This thesis details investigations into the photophysical properties of lanthanide ions in a number of different systems. The preparation and characterisation of lanthanide containing surfactant salts of the type Ln(A0T)(_3) (Ln = Tb, Nd, Eu, AOT = bis-(2-ethylhexyl) sulfosuccinate) is described. Small angle neutron scattering experiments have been used to determine the size and shape of reverse micelles formed by these surfactants in water/cyclohexane microemulsions. The luminescence lifetimes of the lanthanide ions have been used to investigate the solvation environment within reverse micelle systems as a function of water content. The use of lanthanide complexes based on 1,4,7,10-tetraazacyclododecane bearing phenanthridine antenna in luminescence microscopy has been explored. Samples such as silica particles, onion skin cells and guinea pig heart cells have been imaged. Time- resolved measurements have allowed time gating of the sample from a fluorescent background and lifetime maps of the images have been obtained. The preparation and characterisation of deuteriated complexes of dota (1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid) with lanthanide ions is described. Selective deuteriation of both the ring and arm sites allow the relative quenching effects of C-H/D oscillators to be determined for various lanthanides in a series of structurally well defined complexes. Finally, investigations into the distance dependence of the energy transfer between aromatic chromophores and lanthanide ions have been undertaken. The synthesis of a model system linking a phenanthridine donor to a europium complex by poly(valine) spacer units is described. Preliminary photophysical results show that the quantum yield of emission by europium decreases as the distance between the donor acceptor pair is increased.

Mono-dispersed supported Ni catalysts were synthesized using the water-CTAB-hexanol reverse micellar system. The core of the reverse micelles contained an aqueous solution of NiCl2. Dynamic light scattering measurements showed that microemulsions having a water-to-surfactant molar ratio, Wo, of 10 lead to reverse micelles with lowest polydispersity, longest stability, and size range of interest. At an oil-to-aqueous phase ratio of 2, the diameter of the reverse micelles was found to increase with Wo in a linear fashion. At higher values of Wo (i.e. 25-30), the polydispersity was found to increase when lowering the amount of surfactant in the system. Ultimately, O/A = 2 and Wo = 10 were chosen as optimal conditions for microemulsion preparation. The aqueous NiCl2 concentration within the micelles was varied between 0.1 and 0.001 M. DLS results showed that although the average micelle diameter was between 70-83 nm throughout the range of metal salt concentrations, the crystallite size estimate based upon the reported micelle diameter and known aqueous NiCl2 concentration ranged between 2 to 7 nm. Therefore, the Ni crystallite size was varied by changing the aqueous NiCl2 concentration due to instability issues arising when changing the value of Wo. After deposition onto an alumina mesh support, the particles were dried, calcined, and reduced to produce Ni clusters. SEM and EDS analysis was used to confirm the presence of Ni compounds after the calcination stage. By the varying the aqueous NiCl2 concentration within the micelles, .0039, .0013, and .00039 wt. % Ni catalysts were produced and characterized using SEM. Particles in the size range of 10-14 nm were noticed for the .0039 wt. % Ni catalysts after reduction, 7-11 nm for .0013 wt. % Ni, and 5-9 nm for .00039 wt. % Ni. The lower-end of these particle size ranges was comparable to the crystallite size estimates. Ethane hydrogenolysis and ethylene hydrogenation reactions were conducted over the emulsion-prepared catalysts in order to determine particle size effects on catalytic activity. Results showed that the catalytic activity, defined in terms of per unit metal surface atom (or TON, turnover number), decreases with increasing particle size for the hydrogenolysis reaction. This trend may be due to an intrinsic size effect in which smaller particles exhibit the chemical or structural properties necessary for achieving a higher reaction rate. The results for ethylene hydrogenation showed that the reaction rate did not significantly change with crystallite size, confirming that the reaction is facile or structure-insensitive.

