaire thermique et les applications de furtivité.Les récents progrès accomplis dans le domaine des synthèses colloïdales de NPs nous permettent de synthétiser des nanosphères, nanocubes et nanoprismes d’Ag de différentes tailles. Ces NPs sont déposées aléatoirement dans une matrice hôte non-absorbante afin d’être caractérisées optiquement. Les résultats expérimentaux sont validés à l’aide de calculs numériques, permettant en outre de visualiser les phénomènes physiques à l’échelle de la NP.Cette thèse décrit les synthèses chimiques et les caractérisations optiques. Des mesures de spectroscopie ellipsométriques sont effectuées sur différentes couches minces. Un modèle optique simple, constitué d’une loi de Cauchy et d’une ou plusieurs lois de Gauss, est dérivé afin d’obtenir les indices optiques complexes de nos échantillons. La comparaison des coefficients d’extinction des différentes couches montre que les propriétés optiques de chaque NP sont additionnées en mélange et en empilement. Les calculs numériques relient ce résultat à la faible densité de nanoparticules en couche. / Noble metal nanoparticles (NPs) have a broad range of applications thanks to their extraordinary optical, chemical and electrical properties. The optical properties are driven by their ability to support localized surface plasmon resonances, which induce enhanced absorption and scattering at their resonance wavelengths in the visible spectrum. These size and shape dependent optical properties are taken advantage of in the search for a thin film layer perfect absorber in the visible wavelength band. The application for such thin film layers with engineered optical properties ranges from photodetectors, over thermal solar cells to stealth applications.Recent progress in colloidal NP synthesis makes the chemical wet synthesis of silver nanospheres, nanocubes and nanoprisms of various sizes easily feasible. The different NPs are then randomly deposited in a transparent and non-absorbing host matrix for optical characterizations. Computer simulations validate the experimental results and allow a visualization of the phenomena occurring at the nanoparticle scale.This PhD thesis reports the chemical synthesis of the different nanoparticles and their optical characterizations. Spectroscopic ellipsometry measurements are performed on single shape NPs, blends and multilayer stacks. A simple diffusion model, composed of a single Cauchy law and one or several Gauss laws, is chosen to determine the complex optical indices. The comparison of the extinction coefficients of the different layers shows that the optical properties of each NP are simply added in the blend and multilayer samples. Computer simulations relate this to the low density of nanoparticles.

Actuellement, on observe le développement de nouveaux matériaux, à savoir les matériaux actifs, au travers de divers processus et applications. Par exemple, l’utilisation de nanoparticules de fer (NanoFe) absorbantes d’O2 dans le cadre de l’emballage actif, implique la maîtrise de plusieurs paramètres pour une application en tant que matériau actif. En effet, il est indispensable d’avoir une très bonne compréhension des mécanismes d’oxydation et de consommation d’O2, de pouvoir quantifier les capacités d’absorption ainsi que la vitesse d’absorption d’O2. Bien que nécessaires, ces deux paramètres n’ont été jusqu’à présent que peu caractérisés et encore moins mis en relation avec les propriétés morphologiques (tailles, surface spécifique, etc) et physico-chimiques (tel que l’état du fer) des nanoparticules de fer mises en oeuvre.Dans le but de concevoir à façon un film d’emballage monocouche absorbeur d’O2, ce travail vise à combiner une barrière passive, liée au phénomène de tortuosité induit par la présence des lamelles d’argile dispersées dans une matrice polymérique et une barrière active, liée à l’absorption d’oxygène par les NanoFe synthétisées. Les Nano-Fe ont été synthétisées par réduction chimique au Borohydrure de sodium sur support d’argile Montmorillonite (MMT). La caractérisation MET a révélé la formation d'agrégats de nanoparticules de fer d'une taille moyenne de 57 ± 17 nm dispersées sur la surface des MMT. La cinétique Mössbauer sur la poudre MMT-Fe confirme que les différentes phases du fer (Fe0 et FeII) dans les nanoparticules de fer ne s'oxydent pas à la même vitesse. Cela a permis d’ajuster le modèle mathématique de prédiction des propriétés d’absorption de l’O2. L'étude de propriétés d'absorption d’O2 sur les poudres a montré que la constante de réaction (k), le coefficient de proportionnalité (n) et les capacités d'absorption d’O2 sont du même ordre de grandeur pour la poudre humide, séchée et stockée. Les films nanocomposites préparés à partir des poudres séchées de MMT-Fe synthétisées, incorporées dans un polymère de LLDPE ont montré une bonne capacité d’absorption, mais inférieure à celle de la poudre