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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
391

Premiers nanovecteurs supramoléculaires ciblant le cerveau par transport actif / First supramolecular nanovectors targeting the brain by active transport

Marmin, Thomas January 2017 (has links)
La délivrance de médicament dans l’organisme vers des organes cibles tout en minimisant les effets secondaires représente un énorme défi scientifique. Les recherches actuelles révèlent qu’il existe de nombreuses embuches pour acheminer des composés thérapeutiques vers le système nerveux central. De nombreuses maladies (l’autisme, la schizophrénie, la maladie d’Alzheimer…) liées au système nerveux central nuisent à la qualité de vie et entrainent des coûts importants pour la société. Ce mémoire repose sur l’amélioration de l’accessibilité de composés thérapeutiques vers le cerveau en passant la barrière hémato-encéphalique, une barrière biologique difficilement franchissable. Pour introduire des médicaments dans le système nerveux central, il faut passer cette barrière, ce qui est très difficile, car elle est remarquablement efficace pour protéger le milieu cérébral. C’est pourquoi nous allons développer une nouvelle stratégie consistant à élaborer un nouveau type de transporteur. Nous proposons d’utiliser des macrolactames ayant la propriété de s’empiler sous forme de tubes supramoléculaires d’une stabilité adéquate. Il sera alors possible d’y greffer des médicaments et aussi des agents d’ouverture de la barrière hémato-encéphalique. Ce mémoire présente l’élaboration de ces nouveaux macrocycles chiraux, les résultats de différentes analyses structurales prouvant la présence de tubes et de systèmes robustes et enfin la fonctionnalisation du macrocycle par un agent médicamenteux (doxorubicine). / Abstract : Delivering drug into the body to target specific organs, while minimizing side effects, is an enormous scientific challenge. Current research reveals that there are many pitfalls for delivering therapeutic compounds to the central nervous system. Many diseases (autism, schizophrenia, Alzheimer's, etc.) linked to the central nervous system affect the quality of life and entail significant costs for society. This thesis is based on the improvement in the accessibility of therapeutic compounds to the brain by passing the blood-brain barrier, a biological barrier difficult to cross. To introduce drugs into the central nervous system, this barrier must be overcome. This is very difficult because it is remarkably effective in protecting the brain. This is why we will develop a new strategy based on a new type of transporter. We propose to use macrolactams having the property of stacking in the form of supramolecular tubes of adequate stability. It will then be possible to graft medicines and also agents capable of opening the blood-brain barrier. This manuscript describes the development of these new chiral macrocycles, the results of various structural analyses proving the presence of robust tubes and systems, and finally the functionalization of the macrocycles by a medicinal agent (doxorubicin).
392

Foldaxanes : pseudorotaxanes hélicoïdaux auto-assemblés : structures et mouvements moléculaires

Gan, Quan 30 November 2012 (has links)
L'auto-assemblage dynamique est une méthode puissante pour accéder à des édifices moléculaires fonctionnels complexes. Son application à la construction de moteurs moléculaires par le biais de la maîtrise des échelles de temps ouvre la voie à des générations de nano-machines de plus en plus sophistiquées pouvant spontanément renouveler leurs composants ou les changer pour d'autres. La première partie de ce manuscrit est axée sur le design d’hélices d’oligoamides aromatiques qui peuvent s’enrouler le long d’un axe et glisser rapidement le long de celui-ci avant de se dérouler. Le second volet de cette thèse est consacré à la mise en évidence d’un mouvement qui est caractérisé pour la première fois à l’échelle moléculaire: le vissage. Le dernier axe de recherche développé dans ce manuscrit concerne la mise en évidence d’un intermédiaire cinétique de type foldaxane se transformant progressivement en un complexe hôte-invité 2:2 thermodynamiquement stable. / Dynamic self-assembly is a powerful method for fabricating complex, functional molecular structures. Its application to the construction of molecular motors through the control of timescales paves the way for new generations of nano-machines, in which sophisticated components can be spontaneously renewed or changed by others. The first part of this thesis focuses on the design of aromatic oligoamides that can slowly wind along an axis and shuttle along it before unfolding. The second chapter is devoted to the detection of a movement that is characterized for the first time at the molecular level: the screwing motion. The last line of research developed in this manuscript concerns the identification of a long-lived kinetic supramolecular by-product based on foldaxane architecture, which gradually transforms into a thermodynamically favored 2:2 host-guest complex.
393

