The first part focuses on the conversion of limonene to dimethylstyrene in order to produce polymeric materials. Limonene was dehydrogenated over a palladium catalyst with an anhydrous solvent and base using copper chloride as oxidant under argon atmosphere at 120 °C. Solvent, base, catalyst and reaction conditions were varied in an attempt to improve conversion to DMS. The conditions for conversion to dimethylstyrene without by-products were established. Alternative and cheaper bases and catalysts were identified. It was observed that 69% of the polymer obtained was insoluble in organic solvents while the soluble part had an average MW of 3800. The second part focuses on the polymerization of chlorogenic acid, a potato waste product, by enzyme - based solution polymerization as a potential biomaterial. Three environments were used: (i) phosphate buffer pH7 and methanol, (ii) unbuffered water- methanol, and (iii) aqueous buffer pH7 with poly(ethylene glycol) template. To compare and understand this reaction, chlorogenic analogues were studied. Phenol polymerized to high yields in all environments. 2,3 - dihydroxybenzoic acid, catechol and 2,4- dihydroxybenzoic acid polymerized to moderately high yield in (i). Caffeic acid polymerised with 23% yield in (ii) but both caffeic acid and chlorogenic acid produced higher yields when the templating method (iii) was used. The third part of the project focused on the polymerization of oleic acid obtained from mango seed butter. Oleic acid was first purified from mango butter, then esterificated using 1,3 - propanediol, resorcinol and orcinol. The resulting di-esters were epoxidized and crosslinking reactions were attempted using anhydride and amine curing agents. All polymers obtained were in form of waxes and dissolved in organic solvents, with the expection of epoxidized resorcinol di -ester cured using phenylenediamine. Finally a study of the interaction of all the monomers with montmorillonite clay was made. Chlorogenic acid and oleic acid intercalated into the unmodified clay layers while an organoclay was used with D -limonene and dimethylstyrene to obtain intercalation.

Propargylic alcohols are easily accessed through the reaction of alkynes with aldehydes and ketones. The 1,3-isomerisation of propargylic alcohols to enones is known as the Meyer-Schuster rearrangement. We have demonstrated efficient room temperature reaction conditions for the Au-catalysed Meyer-Schuster rearrangement (>30 examples) of a wide array of secondary and tertiary propargylic alcohols to the corresponding enones in generally excellent yields and with high E-selectivity. Primary propargylic alcohols rearrange to give highly reactive terminal enones, which can undergo conjugate addition reactions with nucleophiles to access β-substituted products through suitable one-pot procedures. Diethyl acetal substituted propargylic alcohols can be used to access synthetically useful 3-alkoxy furans in the presence of Au in high yield. The use of silver as a catalyst promotes substitution of the propargylic alcohol with various oxygen, carbon and nitrogen nucleophiles. β-Hydroxyketones can be accessed via a Au-catalysed hydration, employing phenols or acidic alcohols as the reaction additive.