seule, lié à l’oxydation avancée du fer dans ces films, confirmée par la spectroscopie Mössbauer (les films sont oxydés à 60% contre 30% pour les poudres). Un modèle numérique utilisant la seconde loi de Fick couplée au système d’équations de cinétique chimique obtenue sur la poudre, a permis de prédire le phénomène de diffusion et réaction de l'oxygène dans des films réalisés. Ce modèle est comparé aux données expérimentales obtenues par oxydation de films. En parallèle, une étude de la cinétique d'absorption d’absorbeurs d’O2 commerciaux, couramment utilisés dans les emballages sous atmosphère modifiée, a été effectuée. Sur ces systèmes commerciaux, la cinétique d'absorption a été décrite aussi par une réaction de cinétique de second ordre avec un comportement de type Arrhenius pour l’effet de la température. Toutefois, la spectroscopie Mössbauer a révélé que, dans ce cas-là, seule l’espèce Fe0 était prépondérante pour décrire la cinétique (celle de FeII étant négligeable tant elle est rapide). Nous avons montré pour la première fois, que la spectroscopie de Mössbauer peut être couplée avec succès à la mesure de l'oxygène afin de caractériser in situ l’oxydation du fer, sa spéciation et la capacité d’absorption d’O2. Cette configuration associant spectroscopie de Mössbauer et mesure de l’oxygène ont fourni des informations précieuses sur les mécanismes réactionnels régissant les absorbeurs d’O2. Tous ces résultats auront des implications importantes pour la compréhension de l’absorption d’oxygène dans le système actif absorbeur d’O2. / Currently, we are seeing the development of new materials, namely active materials, through various processes and applications. Among these active materials, the use of O2 scavenging iron nanoparticles (NanoFe) as required knowledge of several parameters for efficient application in the field of food packaging such as knowledge about oxidation mechanism and O2 consumption rate. These parameters are necessary to be able to quantify the absorption capacity and absorption rate of O2. Although necessary, these two parameters have so far been little characterized and even less related to the morphological (size, specific surface, etc.) and physico-chemical properties (such as the iron speciation) of iron nanoparticles implemented.In order to tailor nanocomposite film with O2 scavenging properties, this work aims to combine a passive barrier, related to the phenomenon of tortuosity induced by the presence of clay platelets dispersed in a polymeric matrix and an active barrier, related to oxygen uptake by synthesized NanoFe. Nano-Fe were synthesized by chemical reduction with sodium borohydride on Montmorillonite clay (MMT) support. The TEM characterization revealed the formation of iron nanoparticle aggregates with an average size of 57 ± 17 nm scattered on the MMT surface. The Mössbauer kinetics on the MMT-Fe powder confirms that the different iron phases (Fe0 and FeII) in the iron nanoparticles do not oxidize at the same speed. This allowed to adjust the mathematical model of O2 absorption properties prediction. The study of O2 absorption properties on powders has shown that the reaction constant (k), the proportionality coefficient (n) and the O2 absorption capacities are of the same order of magnitude for the wet, dried and stored powders. The nanocomposite films prepared from the synthesized MMT-Fe dried powders incorporated in a LLDPE polymer showed good absorption capacity, but lower than that of the fresh powder, related to the advanced oxidation of iron in these films, confirmed by Mössbauer spectroscopy (films are 60% oxidized versus 30% for powders). A numerical model using the second law of Fick coupled to the system of chemical kinetics equations obtained on the powder, made it possible to predict the phenomenon of diffusion and reaction of oxygen in films produced. This model was compared with experimental data obtained by measuring O2 absorption by films. In parallel, a study of the absorption kinetics of commercial O2 scavengers, commonly used in modified atmosphere packaging, was carried out. On these commercial systems, absorption kinetics has also been described by a second-order kinetic reaction with Arrhenius-like behavior for the effect of temperature. Mössbauer spectroscopy revealed that, in this case, only the Fe0 species were predominant to describe the kinetics (that of FeII being negligible as it was fast). We have shown for the first time that Mössbauer spectroscopy can be successfully coupled to the measurement of oxygen in order to characterize iron oxidation, speciation and O2 absorption capacity in situ. This configuration associating Mössbauer spectroscopy and oxygen measurement provided valuable information on the reaction mechanisms governing the O2 absorbers. All of these results will have important implications for understanding oxygen uptake in the active O2 absorber system.

