Gaseous nitrous oxide (N₂0) undergoes physical and chemical reactions in the atmosphere, contributing to both global warming and the catalytic destruction of stratospheric ozone. This chemically reactive greenhouse gas is produced both naturally and anthropogenically. The greatest source of N₂0 is from the microbial transformation of N compounds during the processes of nitrification and denitrification in natural and cultivated soils. However, there is some uncertainty in the strength of these emission sources. Therefore one of the directives of the Terrestrial Initiative in Global Environmental Research programme, of which the following work was a part, was to elucidate the factors which influence the emission rates of N₂0 from these systems. It is essential that these factors are quantified, in order to correctly assess the effect of N₂0 as an environmental determinant. A reliable automated soil core headspace gas analyser system for the continuous measurement of N₂0 at the laboratory scale was developed. The system determined N₂0 evolution rates from reconstructed soil cores consisting of re-packed aggregates of known diameters, incubated under different environmental conditions. There was an increase in N₂0 emission rate (range = 0.5-61 x 10-7 mol N m-2 h-l) with aggregate size, soil N0₃-concentration and soil water content under unsaturated conditions. However, the extent of these trends was masked by the variability in emission rates. One source of variability in N₂0 emissions from unsaturated soil, was related to localized organic (e.g. faunal) residues. Subsequent investigations involving the incorporation of discrete faunal residues, DFRs (dead Earthworms), was found to greatly stimulate N₂0 emission from unsaturated re-packed soil cores. These N₂0 emission rates approached those attained when the soil was under saturated conditions, which were up to 3 orders of magnitude greater than emission rates from unamended, unsaturated soil. There was no apparent influence of DFR on N₂0 emissions from soil under saturated conditions suggesting that the effect of DFRs under aerobic conditions was the creation of localized anoxic zones. N₂0 emission rates increased with increasing soil water content reaching a maximum under fully saturated conditions for three different soils (range = 0.25-1.8 x 10-4 mol N m-2 h-1). The emissions of N₂0 from the three soils were different under both unsaturated and saturated conditions and appeared to be related to soil parameters, specifically organic matter content, clay content and soil pH. The contrast in rates of N₂0 emission from unsaturated and saturated soil prompted a test of the hypothesis that wetting/draining cycles increase the total emission rate. During the saturated phase, N₂0 is produced, but its egress is restricted by saturated transmission pores. Rapid drainage causes a flush of N₂0 from saturated aggregates by providing open emission channels. The rapid increase in N₂0 flux that was observed during the draining of saturated soil occurred in all three soil types (range = 1-5 x 10-3 mol N m-2 h-1). This almost instantaneous N₂0 pulse, which in some cases lasted less than 2 hours, occurred repeatedly, emitting similar rates of N₂0 during 10 cycles of flooding and draining. An attempt was made to simulate N₂0 emission using the results gained from these investigations to parameterize a reaction-diffusion model. The model successfully predicted N₂0 emission from soil undergoing a transformation from unsaturated to saturated conditions. However, model deficiencies were found during simulations involving the sequential rise and fall in water table height. The inability of the model to accurately predict the rapid increase in flux that occurred following core drainage, exposed gaps in knowledge and areas of future research regarding the short-term fluxes of N₂0 from soil.

The interactions of metal-containing molecules and nanoparticles (NPs) with the interior of hollow graphitic carbon nanostructures (CNs) were investigated and their chemical transformations in the nanoscale channels of CNs appraised. The gas phase insertion of Group VI metal hexacarbonyl complexes (M(CO)6, M=Cr, Mo, W) into CNs was successfully developed and optimised to provide good filling rates as confirmed by transition electron microscopy (TEM). Infrared (IR) and Raman spectroscopy demonstrated that Group VI M(CO)6 complexes with greater polarisability exhibit stronger van der Waals interactions with the interior of single walled carbon nanotubes (SWNTs). The synthesis of metal based NPs inside graphitised carbon nanofibers (GNFs) by the in situ transformation of the encapsulated M(CO)6 precursor molecules was successfully achieved and it was demonstrated that GNFs can act as a source of oxygen in these reactions. The nanotube filling methodology was applied for the multi-step synthesis of new inorganic materials inside CNs by the controlled reactions of M(CO)6, I2 and H2S. This approach yielded unusual van der Waals hybrid materials such as “tube inside a tube” and other hybrid structures of MoS2 and GNFs. In SWNTs, with significantly narrower diameters than GNFs or multi-walled carbon nanotubes (MWNTs), metal complexes form unique 1D arrays of octahedral [M6I14]2- clusters with the nanotube acting as a nanocontainer and a poly-cation balancing the charge of the guest-clusters. The iodides of Mo and W were effectively converted into extremely thin MS2 nanoribbons (NRs) within SWNTs, providing a new more efficient route to the hybrid inorganic nanostructures. In MWNTs, the [Mo6Ii8Ia2Ia a4/2] clusters are packed in a hexagonal pattern to optimise filling of the void, and when reacted with H2S they provide a range of multi-layered MS2NRs with their widths controlled by the internal diameter of the host nanotube.