Syntéza pi-elektronových oligomerů a studium jejich vlastností / The pi-electron oligomers: Their synthesis and properties

Warzecha, Tomáš January 2012 (has links)
The pi-electron oligomers: Their synthesis and properties This diploma thesis is focused on the synthesis of p-oligophenyleneethynylene rods (dimer and trimer) containing laterally attached naphtalenediimide units as electron acceptor groups. These functionalised short oligomers are intended to serve as model oligodentate acceptors in the study on multiple interactions with electron rich molecules. The oligomers were assembled from building blocks such as aryl iodides and aryl alkynes bearing a naphthalenediimide unit. The functionalised monomers were combined in a stepwise way by using Sonogashira reaction to form the target p-oligophenyleneethynylene oligomers. The introductory UV-VIS spectroscopic studies on charge transfer complexes between electron donor (pyrene) and electron acceptor (a naphthalenediimide derivative) were performed. In addition, multiple noncovalent interaction between the electron acceptor dimer containing two naphthalenedimide moieties and the electron donor dimer containing two pyrene moieties were investigated by using 1 H NMR titration. The resulting oligomers and their precursors were characterized by using 1 H NMR, 13 C NMR, MS and IR spectroscopy.
394

Photocontrolled biomimetic communication between molecules and nanosystems in confined compartments / Communication moléculaire biomimétique entre molécules et nanosystèmes photocontrôlés en compartiments confinés

Bofinger, Robin 12 December 2013 (has links)
Cette thèse se focalise sur la synthèse et l'étude de nouvelles molécules photoactives et leurs applications en tant que marqueurs, senseurs moléculaires et récepteurs d’ions photomodulables en milieux aqueux et organisés. Les fluorophores développés sont principalement des dérivés du bore-dipyrométhene (BODIPY), comportant des groupements réactifs (azoture, perfluorophényle), des chaines hydrophobes, ou sont intégrés à un récepteur de calcium biocompatible. Le développement d'architectures auto-assemblées multicompartimentées de type vésicules dans des polymersomes géant y est décrit. Ces architectures ont été utilisées pour la génération de lumière blanche dans un micro-domaine, et constitue un modèle pour l'étude de transfert d'ions calcium entre vésicules localisées dans des polymersomes individuels. Ce transfert entre nano-objets confinés à l'intérieur d'un polymersome géant représente un système prototype de communication cellulaire artificiel rudimentaire. / The thesis focuses on the study and design of novel photoactive molecules and their application as labeling agents, fluorescent molecular Ca2+-sensors and photolabile Ca2+-decaging agents in aqueous media and organized supramolecular assemblies. The designed fluorophores are based on boron-dipyrromethene (BODIPY) bearing hydrophobic chains or a reactive group like an azide or a perfluorophenyl moiety. Biocompatible calcium receptors have been prepared harnessing the fluorescence properties of BODIPY, naphthalimide and furan fluorophores. The development of self-assembled multicompartmentalized architectures, namely fluorocarbon vesicles in giant polymersomes is reported and the system has been used to create white light emission in confined microdomains. The Ca2+-based ion transfer ion the confined polymer compartments between individual fluorinated vesicles has been studied. The ion transfer in between vesicles in polymer microcompartments has been established as an artificial prototype system for cellular communication.
395

Association des composés quinonoïdes: conception de nouveaux solides cristallins pour l’électronique organique

Langis-Barsetti, Sophie 01 1900 (has links)
No description available.
396

Estudo das propriedades de agregados supramoleculares contendo metais de transição / Properties of Supramolecular Aggregates Containing Transition Metals -- A Study