Este trabalho descreve a síntese e caracterização dos compostos de adição obtidos pela reação entre os monocloroacetatos (CA) e dicloroacetatos (DCA) de lantanídeos (III) com a quinolina-N-óxido (QNO), na presença de etanol e ortoformiato de trietila. Os compostos foram obtidos na forma sólida e caracterizados por análise elementar, testes de solubilidade, medidas de condutância eletrolítica, difração de raios X (método do pó), espectros de absorção na região do infravermelho, espectros de absorção na região do visível dos compostos de Nd, espectros de emissão dos compostos de Eu e análise térmica. Os experimentos de análise térmica permitiram estudar o comportamento térmico dos compostos. A associação dos resultados de análise elementar e termogravimétrica permitiu sugerir as seguintes fórmulas mínimas: a) Ln(DCA)3.yQNO.wEtOH onde, y = w = 8/9 para Ln= La; y = w = 1 para Ln= Ce; y = 1 e w =&#190; para Ln= Pr, Nd e Sm; y = 1 e w = O para Ln= Eu ao Lu e Y. b) Ln(CA)3.QNO, onde Ln= La ao Ho e Y. Os compostos não são higroscópicos, e possuem coloração bege, em sua grande maioria. São solúveis em DMF, DMSO, HMPA e água, e insolúveis em hexano, ciclohexano, dimetoxipropano, benzeno, clorofórmio, cloreto de metileno, tolueno, acetonitrila e acetona. As medidas de condutância, em solução de DMF, revelaram que os compostos se comportam como não eletrólitos, indicando que os ânions CA e DCA estão coordenados ao íon Ln3+. Os difratogramas de raios X ( método do pó) mostraram que os compostos de adição de dicloroacetatos possuem três séries isomorfas. Os espectros de absorção no infravermelho indicaram que a coordenção da QNO e dos ânions CA e DCA ocorre através do átomo de oxigênio, mas não permitiram evidenciar a coordenção do EtOH nos compostos de adição de dicloroacetatos, porém os resultados de análise térmica confirmaram a presença do etanol para os compostos de La ao Sm. As associações das técnicas auxiliaram na definição da estequiometria e existência das séries isomorfas. Os espectros de absorção dos compostos de Nd mostraram que as interações Nd3+- ligantes são de caráter eletrostático. Baseando-se nas transições 4I9/2 &#8594; 4G5/2, 2G7/2 foi possível determinar o parâmetro nefelauxético [&#946; = 0,990 (CA) e &#946; = 0,993 (DCA)], o fator de covalência [b1/2 = 0,070 (CA) e b1/2 = 0,0502 (DCA)] e o parâmetro de Sinha [&#948; = 1,01 (CA) e &#948; = 0,705 (DCA)]. Os espectros de emissão dos compostos de Eu, registrados a 77 K, sugeriram a simetria C3v para o composto de Eu(CA)3.QNO e C2v para o composto Eu(DCA)3.QNO. As curvas termoanalíticas evidenciaram que o processo de decomposição térmica ocorre em multi-etapas e que o produto final é o respectivo óxido. / This work describes the synthesis and characterization of the addition compounds obtained between lanthanide (III) mono and dichloroacetates with Quinoline-N-oxide (QNO) in the presence of ethanol and triethyl orthoformate. These compounds were obtained in the solid form and characterized by elemental analysis, solubility tests, electrolytic condutance measures, X-ray diffraction (powder method), infrared absorption spectroscopy, visible absorption spectroscopy of the Nd compounds, emission spectroscopy of the Eu compounds and thermal analysis. The thermal analysis experiments allowed studying the thermal behavior of the compounds. The association of the results of elemental analysis and thermogravimetry allowed to suggest the minimum formule: a) Ln(DCA)3.yQNO.wEtOH, where y = w = 8/9 when Ln = La; y = w = 1 when Ln = Ce; y = 1 and w = 3/4 when Ln = Pr, Nd and Sm; y = 1 and w = 0 when Ln = Eu to Lu and Y. b) Ln(CA)3.QNO, where Ln= La -Ho e Y. The compounds are not hygroscopic and are beige coloration. They are soluble in DMF, DMSO, HMPA and water, but they are insoluble in hexane, ciclohexane, dimetoxipropane, benzene, chloroform, methylene chloride, toluene, acetonitrile and acetone. In DMF solution, the conductance measurements revealed that the compouds behave as non-electrolytes, indicating that CA and DCA ions are coordinated to the ion Ln3+. X-ray patterns suggest that the addition compounds of dichloroacetates