The origins of these investigations are in the pursuit of heterocycles containing an N-O bond. This project as a whole focusses on developing earlier chance observations made by previous members of the Knight Research Group. Chapter 2 focusses on the synthesis of isoxazoles: 5-membered aromatic rings containing a nitrogen to oxygen bond. The origin of this project was the unexpected observation of a small percentage of isoxazole products in the Group’s earlier synthesis of isoxazolines, which were thought to be the oxidation products arising from using silver nitrate as a catalyst for those cyclisations. It has now been found that by using an excess of silver nitrate, isoxazoles can be selectively formed from the same hydroxylamine precursors. Chapter 3 centres on the viability of obtaining unusual 6-endo-trig products from the iodocyclisation of unsaturated tert-butyl carbonates. This Chapter is connected to the theme of N-O chemistry, as the tert-butyl carbonate starting materials were the unexpected products of a synthesis that had been designed to form hydroxylamines. The initial discovery of these unexpected 6-endo products on iodocyclisation was expanded upon to produce a series of cyclic carbonates with a procedure optimised to maximise the yield of this desired structural isomer. Chapter 4 concentrates on building saturated N-O rings onto existing cyclic systems, including transannular cyclisations - investigating previous reports of rearrangement of N and O during cyclisation and working towards a synthesis of the core-structure of the natural product Histrionicotoxin. These schemes prove the utility of this acid-catalysed hydroamination methodology in building heterocycles and the chiral products that can be gleaned from them. For the most part, this project has been concerned with methodology - solving problems and optimising key-step procedures - which can be applied to complex target molecules.

Organic electrochemistry provides a straight forward and efficient method for the generation of a wide variety of reactive intermediates. It does however; suffer from limitations such as the need for supporting electrolytes. The scale up process can also be difficult from preparative to large scale batch syntheses. Interest in the field of microreactor technology has grown over the last 10 to 20 years. This is due to increasing efforts in making organic chemistry a “greener” process, using less solvents and expensive chemical reagents. Combining these two fields of chemistry provides a platform for making organic electrochemistry more appealing to chemists and industry, although the technology is still in its infancy. As there are no commercially available microreactors for electroorganic synthesis, one has been designed and fabricated before it can be used for electroorganic syntheses in a flow environment.

This thesis discusses the synthesis, characterisation, and reactivity studies of a range of new chiral calcium complexes supported by various polydentate N-donor ligands and their suitability as catalysts for intramolecular hydroamination. Chapter One outlines the case for developing organocalcium complexes, including a general overview of their current application to a variety of heterofunctionalisation reactions. Chapter Two introduces the chiral ethylene diamines which are extensively used as calcium supporting ligands and later as precursors for the synthesis of bisimidazoline and potential imoxazoline ligands. Chapter Two provides details of the diamine synthesis and includes studies related to racemisation concerns of the chiral centre. Chapter Three discusses novel calcium complexes supported by the chiral ethylene diamine analogues presented in Chapter Two. Complex synthesis, characterisation, and catalytic performance in intramolecular hydroamination is probed and discussed. Chapter Four details a range of new bisimidazoline ligands and their employment as supporting ligands on calcium. The catalytic performance of the resulting complexes in intramolecular hydroamination is subsequently analysed and discussed. Chapter Five investigates the attempted development of a total synthetic pathway to a new class of imoxazoline ligand and related issues. Chapter Six contains all experimental procedures, characterising data pertaining to all new compounds and complexes presented in this Thesis. Appendices A-K contain additional catalytic figures and tables of crystallographic data for all new crystallographically characterised compounds. Summary sheets of every literature and new compound presented mentioned in this Thesis are also included, along with copies of both printed publications resulting from this Thesis at the time of submission.

