Fullerene research has advanced to elevated levels in a short period of time due to the unique chemical and physical properties of the caged molecule that have been utilized in numerous applications. Due to the spherical shape of the fullerene molecule which allows for a hollow cavity, encapsulation of atoms or small molecules can occur within the ball structure. This encapsulation creates an endohedral component that is limited from interacting with other molecules which creates potential of control over electronic information of the isolated molecule. Endohedral fullerenes have the potential as serving as the base unit in a quantum computer if control over global alignment is attained. Thus, by using the inherent self-assembling capabilities of some organic materials, ordered endohedral fullerenes can be achieved. This dissertation investigates the ability to use self-assembling strategies to obtain alignment which include ordering within a morphologically controlled copolymer matrix, forming a supramolecular polymer complex with cyclodextrin, and encapsulation within the helical wrap of polymer chains. The ultimate goal is to understand the dynamics that control association and orientation of varying fullerene-based molecules in each strategy in order to maximize control over the final alignment of endohedral elements.

L'oxyde de graphène (GO) a attiré un intérêt croissant comme vecteur potentiel pour la délivrance de gènes, en particulier pour l’inhibition de gènes spécifiques. Le but principal de ce travail est le développement de nouvelles plateformes complexant de petits ARN interférents (siRNA) et la rationalisation des interactions supramoléculaires entre la surface du GO et l'ARN double brin. L'étude s'est concentrée d'abord sur la synthèse de GO avec divers groupes oxygénés, puis sur la fonctionnalisation covalente du GO avec des amines et des polymères. De plus, j'ai étudié les facteurs qui pourraient affecter la structure double hélice du siRNA. Enfin, la question que je me suis posé: « l’oxyde de graphène peut-il devenir une plateforme appropriée pour la complexation d’acides nucléiques ?» a été résolue à l’aide d’expériences biologiques prouvant la capacité du GO à délivrer du siRNA dans les cellules. / Graphene oxide (GO) has attracted increasing interest as a prominent potential vector in gene delivery and in particular in gene silencing. The main goal of this work is to develop novel platforms to complex small interfering RNA (siRNA) molecules and to rationalize the supramolecular interactions between GO surface and the double strand RNA. The study focused first on the synthesis of GO with various oxygenated groups, subsequently chemically covalently modified with amines and polymers. Moreover, I investigated on the factors that could affect the double helix siRNA structure. Finally, the question of the thesis, « Can graphene oxide be a suitable platform for complexation of nucleic acids? » could be answered from the biological tests proving the ability of graphene derivatives as a carrier of siRNA into the cells.

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[pt] Neste trabalho são apresentados os resultados da produção e caracterização de novos dispositivos orgânicos eletroluminescentes (OLEDs), que podem ser divididos idealmente em três grupos. O primeiro composto pelos OLEDs que utilizam os distirilbenzenos (DSBs) como camada eletroluminescente. Os DSBs são sistemas utilizados em química supramolecular como pontes para transferência de carga. No segundo colocamos os OLEDs baseados em 2; 6 - bis(dietanolamina) - 4; 8 - dipiperidinopirimida (5; 4-d) pirimidina (DIP), que é uma droga amplamente conhecida e utilizada no tratamento de doenças cardiovasculares, que por possuir uma intensa fluorescência despertou a curiosidade para investigarmos a possibilidade da sua utilização com camada eletroluminescente. A utilização do DIP como camada eletroluminescente resultou em um OLED com a maior luminância dos grupos estudados, 1500 cd/m2. O terceiro grupo é formado por OLEDs que utilizam moléculas de calixarenos ([Al . 1]3+ e [Zn . 