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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.
1

Functionalization and metallization of diamondoids / Fonctionnalisation et métallisation des diamantoïdes

Gunawan, Maria Agatha E. 21 May 2015 (has links)
Ces travaux de thèse développent des méthodes pour la synthèse de nouveaux organohybrides carbone-métal basés sur les diamantoïdes et le palladium.Les pressions de vapeur de divers diamantoïdes ont été mesurées grâce à un protocole original de mesures de l'état d'équilibre thermodynamique solide-vapeur. Leur relative volatilité a permis de réaliser des dépôts de diamontoïdes en phase vapeur, à diverses pressions (ambiante, vide primaire, et vide poussé) sur des substrats comme le silicium ou le mica. Les observations au MEB ont montré que, selon le type de groupes fonctionnels présents sur le diamantoïde, différentes formes cristallines peuvent être produites (tiges, aiguilles, triangles, formes octaédriques tronquées).L’OMCVD de palladium sur les diamantanes fonctionnalisés montre que le palladium se dépose préférentiellement sur le substrat du silicium plutôt que sur les cristaux de diamantoïdes portant des groupes hydroxy ou fluor. Nous avons alors envisagé la synthèse de nouveaux diamontoïdes portant des groupes phosphino, qui pourraient former une liaison covalente entre le diamontoïde modifié et le palladium.Un ensemble complet de diamondoïdes fonctionnalisés par des phosphines a été synthétisé. Certaines nouvelles phosphines primaires ont révélées une stabilité à l’air inattendue.Il a été montré que l’utilisation de phosphine P(III) comme sites d'ancrage a permis la formation du matériau hybride Pd@PH2-Diam-OH. Différents caractérisations (XPS, MEB, MET, et EDX) ont montré que le matériau Pd@PH2-Diam-OH formé est isolant, et présente des interactions Pd–P. / The thesis deals with development of synthetic methods for preparation of novel carbon-metal organohybrid based on diamondoid and palladium. The vapor pressure of various diamondoids was measured from a new measurement protocol at solid-vapor thermodynamic equilibrium state. Their volatile tendency opened a possibility to do deposition from gas phase and at various pressure (ambient, primary vacuum, and high vacuum) of diamondoids on silicon or mica substrates. SEM observations have shown that depending on the type of functional groups on the diamondoid, different crystal shapes can be produced (rods, needles, triangles, truncated octahedral form).OMCVD of palladium on functionalized diamantanes showed that Pd deposition occurs preferentially on the oxide native layer on silicon substrates than on diamondoid crystals bearing hydroxyl or fluorine groups. This urged the synthesis new diamondoids with phosphino groups in order to make strong covalent bonding between the modified diamondoid and palladium.A full set of functionalized diamondoid phosphines were synthesized with unexpected air-stability of some primary diamondoid phosphines were observedIt has been shown that the use of P(III) phosphine as anchoring sites allowed the formation of hybrid material Pd@PH2-Diam-OH. Different characterizations (XPS, SEM, TEM, and EDX) indicated that an insulator material Pd@PH2-Diam-OH formed during the CVD deposition with P–Pd interaction.
2

Self-assembly of synthetic and biological components in water using cucurbit[8]uril

Zayed, Jameel Majed January 2012 (has links)
This thesis discusses progress made towards assembling molecular building blocks in the presence of our molecular host of choice, cucurbit[8]uril (CB[8]). Our studies on the self-assembly of synthetic and biological components in water bridge overlapping conceptsand techniques drawn from the fields of synthetic organic chemistry, supramolecular self-assembly, and applied NMR techniques. Chapter 1 introduces the reader to chemical complexity, and how supramolecular chemistshave advanced in their capability of assembling more complex molecular architectures. The discussion focusses particularly on self-assembly carried out in the aqueousphase, and how, like in biology, molecular design of the building blocks become criticalin enabling non-covalent assembly to occur in this dynamic, and relatively competitiveenvironment. The cucurbit[n]uril family of molecular hosts are then introduced with anoverview of their modes of binding, and affinities towards typical guests. Finally, a practicalintroduction to NMR methods gaining prominence in supramolecular chemistry ispresented. In particular, the use of diffusion NMR, a key tool for probing the solutiondynamics of molecular assemblies, is highlighted. Chapter 2 details work carried out on the CB[8]-mediated self-assembly of supramolecularblock copolymers from polymeric, and small molecule building blocks. Here, endgroup-functionalised polymer guests were shown to assemble with small molecule ditopicguests in the presence of CB[8] to form block copolymers. Copolymers of various molecularweights were assembled, and the supramolecular complexes were studied usingsolution viscometry and diffusion NMR. This study represented the first use of diffusionNMR for probing the assembly of polymeric guests with CB[8].Chapter 3 describes the self-assembly of CB[8] with complementary ditopic guests. Highmolecular weight supramolecular polymers are known to form through the step-growthassembly of complementary ditopic building blocks. Here we sought to probe CB[8]?sability to drive supramolecular polymerisation. Solution viscometry, ESI-MS, and diffusionNMR were used to investigate the self-assembly process, which indicated that cyclicoligomers had formed. The relatively low solubility of CB[8] in water was thought to bea major limitation to polymer formation in this instance. Important observations relating to the effect of salts on the solution viscosities and stabilitiesof the complexes, are also discussed. Chapter 4 places emphasis on the synthetic methods employed towards preparing multivalentguests for CB[8] binding studies. Our synthetic guests were based on watersolubleoligomers of ethylene glycol. A bidirectional elongation route is presented foraccessing higher molecular weight, and monodisperse ethylene glycol oligomers (n = 12)in suitable purity. Chapter 5 describes the assembly of protein-polymer conjugates, and the versatility ofdiffusion NMR as a means to probe the assembly process. Here, end group-functionalisedpoly(ethylene glycol) guests were appended to bovine serum albumin (BSA) through amixed chemical ligation-self assembly protocol. The NMR studies conducted are emphasisedhere, which served to complement other characterisation methods used thatare reported elsewhere. Chapter 6 discusses ongoing work on lipid-based guests, and the resulting liposome assembliesformed. Head group-functionalised phospholipid guests, and cholesterol-basedguests were synthesised. Phospholipid guests were obtained through an enzymatic route,a novelty in our group. Dye-encapsulated liposomes were then assembled, purified, andcharacterised by fluorescence microscopy. Finally, we sought to optimise lipid formulationsto enhance liposome stability, towards conducting molecular recognition studies inthe presence of CB[8].Chapter 7 then closes the thesis with concluding remarks that summarise the describedresearch, while highlighting points of note.

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