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Cyclodextrin receptors have been employed to build supramolecular systems consisting of metal and organic photo/redox-active components. The photo-induced communication between redox-active units assembled in water via non-covalent interactions is established. Receptor ligands consisting of a β-cyclodextrin functionalised with a terpyridine or bipyridine unit, ttp-β-CD and mbpy-β-CD respectively, and their ruthenium(II) metal complexes [(ttp-β-CD)Ru(ttp)][PF₆]₂, [(ttp­β-CD)Ru(tpy)][PF₆]₂, [(ttp-β-CD)₂Ru][PF₆]₂, and [(mbpy-β-CD)₃Ru][PF₆]₂ are synthesised and fully characterised. Addition of redox active guests, such as quinones, to aqueous solutions of [(ttp-β-CD)Ru(ttp)][PF₆]₂or [(mbpy-β-CD)₃Ru][PF₆]₂, leads to a quenching of the ³MLCT emission which is attributed to intramolecular electron transfer from the ruthenium centre to the non-covalently bound guest in the cyclodextrin cavity. Metallo acceptor guests with a hydrophobic binding unit to assure assembly in the cyclodextrin, such as [(biptpy)Os(tpy)][PF₆]₂are investigated to study metal-metal communication. Time resolved spectroscopy and steady state experimental results are given. Binding studies with permethylated β-cyclodextrin to obtain association constants of anthraquinone-4-sulfonic acid, anthraquinone-4-caxboxylic acid and benroquine are performed by emission<i> </i>spectroscopy. Inclusion of a biphenyl unit in permethylated β-cyclodextrin is studied by UV/Vis spectroscopy, using 4’-(<i>p</i>-biphenyl)-2,2’:6’2”-terpyridine and Zn(biptpy)][PF₆]₂as model compounds for a 1:1 and 1:2 inclusion complex formation respectively. The assembly of cyclodextrin recognition sites in macromolecular structures by using simple coordination chemistry is presented. Tris-cyclodextrin complexes are prepared by reaction of the bidentate ligand mbpy-β-CD with iron(II) and rutheniuim(II) or by reaction of the tertendare ligand ttp-β-CD with europium(III). Bis-cyclodextrin complexes axe obtained by addition of iron(II) to ttp-β-CD. The characterisation of the compounds and their luminescent properties are reported.

The self-assembly of model peptides has been studied using Brownian dynamics (BD) computer simulations. In particular, a bead-spring coarse-grained model (a model in which a set of molecules is represented by a single bead and the bonding interactions by simple spring forces) has been designed to mimic small proteins called ‘silaffins’ observed to favour the formation of amorphous silica nanospheres in vitro and involved in the biomineralisation of certain diatoms cell walls. The coarse-grained model used in the simulations keeps the primary characteristics of the silaffins, these being a 15 amino acid hydrophilic backbone and two modified lysine residues near the ends of the backbone each carrying a hydrophobic polyamine chain. In the simulations, the model peptides self-assemble to form micelles, networks of strands, or discontinuous structures depending on the peptide concentration and the system temperature. The simulation results show that over a broad range of peptide volume fractions (0.05-25%) the characteristic structural lengthscales fall in the range 12-45 nm. This suggests that the self-assembled structures observed may act as either nucleation points or scaffolds for the deposition of 10-100 nm silica-peptide composite building blocks from which diatom skeletons and synthetic nanospheres are made. A systematic coarse-grained computer-simulation study of the role of putrescine homologues H₂N-(CN₂)n-NH₂ on silica morphogenesis is presented. Brownian dynamics simulations of model putrescine are performed highlighting the importance of aggregation on the degree of silica deposition. The results suggest that over a broad range of solute concentration (15-50 mM) the characteristic lengthscales of the observed self-assembled structures correlate with structural properties of the silicas observed in vitro.

The tetraheme cytochrome <i>c</i>₃ from <i>Desulfovibrio vulgaris </i>Miyazaki F is involved in sulphate reduction. It contains four <i>c-</i>type hemes covalently bound to a single polypeptides of only 107 amino acids. The protein surface is highly positively charged at physiological pH with a prevalence of lysine residues. All four hemes are bis-histidine ligated and their reduction potentials are very low, ranging form -239 to -358 mV at neutral pH. With a cyclic heme arrangement and their partial exposure to solvent, cytochrome<i> c</i>₃ can transfer electrons in all directions. The purpose of this work is to develop novel methods of controlling the crosslinking selectivity of proteins constructing biological “nanowires” with cytochrome <i>c</i>₃ modules. The crosslinking functional groups are bismaleimide derivatives and the cysteine thiol. And construction strategies involve the electrostatic selection by controlling the surface charge distribution regulating the protein crosslinking, and the use of protein-peptide recognition (i.e. Calmodulin and its binding peptide) to block/protect the crosslinking sites. The electrochemical properties of cytochrome <i>c</i>₃ are also exploited by covalently attaching it to active centre buried redox enzymes (i.e. cytochrome P450 BM3 heme domain) and electrodes to form unique bioelectronic components, which could facilitate the electron transfer between enzymes and electrodes.