Chapter One contains a brief overview of zeolites, their structure, uses and synthesis. Chapter Two relates to the attempted synthesis of quinuclidines via a novel 6-endo-trig radical cyclisation. Chapter Three contains a review of the 'Zip reaction' and the attempted synthesis of triazacyclopentadecane derivatives. Chapter Four relates to the synthesis of pyrrolidines via retro-Cope cyclisation methodology. Reviews of the Cope and retro-Cope reactions, nitrone synthesis and nucleophilic addition of carbon nucleophiles to nitrones are included. The synthetic work is split into three sections relating to the electron withdrawing group used to stabilise the carbanion of the nucleophile - ester, sulphone and sulphoxide - and attempts to indicate the utility of the retro-Cope reaction in the diastereoselective synthesis of substituted pyrrolidines.

The thesis describes infrared spectra recorded during the adsorption of water, acetone, acetic acid and hexifluaroacetone onto oxidized and reduced rutile, and the development of a technique for recording the infrared spectrum of a solid immersed in a liquid. Bands observed on the hydroxylated rutile surface have been assigned to hydroxyl groups on the (110) plane and water IrDlecules adsorbed onto strong and weak Lewis sites on all exposed planes. The hydroxyl groups exist as isolated or hydrogen bonded groups on surface titanium ions or as hydrogen ions on bridging oxygen ions. Reduction of the rutile surface considerably decreased the amount of rmlecular water adsorbed on the hydroxylated surface. The adsorption of acetone onto the hydroxylated surface took place in three consecutive stages, the first involved acetone molecules Lewis bonding to weak sites, the second resulted in the formation of mesityl oxide on strong surface sites and occurred with stage one in the absence of surface water molecules. In the third stage acetate molecules were formed as a result of the decomposition of mesityl oxide. Adsorption of acetic acid onto rutile resulted in the formation of water and arpeaxeme of bands due to acetate groups and Lewis-bonded co lexes on the weak sites. Hexafluoroacetone reacted with surface hydroxyls to produce a salt of the gem-diol hexifluoropropane-2,2-dio1, which decomposed on the removal of water to form trifluoroacetate species. An infrared cell has been developed enabling solid discs to be treated and inmiersed in a solution under inert conditions. The cell, of path length 0.7cm, has been used to study the adsorption of ether, from a solution in carbon tetrachloride, onto silica. Designs of variable path length cells for use Hexafluoroacetone reacted with surface hydroxyls to produce a salt of the gem-diol hexifluoropropane-2,2-dio1, which decomposed on the removal of water to form trifluoroacetate species. An infrared cell has been developed enabling solid discs to be treated and inmiersed in a solution under inert conditions. The cell, of path length 0.7cm, has been used to study the adsorption of ether, from a solution in carbon tetrachloride, onto silica. Designs of variable path length cells for use unier vacuum are included.

