Thesis (Ph. D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008. / Committee Chair: Sandhage, Kenneth; Committee Co-Chair: Kröger, Nils; Committee Co-Chair: Naik, Rajesh; Committee Member: Hud, Nicholas; Committee Member: Marder, Seth.

Thesis (Ph. D.)--University of Delaware, 2008. / Principal faculty advisor: Eric W. Kaler, College of Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 1999. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 303-350). Also available for download via the World Wide Web; free to University of Oregon users. Address: http://wwwlib.umi.com/cr/uoregon/fullcit?p9955917.

Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Oliver Steinbock, Florida State University, College of Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Jan. 24, 2006). Document formatted into pages; contains xii, 123 pages. Includes bibliographical references.

Thesis (Ph.D.)--Ohio University, August, 2006. / Title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 246-276).

Le Lanréotide est un octapeptide amphiphile cationique et un analogue thérapeutique de la somatostatine. Cette molécule synthétique a été conçue au sein de Beaufour-Ipsen comme thérapie contre l’acromégalie. Ce peptide révèle la propriété de former des nanotubes avec un haut degré de monodispersité en diamètre des tubes (244 Å) et épaisseur de la paroi (~18 Å) lorsqu’il est mélangé avec de l’eau pure à 10% (w/w). Le peptide forme des tubes emboîtés à plus haute concentration. Cette propriété d’auto-assemblage est utilisée pour concevoir un implant sous cutané à libération prolongée d’un mois : la Somatuline Autogel. Les gels de Lanréotide deviennent de plus en plus visqueux avec la concentration en peptide et cette viscosité limite la dose maximale injectable. L’ajout d’un adjuvant dans la formulation : le polyéthylène glycol (PEG600) à permit d’augmenter le temps de libération du peptide dans l’organisme tout en diminuant la viscosité du gel. Dans le but d’étudier l’effet du PEG600 sur l’auto-assemblage du Lanréotide, une étude structurale et thermodynamique est proposée. Cette étude est réalisée grâce à une approche par diagramme de phase systématique, par la technique de diffusion des rayons X et de modèles d’analyses des clichés, croisé par différentes techniques de caractérisations moléculaires. Cette étude révèle des interactions fortes du PEG avec le Lanréotide conduisant à la formation d’un complexe en solution. Ce complexe influe sur les équilibres entre deux phases du système biphasique, tube et intermédiaire du Lanréotide (rubans et dimères), ce qui pourrait jouer un rôle important dans les propriétés rhéologiques des gels. Enfin, il est montré qu’il est possible de réaliser la transition pratiquement totale du Lanréotide vers un dimère chimique conduisant à la formation de fibre type amyloïde. La simplicité du procédé de fabrication à température ambiante de ce dimère non actif dans l’organisme par un simple changement d’ordre d’addition des composants, fait de la compréhension des paramètres physico-chimiques de formations de ce dimère, un point capital du point de vue industriel. / The Lanreotide is an cationic octapeptide and a therapeutic analogue of the somatostatin. This synthetic molecule was designed by Beaufour Ipsen as a therapy against acromegaly. This peptide has the capacity to form monodisperse nanotubes with a high degree of monodispersity in diameter (244 Å) and wall thickness (~18 Å) when the peptide is mixed with pure water at 10% (w/w); embedded tubes are found at higher concentration. The viscosity of Lanreotide gels is strongly increasing with the peptide concentration, a property that limits the maximum injectable dose. The addition of a polymer (polyethylene glycol, PEG600) as an adjuvant in the formulation allows one to increase the release time in the organism to be treated and to decrease the gel viscosity. To study the effect of PEG600 on the self-assembly of the Lanreotide, a structural and thermodynamic work is proposed. This study is performed with a systematic phase diagram approach, by X-ray scattering and modeling of the scattering pattern and different experimental techniques at the molecular scale. This study reveals strong interaction between PEG and Lanreotide that form a complex in solution. This complex impacts the equilibrium state between two phases of the biphasic system, i.e., pure tubes and an intermediate state consisting of a mixture between ribbons and dimers of the Lanreotide. This result could play an important role for the gel’s rheological properties. Then, we demonstrate that it is possible to obtain an almost complete transition to a covalent dimer which yields the formation of amyloid fibers. To sum up, we discuss a new process for the fabrication of a dimer that is not active in the organism, this process being (i) based on a simple change of the order at which the components are added in solution and (ii) easy to implement at room temperature. Our findings could impact industrial applications.