Herein we report the solvothermal decomposition of a range of metal dithiocarbamate complexes for the synthesis of metal sulfide nanoparticles. Metal sulfides exist in a variety of structural phases, some of which are known to be catalytically active towards various processes. The aim of this work was to synthesise a variety of different metal sulfide phases for future catalysis testing, particularly the iron sulfide greigite (Fe3S4, a thiospinel containing Fe2+ and Fe3+) which is to be tested for CO2 reduction. A range of metal dithiocarbamate complexes were synthesised and Chapter 2 focusses on the synthesis of iron dithiocarbamates. Both iron(II) and iron(III) complexes were synthesised, the latter being a facile, open bench reaction producing a range of [Fe(S2CNRR’)3] complexes. Iron(II) bis(dithiocarbamates) are extremely air sensitive therefore carbonyl protected [Fe(S2CNRR’)2(CO)2] complexes were prepared for ease of use as precursors. The stability of the complexes was tested by TGA to ensure they were suitable precursors for metal sulfide synthesis, i.e. that the carbonyl ligands were sufficiently labile to leave the complexes before decomposition, which proved to be successful. In the following Chapter these iron dithiocarbamate complexes were solvothermally decomposed, but interestingly a combination of iron(II) and iron(III) precursors did not produce greigite as expected, but pyrrhotite (Fe7S8, containing only Fe2+). Systematic studies into the effect of decomposition temperature, precursor concentration and precursor type, on the phase and morphology of the resulting iron sulfide nanoparticles were performed on the iron(III) dithiocarbamate precursor. The phase was found to be highly dependent on both concentration and temperature. The use of a redox active additive, thiuram disulfide, on the decomposition was also investigated and found to have a significant effect, promoting the formation of the metastable greigite phase. Chapter 4 examines the nickel bis(dithiocarbamate) decomposition system to see if its behaviour was consistent with trends observed in the iron case. In general, similar trends were observed in the phase and morphology of the nickel sulfides when the decomposition parameters were varied, metastable phases were observed at lower temperature and higher concentration. The effect of thiuram disulfide on the system was greater, however, than in the iron case, whereby an additional nickel sulfide phase (NiS2) was observed at high concentration in the presence of this additive. Chapter 5 deals with a broader range of metal dithiocarbamate systems, to attempt to elucidate whether or not the trends seen for nickel and iron are universal for metal dithiocarbamate precursors. The Co, Cu, Zn and In dithiocarbamate systems were examined with and without thiuram disulfide, and some effect were seen on the phase of metal sulfide nanoparticle formed, but only at high concentration in the presence of the additive. Mixed-metal studies were performed to investigate the suitability of metal dithiocarbamates as precursors to ternary metal sulfides, and success was observed for iron-nickel, cobalt-nickel and iron-copper sulfides, though the iron-zinc and iron-indium systems only produced binary sulfides. The final Chapter looks into the metal dithiocarbamate decomposition mechanism in detail, using [Ni(S2CNiBu2)2] as a model system. NMR, in situ UV-vis, MS and powder XRD are all employed to probe the mechanism, in conjunction with XAS and computer modelling which was performed by others. The mechanism was found to rely heavily on an intermediate formed from amide exchange between the dithiocarbamate backbone and solvent amine, indicating the solvent plays an extremely significant role in the solvothermal synthesis of metal sulfides from dithiocarbamate precursors.

Micro structured, high surface energy titanium (Ti) has been shown to be an effective substrate for osseointegration of an implant with surrounding bone tissue. The aim of this project is to test the hypothesis that the enhanced osteogenic differentiation and function of multipotent stromal cells (MSCs) in response to modified Ti surfaces is caused by a selection event within the population. The first cell type capable of producing new bone on an implant after placement are the MSCs which circulate in the bloodstream and are recruited to the site of tissue damage. The reservoirs of these cells are heterogeneous in nature, consisting of a mixture of cells with varying differentiation abilities. In order to utilise these cells and to reduce the chance of unwanted events during regenerative therapies, the selection of a subset of cells that is truly multipotent is required. The behaviour of the cells is altered by the modifications to the Ti surfaces and this underpins the differences seen in clinical performance. Stem cells from various tissues have been used to seed modified Ti surfaces in order to analyse these changes in cell behaviour. Combined with subsequent expansion, selected cells could be used for regenerative or bone engineering applications. The outer atoms of Ti form a stable, passive surface oxide layer that serves as a substrate for the formation of an osseous bond between tissue and fixture. Initial interactions occur between adhesion proteins on bone cell surfaces and the metal oxide layer. I discuss the contribution of van der Waals forces on molecular chemistry at the TiO2 [110] surface. The nano-roughened, hydrophilic surface of Ti has been attributed to improved biocompatibility. Spectroscopic and computational techniques demonstrate that the UV induced hydrophilic conversion of Ti occurs through surface hydroxyl group reorganisation. This enhances the adsorption effect of peptide adhesion domains. Thus, altered chemical interactions between simple molecules and the crystal surface determines the differential cellular osteogenic response to rough, hydrophilic Ti surfaces, through the increased expression of extra cellular matrix (ECM) adhesion components.