1]2+ onde 1 = 8- oxiquinolinacalix[4]areno) como camada transportadora de elétrons e eletroluminescente. Foram estudados dois sistemas calixarenos, o primeiro sistema é coordenado com alumínio (calix[Al]3+) e o segundo coordenado com zinco (calix[Zn]2+). O sistema calix[Al]3+ apresentou uma interessante propriedade de cooperação entre o anel central calix e um grupamento quinolina coordenado com Al. Utilizando este mecanismo de sinergia produzimos um OLED sintonizável, o qual varia o pico de sua banda de eletroluminescência de 510 nm pra 470 nm em função da tensão aplicada. Desta forma a cor da luz emitida pelo dispositivo pode ser variada com continuidade do azul (X=0,26 : Y=0,33 coordenadas CIE) até o verde claro (X=0,18 : Y=0,25).Todos os sistemas orgânicos foram analisados de um ponto de vista térmico através da analise de calorimetria diferencial de varredura (DSC), com a qual determinamos sua temperatura de transição vítrea (Tg). Com o auxilio de medidas eletroquímicas, estabelecemos um procedimento experimental simples e rápido para determinar os níveis energéticos HOMO (highest occupied molecular orbital) dos materiais orgânicos estudados na forma de filmes. Enfim, através da caracterização elétrica foi possível determinar o tipo de injeção de portadores que governa os dispositivos bem como o modelo que controla o transporte de cargas no interior dos OLEDs. / [en] In this work the results of the production and characterization of new organic electroluminescent devices (OLEDs) are presented and discussed. The work can be ideally divided in three parts. The first is composed by the OLEDs that use the distyrilbenzene (DSBs) compounds as electroluminescent layer. The DSBs are systems used in supramolecular Chemistry as bridges for load transfer. This is the first time that they are used in small molecule OLEDs. The second part deals with OLEDs based on dipyridamole (2; 6-bis(diethanolamino) - 4; 8 - dipiperidinopyrimido (5; 4-d)pyrimidine) (DIP) molecule, which is a very well known anti-platelet drug thoroughly used in the treatment of hearth diseases that for possessing an intense fluorescence woke up our curiosity in order to investigate the possibility of its use as electroluminescent layer. The use of DIP as electroluminescent layer resulted in a particular OLED with the highest luminance of the investigated devices, about 1500 cd/m2. Finally, the third part involves OLEDs that use calixarenes molecules [Al . 1]3+ and [Zn . 1] 2+ (1 = 8- oxyquinolinecalix[4]arene) as electroluminescent and electron transporting layer. In this work were studied two calixarenes systems: the first system is coordinated with aluminum (calix[Al]3+) and the second one is coordinated with zinc (calix[Zn]2+). The first one presented an interesting cooperation property among the central calix ring and the quinolina group coordinated with the Al metal. Using this synergic mechanism we were able to produce a tunable OLED, which electroluminescent emission varies continuously from 510 nm to 446 nm as a function of the applied bias voltage. All the organic compounds used in this work were analyzed from a thermal point of view through a Differential Scanning Calorimetry (DSC), in order to determine their transition glass temperature (Tg). By using electrochemistry measurements it was possible to establish a systematic and simple experimental procedure to determine the HOMO (highest occupied molecular orbital) energy levels of the organic materials studied in the form of films. Finally, through the electrical characterization it was possible to determine the type of carrier injection that governs the fabricated devices as well as the model that controls the carrier transport inside the OLEDs.