and monochloroacetates have, respectively, three and four isomorphous series. The infrared spectra indicated that ligand and anions coordination to Ln3+ occurs through the oxygen atom, but they did not confirm the EtOH coordination in the addition compounds of dichloroacetates, however the results of thermal analysis confirmed the alcohol presence in the La to Sm complexes. The techniques association support in stoichiometry definition and isomorphic series. The absorption spectra of the Nd compounds suggest that the Nd3+-ligand interactions are of electrostatic character. Based in the 4I9/2 &#8594; 4G5/2, 2G5/2 transitions was possible to determine the spectroscopic parameters: nephelauxetic parameter [&#946; = 0,990 (CA) and &#946; = 0,993 (DCA)], covalency factor [bl/2 = 0,070 (CA) and b1/2 = 0,0502 (DCA)] and Sinha\'s parameter [&#948; = 1,01 (CA) and &#948; = 0,705 (DCA)]. The emission spectra of the Eu compounds, at 77 K, suggest that the symmetry for the Eu3+ ions is C3v for Eu(CA)3.QNO and C2v for Eu(DCA)3.QNO. The thermoanalytical curves evidenced that the thermal decomposition process occurs in multi-stages and that the final product is the respective oxide.

[pt] As ligas metálicas têm sido amplamente estudadas, visando atender aplicações onde propriedades físicas e químicas diferenciadas se fazem necessárias. Nesse sentido, merecem destaque as ligas voltadas ao recobrimento de substratos metálicos, tendo-se como objetivo a proteção do substrato em ambientes corrosivos. Sendo assim, a presente pesquisa propõe abordar um método de síntese de ligas de Cu-Ni em substratos de cobre através da decomposição térmica do nitrato de níquel, e subsequentemente a redução do óxido NiO formado, mediante redução com H2 a 350 graus Celsius e tratamento térmico na mesma atmosfera a 800 graus Celsius, com tempos variados (3, 4 e 5h), para estimular a difusão do níquel produzido no interior da matriz de Cu. Os filmes serão caracterizados via microscopia eletrônica de varredura (MEV), tanto em sessões transversais, quanto panorâmico, além da difração de raios-x (DRX) com incidência rasante, visando-se identificar a liga Cu-Ni produzida. Os resultados sugerem que o processo proposto foi bem-sucedido, permitindo um amplo recobrimento do substrato e a subsequente difusão do Ni produzido, o que permitiu a identificação, em todas as amostras, da liga de interesse. As amostras selecionadas serão futuramente utilizadas para ensaios de microdureza, bem como de eletro-corrosão, sendo o comportamento medido comparando-se com o substrato puro. Espera-se que a presença do recobrimento eleve a resistência à abrasão, bem como dificultar a corrosão do cobre presente. / [en] Metal alloys has been extensively studied to light upon applications where differentiated physical and chemical properties are required. In this context, its value highlighting the alloys for the coating of metallic substrates with the objective of protecting the substrate in corrosive environments. The present work proposes to approach a method of synthesis of Cu-Ni alloys in copper substrates through the thermal decomposition of nickel nitrate and subsequently to discount the NiO oxide formed by reduction with H2 at 350 degrees Celsius and heat treatment in the same atmosphere at 800 degrees Celsius with (3, 4 and 5h) to stimulate the diffusion of the nickel produced inside the Cu matrix. The films were then characterized by scanning electron microscopy (SEM) in both cross-sectional and panoramic sessions, in addition to X-ray diffraction (XRD) with low incidence, aiming to identify Cu-Ni alloy produced. The results suggest that the proposed process was successful, allowing a wide coating of the substrate and subsequent diffusion of Ni produced, which allowed the identification in all samples of the alloy of interest. Selected samples will be used in the future for microhardness tests, as well as for electro-corrosion, and the measured behavior is compared to that observed for pure substrate. The presence of the coating is expected to raise the abrasion resistance as well as to hinder the corrosion of the copper present.