The work presented in this thesis describes the development and applications of hollow carbon nanostructures both as the catalytically active, magnetically separable carbon nanoreactors, and electrodes for electrocatalytic reactions. The work is separated into three distinct parts, the formation of carbon nanoreactors of different diameters and shapes in which the effect of confinement imposed by the nanotube is probed in exploratory hydrogenation reactions, the functionalisation of carbon nanoreactors with magnetic nanoparticles for magnetically separable catalyst supports, and the development of new hybrid metal-carbon nanoreactors as efficient electrocatalysts for hydrogen fuel cell applications. In the first part of the thesis, a Ru3(CO)12 precursor was successfully inserted into carbon nanoreactors of different diameters – very narrow single walled carbon nanotubes (SWNTs, DSWNT ~1.5 nm) and much wider hollow graphitised carbon nanofibers (GNFs, internal dGNF ~50 nm) using sublimation followed by the formation of uncoated metallic Ru nanoparticles via thermal decomposition. The resultant RuNPs@SWNT and RuNPs@GNF nanoreactors were then tested in hydrogenation reactions using a high pressure scCO2 batch reactor, where the excellent diffusivity and mass transfer properties of scCO2 as solvent enabled the efficient delivery of the reagents to the catalyst surface within the narrow nanoreactors. RuNPs confined in the narrowest channels of SWNT was observed to be highly active and selective in competitive hydrogenation reaction of alkenes, but concurrently reduce the accessible volume of the SWNTs by 30-40 % resulting in lower overall turnover numbers (TONs). In contrast, RuNPs confined in wider GNFs were entirely accessible and indicated outstanding activity in comparison to unconfined RuNPs on the outer surface of SWNTs or carbon black. In the second part of the work, GNFs sidewalls were functionalised by non-covalent attachment of commercial graphene-like carbon coated magnetic Co nanomagnets (Co@Cn) exploiting van der Waals forces via dispersion in an organic solvent using ultrasonic treatment, and by the in situ formation of carbon coated iron nanomagnets (Fe@Cn). A number of experiments were carried out to find the minimum amount of nanomagnets required to enable complete separation of the nanotubes from the solution with an external magnetic field. Characterisation of this composite material by high resolution transmission electron microscopy (HRTEM) showed that Co@Cn and Fe@Cn successfully attached to the GNFs. Magnetic functionalisation steps were then combined with uncoated, palladium and platinum nanoparticle catalyst formation and the resultant catalytically active and magnetically separable hybrid materials were investigated in the reduction of nitrobenzene. The recyclability and stability of these magnetic and catalytic nanoreactors were studied in the reduction of nitrobenzene using magnetic recovery, and only negligible catalyst loss (< 0.5% by wt.) was observed over 5 cycles in comparison to that of filtration based catalyst recovery (>10% catalyst loss by wt.). In the third part, GNFs were shortened by ball milling and combined with palladium catalyst to form (PdNPs/-PdNPs@)s-GNF using a novel procedure and the resultant activity and stability towards hydrogen evolution and hydrogen oxidation reactions (HER/HOR) in acid media was studied. (PdNPs/-PdNPs@)s-GNF exhibited enhanced activity and excellent durability during 30000 electro-catalytic cycles in HER compared to that of state-art commercial Pt/C which exhibited decreasing activity and poor durability during the cycling in acid. Moreover, s-GNF demonstrated an enhanced HER activity and stability during 5000 cycles. HRTEM revealed some chemical transformations at the step edges within GNF during the electrochemical cycling contributing to durability of the electrocatalyst. Overall, the superior HER/HOR activity and durability was attributed to the corrugated morphology of s-GNF, and therefore the ability to stabilise the Pd nanoparticles at the graphitic step-edges effectively through strong bonding and synergetic effects between the Pd and s-GNF support. These results clearly indicate that carbon nanoreactors as catalyst supports and electrocatalystd show significant promise for a variety of chemical reactions.