Caturello, Naidel Antônio Moreira dos Santos 17 November 2015 (has links)
O estudo das reações de agregação em sistemas automontados é de grande interesse científico pela grande variedade de aplicações que tais colunas podem desempenhar. O presente trabalho teve como objetivo investigar as propriedades gerais de colunas supramoleculares formadas por complexos de coordenação que contêm platina, paládio e zinco. Esta investigação foi feita através do método semiempírico PM7. Os agregados supramoleculares investigados tiveram suas geometrias otimizadas e foram submetidos a cálculos termoquímicos. Pôde-se investigar as influências do metal e dos ligantes nos mecanismos gerais e propriedades das colunas, uma vez que utilizaram-se dois ligantes distintos. Estudou-se compostos de coordenação cujos ligantes foram o 2,6-bis(1H-1,2,4-triazol-5-il)piridina e oligofenilenoetinilenos (OPE) piridínicos. Realizou-se cálculos utilizando o modelo de solvatação contínua COSMO com água e metilciclohexano (MCH), o que permitiu avaliar os efeitos dos solventes nas energias de dimerização dos sistemas estudados. Os resultados obtidos para os derivados de OPE indicaram que as colunas supramoleculares desta classe que contêm Zn(II) apresentam anticooperatividade, exibindo energias de Gibbs de formação para o vácuo a 298 K positivas do dímero ao decâmero. Os resultados de solvatação contínua indicaram que a formação de um dímero deste composto é termodinamicamente favorável de 278 K para água e 267 K para o MCH, enquanto que para o vácuo a temperatura na qual a energia de Gibbs de dimerização é negativa ocorre em 246 K. Tal resultado aponta que o principal efeito de formação de colunas baseadas neste composto em altas temperaturas é primariamente um efeito solvofóbico que depende da polaridade do solvente. Observou-se a cooperatividade em vácuo e em ambos os solventes das colunas de derivados de OPE que contêm Pd(II) e Pt(II). Além destes fatos, as distâncias entre os centros metálicos diminuíram conforme monômeros eram adicionados à coluna, o que indica a existência de interações metalofílicas no sistema. Este resultado é corroborado experimentalmente por um artigo de Albuquerque el al. no caso do sistema de derivado de OPE que contém Pd(II). Para os sistemas cujos ligantes eram a 2,6-bis(1H-1,2,4-triazol-5-il)piridina, houve cooperatividade para ambas as colunas baseadas em Pd(II) e Pt(II), e houve para o sistema cujos centros metálicos são o Pt(II) uma transição não observada para todos os outros sistemas estudados; houve comportamento distinto das mudanças de distâncias entre monômeros no sistema triazol pridínico baseado em Pd(II) em relação àquele baseado em Pd(II) derivado de OPE. Este resultado indica a soma de dois efeitos no sistema OPE baseado em Pd(II): o de interações metalofílicas e de empilhamentos π-π. Como um todo, os resultados indicam que as principais interações envolvidas nas formações das colunas supramoleculares são interações de empilhamento π-π e metalofílicas para quatros compostos em graus diversos, exceto para o derivado de OPE baseado em Zn(II), que tem como principal força-motriz de agregação interações solvofóbicas. Perspectivas para este projeto: continuação da modelagem dos sistemas estudados por dinâmica molecular, com a simulação das interações de várias colunas formadas pelos monômeros estudados através