Thermo-responsive homopolymer poly(N-isopropylacrylamide), is a widely studied and used polymer. Our recent observations on thermal behavior of aqueous solutions of this polymer requires a short overview of existing results in order to understand the formation of different phases, both stable and unstable with the addition of hydrophilic Ionic liquids (ILs) 1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-Butyl-3-methylimidazolium acetate ([BMIM][OAc]) and 1-Butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) to the system. PNIPAM is soluble in cold water due to its inter- and intramolecular hydrogen bonding but phase separates upon heating at T > 32 , which is its lower critical solution temperature (LCST). PNIPAM exists in an expanded coil like conformation in water below its LCST which gives a transparent homogenous solution but at T > LCST it undergoes hydrophobic collapse marked by cloudiness of solution and conformational change from coil to globule state. All aqueous PNIPAM solutions undergo phase separation or cloud point transition at T > 32 , regardless of the molar mass of the polymer. Room temperature Ionic liquids (ILs) are unique designer fluids because of the novel physico-chemical properties arising from their structure, which have tremendous implications in the field of IL as solvents or co-solvents for polymeric solutes. During recent years a number of different imidazolium based ILs have also been tested for solubilization and stabilization of proteins as well as polymers due to hydrogen bond formation of the IL ions. Recent studies have shown that certain imidazolium based ILs can decrease the LCST of PNIPAM aqueous solution by hydrophobic collapse/aggregation of the PNIPAM chains, as well as some can induce an upper critical solution temperature (UCST) behavior of PNIPAM in neat IL solution. Even so, experimental studies of such phase transition/ instability of thermoresponsive polymer-IL systems has been a challenging task. In this research we have explored the critical solution temperature (CST) type phase behavior of multicomponent systems i.e. PNIPAM in solution media of water, neat IL and aqueous solutions of IL. The overall fundamental challenge is to understand how the interactions among the components control both structure and dynamics of PNIPAM network in solution. For example the disruption of hydrogen bonding or desolvation interactions between blocks of a PNIPAM molecule and solvent molecules in aqueous mixtures that lead to a LCST type transition at higher temperatures. Interestingly, it was found in our case that PNIPAM shows both LCST and UCST-type phase transition in some aqueous solutions of hydrophilic IL [BMIM][BF4]. It was found for the first time that this IL can influence the LCST type behavior of PNIPAM in aqueous solutions based on our visual and experimental cloud point (CP) observations. In our experiments the effect of the ILs [BMIM][BF4] and [BMIM][OAc] is qualitatively similar to influence of Kosmotropic salts on the LCST of aqueous PNIPAM solutions as predicted by the Hofmeister series.

Ionic liquids are salts that are in liquid form at room temperature. These compounds have been suggested to be environmentally friendly and are proposed to be replacements for commercially available solvents used in laboratory operations today. There is an increasing interest in these compounds, but toxicological data of ionic liquids are still scarce. In this project five imidazolium based ionic liquids, 1-etyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-octyl-3-methylimidazolium and 1-decyl-3-methylimidazolium were evaluated based on responses on aryl hydrocarbon receptor (DR-Ecoscreen), Nrf2 activity (MCF732cARE), androgen receptor (AR-Ecoscreen) and estrogen receptor (VM7Luc4ER). This was done with an effect based in vitro approach using luciferase bioassays. The results show that imidazolium based ionic liquids have the ability to induce androgen and estrogen receptor activity. It is also shown that imidazolium based ionic liquids can act as antagonists on the androgen receptor. Imidazolium based ionic liquids does not seem cause oxidative stress and is shown to not interact with the aryl hydrocarbon receptor. The ability of 1-octyl-3-methylimidazolium and 1-decyl-3-methylimidazolium to pass the gastrointestinal tract was also tested in a modified transwell caco-2 permeability test, which resembled the human GI-tract. It was shown to be difficult to evaluate if 1-octyl-3-methylimidazolium and 1-decyl-3-methylimidazolium have the ability to pass through the GI-tract and antagonize on the androgen receptor. These results are important from both an environmental as well as human health point of view if imidazolium based ionic liquids are to be accidentally or intentionally release into the environment.

No description available.