This thesis presents research into the binding, extraction and transport of the hexachloroplatinate anion, [PtCl6]2-, by organic receptors in a solvent extraction process. The target anion is produced during the processing of platinum-containing ores and the aim was to develop reagents that can selectively extract [PtCl6]2- to optimise the recovery of platinum. Chapter One outlines reasons for the interest in [PtCI6]2-and provides an overview of the processes and techniques used to refine precious metals. An introduction to anion coordination chemistry relevant to the research project is also presented. Chapter Two discusses the design features incorporated into organic receptors to enable strong and selective binding of [PtCl6]2-. These features include a tertiary amine protonation site, hydrogen-bond donor groups and organic solubilising moieties. The synthesis of a series of functionalised tripodal tris(2-aminoethyl)amine based receptors with sulfonamide, amide, urea, thiourea or pyrrole NH hydrogenbond donor groups are reported. Complexation reactions between the receptors and H2PtCl6 to form [(LH)2PtCl6] ion pairs are discussed. Crystallographic analysis of the [(LH)2PtCl6]complexes with TREN-based sulfonamide, urea and amide receptors confirms the presence of hydrogen-bonds between the NH donor groups and the outer-sphere of [PtCl6]2-. The low organic solubility of the complexes prevented the study of these systems in solvent extractions. Chapter Three describes the variation of terminal substituents of the tripodal receptors with the aim of improving the organic solubility of the extractants and their [PtCl6]2-complexes. In these "second generation" receptors the terminal substituents assessed include 3, 5-dimethylphenyl, 4-iso-propylphenyl, 4-tert-butylphenyl, 3, 5- dimethoxyphenyl, 3, 4 dimethoxypheynl and 3, 4, 5-trimethoxyphenyl. Through reaction of the receptors with H2PtCl6 the solubility of the resultant complexes are assessed. Chapter Four describes the development of an optimised solvent extraction method to study the extractive behaviour receptors. A pH swing mechanism is utilised to control the uptake and release of [PtCl6]2-. The extraction results for trioctylamine and the soluble tripodal urea and amide receptors are compared. Attempts are also made to confirm the stoichiometry of the complex in solution. Chapter Five describes the synthesis of tris(2-aminoethyl)amine based receptors with hydrogen- and halogen-bond donor groups with the aim of increasing the strength of the interaction between a receptor and [PtCI6]2-. Receptors with an extended tripodal scaffold based on a tris(3-aminopropyl)amine with urea and amide moieties are also presented. The results of the complexation reactions and solvent extraction studies with these modified extractants are presented. Chapter Six presents the design and synthesis of bipodal and monopodal receptors in order to assess the role of the number of hydrogen-bond donor functionalised arms. The results of the solvent extraction studies with these receptors are discussed and comparisons made between tripodal, bipodal and monopodal extractants. The crystallographic analysis of the [(LH)2PtCl6] complexes formed between the bipodal urea and amide receptors is described. Chapter Seven highlights the important findings from this work. Conclusions are drawn as to the optimum receptor system developed and this is compared to the extractant system thought to be in current use for the extraction and transport of [PtCl6]2-.

This thesis details the preparation and subsequent characterisation of novel nanostructured porous materials with tuneable porosity. The main focus is the development of inorganic and carbonaceous porous materials for catalysis, templating and gas storage applications. Three distinct methods of synthesis are investigated, namely: (i) hydrothermal synthesis of zeotype aluminosilicates, (ii) nanocasting techniques for templated carbons and (iii) sol-gel processes, with/without metal salt 'porogen', to carbon aerogels. Post-synthesis modification methods for carbonaceous materials include supercritical carbon dioxide mediated incorporation of palladium nanoparticles into zeolite templated carbons and chemical activation for carbon aerogels resulting in enhanced textural properties. Chapter 1: Provides the foundation and background to the main themes of nanostructured porous materials investigated in this work. Information about fundamental properties and applications is emphasised. Chapter 2: Gives a brief background of techniques used for characterisation of the porous materials generated in this research programme. Gas sorption techniques used to probe hydrogen storage and carbon dioxide uptake are also presented. Chapter 3: Describes stepwise experimental techniques followed in the preparation of various porous materials. The chapter also describes the instrumentation used in these techniques. Chapter 4 - 7: Each chapter reports a separate but sequential area of research in which appropriate additional theory and background is provided with associated literature review. This is followed by a results and discussion section, with a concluding summary for each chapter. Chapter 4: Details the synthesis of ordered mesoporous aluminosilicates, which exhibit some zeolitisation, prepared from a recipe conventionally used for the synthesis of microporous zeolite SEA. The porosity of the aluminosilicates is modified by simple washing and/or refluxing (in water) of either on the as-synthesised mesophase or the calcined material. The aluminosilicates have excellent hydrothermal stability and strong acidity and thus combine the best properties from mesoporous materials and zeolites. Chapter 5: Describes the preparation of zeolite templated carbons (ZTC) generated as replicas of zeolite Y via a hard template nanocasting process. In order to enhance hydrogen storage, the ZTCs are impregnated with Palladium nanoparticles using supercritical carbon dioxide solvent, scC02, as environmentally benign reaction media. The Pd-doped ZTCs exhibit enhanced hydrogen storage due to optimised (with respect to metal content and particle size) incorporation of Pd. Chapter 6: A two-step process for the generation of zeolite template carbons (ZTCs) was investigated. In this case the nanocasting technique involves liquid impregnation of zeolite 13X with furfuryl alcohol followed by chemical vapour deposition (CVD) of ethylene at variable CVD temperatures. The two-step process was a successful attempt to optimise the replication of the zeolite structure in the carbons. The ZTCs had very high surface area and excellent mechanical stability, and achieved the highest hydrogen storage capacity (7.3 wt% at 77 K and 20 bar) ever reported for any carbon material. Chapter 7: Organic Sol-gel chemistry is explored in the formation of carbon aerogels via conventional methods involving the use of resorcinolformaldehyde resins and melamine-formaldehyde with or without metal salt as a porogen and subcritical drying. Chemical activation is used to modify the porosity of aerogels for potential applications in carbon dioxide uptake. Chapter 8: A brief overall conclusion to this research work is presented together with recommendations for future research.