Nanoparticles have been found to have an increasingly wide range of applications including drug delivery systems, chemical sensors, biomolecule sensors, single electron devices, catalysis, Li-ionbatteries, andsolarcells. Avarietyofmethodshavebeenused to produce nanoparticles, but one widely used approach is the application of reverse micellenanoreactorswherebyblockco-polymersareusedtoencapsulateprecursorsalts and serve as a vessel for precursor salts to react. As the encapsulation of precursor salts can be a multi-step process, some nanoparticle formulations have proven difficult to make within the reverse micelle nanoreactor. To fully understand the difficulties in nanoparticle formation, we need to have a method to probe the internal structure of the reverse micelle. This thesis presents a novel method for probing the internal structure of the reverse micelle using a quantitative mechanical mapping (QNM) mode for atomic force microscopy (AFM). Unloaded reverse micelle nanoreactors were analyzed using the QNM AFM mode. A decrease of the Young’s modulus was noted through the centroid of the reverse micelle. Many models were applied to describe the noted decrease of Young’s modulus. The end result indicated that intrinsic differences between the mechanical properties of polystyrene and poly(2vinyl pyridine) and the co-polymer orientation lead to the measured decrease in Young’s modulus through the centroid. Results from the unloaded case were used to explain changes to the reverse micelle nanoreactor after loading with precursor salts. Across all precursor salts similar trends were noted, however there was no consistent relative Young’s modulus or molar salt loading ratio noted within the trends. Three distinct loading zones were consistent acrosstheprecursorsalts. Region I wastypifiedbyaslightdecreaseinrelativeYoung’s modulus with small resultant nanoparticles. Region II was typified by linear increases in relative Young’s modulus for increases in the molar salt loading ratio. Region III was found to have two possible outcomes, either the micelle reach a maximum effective infiltration, where the relative Young’s modulus ratio no longer increases for increased molar salt loading ratio, or the micelle would unravel for increased molar salt loading ratio. Further studies should be done to confirm the existence of the universal loading regions across further co-polymers, solvents, and precursor salts. / Thesis / Master of Applied Science (MASc)

The use of cyanine dyes in bioanalytical applications has become a widely explored topic of interest in chemistry. Their ability to absorb and fluoresce in the UV-visible and near-infrared region of the electromagnetic spectrum benefits their use as imaging probes and fluorescent labels due to the reduced auto-fluorescence from biological molecules. The behavior of these dyes lies in their structure which consists of two nitrogen containing heterocycles joined by an electron deficient polymethine bridge that allows specific energy transitions to occur. The first portion of this work aims to explore dye functionality for analytical applications regarding the non-covalent labeling of bovine serum albumin. The second portion of the work explores dye interactions with human serum albumin in biological membrane mimetic environments using the ternary system of sodium dioctyl sulfosuccinate (AOT) in water and n-heptane.

Made available in DSpace on 2015-03-26T13:35:17Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2299113 bytes, checksum: b733c6bace2740290d2c97582cadca54 (MD5) Previous issue date: 2012-02-15 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Triblock copolymer (EO13PO30EO13) in p-xylene and small amounts of water forms various self-organized structures, one of which are the reverse micelles. Reverse micelles are a type of self-organized system that forms in solutions and interfaces. Reverse micelles can be used in the extraction of amino acids or as nanoreactors for the synthesis of nanoparticles. In this work, reverse micelles were produced by (EO13PO30EO13) the triblock copolymer in p-xylene at concentration of 15% w/w in the presence of water or 0.1 M aqueous solutions of cadmium chloride, sodium nitroprusside, sodium sulfide, sodium hydroxide, lithium sulfate and tetra methyl ammonium