This thesis presents a comprehensive computational study of the bulk and surface properties of two major iron-bearing minerals: hematite (α-Fe2O3) and mackinawite (tetragonal FeS), and subsequently unravels the interactions of a number of environmentally important molecules with the low-Miller index surfaces of these iron-bearing minerals using a state-of-the-art methodology based on the density functional theory (DFT) techniques. First, we have used the Hubbard corrected DFT (GGA+U) calculations to unravel the interactions of a single benzene molecule with the (0001) and (01 2) surfaces of α-Fe2O3 under vacuum conditions. α-Fe2O3 is correctly described as a charge-transfer insulator, in agreement with the spectroscopic evidence when the optimized value for U = 5 eV is employed. The benzene molecule is shown to interact relatively more strongly with the (01 2) surface via cation-π interactions between the π-electrons of benzene ring and the surface Fe d-orbitals than with the (0001) where van der Waals interactions are found to play important role in stabilizing the molecule at the surface. In the second part of this thesis, DFT calculations with a correction for van der Waals interactions (DFT-D2 scheme of Grimme) have been used to simulate the bulk properties, surface structures and reactivity of layered mackinawite (FeS). We demonstrate that the inclusion of van der Waals dispersive interaction sensibly improves the prediction of interlayer separation distance in FeS, in good agreement with experimental data. The effect of interstitial impurity atoms in the interlayer sites on the structure and properties of FeS is also investigated, and it is found that these contribute considerably to the mechanical stability of the FeS structure. From the geometry optimization of the low-Miller index surfaces of FeS, we have shown the (001) surface terminated by sulfur atoms is by far the most energetically stable surface of FeS. The calculated surface energies are used successfully to reproduce the observed crystal morphology of FeS. As an extension to the surface studies, we have used the DFT-D2 method to model the adsorption mechanism of arsenious acid (As(OH)3), methylamine (CH3NH2) and nitrogen oxides (NO and NO2) molecules on the low-Miller index FeS surfaces under vacuum conditions. The As(OH)3 molecule is demonstrated to preferentially form bidentate adsorption complexes on FeS surfaces via two O‒Fe bonds. The calculated long As−Fe and As−S interatomic distances (> 3 Å) clearly suggest interactions via outer sphere surface complexes with respect to the As atom, in agreement with the experimental observations. The growth modifying properties of methylamine, the capping agent used in the synthesis of FeS, are modelled by surface adsorption. The strength of the interaction of CH3NH2 on the different FeS surfaces is shown to increase in the order: (001) < (011) < (100) < (111) and an analysis of the nature of bonding reveals that the CH3NH2 molecule interacts preferentially with the surface Fe d-orbitals via the lone-pair of electrons located on the N atom. Our simulated temperature programmed desorption process shows that methylamine is stable up to about 180 K on the most reactive (111) surface, which is comparable to the experimental desorption temperatures predicted at metallic surfaces. Finally, the catalytic properties of FeS as a nanocatalyst for the adsorption, activation and decomposition of environmentally important NOx gases have been explored, where we consider the nature of binding of the NOx species to the FeS surfaces and their dissociation reaction mechanisms.