Molecular self-assembly or ligand-metal assembly is a process in which several individual molecules and metal ions organize themselves into an ordered arrangement without external stimuli, the defined structures can lead to distinctive electronic and photonic performances. In the meantime, as the scale of materials decreases, various unique properties arise from their minute scaled dimensions, such as surface effect, volume effect, quantum effect and dielectric confinement effect, etc. Therefore, the design and fabrication of the micro- and nanomaterial via the technique of molecular self-assembly or ligand-metal assembly is becoming an emerging research field, for the purpose of meeting the increased demands of multi-functional materials. Chapter 1 gives an overview of the advanced materials prepared by either molecular self-assembly or ligand-metal assembly. We described the interaction nature in detail, and enumerated the applications as well as developments of this scientific field. Furthermore, the detailed classifications as well as previous work of these advanced materials we researched on, such as two dimensional nanosheets, hetero-structured materials and cyclometalated iridium(Ⅲ) complexes were also amply summarized. Two-dimensional nanosheets have always been a research hotspot since graphene was discovered and isolated. In contrast, molecule-based organometallic nanosheets through bottom-up method exhibit more inner structures. In Chapter 2, we constructed two classes of organometallic nanosheets with different intermolecular forces, one is metal-ligand coordination, while the other one is the aromatic (π-π) interaction. Two-dimensional nanosheets with Hg-acetylide linkages, bis(dipyrrinato)metal linkages as well as bis(terpyridine)metal linkages were synthesized and characterized by UV-Vis absorption spectroscopy, FT-IR spectroscopy, optical and electron microscopy, photoluminescence spectroscopy, thermal gravimetric analysis, X-ray photoelectron spectroscopy and so on. In addition, the potential applications were explored as well, including the tests of charge mobility and current capacitance. Meanwhile we also investigated the two-dimensional nanosheets self-assembled by aromatic (π-π) interaction. The morphology characterizations, crystal form measurements, besides elemental analyses were conducted. By means of surface control, the hybrid nanosheets could achieve many superior performances, like super hydrophobicity, high conductivity and soft magnetism. In Chapter 3, we firstly mentioned that organic hetero-structured micro- or nanomaterials are widely attractive on account of its extensive applications in lasers, bipolar transistors, field effect transistors and solar cells. In our work, we focus on the diverse microrods assembled from π-conjugated small molecules, especially in the construction of heterogeneous organic heterojunction materials with specific components distribution. Two novel kinds of heterostructure, multilayer core-shell structured heterojunction and heterogeneous rod-tail helix were fabricated and developed both via a stepwise seeded-growth route, in which the different constituents possess different colors of luminescence. Through the media of fluorescence microscopy and confocal microscopy, the core-shell hetero- structures can be observed, testified and recorded quite distinctly. Furthermore, the prepared method by employing seeded-precursor could give us a revelation about constructing more sophisticated and functional organic luminescent heterogeneous materials. Chapter 4 focuses on the syntheses and characterization of eight cyclometalated iridium(Ⅲ) complexes, Ir(TPY)2(Dipyrrinato), Ir(PIQ)2(Dipyrrinato), Ir(Ligand 1)2(Dipyrrinato), Ir(Ligand 2)2(Dipyrrinato), Ir(Ligand 3)2(Dipyrrinato), Ir(PPY)2 (Dipyrrinato), Ir(m-PPY)2(Dipyrrinato) and Ir(PPY-m)2(Dipyrrinato). As is known, iridium(Ⅲ) complexes can exploit the energy of both 25% singlet and 75% triplet excited states. Due to their highly efficient applications in phosphorescent OLEDs, these materials are considered as one of the potential candidates for flexible display screen as well as clearing luminary. Among those full-color light-emitting iridium(Ⅲ) phosphors, near-infrared (NIR) phosphors are broadly utilized in phototherapy as well as biosensors. Herein, our eight synthetic cyclometalated iridium(Ⅲ) complexes all gave photoluminescence at 680 - 700 nm in solution, which could be attributed to the NIR region. We continuously tune the extensive conjugation on the C^N ligands in order to make longer wavelength emitting phosphors. The HOMO and LUMO of eight synthetic iridium(Ⅲ) phosphors were also calculated according to their cyclic voltamograms (CV). The design and preparation strategy in this thesis can inspire us to develop near-infrared as well as higher-performance organometallic phosphors.

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