Les liquides ioniques à base de sels d’imidazolium sont une classe très importante de composés, compatibles avec de nombreuses réactions organiques et largement employés dans la synthèse organique en tant que solvants, catalyseurs ou ligands. En particulier, les liquides ioniques peuvent être récupérés à la fin de la réaction. Les sels d’imidazolium présentent également des propriétés d’organisation intéressantes, aussi bien en phase solide, liquide et en solution. Cependant, les liquides ioniques traditionnels présentent certains désavantages lorsqu’utilisés comme solvant dans des réactions intramoléculaires, surtout dans le cas où le réactif est apolaire. La faible solubilité de ce dernier dans le milieu ionique conduit à la formation des produits intermoléculaires. Les travaux présentés dans cette thèse portent sur l’utilisation des propriétés d’organisation des sels d’imidazolium, tout d’abord pour le développement des nouveaux cristaux liquides ioniques, comme le milieu réactionnel pour la réaction de Diels-Alder intramoléculaire, et ensuite pour la préparation des nanparticules d’or anisotropes. Dans un premier temps, le développement des sels d’imidazolium dicationiques portant des chaînes alkyles flexibles et un cœur rigide, avec des unités imidazolium attachées directement à un noyau naphthalène est rapporté. Par la suite, leurs propriétés thermiques et mésomorphes ont été étudiées. Ces sels sont stables thermiquement et forment une phase cristal liquide de type Smectique T, sur une plage de températures appropriées pour des réactions organiques. En utilisant le milieu cristal liquide comme milieu réactionnel dans la réaction de Diels-Alder, le réactif a été piégé dans la structure organisée de cette phase, ce qui a empêché l’interaction entre deux molecules de réactifs, limitant la formation du produit intermoléculaire. D’ailleurs, le milieu cristal liquide ionique a pu être récupéré et reutilisé à la fin de la réaction. Dans un deuxième temps, l’influence de la structure de la mésophase sur la réaction de Diels-Alder intramoléculaire a été étudiée. Des sels d’imidazolium tricationiques ayant une symétrie C3 ont ete développés dans le but d’obtenir des phases colonnaires. Ces sels possèdent un cœur rigide formé par trois cations imidazolium liés à un noyau benzène et des chaînes alkyles flexibles. Des études thermiques et mésomorphes sur ces composés ont été ensuite réalisées. Ces composés possèdent une haute stabilité thermique et forment une phase colonnaire rectangulaire, stable sur une large gamme de températures. L’influence de cette phase sur la réaction de Diels-Alder a ete étudiée. L’utilisation de la phase colonnaire favorise également la réaction intramoléculaire. En particulier, elle s’est avèree plus efficace que la phase Smectique T, probablement dû à sa structure plus organisée, indiquée par une enthalpie de tranisition cristal liquide – liquide isotrope plus élevée. Dans un dernier temps, nous nous sommes intéressés à l’utilisation des propriétés d’organisation des sels d’imidazolium dans la préparation des nanoparticules d’or anisotropes. Dans cette optique, différents mélanges binaires, composés d’un sel d’imidazolium et le diméthylformamide (DMF), ont été préparés et utilisés comme solvants et stabilisants, dans la synthèse des nanoparticules d’or à température ambiante. L’utilisation de ces milieux nous a permis d’obtenir des particules d’or avec différentes géométries. La forme des nanoparticules d’or obtenus dépend de la structure des sels d’imidazolium utilisés et de la concentration du mélange binaire, à la fois. / Ionic liquids based on imidazolium salts are an important class of compounds, possessing a very good compatibility with various organic reactions, and are widely used as solvents, catalysts and ligands in organic synthesis. Moreover, imidazolium salts possess interesting supramolecular organization in the solid, liquid and solution state. However, ionic liquids present some disadvantages when used as solvents for intramolecular reactions, especially in the case of apolar reactants. The low solubility of ionic compounds in ionic media promote the formation of intermolecular products. The main goal of the research presented in this thesis is to explore the supramolecular organization of imidazolium salts, first in the development of ionic liquid crystals as reaction media for intramolecular Diels-Alder reactions and secondly for the preparation of anisotropic gold nanoparticles. First, the development of dicationic imidazolium salts having a rigid core and flexible alkyl chains is reported. The rigid core is forned by direct attachment of two imidazoliums on a naphthalene moiety. Their thermal and mesomorphic analyses were then carried out. These dicationic salts show a high thermal stability and form a very ordered smectic T phase, over a wide range of temperatures. This mesophase was subsequently used as reaction medium for intramolecular Diels-Alder reactions. In this phase, reactants are trapped in the highly organized structure of the liquid crystal medium, limiting the formation of intermolecular products. Moreover, the ionic liquid crystal, was recoved at the end of reaction by simple extraction. Secondly, the influence of the mesophase’s structure on the Diels-Alder reaction was explored. Tricationic imidazolium satls having a C3 symmetry were developed in order to obtain columnar phases. The rigid core of these salts is composed of three imidazolium units directly attached to the benzene ring. Their thermal stabilities and mesomorphic properties were investigated. The columnar phase formed by these salts was then used as reaction media for Diels-Alder reactions, and it proved to be more efficient than the previously used smectic T phase, due to their more organized structure, as indicated by the higher enthalpy value of the liquid crystal - isotropic liquid transition. iv Finally, the supramolecular organization in solution of two imidazolium salts was explored with the aim to prepare anisotropic gold nanoparticles. Different binary mixtures composed of an imidazolium salt and dimethylformamide (DMF) were prepared and used both as solvent and capping agent in the synthesis of gold nanoparticles, at room temperature. The use of these binary mixture allowed us to synthesize nanoparticles with various geometries. The form of the gold nanoparticles prepared in these binary mixtures was influenced by both, the structre and the concentration of the imidazolium salt used.