The Drug Discovery project is centred on the design, synthesis and characterisation of novel positive allosteric modulators (PAMs) for α7 nicotinic receptors (nAChR). These receptors are widely found in the central and peripheral nervous systems and are involved in a range of physiological processes. They are active targets for the treatment of pain as well as psychiatric and neurodegenerative disorders. Nicotinic receptors are ion channels which open and allow ions to flow in or out of the neuron upon binding of an agonist. Positive allosteric modulators (PAM) enhance the receptor’s response to the binding of the endogenous agonist, giving greater ion flow than the effect for binding of the agonist alone. A number of novel heterocycles were designed and synthesised and their effect on the α7 nAChR evaluated. The nitrogen heterocycles gave varied pharmacological effects on the receptor and small changes in structure led to large changes in pharmacological activity. During the course of this project we have discovered Au-catalysed and non-catalysed processes for the dihalohydration of alkynols to form diiodoketoalcohols, dichloroketoalcohols and dichlorolactols.

The overall aim was to produce a magnetolipopolyplex, a multimodal-imaging agent, for the detection of cancer. Iron oxide nanoparticles, which are used as negative contrast agents in magnetic resonance imaging were encapsulated into biocompatible liposomes alongside plasmid DNA and targeting peptides. The plasmid DNA provides the potential for optical imaging and PET through the inclusion of the red fluorescent protein reporter gene and the human sodium iodide symporter, which can be radiolabelled. The inclusion of targeting peptides in the formulation of the magnetolipopolyplexes allows for its site-specific delivery. Initially, poly(L)lysine (PLL) was bio-conjugated to the surface of commercially available iron oxide nanoparticles (MNPs) coated with dextran, rendering the surface charge of the MNPs positive and thus allowing for the electrostatic binding of negatively charged plasmid DNA (pDNA) to the surface. Two plasmids were produced; one coding for the red fluorescent protein (RFP gene) for optical imaging and the other with both RFP and the human sodium iodide symporter (hNIS) which can be radiolabelled for PET imaging. Once the pDNA was electrostatically bound to the PLL on the surface of the MNP, the functionalised MNP was encapsulated into a cationic liposome in order to produce a biocompatible means of delivering the liposome both in vivo and in vitro. Unfortunately, poor results were obtained for the in vitro transfections, which were attributed to their large size and negative surface charges. To overcome the issues faced by the formulation method and in vitro transfections studies, an alternative method of magnetolipopolyplex formulation was carried out. Here, negatively charged MNPs, coated with either carboxymethyldextran or citric acid, were added to preformulated cationic liposomes. The negative surface charge of the MNP allowed the successful diffusion of the MNPs through the positively charged lipid membrane to form magnetoliposomes. To these magnetoliposomes co-condensed pDNA and K16 peptides was also added, ultimately forming magnetolipopolyplexes. Dynamic light scattering and zetapotential characterisation data confirmed the successful formulation of the magnetolipopolyplexes and subsequent in vitro transfection studies were carried out to establish the transfection efficiency of the magnetolipopolyplexes by measuring the RFP expression of the pDNA. SQUID magnetometry data was obtained to determine the concentration of the MNPs taken up into the cells following the incubation of the cells with the magnetlipopolyplexes. The encapsulation of MNPs, pDNA and peptides into liposomes demonstrates the successful formulation of a multimodal-imaging agent with the potential for optical, PET and MRI imaging modalities.