This thesis describes the synthesis, characterisation and reactivity studies of a range of Group 3/Lanthanide complexes supported by bis(oxazolinyl)phenyl amide (BOPA). Chapter 1: Provides an introduction to the properties of the Lanthanides. Their application in asymmetric catalysis is reviewed, including catalysts supported by oxazoline ligands. Chapter 2 Describes density functional theory on a series of Group 3 BOPA complexes, the synthesis and characterisation of a new scandium amide-chloride precursor, thirty Group 3/lanthanide compounds supported by BOPA, six cation compounds supported by BOPA and three lithium BOPA compounds along with a discussion of the reactivity of compounds. Chapter 3: Describes the application of compounds described in Chapter 2 to the intermolecular hydroamination reaction of aminoolefins. Chapter 4: Describes a brief introduction to ring-opening polymerisation of rac-lactide and the application of compounds described in Chapter 2 to the ring-opening polymerisation of rac-lactide. Chapter 5: A brief introduction to luminescence is provided and the photophysical properties of a selection of diamagnetic complexes and all paramagnetic complexes discussed in Chapters 2 are described. Also, the synthesis, characterisation and photophysical properties of five Group 3/lanthanide compounds supported by pseudosubstrate ligands are described. Chapter 6: Details full experimental procedures and contains characterising data for all new compounds. Appendices A-B: Full tables of crystallographic data for all new crystallographically characterised compounds described herein are provided in Appendix A. Publications from this thesis are provided in Appendix B.

This thesis is concerned with the luminescent properties ·of rare earth doped oxides and the IT-VI chalcogenide CaCdS. Both materials are luminescent by very different mechanisms. Luminescence from CaCdS is due to transitions between the conduction and valence band. Emission spectra were found to be much sharper than in previously reported work. The narrowness of the peak appears to coincide with a reduction in particle size. With increasing cadmium concentration, this short wavelength (370 nm) emission band became distorted in symmetry and exhibited a red shift. This was seen as being indicative of a solid solution in which Cd substituted into the Ca sublattice. The excitation and emission mechanisms of rare earth doped materials are distinctly different from those of the IT-VI chalcogenides. Rare earth emissions consist of narrow emission bands which are predominantly due to transitions within the sheilded 4f orbital The visible emission spectra measurements of rare earth doped Y£J3, YV04' Gd202S and Y202S phosphors under 244 nm and 257 nm excitation were undertaken in order to examine the mechanisms of their emission processes. 1bis makes possible a comparison with the upconversion visible emission spectra that are obtained from these phosphors when they are excited with red light of 632.8 nm. .The motivation for this research was to develop improved phosphors for lighting applications that can be excited in the ultraviolet region.

A synthetic membrane is an organized supramolecular membrane that encompasses molecular recognition with signal transduction analogous to a natural biosensing system in a cell membrane. These synthetic based models allow the study and application of receptor-ligand binding to biosensor design. In order to enable a recognition event and a response the liposome incorporates a known ligand with a suitable receptor interaction that upon complementary binding can elicit a measurable response. Polydiacetylene based sensors have been previously considered and utilised for the detection of biologically important species due to the stimuli-responsive colour changing properties. These colorimetric biosensors are self-assemblies of diacetylene lipids mixed with natural or synthetic biological receptor molecules. Polydiacetylene liposomes functionalised with molecular recognition groups can bind and thus detect colorimetrically if the binding is complementary. Biodetection of an analyte in aqueous media requires that the structure of the diacetylenic compound is able to form a stable dispersion in water, polymerizes efficiently yielding a coloured material, incorporating a suitable receptor that binds with an analyte and transduction of the binding interaction by means of a colour change. The structural features to be considered are chain length, solubility, amphiphilicity, functional group for modification.

