L’orchestration des mouvements directionnels d’architectures supramoléculaires s’avère cruciale pour la préparation de machines moléculaires artificielles. Les oligomères d’amides aromatiques (i.e. foldamères) peuvent adopter des conformations stables capables de se complexer à des tiges moléculaires pour former des (pseudo)-rotaxanes. Un contrôle fin des cinétiques d’association et de dissociation de l’hélice autour de la tige permet à l’oligomère hélicoïdal de glisser le long de celle-ci sans dissociation. Des études RMN et cristallographiques ont montré que des tiges moléculaires possédant plusieurs sites de reconnaissance pour des hélices permettaient l’élaboration d’architectures supramoléculaires hélicoïdales chirales avec une haute-fidélité. Chaque station possédant une longueur et une chiralité définie peut induire la complexation de foldamères de taille et d’hélicité concordante. Le glissement directionnel d’une double hélice le long d’une tige possédant plusieurs stations a également été investigué. Insérer un espaceur encombrant (i.e. plus large que la cavité de l’hélice) sur le chemin du foldamère le force à se déplier et se replier pour atteindre le site le plus favorable thermodynamiquement. Un oligomère asymétrique montrant de hautes affinités et de fortes sélectivités pour des tiges asymétriques a été préparé. L’enfilement de cet oligomère sur des tiges asymétriques a été étudié. Des données cinétiques (RMN) indiquent que l’enfilement de celui-ci s’effectue de façon polarisée en fonction de la nature de la tige. / The directional motion orchestration of supramolecular architectures is crucial for the construction of artificial molecular machines. Aromatic amide oligomers (i.e. foldamers) can adopt stable helical conformations able to wind around dumbbell-like guests to form (pseudo)-rotaxanes. A fine control of the association-dissociation kinetics allows the oligomers to slide along the rods without dissociation. In this thesis, based on the segregation of the kinetics of association-dissociation and sliding, helical oligomer motions were orchestrated to form complex self-assemblies and to perform directional motion. NMR and crystallographic studies showed that multistation rod guests can template the formation of well-defined multi-helical supramolecular polymers with high fidelity. Each station possessing a defined length and chirality can induce the complexation of oligomers presenting matching length and chirality. Directional sliding of a double helical oligomer along linear multistation rod guests was investigated. Placing a bulky spacer on the rod prohibits the sliding process, forcing the oligomer to dissociate and reassociate onto the thermodynamically favored station. An asymmetrical oligomer was prepared showing highly selective binding toward asymmetrical rod guests. The threading of this oligomer onto linear asymmetrical guests was investigated. Kinetic data indicated that the threading orientation of this asymmetrical oligomer was polarized by its passage along guest molecules.

The demand for multifunctional nanocontainers possessing both recognition ability and responsive nature is increasing greatly because of their high potential in various biomedical applications. The engineering of such smart nanovesicles is useful to enhance the efficiency of many therapeutic and diagnostic tools that have the applicability in targeted drug delivery systems as well as designing sensing devices or conducting selective reactions as nanoreactors in the scope of nanobiotechnology. For this purpose, this study demonstrates the formation of multifunctional and stimuli-responsive polymersomes comprising various abilities including pH and light sensitivity as well as many reactive groups with sufficient accessibility to be used as smart and recognitive nanocontainers. The fabrication included several steps starting from the synthesis of azide and adamantane terminated block copolymers, which were then self-assembled to prepare the polymersomes with the corresponding functional groups for the subsequent post-conjugations at the vesicle periphery. The accessible and sufficiently reactive groups were quantitatively proven when UV and IR cleavable NVOC protected amino groups as well as β-cyclodextrin molecules were conjugated to the pre-formed polymersomes through click chemistry and strong host-guest complexations. The gained light responsivity with the aid of successful NVOC attachment enabled further selective photochemical reactions triggered either by UV or NIR light leading to liberated amine groups on the polymersome surface. Therein, these released amino groups were further conjugated with a model fluorescent compound as mimicking the attachment of biorecognition elements to see the direct picture of the applicability. To realize this concept in a more localized and selective way as well as to avoid the possible side effects of UV light, the NIR-light induced photochemical reactions and further dye coupling were performed when polymersomes were immobilized onto solid substrates. This fixation was achieved by adapting the host-guest chemistry into this part and conjugating the adamantane decorated polymersomes onto β-cyclodextrin coated substrates. Several investigations including adhesion behavior, pH sensitivity and mechanical properties of the established multifunctional polymersomes under liquid phase have been performed. It has been found that the polymersome shape is highly dependent on the attractive forces of the substrate and needs to be optimized to avoid the flattening of the vesicles. For these optimization steps, different conditions were investigated including the decrease of cyclodextrin amount and additional surface passivation with PEG molecules on the solid substrates. Besides, the calculated Young’s and bending modulus of the polymersome membrane from AFM measurements showed a robust but still flexible “breathable” membrane which is an important criterion for the applicability of these smart and stable vesicles. In addition, the hosting ability as well as diffusion limits and sufficient membrane permeability of the polymersomes were observed by encapsulating gold nanoparticles as a smart cargo and doxorubicin molecules as an anticancer drug. In conclusion, the established multifunctional polymersomes are highly versatile and thus present new opportunities in the design of targeted and selective recognition systems which is highly interesting for various applications including development of microsystem devices, design of chemo/biosensors, and also for conducting enhanced, combined therapy in the field of drug delivery.

