L’implémentation d’un agent structurant impliquant un macrocycle à 31membres et intégrant un récepteur de type Hamilton / bis(2,6-diamidopyridine) a permis deconcevoir des [2]rotaxanes via une réaction click catalysée par du cuivre(I), soit à partir d’unpseudorotaxane en présence d’un barbiturique fonctionnalisé, soit par une méthode de« gabarit actif ». Ces structures supramoléculaires ont été rendues photochimiquement activesen exploitant des analogues de récepteurs Hamilton incorporant des groupementsphotodimérisables de type 9-anthracène. La photodimérisation et la retrodimérisation de cesrécepteurs en présence d’un fil barbiturique comportant des groupements terminauxencombrants (bouchons) permettent l’assemblage et le désassemblage de rotaxanes via unprocessus de photocapture. Ces unités 9-anthracène jouent également le rôle de bouchonsphotoactifs dans la formation d’un [2]rotaxane composé d’un plus petit anneau de typedibenzo-24-couronne-8, dont la photoirradiation résulte en une interconversion topologiqueinhabituelle entre un rotaxane et un caténane. Deux approches photochimiques ont permis deréguler des machines moléculaires distantes par une communication chimiqueintermoléculaire, c’est à dire soit par un transfert de molécule photoguidée, soit par untransfert d’électron photoinduit exalté par la présence d’un transfert d’énergie électroniqueréversible. / A templating motif involving a 31-member macrocycle integrating a bis(2,6-diamidopyridine) / Hamilton-type receptor aided [2]rotaxane sythesis, via a copper(I)catalyzed Huisgen reaction, in the presence of a designer barbiturate or by functionalizationusing an active template synthesis. Homologous supramolecular structures were madephotochemically-active, harnessing Hamilton receptors incorporating photodimerizable 9-anthracene groups. Photodimerization and retrodimerisation of these receptors in the presence of a barbiturate thread bearing terminal bulky stopper groups permitted rotaxane assembly /disassembly. The 9-anthracene units serve as stoppers in the formation of a [2]rotaxanecompound comprising a smaller dibenzo-24-crown-8 ring. Photoirradiation of these photoactive stoppers results in an unusual all-optical topological rotaxane - catenaneinterconversion. Two approaches to photoregulate remote molecular machines byintermolecular chemical communication involving a photoguided molecule or by photoinduced electron transfer aided by reversible electronic energy transfer are considered.

>Magister Scientiae - MSc / Electrochemiluminescence (EeL) is applied for industrial applications that have considerable potential, such as clinical diagnostic, analytical chemistry, and light-emitting devices, due to selectivity, sensitivity for detection and quantification of molecules through generation of fluorescence light when electric current is applied on the materials. In EeL the electrochemical reaction allows for precise control over the time and position of the light emitting reaction. The control over time allows one to synchronise the luminescence and the biochemical reaction under study and control over position not only improves sensitivity of the instrument by increasing the signal to noise ratio, but also allows multiple analytical reactions in the same sample to be analyzed using an electrode array. The EeL generation fluorescent materials are based on inorganic semiconductor materials for light-emitting devices. Further progress in this EeL field mainly depends on discovery of new advanced materials, interfacial films and nanoparticle coatings, advances in microfluidics leading to total increase in EeL properties. There has been extensive use of polymers for enhancement of EeL properties. Electrochemiluminescent conjugated polymers constitute a new class of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials for the commercial market of light-emitting devices such as lightemitting diodes and polymer laser devices (PLDs).