chloride. We evaluated the scattered intensity and hydrodynamic diameter in different amounts of water or salts by the techniques of static and dynamic light scattering, respectively. There was an increase in the hydrodynamic diameter in the presence of all salts in comparison with that of water. The scattered intensity also increased for all salts, except for the micelles with tetra methyl ammonium chloride. We measured the variation of the refractive index of solution of 15% w/w (EO13PO30EO13) in p-xylene with different amounts of water or aqueous solutions and compared to with solution of 15% w/w (EO13PO30EO13) without amounts of water or aqueous solutions. The variation of refractive index indicated the point of formation of reverse micelles for some salts, which was not possible to determine using light scattering, and the transition point in the form of reverse micelles from spherical to ellipsoidal. In addition to the scattering experiments, microcalorimetric measurements of the reverse micelles systems were carried out using the Isothermal Titration Calorimetry technique. The results showed that the enthalpy of mixing has changed from exothermic (micelles with water) to endothermic (micelles with salt) for very low water content. In addition, reverse micelles with tetra methyl ammonium chloride and sodium hydroxide showed enthalpy of mixing much smaller in magnitude than the reverse micelles with other salts or water. For the low aqueous solution content inside the reverse micelles the endothermic enthalpy of mixing indicates that the process of desolvation of salts by molecules of water and the interaction of salts and water with the EO segments happens with cost of energy. Nuclear magnetic resonance spectra of hydrogen of the molecules of water showed the formation of free water and bound water inside the reverse micelles. The chemical shift curves increased slightly in the presence of all salts. The relaxation spin-spin of hydrogens of groups CH3 decrease with the increase of water or aqueous solution content. This was interpreted as the passage of molecules of (EO13PO30EO13) from the form of free chain to the form of reverse micelles. The value of relaxation of groups CH2 did not show significant change with the increase of water or aqueous solution content. Measurements of the relaxation of the water molecules inside the reverse micelles were made and it was determined the relaxation constant T2 of the molecule of water in the macroscopic water phase and inside the reverse micelles. The value of T2 decreases from 3.2 seconds in the macroscopic phase to a few microseconds in the inside of reverse micelles. The presence of salt in the inside of reverse micelles induced a more significant decrease in the value of T2 of molecules of water than when there was only water inside the reverse micelles. / O copolímero tri-bloco (EO13PO30EO13) em p-xileno e com a adição de água forma diversas estruturas auto-organizadas, uma das quais são as micelas reversas. As micelas reversas são um tipo de sistema auto-organizado que se forma em soluções e interfaces. As micelas reversas podem ser usadas na extração de aminoácidos ou como nanorreatores para a síntese de nanopartículas. Nesse trabalho, micelas reversas foram produzidas pelo copolímero tri bloco (EO13PO30EO13) em p-xileno na concentração de 15% m/m com adição de água ou soluções aquosas 0,1 M de cloreto de cádmio, nitroprussiato de sódio, sulfeto de sódio, hidróxido de sódio, sulfato de lítio e cloreto de tetrametilamônio. Foram avaliados a intensidade espalhada e o diâmetro hidrodinâmico em diferentes quantidades de água ou solução aquosa 0,1 M, pelas técnicas de espalhamento estático e dinâmico de luz, respectivamente. Observou-se o aumento do diâmetro hidrodinâmico na presença de todos os sais em comparação com a água. A intensidade espalhada também aumentou para todos os sais, exceto para as micelas com cloreto de tetrametilamônio. Foi medida a variação do índice de refração para a solução com 15% m/m de copolímero (EO13PO30EO13) em p-xileno com diferentes quantidades de água ou soluções aquosa e comparada com a solução de 15% m/m de copolímero (EO13PO30EO13) sem a adição de água ou solução aquosa. A variação do índice de refração indicou o ponto de formação das micelas reversas com água