A substituição da água por líquidos iônicos (LI) oferece uma alternativa promissora para o desenvolvimento de processos de separação de gases, principalmente devido à significativa demanda energética em processos convencionais que utilizam soluções aquosas de aminas. Esta proposta apresenta-se interessante por aliar as propriedades dos LI à reatividade de aminas perante o CO2. A físico-química que governa as interações entre os íons dos líquidos iônicos é bastante diversa das encontradas em solventes moleculares, sendo que ainda permanecem muitas questões fundamentais acerca destes materiais. A melhor compreensão das interações estabelecidas entre aminas e LI, e dos produtos formados após a reação com CO2, pode contribuir para o desenvolvimento de processos mais eficazes que permitam a substituição da água nos processos convencionais. O presente trabalho teve como objetivo investigar soluções das aminas primárias propilamina (PA), 2-metoxietilamina (MOEN) e monoetanolamina (MEA) em líquidos iônicos imidazólicos com diferentes ânions: 1-butil-3-metilimidazólio tetrafluoroborato (BMIBF4), hexafluorofosfato (BMIPF6), bis-(trifluorometilsulfonil)imida (BMITFSI) e dicianamida (BMIN(CN)2). Para tal, foram utilizadas as espectroscopias Raman e infravermelho (IR), cujos resultados foram suportados por cálculos baseados na teoria do funcional da densidade (DFT). Os resultados mostram que o modo de estiramento assimétrico do grupo NH2 das aminas, νas(NH2), é o mais adequado para se inferir sobre o grau de agregação das aminas em solventes orgânicos e em LI. No caso das reações das aminas com CO2 nos diferentes LI, o comportamento foi similar à reação com as aminas puras, ou seja, na PA houve cristalização, na MOEN, a formação de um líquido miscível com os LI, e na MEA, a formação de um gel com a subsequente separação de fases. Em particular, no caso da reação entre MEA e CO2 em LI, além da separação de fases, foi observada a diferente solubilidade dos produtos de reação dependendo do LI em questão. Em contraste ao processo convencional que utiliza soluções aquosas de aminas para a captura do CO2, acredita-se que a separação de fases observada em LI seja uma vantagem a ser explorada, já que permitiria um menor gasto energético na recuperação da amina absorvedora, além da recuperação do solvente não volátil / The replacement of water by ionic liquids (IL) offers a promising alternative for the development of gas separation processes, mainly due to the significant energy demand in conventional processes using aqueous solutions of amines. This proposal is exciting because it combines the properties of IL with the reactivity of amines towards CO2. The physical-chemistry that governs the interactions between the ionic liquids ions is quite different from those found in molecular solvents, and many fundamental questions still remain about these materials. A better understanding of the interactions between amines and IL, and the products formed after the reaction with CO2, may contribute to the development of more efficient processes to enable the replacement of water in conventional processes. This study aimed to investigate solutions of the primary amines propylamine (PA), 2-methoxyethylamine (MOEN) and monoethanolamine (MEA) in imidazolium ionic liquids with different anions: 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4), hexafluorophosphate (BMIPF6), bis (trifluoromethylsulfonyl)imide (BMITFSI) and dicyanamide (BMIN(CN)2). For these purposes, the Raman and infrared (IR) spectroscopies were used, whose results were supported by calculations based on density functional theory (DFT). The results show that the asymmetric stretching mode of the amines group NH2, νas(NH2), are the most suitable for inferring the degree of aggregation of amines in organic solvents and IL. In the case of reactions of amines with CO2 in different IL, the behavior was similar to the reactions with neat amines, that is, it was observed crystallization with PA, the formation of a liquid miscible with IL in MOEN, and the formation of a gel-like product with subsequent phase separation in MEA. In particular, the case of the reaction between MEA and CO2 in IL, in addition to the phase separation, it was observed the different solubility of the reaction products depending on the IL concerned. In contrast to the conventional process using aqueous solutions of amines for the capture of CO2, it is believed that the phase separation observed in IL is an advantage to be exploited, since they allow lower energy consumption in the recovery of the amine absorber, besides the recovery of the non-volatile solvent.