Les multicouches de polyélectrolytes, systèmes auto-assemblés par adsorptions successives de polycations et polyanions, peinent à trouver des applications concrètes en raison de leur fragilité mécanique et du temps nécessaire à leur assemblage. Pour améliorer leur tenue mécanique, nous avons développé une méthode d'assemblage couche-par-couche par liaisons covalentes de films polymères. Des films formés de polymères portant des groupements alcynes et azides ont ainsi été réticulés par une réaction click catalysée par les ions Cu+ obtenus par voie électrochimique. Pour améliorer le mode d'assemblage, l'auto-construction en une seule étape de films par approche morphogénique, a été développée. Cette approche, confinée à la surface et caractérisée par la présence en solution de l'ensemble des constituants, marque une rupture. Elle permet ainsi un contrôle spatial de l'assemblage des films et la combinaison de plusieurs modes d'interactions pendant leur assemblage. Des films dont la cohésion repose sur des interactions covalentes, hôtes-invités et supramoléculaires, ont ainsi été assemblés. L'introduction de nanoparticules métalliques dans les films (multicouches et auto-construits) a également été effectuée dans le but de développer des électrodes de grande surface spécifique. / Polyelectrolyte multilayer films, built by alternated adsorption of polycations and polyanions, face two main challenges: their construction process is tedious and their mechanical stability is poor. We developped a layer-by-layer strategy to improve the film stability by covalent reticulation of the polymers chains by click chemistry. Polymers bearing alkyne and azide functions were reticulated by triggering electrochemically the production of Cu+ catalyst ions. A one pot morphogen driven self-construction strategy was also developped to improve the buildup process of the films.In this case, all the constituants are simultaneously present in solution while the film grows up only at the electrode. Films based on covalent, host-guest and supramolecular interactions were obtained and the possibility of combining different interactions was also demonstrated. Nanoparticles were also included in layer-by-layer and self-constructed films in order to improve the electrode specific area.

L’aromaticité et l’antiaromaticité demeurent un sujet d’actualité au niveau fondamental puisque ces concepts permettent d’expliquer la réactivité de diverses classes de molécules. Certains composés polycycliques ayant une conjugaison π étendue, comme par exemple les tétraoxa[8]circulènes, ont des cycles aromatiques et antiaromatiques qui affectent leurs propriétés physicochimiques. Les oxacirculènes sont formés d’un anneau de quatre furanes et de quatre benzènes positionnés en alternance et créant un cœur formellement antiaromatique de cyclooctatétraène (COT). Malgré cela, ces composés démontrent une grande stabilité et peuvent servir en tant que composantes de dispositifs optoélectroniques comme des diodes électroluminescentes. Les propriétés optoélectroniques de ces composés et leur organisation moléculaire à l’état solide sont à l’origine d’un comportement unique. Le présent mémoire décrit la synthèse de tétraoxa[8]circulènes par une réaction très spéciale de cyclocondensation de 1,4-quinones catalysée par des acides, permettant d’accéder à des grandes molécules conjuguées en une étape. Les composés synthétisés ont une géométrie qui empêche leur empilement efficace et crée des vides dans la structure cristalline pouvant servir à l’inclusion de molécules invitées. En particulier, l’inclusion de C60 effectuée par cocristallisation cause l’uniformisation des longueurs des liens du cœur COT des oxacirculènes, suggérant des interactions de transfert de charge. Enfin, les propriétés optiques étudiées par spectroscopie UV-vis et par fluorescence indiquent que les oxacirculènes sont sensibles à leur environnement moléculaire et pourraient donc être utilisés comme des senseurs chimiques. / Aromaticity and antiaromaticity remain important topics of chemical research because these concepts explain the reactivity of various classes of molecules. For instance, certain polycyclic compounds with π-extended conjugation, such as tetraoxa[8]circulenes, contain both aromatic and antiaromatic rings, which affect their physicochemical properties. Oxacirculenes consist of a circular arrangement of four furan and four benzene rings positioned in an alternating fashion, thus creating a formally antiaromatic cyclooctatetraene (COT) core. Despite this, oxacirculenes exhibit great stability. They can serve as components in optoelectronic devices such as electroluminescent diodes, and their molecular organisation in the solid state can be controlled in ways that influence their properties. The present memoir describes the synthesis of tetraoxa[8]circulenes by a very special acid-catalysed cyclocondensation reaction starting from suitable 1,4-quinones, thereby allowing the preparation of large conjugated molecules in a single step. The compounds prepared have an awkward molecular structure that inhibits efficient packing and creates voids in the crystal structure, allowing the inclusion of guests. In particular, the inclusion of C60, achieved by cocrystallization, appears to create charge-transfer interactions as indicated by uniformization of bond lengths in the COT core. Optical properties studied by UV-vis spectroscopy and fluorescence show that oxacirculenes are sensitive to their local chemical environment, suggesting that they can be used as chemical sensors for the rapid detection of guests.