Organophosphorus-mediated reactions are important tools in organic chemistry and are used in the synthesis of highly desirable drug targets, such as morphine.1 A major drawback of traditional phosphorus-mediated reactions is the formation of stoichiometric amounts of phosphine oxide by-products; this renders the product purification difficult and reduces the atom efficiency of these transformations. For these reasons, catalytic variants become desirable; there being two potential strategies to achieve the catalysis; i) redox-driven and ii) redox-neutral.2-4 The redox-driven catalytic cycle requires a reductant for the turnover whilst the redox-neutral system uses a sacrificial reagent to directly turn over the phosphine oxide to the active phosphorus (V) reagent. This thesis will report upon a new class of Hydroxylmethyl-Aryl phosphine 1 and phosphine oxide 3 catalyst for use in a redox-driven catalytic reaction; the Staudinger reduction Scheme 1, and routes to a potential redox-neutral catalytic Mitsunobu reaction Scheme 2.

The C60 molecule, in a number of different environments and configurations, was studied via a range of theoretical and experimental techniques. Experimentally, scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) techniques were employed to firstly study orientational ordering in C60 monolayers and multilayers, and subsequently, potassium doping of isolated C60 molecules, and C60 monolayers. A single C60 molecule was manipulated over successive K atoms, such that it is progressively doped, it was then studied via STM and AFM, where molecular charging was seen to influence both electronic structure and force characteristics. Two Monte Carlo simulations were written to investigate different aspects of C60 molecular kinetics on surfaces. The first is a novel simulation into the orientational ordering of C60 monolayers and multilayers, with the inclusion of a surface interaction. By pre-calculating a repulsive pairwise intermolecular interaction, using Hückel theory, hundreds of molecules in a molecular assembly could be efficiently simulated. Numerous complex monolayer and multilayer long range rotational configurations, as observed via STM from literature and our own experiments, were successfully modelled. A second Monte Carlo simulation was written to study the kinetics of a diffusing C60 on a hydrogen passivated silicon surface. This to estimate the feasibility of a future SPM recreation of the famous Maxwell’s Demon thought experiment. A Girifalco potential was applied from a number of static molecules to a sinusoidal surface potential. A Monte Carlo simulation was applied to this surface potential to fully explore the dynamics of the system. As a result, a number of optimal chamber configurations were suggested from outcomes observed in simulation.

Rolls-Royce is a well reputed and multinational company that develops and manufactures propulsion systems including gas turbines for many applications, with aerospace being the most well-known. In the process of developing new turbine engines to power ever larger, more efficient and environmentally friendly aircraft, the conditions within their engines are pushing the boundaries of what was previously thought possible. One of the major factors that needs to be considered and controlled in the engine development is the temperature at which the engine components are exposed to. Currently, temperatures produced within their engines are in excess of 1600 °C, which is far beyond the melting point of the metal alloys that make up the engine itself. Due to this, many creative cooling technologies have been modelled and implemented to reduce the temperatures experienced by engine components. These cooling technologies must be validated in situ with precise temperature analysis tools that can give accurate temperature readings on moving parts, deep within the engine. Of the tools available, thermal paints have proven to be highly effective and versatile. Thermal paints are irreversible thermochromic coatings that are applied to component surfaces, and on deconstruction of an engine, reveal the maximum temperatures reached and give a visual display of temperature gradients across a surface. These paints have been used within Rolls-Royce for over 50 years and are now a focal point for development due to recent REACH legislation preventing the use of many outdated pigments that are used within the paint formulations. This project was created to build an understanding of the chemistry behind the thermochromic effect and to develop new, safer thermochromic paints to secure the techniques future within the development of state of the art turbine engines. Two of Rolls-Royce’s thermal paints, TP11 and TP8, have been fully investigated and the previously unknown chemistry behind the thermochromic effect exhibited by these paints has been identified (Chapter 3). From the information gained from this initial investigation, new thermochromic paints based on REACH compliant compounds have been produced and characterised. The results obtained from this work have shown great promise and have had an influential impact within the aerospace industry.