[pt] O objetivo da pesquisa foi dedicado à preparação de novos materiais híbridos à base de sílica contendo sistemas moleculares ou nanométricos de carbono com sistema de elétrons pi conjugados, imobilizados covalentemente para posterior aplicações como adsorventes e eletrodos para pré-concentração e determinação de compostos aromáticos. Deste modo, propôs-se o desenvolvimento das metodologias para as imobilizações covalentes de antraceno (Ant), pontos quânticos de óxido de grafeno (GOQDs) e nanopontos de carbono (CDs) na superfície da sílica (SiO2). Estes compostos são constituídos de sistemas conjugados de elétrons pi e, portanto, podem formar interação intramolecular de empilhamento pi–pi com compostos aromáticos. Nanocompósito de GOQDs imobilizados foi preparado através da interação covalente de fragmentos nanoméricos de óxido de grafeno (GO). Três tipos de SiO2-Ant foram obtidos através de abordagem de montagem da superfície pela reação de alquilação condensação de sílica modificada com grupos aminopropila. Estes materiais podem ter diferentes arranjos de ligantes de antraceno na superfície da sílica e, portanto, podem apresentar diferentes propriedades doadoras de elétrons-pi. Nanocompósitos de sílica gel com CDs imobilizados foram preparados por duas abordagens diferentes. Na primeira, os CDs foram obtidos a partir do ácido cítrico como material de partida e posteriormente imobilizados em sílica. O segundo método consistiu no uso de sílica gel porosa como nanorreator para a preparação de CDs. Este método é simples e robusto, o qual permite um maior controle do tamanho e da composição do nanomaterial. Além disso, os efeitos da modificação da sílica, tamanho dos poros, tempo de síntese, estabilidade hidrolítica, tamanho das nanopartículas de carbono e rendimento quântico da fluorescência foram avaliados. Foi demonstrado que a carbonização do gel aminosilica com ácido cítrico incorporado resultou na formação de CDs não imobilizados e CDs imobilizados. Devido à forte fixação na superfície, os CDs podem ser facilmente purificados através de simples lavagem do nanocompósito com água. Os C-pontos preparados apresentaram fotoluminescência independente de excitação a 445 nm com rendimento quântico até 80 porcento, o que os tornam atraentes para aplicação bioanalítica. O nanocompósito imobilizado com GOQDs foi preparado por ligações covalentes dos fragmentos de GO em nanoescala. A composição da camada superficial de todos adsorventes foi determinada a partir de análises elementares e termogravimétricas, fotoelétrons de raios X, ressonância magnética nuclear no estado sólido, Raman, FTIR e espectroscopia de fluorescência. As propriedades texturais dos adsorventes foram determinadas, bem como a cinética de imobilização do ligante, o grau de transformação da superfície e a estabilidade hidrolítica dos grupos enxertados, o efeito da porosidade da sílica no grau de conversão do ligante. As propriedades de adsorção dos materiais foram avaliados pela extração em fáse sólida nos modos dinâmico e estático para os compostos modelos azul de metileno e antraceno em várias fases móveis aquosas-orgânicas e orgânicas, na presença de componentes interferentes. Os nanomateriais obtidos apresentaram maior afinidade para compostos aromáticos do que os cartuchos comerciais C18 para extração em fase sólida (SPE) de fases orgânicas móveis que permitem a separação em uma etapa dos hidrocarbonetos aromáticos policíclicos (PAHs) na matriz com alta concentração de ácidos graxos. Ademais, sílica gel com GOQDs imobilizados foi usado para análise eletroquímica de antibióticos e hormônios selecionados. O eletrodo demonstrou atividade eletrocatalítica em relação ao estriol (ET), dietilestilbestrol (DES), sulfametoxazol (SMZ) e trimetoprim (TMP) que possibilitaram determinar esses analitos com até 0.009 μmol L(-1) (ET). / [en] The objective of the present research was devoted to the preparation of new silica-based hybrid materials having covalently immobilized carbon-containing molecular and nanometric systems with delocalized pi-electrons that can be used as adsorbents and electrodes for preconcentration and determination of aromatic compounds. For this purpose, methodologies for covalent immobilization of anthracene (Ant), graphene oxide quantum dotes (GOQDs) and carbon nanodots (CDs) on silica surface (SiO2) have been developed. These compounds have a conjugated system of pi-electrons and thus can form intramolecular pi–pi stacking interaction with aromatic compounds. The nanocomposite with immobilized GOQDs was prepared by covalent immobilization of nanoscale graphene oxide (GO) fragments. Three sets of SiO2-Ant were obtained using reaction surface assembling reactions by alkylation