No description available.

The general purpose of this thesis is concerned with the intricate interactions of pure aluminium species with biomolecules. Pure aluminium reference systems (aluminium monomers, Keggin aluminium polyoxocations - Al13 and Al30, and aluminium hydroxide suspensions) were used for systematic mechanistic studies of the sol-gel transformation of aqueous solutions of aluminium-ions into aluminium (oxy) hydroxides induced by the addition of a 'soft base' - Trizma-base, which does not ionize fully in an aqueous solution. The conversion proceeds via forced hydrolysis-condensation of aluminium-ions into molecular clusters, structural conversion of aluminium Keggin-like polynuclear clusters into nanoparticles of aluminium (oxy) hydroxide, aggregation of primary nuclei of aluminium (oxy) hydroxide into larger clusters and finally the 'arrested growth' of the aggregates with the formation of the three-dimensional gel network. The next part of the study concentrated on the development and the optimisation of a potentiometric method for the determination of the 'formal' hydrolysis ratio of aluminium-containing solutions. The method made it possible to establish the aluminium speciation of the selected systems. The interactions of aluminium species with three model biomolecules - lactic acid, hen egg lysozyme and porcine mucin - were investigated. Aluminium and lactic acid underwent a strong coordination in aqueous solutions, with increasing concentrations of lactic acid appearing to force all the aluminium species initially introduced to convert into monomers and dimers as a result of an acidic hydrolysis. Subsequently, the resulting hydrolysed products formed new aluminium-lactate chelates. The evolution of both the inorganic and biomolecular phases of the lysozyme-aluminium systems demonstrated that specific charge-stabilised bioinorganic assemblies involving aluminium species and lysozyme formed. The chemical and structural alterations of the protein on interaction with the inorganic species showed that the interactions occurred. The interactions of aluminium with mucin appeared predominantly electrostatically driven. The formation of the aluminium-mucin entities modified the native conformation of the protein: initially organised into b-sheet structure, mucin, within the complexes, acquired a more compact organisation involving intermolecular bonding. Furthermore, in the case of the aluminium hydroxide systems, the established complexes were ordered into sheet-like structures. Although the level of concentrations of aluminium and biomolecules exceeded those normally found in the human body and environmental media, we believe that the better understanding of aluminium species-biomolecule interactions would be of benefit to those working in the biomedical and environmental sciences.

X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Fine Structure spectroscopy (XAFS), X-ray Diffraction (XRD) and Pyridine Adsorption Spectroscopy (PAS-S) were used to investigate the solid superacid high surface area AIF3 (HS AIF3). The aim of this work was to establish correlations between Lewis acidity, surface area, geometric and electronic structure of the materials. The aim of this study was to obtain structure/activity relationships for AIF3 materials synthesised by different routes, with a view to future tailoring of the properties of these materials to potential industrial applications.

- / -