e com os sais cloreto de cádmio e cloreto de tetrametilamônio, que não foi possível determinar com as medidas de intensidade espalhada. Além disso foi possível determinar o ponto de transição na forma das micelas reversas de esféricas para elipsoidais para todos os sais. Complementando as medidas de espalhamento de luz foram feitas medidas energéticas do sistema de micelas reversas usando a técnica de microcalorimetria isotérmica de titulação. As medidas microcalorimétricas mostraram que a entalpia de mistura mudou de exotérmica (micelas com água) para endotérmica (micelas com solução salina) nas primeiras adições. Além disso, micelas reversas com o cloreto de tetrametilamônio e hidróxido de sódio apresentaram entalpia de mistura muito menor em módulo do que as micelas reversas com os outros sais ou água. Em baixos conteúdos de água a entalpia de mistura endotérmica indica que o processo de desolvatação dos sais pelas moléculas de água e a interação dos sais e água com os segmentos EO ocorre com gasto de energia. Espectros de resonância magnética nuclear dos hidrogênios da molécula de água mostraram a formação de água livre e água ligada no interior das micelas reversas. As curvas de deslocamentos químicos aumentaram levemente na presença de todos os sais. Ocorreu uma redução da constante relaxação spin-spin dos prótons dos grupos CH3 da molécula de L64 com o aumento do conteúdo de água ou solução salina. Esse resultado foi interpretado como a passagem de moléculas do copolímero (EO13PO30EO13) da forma de cadeia livre para a forma de micelas reversas. Já as medidas dos grupos CH2 mostraram que a relaxação spin-spin não variaram significativamente com a quantidade de água ou solução salina. As medidas de relaxação das moléculas de água no interior das micelas reversas foram feitas e foi determinada a constante de relaxação T2 da molécula de água em fase macroscópica e no interior das micelas reversas. O valor de T2 diminui de 3,2 segundos em fase macroscópica para dezenas de milisegundos no interior das micelas reversas. A presença do sal no interior das micelas reversas induziu uma diminuição mais acentuada no valor de T2 das moléculas de água do que quando havia apenas água no interior das micelas reversas.

Hidrogéis (redes poliméricas tridimensionais capazes de absorver grandes quantidades de água) micro e nanoestruturados têm grande potencial como biomateriais em aplicações tais como dispositivos de liberação de fármacos e agentes embólicos. Neste trabalho foram estudadas técnicas de produção desses hidrogéis micro e nanoestruturados à base de poli(N-vinil-2-pirrolidona) (PVP), a partir da reticulação do polímero através de reações de Fenton, foto-Fenton e fotólise direta. Microgéis de PVP foram obtidos a partir da reticulação de esferas obtidas por eletropulverização ou de gotículas de solução aquosa do polímero em emulsão a/o. No primeiro caso, obtiveram-se partículas que, quando reticuladas com a reação de Fenton durante o processo de eletropulverização, apresentaram formato indefinido. No segundo caso, foram obtidas microesferas de PVP, tanto pela reticulação com a reação de Fenton, obtendo-se partículas menores da - ordem de 1 µm - como com a reação de foto-Fenton, que gerou partículas maiores de - 34 µm. Hidrogéis sub-micrométricos foram obtidos a partir da formatação em vesículas de lecitina e reticulados por meio da reação de foto-Fenton. Essas vesículas foram capazes de encapsular grande quantidade de polímero, mesmo sendo este de alta massa molar média. Os hidrogéis sintetizados apresentam estreita distribuição de diâmetro, porém sem forma definida e com baixo índice de intumescimento. Por fim, nanogéis (nanopartículas de hidrogéis) foram obtidos da reticulação de PVP com a reação de Fenton (Fe2+ na presença de H2O2), utilizando como sistema formatador o interior aquoso de micelas reversas de CTAB. Os nanogéis assim formados são esféricos e apresentam propriedades interessantes, como fator de intumescimento de até 6000, inédito na literatura, que os colocam na categoria de hidrogéis superabsorventes. Além disso, o intumescimento é passível de controle tanto pela remoção dos íons Fe3+ complexados, como pela acidez e composição iônica do meio. Durante o desenvolvimento da síntese dos nanogéis foi possível estudar a influência do