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Title: Novel functional materials based on perylene diimides using ionic self-assembly
Author: Echue, Geraldine
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2012
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A library of materials based on the ionic self-assembly (ISA) of a chiral perylene diimide (POI) with oppositely charged surfactants were prepared and characterised. Three classes of structurally related surfactants were used, so as to establish a set of design rules for the preparation of materials. The self-assembly behaviour of the materials in solution and the solid state was investigated; results and obtained structures were evaluated in terms of the influence of surfactant structure, solvent, concentration and non-covalent interactions. A general methodology was developed to synthesise a chiral amine, from the amino acid precursor Lphenylalanine, for the production of the chiral POI building block used throughout this study. Circular dichroism confirmed that this synthesis proceeded without racemisation and therefore represents a new route for the production of chiral amines from appropriate amino acids. It was found that the molecular chirality of the building blocks was expressed in the supramolecular chirality of the produced ISA materials in both solution and thin films. By careful selection of solvent, concentration and surfactant, the supramolecular chirality could be tuned to yield both right- or lefthanded helical arrangements. Self-assembled solid-state structures of the complexes were characterised by electron microscopy and initial investigations were made into the solventdependent mesophase properties of these materials using polarised optical microscopy and X-ray diffraction. In addition to the synthesis of chiral ISA materials, two novel lyotropic POI systems were prepared and proof-of-principle investigations carried out into the application of these mesophases as novel alignment media in NMR. Using L-proline as a model test substrate, it was demonstrated that POls could orient this substrate and thus allow the measurement of order-dependent NMR parameters such as residual dipolar couplings (ROCs). The magnitude of the couplings observed are highly comparable to those reported for established alignment media. The low cost, facile preparation and comparable results from these POI-based systems present an exciting opportunity with broad potential impact for the measurement of NMR anisotropic properties. Keywords: Perylene diimide, chiral, ionic self-assembly, chiral resolution agents, alignment media, NMR, residual dipolar coupling, surfactant, self-assembly.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available