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Hydrogen Bonding Interactions of Ferrocene-peptides: From Molecule to Large Scale Assemblies

The main goal of this thesis was to explore the role of H-bonding interactions in ferrocene peptide conjugates at the molecular and supramolecular level. With the help of detailed spectroscopic and crystallographic studies, the intermolecular association of a range of conjugates was studied and described here. It was shown that C-terminal modifications directed the supramolecular assembly. In the case of Fc[CO-Gly-Val-OH]2, the C-terminal carboxylate group directed intermolecular interactions, causing formation of a supramolecular architecture that was characterized by large solvent-filled hydrophobic channels. In the absence of this directional group, as was the case in Fc[CO-Leu-Val-OMe]2 extended β-sheets were formed. Hierarchical self-assembly of disubstituted ferrocene peptide conjugates possessing Gly-Val-Phe and Gly-Val-Phe-Phe peptide substituents gave rise to nano- and micro-sized assemblies. Spontaneous self-assembly of Fc-peptides through intra-and intermolecular hydrogen bonding interactions induced supramolecular building blocks, which further associated to fibers, large fibrous crystals, and twisted ropes. Next, intermolecular H-bonding interactions were studied using a surface-based approach. A fragment of the amyloid-beta (Aβ) peptide was bound to a gold surface through a C-terminal Cys. Various aspects of the peptide film were examined using different electrochemical and surface analytical techniques. The interaction of Congo red and of Lys-Leu-Val-Phe-Phe with the immobilized Aβ fragment was studied using electrochemical methods, showing responses that indicated intermolecular interactions. This surface approach was used to probe the interaction of a series of ferrocene peptides (Fc-CO-Leu-Val-Phe-Phe-OX and Fc-CO-Lys(Boc)-Leu-Val-Phe-Phe-OX with X=H and Me) with the surface-bound Aβ fragment. Biomolecular interactions between Fc-peptides and the Aβ-modified surface were studied by electrochemical methods. The current response of the Fc redox process was modulated by the interaction with the Aβ-modified surface.

Identiferoai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OTU.1807/33930
Date10 December 2012
CreatorsBeheshti, Samaneh
ContributorsKraatz, Heinz-Bernhard
Source SetsLibrary and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada
Languageen_ca
Detected LanguageEnglish
TypeThesis

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