Cyclodextrins (CD) are cyclic oligosaccharides composed of six to more than sixty glucose units. Large-ring cyclodextrins (LR-CD) are novel CD comprised of more than eight glucose units with cavity structures and sizes different from that of commercially available CD₆ – CD₈. LR-CD may offer unique molecular recognition properties and can be produced biocatalytically from starch using cyclodextrin glucanotransferase (CGTase, E.C. 2.4.1.19) in a short reaction time. LR-CD were isolated from glucose, CD₆ – CD₈ and other compounds by complexation of CD₆ – CD₈ as well as precipitation techniques. The yield of LR-CD (degree of polymerization from 9 to 21) was optimized using central composite design. Addition of polar organic solvents to the synthesis resulted in higher yields of LR-CD. LR-CD composed of 9 to 21 glucose units were successfully separated using reversed-phase of ODS-AQ chromatography and normal-phase of polyamine II chromatography. Maintaining optimized reaction conditions aided in a high yield of CD₉; it could be separated with reasonable yield using a single step of polyamine II chromatography. A co-grinding method helped to obtain higher solubilization levels of glibenclamide, vitamin A acetate and vitamin D₃ in CD₁₃, CD₁₀ and CD₁₁, respectively when compared to other CD. Vitamin K₁ was solubilized in distilled water with CD₆ – CD₁₃ using a co-precipitation method. When compared with other CD, CD₉ was seen to be the best solubilizer. The analysis of complexes using ESI MS showed spironolactone and glibenclamide complexed with CD₉ and CD₁₃, respectively.

The adhesive and frictional response of an AFM tip connected to a substrate through supramolecular host–guest complexes is investigated by dynamic Monte Carlo simulations. Here, the variation of the pull-off force with the unloading rate recently observed in experiments is unraveled by evidencing simultaneous (progressive) breaking of the bonds at fast (slow) rates. The model reveals the origin of the observed plateaus in the retraction force as a function of the tip-surface distance, showing that they result from the tip geometrical features. In lateral sliding, the model exhibits a wide range of dynamic behaviors ranging from smooth sliding to stick-slip at different velocities, with the average friction force determined by the characteristic formation/rupture rates of the complexes. In particular, it is shown that for some molecular complexes friction can become almost constant over a wide range of velocities. Also, we show the possibility of exploiting the ageing effect through slide-hold-slide experiments, in order to infer the characteristic formation rate. Finally, our model predicts a novel ‘‘antiageing’’ effect which is characterized by a decrease of the static friction force with the hold time. Such an effect is explained in terms of enhancement of adhesion during sliding, especially observed at high driving velocities.