Fe3+ na estruturação da solução polimérica e do hidrogel. Além disso, a cinética da reticulação do polímero dentro das micelas e uma comparação entre dois sistemas micelares diferentes na formatação do nanogel foram analisados. A análise do produto também permitiu constatar a baixa toxicidade do material obtido com testes in vitro utilizando macrófagos e fibroblastos. / Micro and nanostructured hydrogels (three-dimensional polymeric networks capable of absorbing large amounts of water) have great potential as biomaterials in applications such as drug delivery devices and embolic agents. In this work techniques to produce micro and nanostructured hydrogels from poly(N-vinyl-2-pyrrolidone) (PVP) were studied from various crosslinking reactions like Fenton, photo-Fenton and direct photolysis. PVP microgels were obtained from crosslinking of polymer spheres obtained by electrospraying a polymer solution or from droplets of aqueous polymer solution in w/o emulsion. In the first case, particles were obtained that, when crosslinked with the Fenton reaction, showed undefined morphology. In the second case, spherical PVP hydrogel microparticles were obtained, which were formed by crosslinking with Fenton reaction, resulting in smaller particles - about 1µm - while with photo-Fenton reaction it generated larger particles - about 34 µm. Sub-micrometric hydrogels were obtained from lecithin vesicles as formatting system through crosslinking with photo-Fenton reaction. These vesicles were able to encapsulate large amounts of polymer, in spite of its high average molecular weight. Hydrogels synthesized by this method are formless, with narrow diameter distribution and low swelling properties. Finally, nanogels (hydrogel nanoparticles) were obtained from crosslinking of PVP by the Fenton reaction (Fe2+ in presence of H2O2), using aqueous pool of CTAB reverse micelles as formatting system. The thus formed nanogels are spherical and present interesting properties such as swelling ratio of 6000, a level unreported in literature, which classifies them as superabsorbent hydrogels. Moreover, the swelling is susceptible to control either by the removal of complexed Fe3+ ions or by acidity and ionic composition of the medium. During the nanogels synthesis development, the influence of Fe3+ in the arrangement of the polymer solution and of the hydrogel was studied. Morever, the polymer crosslinking kinetics inside the micelles and a comparison between two different micellar systems in formatting of nanogel were analyzed. The product analysis also revealed low toxicity of the obtained material by in vitro experiments using macrophages and fibroblasts.

This thesis studies the formation of mobile and surface-bound electric charges in nonpolar liquids. Unlike aqueous media with their natural abundance of charged species, liquids of low dielectric constant do not readily accommodate charges, but can do so in the presence of certain surfactant additives. Surfactant-mediated charging in nonpolar oils has long been exploited industrially, but the underlying charging mechanisms are far from understood. The present work seeks clarification by comparing the effect of ionic and nonionic surfactants on the conductivity of nonpolar solutions and the electrophoretically observable surface charge of suspended polymer particles. Both types of surfactant are found to generate mobile ions in solution as well as particle charge; and in the more surprising case of nonionic surfactants, the occurrence of particle charge and screening ions is confirmed independently by measurements of the electrostatic particle interaction energy. A systematic variation of the particle material and functionalization, the residual water content, and the surfactant concentration above and below the critical micelle concentration provides insights about the possible charging pathways. Reverse surfactant micelles are explored not only as charging agents, but also as reactors and templates for the synthesis of novel nanogels with promise for drug delivery. Synthesis via copper-free Click chemistry is shown to allow for better control of the particle size than a more conventional polymerization scheme, while avoiding metal catalysts and free radicals that are considered hazardous for most biomedical applications.