and condensation of silica with immobilized primary amines. These materials can have different arrangements of anthracene ligands on silica surface and so pi-donor properties. Silica gel nanocomposites with immobilized CDs were prepared by two different approaches. For the first one, the CDs were obtained from the molecular precursor and then immobilized on silica. For the second method, CDs were prepared by nanoreactor approach directly in silica gel pores. The second method is facile and robust and also allows better control of the particle size and composition. The effects of silica gel modification, pore size, synthesis time, hydrolytic stability, carbon nanoparticle size and quantum yield of the fluorescence were studied. It was demonstrated that the carbonization of aminosilica gel with embedded citric acid resulted in the formation of unbound CDs and immobilized CDs. Due to firm attachment to the surface CDs can be easily separated from low-molecular-weight impurities and CDs by simple rinsing of the nanocomposite with water. As prepared CDs demonstrate excitation-independent photoluminescence at 445 nm with quantum yield up to 80 percent that makes them attractive for bioanalytical application. The composition of the surface layer of the adsorbents was determined from elemental and thermogravimetric analysis, X-ray photoelectron, solid nuclear magnetic resonance, Raman, FTIR, and fluorescent spectroscopy. The textural properties of the adsorbents were determined as well as ligand immobilization kinetics, the degree of surface transformation and hydrolytic stability of the grafted groups, the effect of silica porosity on ligand conversion degree. The adsorption properties of the materials were studied in dynamic and static solid-phase extraction (SPE) modes for the model compounds methylene blue and anthracene in various aqueous-organic and organic mobile phases, in the presence of interfering components. It was demonstrated that studied materials have a higher affinity towards aromatic compounds than commercial C18 SPE cartridges in organic mobile phases that allow one-step separation of polycyclic aromatic hydrocarbons in the matrix with a high concentration of fatty acids. Also, silica-immobilized GOQDs was used for electrochemical analysis of selected antibiotics and hormones. The electrode demonstrated electrocatalytic activity towards estriol (ET), diethylstilbestrol (DES), sulfamethoxazole (SMZ), and trimethoprim (TMP) that made it possible to determine these analytes with up to 9 nmol L(-1) (ET).

Reported in this dissertation are the results of investigations performed at the New Orleans Center for Mass Spectrometry at the University of New Orleans. The projects that are detailed in the coming pages take on a variety of subjects, but a common thread is that each employs matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to solve a problem. Fundamental aspects of MALDI in-plume ionization are implicated in the introduction of a newly developed electron-transfer secondary ionization matrix. The remaining projects are related to the ever expanding field of proteomics. Mass spectrometry was used to investigate the site specificity of a newly developed bilin-lyase enzyme, a new approach was developed to distinguish between A-ring and D-ring attachment of bilins, and F. grandis protein expression pattern was investigated in several tissues. All obtained results were acquired using a MALDI TOF/TOF mass spectrometer. The sensitivity, mass accuracy, mass resolution and the ability to perform collision induced decomposition (CID) experiments were all valuable features that served to raise the quality of data, and thereby improved the detail of inferences to be drawn for the different projects.

Understanding of the fate of oil in the environment is of utmost importance; however, accurate, predictive models are still in very early stages. To aid in the development of these models, photodegradation of selected polycyclic aromatic hydrocarbons (PAHs) in an n-alkane hydrocarbon matrix was followed for individual PAHs and mixtures of PAHs similar to that found in the Deepwater Horizon spill. Tetracene in tetradecane photodegraded quickest of all observed PAHs, with a loss of 99% after only one hour of irradiation. Binary mixtures of PAHs showed different degradation amounts, including changes in PAH kinetics. These results suggest that the formation of dimers or aggregates as well as photosensitization reaction is important in the degradation of PAHs in oil. Kinetics of PAH photodegradation and PAH sensitized photodegradation will be presented. This information will provide a better understanding of the fate of oil in environmental systems.