do CP2K e publicação de um artigo com os resultados obtidos. / The study of aggregation reactions in self-assembled systems is of great scientific interest due to the wide range of applications which such resulting columns can play. Herein, we had the objective of investigating the general properties of supramolecular columns formed coordination complexes which contain platinum, palladium and zinc. This investigation was carried through the semiempirical method PM7. The investigated supramolecular aggregates were optimized, and their optimized geometries were subjected to thermochemical calculations. In this sense we could probe the influences of metals and ligands onto the general mechanisms and columnar properties, once were herein used two different ligands. The two ligands were 2,6-bis(1H-1,2,4-triazol-5-il)pyridine and oligophenyleneethynediyl (OPE) pyridine derivatives. COSMO solvation model -based calculations in water and methylcyclohexane (MCH) were performed in order to evaluate solvents effects on dimerization Gibbs energies of the studied systems. The results obtained for the OPE derivative based on Zn(II) pointed an anticooperative process in vacuum at 298K, exhibiting positive Gibbs energies of formation from the dimer to the decamer. The results from continuum solvation calculations indicate the formation of a dimer based on this Zn(II) molecule to be thermodynamically favorable at 278 K for water and at 267 K for MCH, while in vaccum this point lies at 246 K. This results indicates the formation of supramolecular columns based on this compound are formed in higher temperatures primarily due to solvophobic effects, and the intensity of this effect depends on the solvent polarity. The columns of OPE derviatives which contained Pd(II) and Pt(II) both showed cooperativity in the aggregation process. Besides these thermodynamic results, both of those columns showed monotonic distance shortening due to columns increasing process. This is an indicative of metallophilic interactions taking place in these aggregates. This result for Pd(II) is experimentally supported by a paper od Albuquerque et al. for the columns containing 2,6-bis(1H-1,2,4-triazol-5-il)pyridine cooperativity was observed for both the columns--those which contain Pd(II) and Pt(II)--, and for the Pt(II)-based columns of this class it was observed a transition not of most eneregetically favoured mechanisms not observed for all the other systems studied. A difference on the behavior of average monomer distances took place in the triazol pyridine Pd(II) compound when compared to its metal-related OPE derivative. This result indicates the summation of effects in the OPE-based Pd(II) system: the one of metallophilic interactions and π-π stacking interactions. As a whole, the results indicate π-π stacking and metallophilic interactions to be responsible for aggregation processes in diverse intensities for four of the compounds, except for that in the Zn(II)-based OPE derivative, which has the main aggregation effect as solvophobic interactions. The main perspectives for this project are the continuation of the modelling of the herein studied systems by molecular dynamics, simulating the interactions of many columns by the CP2K program, and the publication of a paper which contains the results obtained and presented in this dissertation.
397