Líquidos iônicos imidazólios (LIIs) associados a ânions com caráter básico foram sintetizados, caracterizados e seu comportamento estudado em solução. Inicialmente a troca isotópica H/D preferencial no grupo C2-CH3 de sais de 1-nbutil-2,3-dimetilimidazólio (BMMI) foi avaliada. Ficou evidente que o contato entre os pares de íons e a atuação do ânion como uma base neutra influenciaram fortemente a deuteração. Após a análise dos resultados de RMN, cálculos de DFT (Teoria do Funcional de Densidade) e Difração de Raios X, um complexo entre uma molécula de água e alguns LI foi sugerido, modificando fortemente a estrutura organizacional e afetando também a troca isotópica nestes sais. Através do mecanismo reacional proposto, surgiu a possibilidade de deuteração de novos substratos contendo H ácidos, usando os LIIs como catalisadores. A reação de troca isotópica em alcinos e cetonas foi estudada e bons resultados foram obtidos. O efeito da variação de cátions e ânions na atividade catalítica foi analisado, assim como a variação dos substituintes dos substratos. Além disso, um estudo cinético foi realizado através de análises de RMN de 1H e o mecanismo reacional foi proposto. Por fim, a capacidade de formação de pares iônicos em soluções aquosas de LIIs foi avaliada na captura de CO2. Ótimos resultados foram obtidos e atribuídos à ocorrência de sorção física e química devido à ativação da água pelo LII. / Imidazolium based ionic liquids (ImIL) associated with basic anions were synthesized, characterized and studied. Initially the preferred H/D isotopic exchange to C2-CH3 group of 1-nbutyl-2,3-dimethylimidazolium salts (BMMI) was studied. In this context, it became evident that the ion-pairing formation and the anion action as a neutral base strongly influence the deuteration reaction. NMR analysis, theoretical calculation (Density Functional Theory) and X-ray Diffraction have been performed and a complex between a water molecule and the IL have been suggested, strongly modifying the IL structure and characteristics. The isotope exchange reaction in alkynes and ketones was studied using imidazolium based ionic liquids as catalysts and good results obtained. The effect of cation and anion variation on the catalyst activity were analyzed, also a variation of the substrate substituent’s. Also, a kinetic study was performed by 1H NMR analyzes and the reaction mechanism were proposed. Finally, the ability to form ion pair contact of ILs in aqueous solutions was evaluated for CO2 capture. Great results were obtained and this success can be attributed to the occurrence of physical and chemical sorption due to water activation by the IL.