Molecular modelling techniques have been applied to the investigation of structures of stable complexes which form when organic ligands bind to lightly oxidised metal surfaces. Such complexes are thought to protect metal surfaces and account for modification effects in applications such as corrosion protection, adhesion promotion and lubrication enhancement. Three separate projects were undertaken: a) benzotriazole as a corrosion inhibitor for copper, b) 3-(4-methylbenzoyl)-propionic acid as a corrosion inhibitor for iron/steel, and c) 1,2,3,-trihydroxybenzne or pyrogallol derivatives as dispersants for aluminium trihydroxide. Surface-sensitive physical experimental techniques do not currently provide structural information from such interfaces with a sufficient level of resolution. For any given system involving a metal substrate and a surface-active ligand, the fundamental approach involved simulating the chemisorption of a monolayer of the organic onto the oxidised metal surface. Models for this were obtained by considering prominent (hydr)oxide compounds and assessing their likely surface structures on the merits of crystal morphology observations and calculations. The organic active was attached to those surfaces in chemically realistic coordination modes as observed in relevant polynuclear crystal structures. Some of these were determined locally and others were obtained from the Cambridge Structural Database. Interfacial models were treated with force field-based molecular mechanics and dynamics methods which were customised for this application. Results were assessed in terms of conventional coordination stereochemistry and the implications that surface packing arrangements would have on surface protection.

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The synthesis and characterisation of a range of ligands capable of binding four or five transition metals has been explored in an attempt to synthesise a model for the oxygen evolving centre of photosystem II. Difficulty was encountered in isolating the pure, deprotected ligands. A ligand based on 1,4,7-triazacyclononane containing three alcohol donors was isolated, investigated and compared against similar ligands. A series of copper N-oxide Bis(N,N'-Disalicylalethylenediamine) derivatives were synthesised and fully characterised. The electron paramagnetic resonance spectra (EPR) of these complexes were measured and compared in order to determine the relative Lewis acidity of the central metal. Electron nuclear double resonance (ENDOR) spectra were recorded of the complexes they revealed the catalytic activity of these complexes towards cyclopropanation was tested with a variety of styrene derivatives. A zinc N-oxide Bis(N,N'-Disalicylalethylenediamine) derivative was extensively studied for enantiomeric discrimination of a small amine, methylbenzyl amine (MBA). This was monitored via lH NMR titrations in three different solvents, CDCI3, CD3CN and CD3OD. The ability of MBA to displace a solvent molecule from the coordination sites was investigated and the data inserted into a kinetic model. Chloroform was found to have the weakest interaction while methanol had the strongest. The difference in affinity of ii-complex for i-MBA over S-MBA was also investigated and a preference for the heterochiral mixture was revealed.

The binding of a range of biologically prevalent anions to several novel lanthanide(III) complexes has been studied by emission spectroscopy, (^1)H-NMR and mass spectrometry. In each case, the resultant solution adduct and the mode of anion binding was characterised through analysis of spectral response. Following the first chapter, in which relevant background work and literature reports are discussed, the novel lanthanide(III) complexes described herein are separated into three chapters. Chapter 2 describes a range of complexes bearing a pendant azaxanthone or aza-thioxanthone derived chromophore. Binding of anions was examined largely through sensitised emission, additionally the cellular localisation and toxicity profiles of each complex was studied. Of particular interest was the discovery of a family of complexes that localised within the mitochondria of the cell lines examined, and exhibited pC0(_2) dependent luminescence, notwithstanding protein quenching. Chapter 3 describes the synthesis and evaluation of two stereoisomeric dimeric complexes, in which the conformation of each was controlled by the differing relative stereochemistry of their linking unit. A range of luminescence and NMR studies was performed to establish the relative affinities of these complexes for selected anionic species, and to compare their binding properties to that of the related monomeric complex. Chapter 4 describes the immobilization of two related complexes onto various solid-phase supports. The ability of the immobilized complexes to selectively bind to, retain then release phospho-anions on addition of a competitive aqueous anionic buffer is examined. The utility and advantages of using such materials as tools for the enrichment of phospho-peptides is discussed in relation to previously published procedures and materials.