Planejamento, obtenção e caracterização de novas formas sólidas de fármacos tuberculostáticos / Design, production and characterization of new solid forms of tuberculostatic drugs

Diniz, Luan Farinelli 29 November 2017 (has links)
As propriedades no estado sólido de um insumo farmacêutico ativo (IFA) estão diretamente relacionadas com a eficácia terapêutica de um medicamento. Entre todas as propriedades físicas e químicas, que são dependentes doarranjo cristalinodo IFA, destaca-se a solubilidade e a estabilidade, que são as características mais importantes de um fármaco, na medida em que podem alterar a biodisponibilidade. Dentro dessa perspectiva, a engenharia de cristaistem cada vez mais se consolidado como uma estratégia para aperfeiçoar as propriedades no estado sólido de um IFA. Neste trabalho, oito novas formas sólidas cristalinas, entre sais e cocristais, dos fármacos com ação anti-tuberculose etionamida (ETH), etambutol (ETB) e isoniazida (INH), foram preparadas e tiveram suas estruturas cristalinas determinadas por difração de raios X por monocristal. Além disso, todas as modificações cristalinas obtidas foram caracterizadas por difração de raios X por policristais, espectroscopia vibracional no infravermelho e Raman, calorimetria exploratória diferencial, termogravimetria e microscopia ótica térmica. Por fim, estudos de solubilidade em equilíbrio e de estabilidade em atmosfera úmida também foram realizados. A nova modificação cristalina da ETH, o sal nitrato de ETH, foi planejada visando melhorar a solubilidade aquosa deste IFA (∼0,4 mg mL-1). Este é o primeiro relato de uma estrutura de ETH que cristalizou com quatro independentes pares iônicos (ETH+/NO3-) na unidade assimétrica. A análise do empacotamento cristalino e das interações intermoleculares permitiu estabelecer os atributos estruturais que explicam a menor estabilidade térmica e a elevada solubilidade (cerca de 300 vezes maior) deste sal, em comparação com a forma neutra da ETH. A preparação dos novos sais de ETB foi feito considerando o cárater básico da molécula, o que permitiu a obtenção de três novos sais a partir da reação do ETB com os ácidos oxalico, maleico e tereftálico. O desenho dessas formas sólidas teve como principal objetivo minimizar os efeitos da elevada higroscopicidade do ETB, que é tão prejudicial para formulações farmacêuticas. Este objetivo foi alcançado, uma vez que o sal oxalato de ETB, reportado neste trabalho, mostrou ser não-higroscópico. Por fim, quatro novos cocristais da INH, sendo dois cocristais polimórficos, foram preparados por meio de reações estequiométricas deste IFA com ácidos carboxílicos aromáticos derivados do ácido benzóico. O desenho dessas novas modificações cristalinas teve como intuito principal explorar a diversidade de síntons supramoleculares formados entre a INH e moléculas contendo o grupo COOH. A análise dos empacotamentos cristalinos das formas I e II do cocristal INH-PABA, mostrou que este é um típico caso de polimorfismo orientacional. Portanto, os resultados desta dissertação trazem importantes contribuições científicas para a diversidade de formas sólidas, apresentando revelância para o setor farmacêutico no que se refere ao desenvolvimento de novas formulações contendo fármacos anti-tuberculose. / Solid state properties of an active pharmaceutical ingredients (API) are directly related to drug performance. Among all physical and chemical properties dependent on the crystal arrangement of a drug, stability and solubility are the main ones that alter its bioavailability. In this sense, crystal engineering is a strategy to improve solid state properties of drugs. In this work, eigth new multicomponent solid forms (salts and cocrystals) of the tuberculostatic drugs ethionamide (ETH), ethambutol (ETB) and isoniazid (INH) were prepared and their crystal structures were elucidated by single crystal X-ray diffraction. In addition, the crystal modifications were also characterized by powder X-ray diffraction, infrared and Raman vibrational spectroscopy, differential scanning calorimetry, thermogravimetry and Hot-stage microscopy. Finally, equilibrium solubility studies and stability experiments in humid atmosphere were also performed. The new supramolecular modification of ETH, ethionamide nitrate salt, was designed in order to improve the aqueous solubility of the API (∼0.4 mg ml-1). This salt is the first ETH structure that has been crystallized with four independent ionic pairs (ETH+/NO3-) in the asymmetric unit. The analysis of crystal packing and intermolecular interactions allowed to establish the structural attributes that explain the lower thermal stability and high solubility (about 300 times higher) of this salt compared to the neutral ETH form. Due its high hygroscopicity, ETB is known for catalyzing the degradation of isoniazid and rifampicinin pharmaceutical formulations. In order to avoid or even minimize these mutual drug-drug interactions, in this work we have focused on the development of less hygroscopic multicomponent solid forms of ETB. The preparation of the new ETB crystal modifications was carried out considering the pKa values of the molecule, which allowed the design of three new salts (namely oxalate, maleate and terephthalate). These salts were obtained from the reaction of ETB with the carboxylic acids: oxalic, maleic and terephthalic. The hygroscopic nature of these salts was evaluated and all of them were found to be hygroscopic, with exception of ETB oxalate. Finally, four novel INH cocrystals, being two polymorphic forms, with aromatic carboxylic acids derivatives were rationally prepared. The design of these crystal forms aimed to explore the diversity of supramolecular synthons formed between INH and molecules containing COOH. The crystal packing analysis of the INH-PABA cocrystals (polymorphs I and II), showed that this is a typical case of orientational polymorphism. Therefore, the scientific contributions of this work show the diversity of the solid forms and define candidates to new anti-tuberculosis API\'s solid formulations.
398

Desenvolvimento de dispositivos moleculares fotovoltaicos / Development of molecular photovoltaic devices