por fatores químicos e físicos, promovendo infecções hospitalares relacionadas ao uso de cateteres e demais instrumentos hospitalares, elevando os índices de mortalidade e morbidade de pacientes. Portanto, garantir a correta desinfecção capaz de impedir contaminações e infecções em ambientes hospitalares é de extrema importância. Para este fim, neste estudo explorou-se a seleção de uma substância capaz de marcar e ser biocida contra biofilmes fúngicos em superfícies de aço inox, a partir de nove candidatos benzimidazóis fluorescentes, com códigos NB1 a NB9 e oito sais imidazólicos de corantes azóicos, denominados C4MImErioCr, C10MImMO, C16MImMO, (C10)2MImMO, C4MImMO, C10MImORANGEII, C16MImORANGEII e (C10)2MImORANGEII. Desenvolveu-se para este fim um roteiro metodológico para determinar quais destas substancias são capazes de marcar e eliminar biofilmes de forma eficaz e segura. Os métodos utilizados para avaliar as substâncias foram (1) a Concentração Mínima Inibitória (MIC) conforme protocolo do CLSI M27-A3, (2) microscopias verificando capacidade das substâncias em marcar células, (3) ensaios com deposição sobre superfície do corpo de prova (placas de aço inox) com biofilme, (4) verificação da atividade biocida sobre biofilmes utilizando microscopias e (5) ensaios de citotoxicidade. Essas substâncias foram testadas frente a nove cepas de Candida spp., incluindo C. tropicalis, C. albicans e C. parapsilosis Na avaliação das substâncias, SI de corantes azóicos inibiram o crescimento celular de fungos, já o benzimidazol fluorescente NB7 apresentou atividades simultâneas de detecção e ação biocida sobre o biofilme. Todas as cepas testadas foram sensíveis a essa substância. Além disso, os biofilmes formados pelas cepas ATCC 18804 (C. albicans,) ATCC 22019 (C. parapsilosis) e ATCC 750 (C. tropicalis) na superfície de aço inox 304 sofreram ação biocida, quando expostas por 15 segundos a NB7, sendo um potencial sanitizante. / Biofilms provide an environment capable of protecting microbial cells from damage by chemical and physical factors of the immune system, and hinder the penetration of various antimicrobial agents, promoting nosocomial infections related to catheters, increasing mortality and morbidity of patients. Therefore, it is important to ensure proper hygiene to prevent contamination and infections in hospital environments. For this purpose, this study explored the identification of a substance that both detects and have biocide activity against fungal biofilms on stainless steel surfaces. Both nine fluorescent benzimidazole substances, coded NB1 to NB9 and eight imidazolium salts of azo dyes, named denominados C4MImErioCr, C10MImMO, C16MImMO, (C10)2MImMO, C4MImMO, C10MImORANGEII, C16MImORANGEII e (C10)2MImORANGEII were tested as candidates. These substances were tested applying a methodology developed to determine if a substance is able detecting and have biocide activity against fungal biofilms. Overall, this study involved the following methods: (1) Minimum Inhibitory concentration test following the CLSI protocol (M27-A3; the substances were tested against nine fungal strains, including C. tropicalis, C. albicans and C. parapsilosis.), (2) microscopy to determine the marker capacity, (3) spraying tests of the substances on surfaces (stainless steel) with fungal biofilms, (4) tests to verify the capability of the substances to both stain and were biocide against fungal biofilms, applying microscopic techniques and (5) cytotoxicity tests Within the set of seventeen substances, benzimidazole derivative NB7 was identified with the desired capabilities, staining and biocide activity against fungal biofilms at the same time. All tested fungal strains were sensible to this substance. A biocide activity was identified on the biofilms of ATCC 18804 (C. albicans), ATCC 22019 (C. parapsilosis) and ATCC 750 (C .tropicalis), grown on stainless steel 304, when exposed fifteen seconds to substance NB7. Although this substance showed being cytotoxic, it represents a promising candidate for sanitization purposes, including medical tools.

La synthèse de matériaux zéolithiques est régie par de nombreux paramètres, en particulier la nature de l'hétéroélément associé au silicium et celle de l'agent organique structurant. Ainsi, l'introduction de germanium dans les milieux réactionnels ainsi que l'utilisation de structurants dérivés d'imidazole, les cations 1-éthyl-3-méthylimidazolium et 1-butyl-3-méthylimidazolium, ont permis la découverte de deux nouveaux solides microporeux nommés respectivement IM-16 et IM-20 et présentant des topologies de charpente inédites (respectivement UOS et UWY). De plus, un troisième germanosilicate poreux nommé IM-17 a été obtenu en présence du cation décaméthonium. Chacun de ces trois matériaux possède un système tridimensionnel de canaux avec des ouvertures de 8 et 10 atomes T (IM-16) ou de 10 et 12 atomes T (IM-17 et IM-20), ainsi que des unités de construction composites d4r au sein de leur charpente. Enfin, une partie importante du travail a été consacrée à l'élaboration de molécules structurantes originales (dérivés du décahydro-dicyclopenta[b,d]pyrrole) puis de leur emploi en synthèse hydrothermale. Ces essais ont permis d'obtenir divers matériaux déjà connus, parmi lesquels les zéolithes IM-12 (UTL), ITQ-7 (ISV), ITQ-17 (BEC) et ITQ-21.