Hidrogéis (redes poliméricas tridimensionais capazes de absorver grandes quantidades de água) micro e nanoestruturados têm grande potencial como biomateriais em aplicações tais como dispositivos de liberação de fármacos e agentes embólicos. Neste trabalho foram estudadas técnicas de produção desses hidrogéis micro e nanoestruturados à base de poli(N-vinil-2-pirrolidona) (PVP), a partir da reticulação do polímero através de reações de Fenton, foto-Fenton e fotólise direta. Microgéis de PVP foram obtidos a partir da reticulação de esferas obtidas por eletropulverização ou de gotículas de solução aquosa do polímero em emulsão a/o. No primeiro caso, obtiveram-se partículas que, quando reticuladas com a reação de Fenton durante o processo de eletropulverização, apresentaram formato indefinido. No segundo caso, foram obtidas microesferas de PVP, tanto pela reticulação com a reação de Fenton, obtendo-se partículas menores da - ordem de 1 µm - como com a reação de foto-Fenton, que gerou partículas maiores de - 34 µm. Hidrogéis sub-micrométricos foram obtidos a partir da formatação em vesículas de lecitina e reticulados por meio da reação de foto-Fenton. Essas vesículas foram capazes de encapsular grande quantidade de polímero, mesmo sendo este de alta massa molar média. Os hidrogéis sintetizados apresentam estreita distribuição de diâmetro, porém sem forma definida e com baixo índice de intumescimento. Por fim, nanogéis (nanopartículas de hidrogéis) foram obtidos da reticulação de PVP com a reação de Fenton (Fe2+ na presença de H2O2), utilizando como sistema formatador o interior aquoso de micelas reversas de CTAB. Os nanogéis assim formados são esféricos e apresentam propriedades interessantes, como fator de intumescimento de até 6000, inédito na literatura, que os colocam na categoria de hidrogéis superabsorventes. Além disso, o intumescimento é passível de controle tanto pela remoção dos íons Fe3+ complexados, como pela acidez e composição iônica do meio. Durante o desenvolvimento da síntese dos nanogéis foi possível estudar a influência do Fe3+ na estruturação da solução polimérica e do hidrogel. Além disso, a cinética da reticulação do polímero dentro das micelas e uma comparação entre dois sistemas micelares diferentes na formatação do nanogel foram analisados. A análise do produto também permitiu constatar a baixa toxicidade do material obtido com testes in vitro utilizando macrófagos e fibroblastos. / Micro and nanostructured hydrogels (three-dimensional polymeric networks capable of absorbing large amounts of water) have great potential as biomaterials in applications such as drug delivery devices and embolic agents. In this work techniques to produce micro and nanostructured hydrogels from poly(N-vinyl-2-pyrrolidone) (PVP) were studied from various crosslinking reactions like Fenton, photo-Fenton and direct photolysis. PVP microgels were obtained from crosslinking of polymer spheres obtained by electrospraying a polymer solution or from droplets of aqueous polymer solution in w/o emulsion. In the first case, particles were obtained that, when crosslinked with the Fenton reaction, showed undefined morphology. In the second case, spherical PVP hydrogel microparticles were obtained, which were formed by crosslinking with Fenton reaction, resulting in smaller particles - about 1µm - while with photo-Fenton reaction it generated larger particles - about 34 µm. Sub-micrometric hydrogels were obtained from lecithin vesicles as formatting system through crosslinking with photo-Fenton reaction. These vesicles were able to encapsulate large amounts of polymer, in spite of its high average molecular weight. Hydrogels synthesized by this method are formless, with narrow diameter distribution and low swelling properties. Finally, nanogels (hydrogel nanoparticles) were obtained from crosslinking of PVP by the Fenton reaction (Fe2+ in presence of H2O2), using aqueous pool of CTAB reverse micelles as formatting system. The thus formed nanogels are spherical and present interesting properties such as swelling ratio of 6000, a level unreported in literature, which classifies them as superabsorbent hydrogels. Moreover, the swelling is susceptible to control either by the removal of complexed Fe3+ ions or by acidity and ionic composition of the medium. During the nanogels synthesis development, the influence of Fe3+ in the arrangement of the polymer solution and of the hydrogel was studied. Morever, the polymer crosslinking kinetics inside the micelles and a comparison between two different micellar systems in formatting of nanogel were analyzed. The product analysis also revealed low toxicity of the obtained material by in vitro experiments using macrophages and fibroblasts.