Capteur électrochimique basé sur des matériaux carbonés fonctionnalisés, pour la détection de deux micropolluants faisant partie des substances prioritaires de la Directive Cadre européenne sur l’Eau (DCE2000/60/CE) : le plomb et l’anthracène. Les capteurs électrochimiques permettent d’atteindre des limites de détection et une sélectivité adéquates pour l’analyse de micropolluants dont les concentrations sont de l’ordredu μg/L, et sont simples d’utilisation pour des analyses in situ à moindre coût comparés aux appareils d’analyses conventionnels. Leur robustesse est un paramètre important afin de permettre des mesures en continu ou semi-continu dans les eaux. Cette thèse propose tout d’abord le développement du capteur pour la détection du plomb. La formulation d’une encre conductrice de carbone est étudiée pour la sérigraphie de ’électrode réceptrice, permettant ainsi de contrôler la composition de l’encre et d’étudier l’influence de la phase carbonée sur les propriétés électrocatalytiques des électrodes. La fonctionnalisation des électrodes par greffage électrochimique d’un sel de diazonium est également étudiée afin de maîtriser la sensibilité et la reproductibilité des électrodes greffées, en contrôlant l’épaisseur et la qualité des couches. Avec cet objectif, la fonctionnalisation dans un liquide ionique protique qui permet le contrôle de la monocouche en modulant la viscosité de ce milieu a été étudiée. Les électrodes greffées montrent des performances analytiques améliorées notamment en termes de répétabilité et de reproductibilité. Enfin ce travail de thèse porte également sur le développement du capteur pour la détection électrochimique de l’anthracène, molécule sans fonctions chimiques. Les électrodes sont, dans ce cas, fonctionnalisées par un polymère à empreinte moléculaire, matériau connu pour sa très grande sélectivité. Les performances de ce capteur, dont la sélectivité est basée uniquement sur le facteur de forme de la molécule, pour la détection de l’anthracène sont alors mises en évidence. / Electrochemical sensor based on functionalized carbon materials, for the detection of two micropollutants, lead and anthracene, which are among of the priority substances of the European Framework Directive on Water(DCE 2000/60 / EC). Electrochemical sensors allow to achieve detection limits and selectivities for the analysis of micropollutants whose concentrations are of the order of μg/L. They are easy to use for in situ analyzes at lower costs compared to those of the conventional analysis equipment. Their robustness is an important parameter in order to allow continuous or semi-continuous measurements in water. First of all, this thesis proposes the development of a sensor for lead detection. The conductive carbon ink formulation is studied for the screen-printing of the receiving electrode, thus allowing to control the ink composition and to study the influence of the carbon phase on the electrocatalytic properties of electrodes. Functionalization of electrodes by electrochemical grafting of a diazonium salt is also studied in order to control the sensitivity and reproducibility of grafted electrodes, by controlling the thickness and the quality of the layers. With this aim it has been studied the functionalization in a protic ionic liquid in order to allow the control of the monolayer bymodulating the viscosity of this medium. The grafted electrodes show improved analytical performance especially in terms of repeatability and reproducibility. Finally, this work reports the development of a sensor for the electrochemical detection of anthracene, a molecule without chemical functions. In this case, a molecularly imprinted polymer, a material known for its very high selectivity, functionalizes the electrodes.Having a selectivity is only based on the form factor of the molecule, the performance of the sensor developed for the detection of anthracene is also highlighted.