Bovine serum albumin (BSA) is the most abundant protein in plasma and it is responsible for the transport of most of the exogenous and endogenous compounds present in blood. Roxarsone (RX) and its metabolite acetarsone (AC) are organic compounds of arsenic(V) used in poultry as a food additive. In this sense, the interaction process of RX and AC compounds with BSA was evaluated under physiological conditions using spectroscopic techniques. It was possible to determine the formation of a supramolecular complex between RX and AC ligands using molecular fluorescence. The interaction degree was moderate, with a binding constant (Kb) of 4.27x105 L mol-1 and 0,27x105 L mol-1 for RX and AC, respectively. The quenching mechanism involved in the interaction process for both ligands was static and, preferably, by electrostatic interactions to the BSA-RX complex and hydrogen bonds and Van der Waals forces to BSA-AC. Both the formation of the complex and the quenching mechanism were confirmed by UV-vis spectroscopy. The 3D fluorescence analysis evidenced structural changes in the BSA polypeptide chain, being more pronounced in the presence of the RX ligand in comparison to AC. In addition, the BSA-RX interaction process modified the BSA surface, leading to reduction of hydrophobic regions more effectively compared to BSA-AC. About the binding site, both ligands are preferably in the site II of BSA. From the results obtained by 1H NMR, greater chemical shift was observed in the presence of the AC ligand, being the region close to amide group interacting with BSA, while the RX ligand possibly interacts more superficially in the protein. Thus, the RX and AC ligands do not favor the kinetics of protein fibrillation, giving indications that the possible deleterious effects in the evaluated in vitro system are not related to this process. Alkaline phosphatase inhibition kinetics demonstrated inhibition of enzymatic activity from 5 min and signal stabilization in 55 min of analysis for both RX and arsenate (positive control). Finally, the evaluation of in vitro alkaline phosphatase activity showed inhibition of enzymatic activity in 42% in the presence of the RX ligand and 5% in the AC ligand, giving indications of more detrimental effects for RX when compared to AC. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A albumina do soro bovino (BSA) é a proteína mais abundante do plasma e responsável pelo transporte da maioria dos compostos exógenos e endógenos presentes no sangue. Roxarsone (RX) e seu metabólito acetarsone (AC) são compostos orgânicos de arsênio(V) empregados na avicultura como aditivo alimentar. Neste sentido, o processo de interação dos compostos RX e AC com a BSA foi avaliado sob condições fisiológicas utilizando técnicas espectroscópicas. Empregando fluorescência molecular foi possível determinar a formação do complexo supramolecular para os ligantes RX e AC. O grau de interação foi moderado, com constante de ligação (Kb) de 4,27x105 L mol-1 e 0,27x105 L mol-1 para RX e AC, respectivamente. O tipo de quenching envolvido no processo de interação para ambos os ligantes foi estático e, preferencialmente, por interações de natureza eletrostática para o complexo BSA-RX e ligações de hidrogênio e forças de Van der Waals para BSA-AC.Tanto a formação do complexo quanto o tipo de quenching foram confirmados por espectroscopia de UV-vis. A análise por fluorescência 3D evidenciou mudanças estruturais na cadeia polipeptídica da BSA, sendo mais pronunciadas na presença do ligante RX em comparação ao AC. Ademais, o processo de interação BSA-RX modificou a superfície da BSA, levando à redução de regiões hidrofóbicas de forma mais efetiva em comparação à BSA-AC. Com relação ao sítio de ligação, ambos os ligantes encontram-se preferencialmente no sítio II da BSA. A partir dos resultados obtidos por RMN 1H observou-se maior deslocamento químico na presença do ligante AC, estando a porção próxima ao grupamento amida interagindo com a BSA. Enquanto que o ligante RX possivelmente interage mais superficialmente na proteína. Além disso, os ligantes RX e AC não favorecem a cinética de fibrilação protéica, dando indícios que os possíveis efeitos deletérios no sistema in vitro avaliado não estão relacionados a este processo. A cinética de inibição da fostatase alcalina demonstrou inibição da atividade enzimática a partir de 5 min e estabilização do sinal em 55 min de análise tanto para o RX quanto para o arseniato (controle positivo). Por fim, a avaliação da inibição da atividade da fosfatase alcalina in vitro evidenciou inibição da atividade enzimática em 42% na presença do ligante RX e 5% para o ligante AC, dando indícios de efeitos mais prejudiciais para o RX quando comparado ao AC.