The demand for multifunctional nanocontainers possessing both recognition ability and responsive nature is increasing greatly because of their high potential in various biomedical applications. The engineering of such smart nanovesicles is useful to enhance the efficiency of many therapeutic and diagnostic tools that have the applicability in targeted drug delivery systems as well as designing sensing devices or conducting selective reactions as nanoreactors in the scope of nanobiotechnology. For this purpose, this study demonstrates the formation of multifunctional and stimuli-responsive polymersomes comprising various abilities including pH and light sensitivity as well as many reactive groups with sufficient accessibility to be used as smart and recognitive nanocontainers. The fabrication included several steps starting from the synthesis of azide and adamantane terminated block copolymers, which were then self-assembled to prepare the polymersomes with the corresponding functional groups for the subsequent post-conjugations at the vesicle periphery. The accessible and sufficiently reactive groups were quantitatively proven when UV and IR cleavable NVOC protected amino groups as well as β-cyclodextrin molecules were conjugated to the pre-formed polymersomes through click chemistry and strong host-guest complexations. The gained light responsivity with the aid of successful NVOC attachment enabled further selective photochemical reactions triggered either by UV or NIR light leading to liberated amine groups on the polymersome surface. Therein, these released amino groups were further conjugated with a model fluorescent compound as mimicking the attachment of biorecognition elements to see the direct picture of the applicability. To realize this concept in a more localized and selective way as well as to avoid the possible side effects of UV light, the NIR-light induced photochemical reactions and further dye coupling were performed when polymersomes were immobilized onto solid substrates. This fixation was achieved by adapting the host-guest chemistry into this part and conjugating the adamantane decorated polymersomes onto β-cyclodextrin coated substrates. Several investigations including adhesion behavior, pH sensitivity and mechanical properties of the established multifunctional polymersomes under liquid phase have been performed. It has been found that the polymersome shape is highly dependent on the attractive forces of the substrate and needs to be optimized to avoid the flattening of the vesicles. For these optimization steps, different conditions were investigated including the decrease of cyclodextrin amount and additional surface passivation with PEG molecules on the solid substrates. Besides, the calculated Young’s and bending modulus of the polymersome membrane from AFM measurements showed a robust but still flexible “breathable” membrane which is an important criterion for the applicability of these smart and stable vesicles. In addition, the hosting ability as well as diffusion limits and sufficient membrane permeability of the polymersomes were observed by encapsulating gold nanoparticles as a smart cargo and doxorubicin molecules as an anticancer drug. In conclusion, the established multifunctional polymersomes are highly versatile and thus present new opportunities in the design of targeted and selective recognition systems which is highly interesting for various applications including development of microsystem devices, design of chemo/biosensors, and also for conducting enhanced, combined therapy in the field of drug delivery.

A new rising star in the carbon nanomaterial family is carbon dots. Carbon dots have received great attention due to their excellent luminescence and low toxicity. In this project, a new carbon dot derived from birch leaves is studied and characterized. The birch leaf carbon dot (BL-CD) exhibits narrow red photoluminescence (peak = 670 nm, full width at half maximum = 23 nm) with a photoluminescence quantum yield of 26% in dilute methanol solution.  The presence of the characteristic peaks of the pigment pheophytin-a in the absorption spectrum and the photoluminescence spectrum of the BL-CD and the absence of a crystal structure together with the narrow and excitation-independent photoluminescence indicate a carbon dot with a non-emissive amorphous structure with emissive molecular sites consisting of the pigment. The photoluminescence quenching of the BL-CDs in solid-state is reduced by the introduction of a hostmaterial. The use of a host enabled the employment of BL-CDs as the emitter in a light-emitting electrochemical cell (LEC). This project paves the way for further development of the environmentally friendly and sustainable BL-CD LEC.

Raman multivariate curve resolution (Raman-MCR) spectroscopy is used to study water-mediated interactions by decomposing Raman spectra of aqueous solutions into bulk water and solute-correlated (SC) spectral components. The SC spectra are minimum-area difference spectra that reveal solute-induced perturbations of water structure, including changes in water hydrogen-bonding strength, tetrahedral structure, and formation of dangling (non-hydrogen-bonded) OH defects in a solute's hydration shell. Additionally, Raman-active intramolecular vibrational modes of the solute may be used to uncover complementary information regarding solute--solute interactions. Herein, Raman-MCR is applied to address fundamental questions related to: (1) confined cavity water and its connection to host-guest binding, (2) hydrophobic hydration of fluorinated solutes, (3) specific ion effects on nonionic micelle formation, and (4) ion pairing in aqueous solutions.

<p>  </p> <p>Experimental and computational techniques are used to study physico-chemical phenomena occurring in water on which hydrophobic interactions play a role. In particular, hydrophobic self-aggregation, including host-guest binding, and the affinity of ions to oil/water interfaces are investigated. Raman multivariate curve resolution (Raman-MCR) spectroscopy was the experimental technique used to unveil intermolecular interactions through the analysis of solute-correlated (SC) vibrational spectra. Molecular simulations, including molecular dynamics (MD) simulations, quantum-mechanical calculations, or a combination of both, were carried out to assist with the molecular-level interpretation of the experimental SC spectra.</p>