Le contrôle spatial et temporel de l'auto-assemblage de molécules fluorescentes en nano-objets organisés et en matériaux mous a été réalisé par photochimie.La photodécarbonylation quantitative du progélifiant dkDDOA sous irradiation génère le super gélifiant 2,3-didécyloxyanthracène (DDOA) à température ambiante et simultanément gélifie le DMSO. DkDDOA est réactif sous excitation avec de la lumière bleue en raison de la fonction alpha-dicétone sensible à la lumière qui est ajoutée au noyau aromatique. De plus,l’ajustement de la couleur de l'émission du gel du bleu au vert a été obtenu en ajoutant un dérivé 1,2-dicétone-5,12-diphényltétracène photo réactif qui donne un 5,12-diphényltétracène émissif vert sensibilisé par un transfert d'énergie efficace.Sous un microscope, l'irradiation laser focalisée permet la structuration de nanofibres émissives sur une surface de verre. Bien que la surface de verre soit non traitée, on peut obtenir des micropattern de nanofibres de DDOA hautement alignées. Ces surfaces émettent une lumière bleue polarisée linéairement, comme le prouve la microscopie de polarisation. L'anisotropie élevée et l'orientation des fibres ont été obtenues en contrôlant la densité de nucléation et la direction de balayage du laser focalisé. Des micropattern orientés perpendiculairement peuvent ainsi être juxtaposés sur la même surface. / The spatial and temporal control of the self-assembly of fluorescent molecules into organized nano-objects and into soft materials was achieved by photochemistry. The quantitative photodecarbonylation of the progelator dkDDOA under irradiation generates the supergelator 2,3-didecyloxyanthracene (DDOA) at room temperature and simultaneously gelates DMSO. dkDDOA is reactive under excitation withblue light due to the light sensitive alpha-diketone moiety that is added to the aromatic core.Additional colour-tuning from blue to green emission from the gel was achieved by adding a similar photoreactive 1,2-diketone-5,12-diphenyltetracene that yields a green emissive 5,12-diphenyltetracene sensitized through an efficient energy transfer. Under a microscope, focused laser irradiation enables the patterning of blue-emissive nanofibers on to a glass surface. Although the surface is non-treated, micropatterns of highly aligned DDOA nanofibers can be obtained. These surfaces emit linearly polarized blue light,as proven with polarization microscopy. The high anisotropy and the orientation of the fibers was achieved by controlling the nucleation density and the direction of scanning of the focused laser. Perpendicularly oriented micropatterns can thereby be juxtaposed on the same surface.

Gegenstand der Arbeit ist die lichtinduzierte Orientierung von multifunktionalen Polymeren, die u.a. für die Herstellung von optischen Schichten in Flüssigkristalldisplays verwendet werden können. Dafür wurden Polymere entwickelt, die wenigstens eine mesogene und eine lichtsensitive Gruppe enthalten. Diese Gruppen zeigen Eigenschaften, die für die Orientierung der kompletten Polymerfilme verantwortlich sind. Das Material wird dafür zunächst in einem ersten Schritt kurz mit linear polarisiertem Licht bestrahlt, wobei richtungsabhängig eine photochemische Reaktion an der lichtsensitiven Gruppe erfolgt und dadurch ein "Orientierungskeim" gelegt wird. Durch die thermische Ausrichtung der mesogenen Gruppen an den photochemisch generierten "Orientierungskeimen" erfolgt die komplette Orientierung des Filmes in einem zweiten Schritt. Dadurch wird eine hohe optische Anisotropie erhalten. Dieses Verfahren wurde als Zwei-Stufen-Bulk-Orientierungsprozess bezeichnet. <br><br> In der vorliegenden Arbeit wurden die Photoreaktionen verschiedener lichtsensitiver Gruppen, wie z. B. Azobenzen, Stilben und Zimtsäureester und deren Orientierungsfähigkeit in flüssigkristallinen Polymeren untersucht. Der Orientierungsprozess wurde durch die Wahl geeigneter Bestrahlungsbedingungen optimiert. Die Effizienz der Orientierung wurde anhand der sich verändernden winkelabhängigen Absorptionseigenschaften und der Doppelbrechung des Materials analysiert. Es wurde gezeigt, dass eine effiziente lichtinduzierte Orientierung bei einer Vielzahl von flüssigkristallinen Polymeren realisierbar ist. So wurde z. B. erstmalig gefunden, dass durch eine Photo-Fries-Orientierung eine hohe optische Anisotropie erhalten werden kann. Außerdem wurde eine neue lichtsensitive Gruppe auf der Basis von Donor-Akzeptor-substituiertem Ethen entwickelt, die farbneutral ist und durch polarisiertes UV-Licht sowohl orientiert als auch re-orientiert werden kann. <br><br> Es wurden weiterhin Polymere entwickelt, die zusätzlich zu den photosensitiven und flüssigkristallinen Einheiten, fluoreszierende Gruppen enthalten. Die Auswahl geeigneter Fluoreszenzverbindungen erfolgte aufgrund ihrer