Furtado, Luis Fernando de Oliveira 05 December 2007 (has links)
Nesta tese são discutidos alguns aspectos importantes no desenvolvimento de sistemas fotovoltaicos moleculares. São abordados temas de interesse como a síntese de novos sensibilizadores para células solares sensibilizadas por corante, o desenvolvimento de novos materiais fotoativos, Química Supramolecular, bem como a aplicação de sistemas fotovoltaicos em eletrônica molecular, especificamente no desenvolvimento de portas lógicas moleculares e dispositivos de memória. A porfirina TBPyP, contendo quatro ligantes 2,2\'-bipiridina ligados covalentemente aos carbonos meso do anel porfirínico, foi sintetizada. Este derivado porfirínico serviu como bloco de construção de sistemas supramoleculares. A utilização desses sistemas como sensibilizadores em células solares (células de Grätzel) é discutido. Fios moleculares derivados da TBPyP foram obtidos via coordenação com íons de metais de transição e são investigados quanto à possibilidade de utilização em eletrônica molecular. Novos sistemas fotovoltaicos multicamada, utilizando filmes de porfirina depositados por evaporação a vácuo como elementos fotoativos e filmes de V2O5 como eletrodo passivo, foram estudados quanto a sua eficiência e quanto ao seu mecanismo de funcionamento. Os filmes finos de porfirina obtidos neste estudo foram testados como elelementos fotoativos em células fotovoltaicas com diferentes configurações, além daquelas utilizando filmes de V2O5. A obtenção de filmes híbridos compostos de nanopartículas de ouro e ligantes orgânicos foi desenvolvida e sua aplicação em sistemas fotovoltaicos bem como em dispositivos de memória investigada. Novas portas lógicas moleculares foram obtidas utilizando-se o arranjo de células de Grätzel convencionais sensibilizadas por clusteres trigonais de rutênio sintetizados para este fim. Seu princípio de funcionamento é discutido, bem como a seu potencial de integração em circuitos lógicos. / In this thesis some aspects concerning the development of molecular photovoltaic systems are discussed. Themes of current interest such as the synthesis of new sensitizers for dye-sensitized solar cells, the development of new photoactive materials, and Supramolecular Chemistry are treated, as well as the application of photovoltaic systems in molecular electronics, specifically in the development of molecular logic gates and memory devices. The porphyrin TBPyP, comprised of four 2,2\'-bipyridine ligands covalently linked to the porphyrin meso carbons, was synthesized. This porphyrin derivative was used as a building block on supramolecular systems. The utilization of these supramolecular species in solar cells (Grätzel cells) is discussed. The coordination of the porphyrin TBPyP with transition metal ions gave rise to molecular wires, which are investigated about its potential use in molecular electronics. New multilayer photovoltaic systems, using thermo-evaporated porphyrin films as photoactive elements and V2O5 films as passive electrodes, had their efficiency and mechanism studied. The confection of hybrid films comprised of gold nanoparticles and organic ligands was developed and its application in photovoltaic systems, as well as in memory devices, was investigated. New molecular logic gates were realized using the a Grätzel cell in its conventional configuration, sensitized by ruthenium trigonal clusters synthesized to this end.
399

Espectroscopia Raman de sistemas supramoleculares envolvendo espécies oxocarbônicas / Raman spectroscopy of supramolecular systems involving oxocarbon species

Lopes, José Guilherme da Silva 24 October 2001 (has links)
Na última década sistemas supramoleculares vêm atraindo a atenção de muitos pesquisadores na área da química. Este interesse é devido a capacidade dos sistemas supramoleculares mimetizarem sistemas biológicos e pelo seu importante papel na construção de novos materiais com interesse tecnológico. No contexto de interações supramoleculares as espécies oxocarbônicas têm se mostrado como excelentes sondas para o estudo dessas interações devido às características sui generis dos seus espectros eletrônicos e vibracionais, o que por sua vez decorre da presença do efeito Jahn-Teller. Neste trabalho foram investigados os sistemas supramoleculares: mordenita/ácido esquárico, tiouréia/ácido esquárico e agregação de esquaraínas em solução. Nessa investigação foram utilizadas técnicas de espectroscopia eletrônica e vibracional. As espectroscopias Raman e Raman ressonante se mostraram eficientes para o estudo dos sistemas supramoleculares acima. Através do uso das espectroscopias eletrônica e vibracional foi possível caracterizar interações do tipo \"transferência de carga\" em mordenitas incluídas, caracterizar clatratos formados por tiouréia e espécies oxocarbônicas, e determinar os modos vibracionais envolvidos no processo de agregação em solução de esquaraínas e, conseqüentemente, sua geometria de agregação. / Over the last decade supramolecular systems have received the attention of many researchers. Such interest can be explained by the ability of supramolecular systems to mimic biological systems, as well as by their important role in the design of new materials with technological relevance. In the context of supramolecular interactions oxocarbon species have proved to be excellent probes for the study of such interactions thanks to the unique features of their vibrational and electronic spectra, a consequence of the Jahn-Teller effect. In the present work the following systems were investigated: Mordenite/squaric acid, thioureia/squaric acid and aggregated squaraines in solution. Electronic and vibrational spectroscopies were the techniques of choice. Raman and resonance Raman spectroscopies showed to be convenient techniques for the study of the forementioned systems. It was possible to characterize the charge-transfer interaction induced by the restrict geometry in mordenite, the clathrate-like host formed by thioureia squaric acid, as well as to determine the nature of the squaraines aggregates formed in solutions.
400