Recent years have seen research into non-metal electrocatalysts emerge, as many metallic sources become scarce and associated environmental issues are considered. This thesis explores the electrochemical ability of two metal-free electrocatalysts: carbocatalyst nanodiamond and biocatalyst Saccharomyces cerevisiae (baker’s yeast) to catalyse electrode reactions when immobilised on a boron-doped diamond electrode. The electrode reaction of interest is the Fe(II)/Fe(III) redox cycle in the form of ferro/ferricyanide and the ferrocene derivatives: -methanol, -dimethanol, -carboxylic acid, and -dicarboxylic acid. The electrochemistry of the ferrocene derivatives at a nanodiamond modified electrode yielded significantly enhanced catalytic currents compared to those observed previously with highly charged inorganic complexes; a ten-fold current enhancement compared to the four-fold increase seen for Fe(CN) 4 – 6 with 5 nm nanodiamond. This is a direct result of adsorption of the ferrocenium cation onto the nanodiamond surface which participates in an adsorption-mediated catalytic cycle. The magnitude of the catalytic current was found to decrease in the order FcMeOH > Fc(MeOH)2 > FcCOOH Fc(COOH)2. A trend influenced by the ferrocene derivatives redox potential and its physical attractive or repulsive interaction with nanodiamond surface. Nanodiamond particle size and hence the surface functionality density limits the maximum achievable catalytic currents; with current enhancement decreasing in the order 5 nm > 10 nm > 100 nm > 250 nm > 1000 nm. Mediated extracellular electron transfer from S. cerevisiae using FcMeOH was able to distinguish between respiratory and fermentation metabolism and the effects of pressure on yeast fermentation. However, attempts at in-situ measurements were hindered by the weak yeast-electrode attachment. Finally, SECM was used to quantify electron transfer between the catalyst and solution redox species. While successful for nanodiamond, experimental design issues prevented the quantification of reduced mediator production rate from a single yeast cell.

Water/solid interfaces are of utmost importance to a number of technological processes. Theoretical studies, based on ab initio approaches are suitable to unveil processes occurring at water/solid interfaces and can therefore be instrumental to delineate guidelines to improve the efficiency of these processes. In this thesis we study several systems of current interest using ab initio methods based on density functional theory (DFT). By going often beyond the use of standard DFT methods and approximations we have provided insights into processes occurring at water/solid interfaces under ambient conditions and in non stoichiometric conditions. Specifically, we will investigate the interactions between water and ZnO, an important metal-oxide especially used in industry to produce methanol. One of the most mportant results of this study is that proton hopping is dramatically enhanced under wet conditions compared to ideal ultra-high vacuum conditions. Also, we will compute the friction between liquid water in contact with 2-D layered materials, and delineate the guidelines on how to alter the friction coe cient in membranes used for desalination or osmotic power harvesting. Finally, in collaboration with Geoff Thornton's group we have investigated the role of defects on the surface chemistry of the rutile TiO2(110), which is the model oxide surface used in photocatalysis applications. On the whole, in this work we have used ab initio methods to reduce the gap between the ultra-high vacuum-style studies of adsorption on perfect defect-free surfaces and the complex behaviour of liquid/solid interfaces under technologically relevant conditions.

The work undertaken in this project has focused on developing methodologies to determine the atomic architecture of catalytic materials over short-, medium- and long-range structures. The main objective of the work has been to employ in situ techniques at synchrotron sources to enable development of new analytical methods which will provide a unique opportunity to characterise multi-phase systems. The reduction behaviour of a model cobalt Fisher-Tropsch catalyst was investigated using in situ combined XANES/EXAFS/XRD techniques where the sensitivity and selectivity of X-ray absorption spectroscopy (XAS) was exploited to obtain detailed structural information on the dynamic local structure. From these studies a new model on the structure of Co/Al2O3 catalyst in the reduced form has been proposed. Model metallic cobalt systems consisting of both HCP and FCC structures were characterised in detail using both pair distribution function (PDF) and XAS techniques. In-depth structural knowledge over the short-short and medium-range order has been garnered through multi-cluster modelling of EXAFS and PDF data providing new insights into the cobalt phase composition and phase transformation. In situ PDF studies were carried out on a Pd/Al2O3 model catalyst to determine, quantitatively, the phase composition at various temperatures during which PdO ↔ Pd transformations occur. Differential PDF analysis was successful in characterising the metal particles of interest despite the significant contribution from the disordered support phase. Supporting in situ XAS studies were undertaken and the findings were in good agreement with those from PDF. Finally, using low energy chlorine K-edge XAS, real Vehicle Emission Control (VEC) catalysts were studied in order to determine the speciation of chloroplatinate compounds within fresh and road aged catalysts. With a high sensitivity and selectivity, an investigation of this type demonstrated the advantages of performing XAS speciation studies at the chlorine K-edge.