Les liquides ioniques connaissent depuis quelques décennies un essor particulier en raison de leurs nombreuses propriétés physico-chimiques intéressantes, telles qu’une faible pression de vapeur saturante, une viscosité limitée, une faible miscibilité avec la plupart des solvants communs, ou encore des propriétés d’agencement supramoléculaire, qui en font des outils puissants dans de nombreux domaines de la chimie. Les sels d’imidazolium représentent la plus grande famille de liquides ioniques à ce jour. Leur modulabilité leur permet d’être dérivés pour de nombreuses applications spécifiques, notamment en synthèse organique, où ils sont utilisés majoritairement comme solvants, et plus récemment comme catalyseurs. Les travaux présentés dans cette thèse se concentrent sur leur utilisation en synthèse organique, à la fois comme solvants et principalement comme catalyseurs chiraux, catalyseurs pour lesquels l’anion du sel est l’espèce catalytique, permettant d’ajouter de la flexibilité et de la mobilité au système. En tirant parti de la tolérance des liquides ioniques envers la majorité des macromolécules naturelles, l’objectif principal des travaux présentés dans cette thèse est le développement d’un nouveau type de catalyseur bio-hybride reposant sur l’encapsulation d’un sel d’imidazolium dans une protéine. Par le biais de la technologie biotine-avidine, l’inclusion supramoléculaire de sels d’imidazolium biotinylés portant des contre-anions catalytiques dans l’avidine a été réalisée et exploitée en catalyse. Dans un premier temps, le développement et l’étude de deux sels de 1-butyl-3-méthylimidazolium possédant des anions chiraux dérivés de la trans-4-hydroxy-L-proline sont rapportés, ainsi que leur comportement dans des réactions énantiosélectives d’aldol et d’addition de Michael. Ces types de composés se sont révélés actifs et performants en milieu liquide ionique. Dans un second temps, la préparation de sels d’imidazolium dont le cation est biotinylé et portant un contre-anion achiral, a été réalisée. Le comportement de l’avidine en milieu liquide ionique et son apport en termes de chiralité sur le système bio-hybride ont été étudiés. Les résultats montrent le rôle crucial des liquides ioniques sur la conformation de la protéine et l’efficacité du catalyseur pour des réactions d’aldol. Dans un dernier temps, l’influence de la structure du cation et de l’anion sur le système a été étudiée. Différents espaceurs ont été introduits successivement dans les squelettes cationiques et anioniques des sels d’imidazolium biotinylés. Dans le cas du cation, les résultats ne révèlent aucune influence majeure sur l’efficacité du catalyseur. La structure de l’anion se montre cependant beaucoup plus importante : la préparation de différents catalyseurs bio-hybrides possédant des anions aux propriétés physico-chimiques différentes a permis d’obtenir de plus amples informations sur le mode de fonctionnement du système bio-hybride et de la coopérativité entre l’avidine et l’anion du sel d’imidazolium.La nature ionique de la liaison cation-anion offrant une liberté de mouvement accrue à l’anion dans la protéine, la tolérance à différents substrats a également été abordée après optimisation du système. / Ionic liquids have gained a growing interest due to many interesting properties, such as low vapor pressure, reasonably low viscosity, poor miscibility with common organic solvents, and also exhibit supramolecular organization in solution, which make them interesting tools for several fields of applications in chemistry. As of today, imidazolium salts make up the largest family of ionic liquids. Their modulability allows them to be used for a wide range of applications, notably in organic chemistry, where they are mainly used as solvents, but also more recently as actual catalysts. The work presented in this thesis focuses on their use as solvents and chiral catalysts, in which the catalytic species is the anion of the imidazolium salts, adding more flexibility and mobility to the whole system. Taking advantage from the tolerance of ionic liquids toward biological macromolecules, the main goal of this work is the design and development of a new type of bio-hybrid catalyst based on the encapsulation of an imidazolium salt inside the cavity of a host protein. Based on the biotin-avidin technology, the supramolecular ligation of biotinylated imidazolium salts inside avidin, bearing catalytic counter-anion, is discussed. As a first step, the development and studies of two 1-butyl-3-methylimidazolium-based salts, bearing trans-4-hydroxy-L-proline-derived anions are reported. Their use for asymmetric catalysis in ionic liquids media is disclosed, both for the aldol and Michael additions. Results show that these compounds are viable and efficient organocatalysts in ionic liquids. Subsequently, the preparation of biotinylated imidazolium salts, bearing a racemic pyrrolidine-based counter-anion is reported. Avidin behaviour in ionic liquid media, as well as its contribution for the stereocontrol for the whole bio-hybrid system, is assessed. Results highlight the critical role of the ionic liquid reaction medium on the protein’s conformation, and thus the efficiency of the bio-hybrid catalyst towards aldol reactions. Finally, the influence of the structure of the cation and anion on the catalytic properties of the biohybrid system were investigated. Several spacers were inserted successively both in the cation and anion structures of the biotinylated imidazolium salts. Regarding the cation modifications, results show no major influence on the bio-hybrid catalyst behaviour. However, modifying the anion structure revealed the much more important role of the anion towards catalysis. Preparation of different anions, each bearing a different spacer, granting them different physico-chemical properties, gives rise to further information regarding the behaviour of the bio-hybrid catalyst, and possible cooperativity between avidin and the imidazolium salt. The ionic character of the interaction between the anion and the cation, allowing a greater freedom of movement of the anion inside the avidin’s cavity, and the tolerance of the bio-hybrid system to different substrates were studied.