Systèmes supramoléculaires biomimétiques : les complexes bols, synthèse, propriétés et réactivité / Biomimetic supramolecular systems : bowl complexes, synthesis, properties and reactivity

Parrot, Arnaud 16 December 2015 (has links)
Le ligand Rim3, constitué d’une cavité resorcinarène fonctionnalisée par 3 groupements méthylimidazole a été synthétisé et étudié. Ce ligand est capable de coordiner différents métaux de transitions comme le zinc et le cuivre. Ces complexes possèdent des propriétés hôte-invité intéressantes et une sélectivité avec la taille de la cavité. La complexation d’invités acides nécessite l’addition d’une base exogène. De plus, la présence de base peut être nécessaire pour réaliser des réactions d’hydratation ou d’hydrolyse. Dans ce manuscrit sont présentés différents ligands cavitaires resorcinarène avec 4 imidazoles greffés. Chaque ligand et complexe associé présente des solubilités différentes. Nous étudierons d’abord la synthèse et la caractérisation des systèmes en milieu organique ou aqueux. Les études de complexation montreront la forte affinité associée à ces complexes en milieu organique. L’étude des propriétés hôte-invité montre que le complexe est capable de coordiner un invité acide de manière quantitative dans les conditions RMN. Cette coordination ne nécessite pas l’addition de base. Le 4e imidazole joue le rôle de base intramoléculaire et n’est pas nécessaire à la coordination. Deux positions labiles en cis sont également disponibles, attesté par la coordination de ligands bidentes. Le complexe zincique [Rim4ZnII(EtOH)](ClO4)2 montre des propriétés d’hydratation des nitriles. Dans l’acétonitrile avec 35% d’eau à 70°C, le complexe forme de l’acétamide de manière catalytique. L’addition de base n’est pas nécessaire et le pH n’évolue pas avec la réaction. Dans l’eau avec 10% d’acétonitrile, [WRim(OH)44 Zn(H2O)](NO3)2 catalyse l’hydratation en acétamide mais est inhibé par l’hydrolyse successive en acétate. / In this manuscript, we present the synthesis and caracterisation of three tetradentate bowlshaped ligand. These ligands are resorcin[4]arene functionnalized by four methylimidazole. Each ligand is soluble in a different medium, such as organic solvent, water and mixed solvent. The four methylimidazoles are able to coordinate several metal ions, such as zinc, copper and iron. We then present the host-guest properties of the complexes. The complexes are able to coordinate acidic guests without addition of an exogenous base, thanks to the fourth imidazole. Two labiles positions are avalaible in cis, and bidentate ligands are able to coordinate the metal ions. Finally, we present the reactivity of the complexes. The zinc complex, [Rim4Zn]2+ catalyses the acetonitrile hydration with 35% water at 70°C. In an aqueous media with 10% water,[WRim(OH)44 Zn(H2O)](NO3)2 catalyses not only the acetonitrile hydration but also it’s subsequent hydrolysis into acetate.

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