Made available in DSpace on 2014-12-17T15:41:47Z (GMT). No. of bitstreams: 1 WashingtonCMGpdf.pdf: 1072479 bytes, checksum: d37434aed1d2ae898ee7a9fd3701e0d7 (MD5) Previous issue date: 2009-04-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This work deals with the application of X-Ray Absorption Spectroscopy on the study of the behavior of Cu2+ ions in inverse micelles. The formation of copper nanoparticles in water-in-oil microemulsions in pseudo-ternary systems of cetyl trimethylammonium Bromide (CTAB) surfactant, butanol co-surfactant, heptane as oil phase and aqueous solutions of CuSO4.5H2O, and NaBH4. The microemulsions were prepared with a fixed percentage (60 %) of oil phase and a variable water to tensoative proportion. It was observed an increase on Cu2+ reduction by the sodium borohydride in microemulsions with 13 % of aqueous phase, independent of the reaction time. For the microemulsions in which the aqueous phase is composed only by the CuSO4 solution, it was observed that the color of the solution depends on the water to surfactant ratio. These changes in color were attributed to a competition for the hidratation water between the polar head of the tensoative and Cu2+ ions with the eventual substitution of oxygen by bromine atoms in the first coordination shell of Cu2+ ions / Neste trabalho estudou-se aplica??o da espectroscopia de absor??o de raios x no estudo do comportamento dos ?ons Cu2+ em micelas inversas. Estudou-se a forma??o de nanopart?culas de cobre em microemuls?es ?gua-em-?leo de sistemas pseudo-tern?rios tensoativo (brometo de hexadeciltrimetilam?nio, CTAB)-cotensoativo (butanol) / fase oleosa (heptano) / fase aquosa (solu??es de CuSO4.5H2O, e NaBH4). As microemuls?es foram preparadas fixando em 60% a fase ?leo (Heptano) e variando 40% de fase aquosa com tensoativo/cotensoativo na mesma propor??o, sendo que a fase aquosa do agente redutor NaBH4 foi usada em excesso de 0,4 mol.L-1 e 0,8 mol.L-1 em rela??o 0,2 mol.L-1 de fase aquosa de CuSO4.5H2O. Observou-se uma maior redu??o dos ?ons Cu2+ pelo boridreto de s?dio em microemuls?es com 13% de ?gua, independente do tempo de rea??o. Para as microemuls?es em que a fase aquosa corresponde a solu??o de CuSO4, observou-se uma depend?ncia na colora??o em fun??o da rela??o entre as concentra??es de ?gua/tensoativo. Essa mudan?a de colora??o foi atribu?da a uma competi??o pelas mol?culas de ?guas entre a cabe?a polar do tensoativo e os ?ons Cu2+ com uma eventual substitui??o do oxig?nio da primeira esfera de coordena??o por bromo

L’objet de cette étude est d’utiliser la technique des micelles inverses pour synthétiser des nanoparticules à transition de spin, de taille et de forme contrôlées afin d’en permettre l’utilisation en électronique moléculaire. Dans la première partie, nous avons déterminé les paramètres de synthèse influençant la taille et la forme des particules d’un complexe à transition de spin à fort potentiel d’application. Dans un deuxième temps, nous avons utilisé ces paramètres sur trois autres complexes afin de comprendre la relation entre les paramètres de la synthèse et la morphologie des particules. Les nanoparticules ainsi synthétisées constituent la base d’une discussion sur l’existence d’un lien entre la taille/forme des particules et les propriétés de transition de spin. Enfin, la dernière partie de ce travail est consacrée à l’utilisation de ces matériaux en électronique moléculaire, et l’observation des propriétés de photoconductivité et photovoltaïque à l’échelle des nanoparticules. / The aim of this project is to use the reverse micelles technique to synthesize spin crossover (SCO) nanoparticles with controlled size and shape in order to use them in molecular electronic applications. In the first part, we have determined the synthesis parameters that influence the particles size and shape of an attractive spin crossover complex, due to his potential application. In a second time, we used the determined parameters on three other SCO complexes to generalize the relationship between the synthesis parameters and the particles morphology. All the as-prepared nanoparticles are the basis of a discussion about the existence of a link between the size and/or shape of the particles and the SCO properties. The last part of this work is dedicated to the utilization of this materials in molecular electronic, and the observation of photovoltaic and photoconductive properties at the nanoparticles scale.