A detailed investigation into the transition metal complexes of various chelating nitrogen donor ligands, form the basis of this thesis. Chapter 1 discusses the synthesis and co-ordination of a xylyl bridged bis-tacn ligand, which has been shown to form sandwich type structures. Chapters 2 and 3 discuss the synthesis and co-ordination behaviour of two novel tripodal tris-(pyridylpyrazolyl) ligand frameworks, L2 and L3. The ligand L2, forms stable mononuclear compounds which display predominantly trigonal prismatic geometries for a series of transition metals, with only a few exceptions (Cr(III), Re(I) and In(III)). For L1, the relationship between octahedral and trigonal prismatic character has been investigated, with varied d-electron configurations of the metal centre. Continuous shape mapping analysis (CShM) has been employed to assist in the quantification of their geometric distortions. For L3, a similar investigation has been discussed, where the potentially hexadentate ligand was found to form a series of five coordinate transition metal complexes, with predominately square pyramidal geometries. Chapter 4 investigates the co-ordination chemistry of a tetradentate bis-(pyrazolyl)bipyridine ligand with various di-cationic transition metals, forming distorted octahedral geometries, often involving co-ordination of the perchlorate counter ions. In Chapter 5, the synthesis of a novel tripodal bis-quinoline ligand, L5, has been introduced along with a detailed discussion of its coordination behaviour with a variety of transition metals, where the Cu(II) complex forms a trimeric structure involving co-ordination of a capping perchlorate counter-anion. The addition of a para-substituted phenyl-bromide group, as the third tripodal ‘arm’, gives this molecule potential for further functionalisation through coupling reactions. Chapter 6 investigates the coordination properties of Cu(II) and Re(I) with a similar bis-quinoline tripodal ligand, which contains a lipophilic butyl appendage. A series of luminescence experiments were performed for the Re(I) complex in order to determine its photophysical properties with varying levels of acid.

Supported metal catalysts have applications across a broad range of industrial processes. The metal species are often the active catalysts in these processes, but supporting these materials upon a different material can produce desirable characteristics in the overall catalyst. These effects can include, but are not limited to, increased dispersion of active material, increased stability of the active material, and, depending on the supporting material, beneficial metal-support interactions can be generated. The production of benzaldehyde from benzyl alcohol is a reaction with high commercial value. Gold-palladium catalysts have been shown to be effective at production of benzaldehyde from benzyl alcohol under relatively mild, solvent-free conditions. It has also been shown that the selectivity of this reaction is dependent upon the acidic or basic character of the support material. Perovskites are a class of highly stable minerals with a general formula of ABO3, with A being a cation with a larger ionic radius than B. The acidic and basic character of a perovskite is strongly determined by the nature of the A cation, which allows for the possibility of adjusting this character by metal substitution. This study investigates the effects of gradual substitution of lanthanum for strontium in vanadate perovskites, and showed that incorporation of the substituted metal is effective up to a certain point, beyond which the material switches to two spate perovskite phases. The substitution of the metal ions was shown to have an effect on the acidic and basic properties of the perovskite materials using the Isopropyl Alcohol (IPA) reaction, which forms different products on acidic or basic sites. Following this, substitution with a wider range of group II metals was investigated and tested, both in the IPA reaction and as supports for precious metals in the production of benzaldehyde. A separate series of investigations were performed on Fischer-Tropsch (FT) catalysts. Fischer-Tropsch is a name given to a wide range of catalytic processes involving the production of hydrocarbons from a mixture of carbon monoxide and hydrogen, known as syngas. The formation of products is generally believed to proceed through a chain-lengthening process using single-carbon units. This leads to a broad distribution of products Abstract as opposed to a single highly selective product, and the selectivity pattern is often described using the Shulz-Florey-Anderson distribution. Much of the work on FT catalysts is involved in modifications of the catalyst system to produce a tighter distribution of products. In this study a series of investigations have been made into the effects that variations of the preparation method of CoMnOx supported on activated carbon. The basic preparation is an impregnation method, and several changes in catalyst activity and selectivity were observed following changes to this. An investigation into the effects of altering the amount of manganese relative to cobalt in the system also highlighted several trends, leading to a greater understanding of the factors affecting the conversion and selectivity of the catalyst system. A separate are of research in FT-style reactions is the production of alcohols from syngas, typically at higher pressures. As in the previous section, these an attempt was made to improve the activity and selectivity of these catalysts by alterations to the preparation methods, and also by alteration of the amount of secondary metal relative to cobalt. The catalysts used in these investigations consisted of CoMoOx supported on activated carbon. The standard preparation used a coprecipitation method based upon a similar method used for the production of CoMoS2 catalysts, which were also investigated in this study. Later investigations, notably those in which the amount of molybdenum relative to cobalt was altered, were prepared using an impregnation method. A series of improvements to a base catalyst were achieved by alteration to the preparation conditions, but more substantial improvements were observed when the alteration of the metal ratios was investigated. With regards to the use of activated carbon as a support material, it was also observed that it was possible to bring about the reduction of the cobalt species, and to a lesser extent the manganese and molybdenum species, by heating the catalysts to a high temperature in an inert atmosphere, namely helium.