anisometrischen Form, ihrer Ordnungsparameter in einer niedermolekularen Flüssigkristallmischung und ihrer Photostabilität. Das Orientierungsverhalten von ausgewählten Fluorophoren wurde in sechs Ter- und zwei Copolymeren untersucht. Das Prinzip der Orientierung beruht auf einer kooperativen Ausrichtung der Seitengruppen. Aus diesem Grund kommt dem Nachweis der Kooperativität in der vorliegenden Arbeit eine besondere Stellung zu. <br><br> Durch lichtinduzierte Bulk-Orientierung wurden Filme erhalten, welche durch eine richtungsabhängige Fluoreszenz und Absorption im sichtbaren- oder UV-Bereich charakterisiert sind. Die Fluoreszenz wird durch einige lichtsensitive Verbindungen komplett gelöscht. Die wahlweise erhaltenen anisotropen Filme von farbigen, fluoreszierenden oder farbneutralen Verbindungen, die zudem in kleinen Pixeln von wenigen Mikrometern orientiert werden können, eröffnen vielfältige Möglichkeiten für den Einsatz von multi-funktionalen Polymeren als optische Schichten in Flüssigkristalldisplays. / The work presents the light-induced orientation of multifunctional polymers, which can be used for the preparation of optical films in liquid crystal displays (LCDs). Polymers which contain at least one mesogenic and one photosensitive side group were developed for this approach. The side groups of the specially designed polymers show properties which allow for the orientation of the whole polymer film. Isotropic films of the polymeric material were shortly irradiated with linearly polarised light in a first step. So, a photochemical reaction on the light-sensitive group takes place and results in the generation of "orientational seeds". The complete orientation of the polymer film takes place applying a secondary thermal step which aligns the mesogenic groups near to these "orientational seeds". In this way highly anisotropic films are generated. This method was called two-step-bulk-orientation process. <br><br> The photoreaction of different light-sensitive groups, such as azobenzene, stilbene, cinnamic ester and their ability to orient liquid crystalline polymers were investigated in this thesis. The orientation process was optimised using suitable irradiation conditions. The efficiency of the orientation was analysed measuring the angular dependent absorbance and the birefringence of the material due to the ordering procedure. It was shown, that a light-induced orientation is practicable in a high amount of different liquid crystalline polymers. So, for the first time it was found, that the generation of a high optical anisotropy is achieved as result of the rearrangement of the Photo-Fries-Reaction. Moreover, a new light-sensitive group based on donor-acceptor substituted ethylene was developed, which is colourless and allow the orientation and reorientation using polarised UV light. <br><br> Moreover, polymers were developed, which contain fluorescent groups in addition to the photo-sensitive and mesogenic units. The selection of suitable fluorophores was carried out with respect to their anisometric shape, their order parameter in a low molecular liquid crystalline mixture and their photostability. The orientational behaviour of selected fluorophores in six terpolymers and in two copolymers were investigated. The principle of the ordering is based on the cooperative orientation of the side groups. In this way the verification of the cooperativity of the process plays an important role in this work. <br><br> It was shown, that films can be fabricated by means of the light-induced bulk-orientation, which is characterised by an angular selective fluorescence and absorption in the UV or visible region. The fluorescence was completely quenched by some light-sensitive groups. In this way the anisotropic films became optional coloured, fluorescent or colourless and can be patterned in small anisotropic pixels of some micrometers. So, the developed multifunctional materials and the ordering method open new possibilities for the generation of different types of optical films in LCDs.

<p>In this work, a simple, less time consuming electrochemical method in the form of an electrochemical sensor has been developed for the detection of PAHs. The sensor was fabricated by the deposition of silver-gold (1:3) alloy nanoparticles (Ag-AuNPs) on ultrathin overoxidized polypyrrole (PPyox) film which formed a PPyox/Ag-AuNPs composite on glassy carbon electrode (PPyox/Ag-AuNPs/GCE). The silver-gold alloy nanoparticles deposited to form the composite were chemically prepared by simultaneous reduction of silver nitrate (AgNO3) and chloroauric acid (HAuCl4) using sodium citrate and characterized by UV-visible spectroscopy technique which confirmed the homogeneous formation of the alloy nanoparticles.</p>

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