Líquidos iônicos imidazólios (LIIs) associados a ânions com caráter básico foram sintetizados, caracterizados e seu comportamento estudado em solução. Inicialmente a troca isotópica H/D preferencial no grupo C2-CH3 de sais de 1-nbutil-2,3-dimetilimidazólio (BMMI) foi avaliada. Ficou evidente que o contato entre os pares de íons e a atuação do ânion como uma base neutra influenciaram fortemente a deuteração. Após a análise dos resultados de RMN, cálculos de DFT (Teoria do Funcional de Densidade) e Difração de Raios X, um complexo entre uma molécula de água e alguns LI foi sugerido, modificando fortemente a estrutura organizacional e afetando também a troca isotópica nestes sais. Através do mecanismo reacional proposto, surgiu a possibilidade de deuteração de novos substratos contendo H ácidos, usando os LIIs como catalisadores. A reação de troca isotópica em alcinos e cetonas foi estudada e bons resultados foram obtidos. O efeito da variação de cátions e ânions na atividade catalítica foi analisado, assim como a variação dos substituintes dos substratos. Além disso, um estudo cinético foi realizado através de análises de RMN de 1H e o mecanismo reacional foi proposto. Por fim, a capacidade de formação de pares iônicos em soluções aquosas de LIIs foi avaliada na captura de CO2. Ótimos resultados foram obtidos e atribuídos à ocorrência de sorção física e química devido à ativação da água pelo LII. / Imidazolium based ionic liquids (ImIL) associated with basic anions were synthesized, characterized and studied. Initially the preferred H/D isotopic exchange to C2-CH3 group of 1-nbutyl-2,3-dimethylimidazolium salts (BMMI) was studied. In this context, it became evident that the ion-pairing formation and the anion action as a neutral base strongly influence the deuteration reaction. NMR analysis, theoretical calculation (Density Functional Theory) and X-ray Diffraction have been performed and a complex between a water molecule and the IL have been suggested, strongly modifying the IL structure and characteristics. The isotope exchange reaction in alkynes and ketones was studied using imidazolium based ionic liquids as catalysts and good results obtained. The effect of cation and anion variation on the catalyst activity were analyzed, also a variation of the substrate substituent’s. Also, a kinetic study was performed by 1H NMR analyzes and the reaction mechanism were proposed. Finally, the ability to form ion pair contact of ILs in aqueous solutions was evaluated for CO2 capture. Great results were obtained and this success can be attributed to the occurrence of physical and chemical sorption due to water activation by the IL.

Os métodos computacionais da química quântica foram empregados para estudar as estruturas moleculares e as energias de interação de cátions e ânions que são componentes de alguns líquidos iônicos funcionalizados, derivados do imidazólio. O estudo teve como objetivo comparar e relacionar os efeitos da presença de funcionalização nos substituintes das posições 1 e 3 do cátion imidazólio, nas propriedades desses líquidos iônicos. Essa funcionalização pode ocorrer pela presença de insaturações, grupos aromáticos, éteres, álcoois, tióis, aminas, nitrilas entre outros grupos nas cadeias dos substituintes. Nesta tese são reportados os estudos dos complexos formados por ânions tetrafluorborato e cátions imidazólio substituídos por grupos metila, etila, propila, butila, isobutila, vinila, propargila, alila, crotila e metalila, observando assim o efeito da presença de substituintes contendo cadeias insaturadas em comparação com os de cadeias saturadas nas estruturas, distribuições de carga, energias de interação e propriedades físico-químicas desses sistemas. Nesses sistemas foram observados intensos efeitos de polarização e transferência de carga ânion-cátion. Foram encontradas diversas relações entre volumes iônicos, energias de interação dos íons e as propriedades de transporte dos respectivos líquidos iônicos. / The methods of computational quantum chemistry have been used to study the molecular structures and the interaction energies of cations and anions which are components of some functionalized ionic liquids derived from imidazolium. The objective of this study is comparing and relating the effects of the presence of functionalization of the side chains of the imidazolium with the properties of these ionic liquids. This functionalization can occur by the presence of unsaturated side chains, aromatic groups, ether, alcohols, thiols, amines, nitriles among other groups in the side chains. In this thesis are reported the studies of the complexes formed of tetrafluorborate anions and imidazolium cations with side chains methyl, ethyl, propyl, butyl, isobutyl, vinyl, propargyl, allyl, crotyl and methallyl, thus observing the effects of the presence of unsaturated side chains compared to saturated ones on the structures, charge distributions, interaction energies and physicochemical properties of these systems. It was observed in these systems strong effects of polarization and anion-cation charge transfer. It was found several relations between ionic volumes, interation energies of the ions and the transport properties of the respective ionic liquids.