The basics of the oxidation mechanism of different alkanes within zeolites and over molybdenum oxide surfaces were studied employing state of the art computational modelling. It was shown that the constrained environment inside MFI, MFS and MOR induces terminal selectivity on the reaction of 6-, 8- and 10- term linear alkanes, i.e. hexane, octane and decane, respectively. The Monte Carlo (MC) random alkane configuration sampling showed that the oxidation reactivity is driven by the fact that the terminal C atoms of the substrate are more likely to be closer to the zeolites internal walls than the methylene (–CH2–) C atoms. As a confirmation of this, the calculation of kprim/ksec for all the host/guest (alkane/zeolite) systems estimated that the pore effect exerted by the zeolites in the reaction favors terminal products (terminal selectivity). The alkane oxidation over MoO3(010), Fe2(MoO4)3(001) and (110) surfaces involved the activation of a C–H bond of the substrate. The surface calculations were carried out using DFT+U to localize the electrons at a terminal point of the surface. Energy comparison with hybrid DFT (B3LYP) calculations for cluster models of the MoO3(010) surface showed consistency with the DFT+U results. The propane terminal C–H bond activation generated a propyl radical. Transition state structures were found for the adsorption of radical species on MoO3(010) and Fe2(MoO4)3(001) surface and the corresponding energy barriers showed that the adsorption on the former system is favored, which indicates that the Fe2(MoO4)3 surface alone is not a good catalyst for the reaction studied.

This thesis is split into six chapters. The first chapter introduces the homocoupling reaction of arylboronic acids, surfactants and aqueous solutions and nanoparticles. The second chapter describes the synthesis of two different bisimidazolyl palladium catalysts, the characterisation of these catalysts, particularly the crystal structure, formation of aqua- and halogeno- complexes by NMR spectroscopy and the pKa with varying halide concentration in both Laureth-10 and CTAB and the use of the of these catalysts in both Laureth-10 and CTAB to catalyse the homocoupling reaction of arylboronic acid and the pH rate profile in CTAB and in Laureth-10 at a variety of different halide concentrations, the origin of which is identified. The third chapter describes the use of polystyrene-immobilised polypyrrole-palladium nanocomposite catalyst in the homocoupling reaction of arylboronic acids in aqueous solutions, with a particular interest in the effect of pH and halide addition on the reaction, and that the particles are recoverable and reusable with centrifugation. The fourth chapter describes the use of a paper-immobilised palladium nanoparticle catalyst in the homocoupling reaction of arylboronic acids in aqueous and ethanolic aqueous solutions, and the Suzuki-Miyaura cross-coupling reaction in ethanolic aqueous solutions. The fifth chapter describes the effect of nitric oxide release in the body and the synthesis of CTAB capped gold nanoparticles and their use in the release of nitric oxide from S-Nitrosothiols which will be measured using an NO selective probe. The final chapter is an epilogue in which ideas for future experiments, or plans for experiments that were not accomplished are discussed.