The history of chromatographic theory has always been driven to the development of smaller particles. The use of smaller more uniform particle diameters results in more effective separations and faster optimal mobile phase velocities, therefore producing lower plate heights; consequently the use of sub 2 micron silica particles has delivered a significant impact on the practice of high pressure liquid chromatography. The main issue with sub 2 micron silica particles however, is related to their manufacture. It is difficult to produce such highly specialised materials homogeneously and there are only a handful of methods in the literature. This dissertation outlines work that is intended to improve our technical knowledge of this subject by studying the synthesis (of both non porous and totally porous) spherical silica particles to drive improvements. Further investigations into surface functionalisation as well as column packing are also studied. Several experimental tools have been developed to drive improvements to the manufacture of such materials. For example, the experimental challenges necessitated the development and implementation of the following in this work; Full evaluation of the experimental and technical requirements of the Stöber reaction to produce good quality particles greater than one micron in diameter. 2. Transfer of the key outcomes from non porous particle synthesis to produce totally porous particles via modified Stöber reactions and pseudomorphism, 3. Indentified new types of surfactants that could produce high porosity silica particles, 4. The use of microwave irradiation to dramatically speed up surface functionalisation processes, 5. Investigation of column packing’s via computer simulation. On the basis of this works experimental data, it is concluded that good quality non porous and totally porous spherical silica particles can be produced from the ethanol/water/ammonia hydrolysis system of the Stöber reaction up to two microns in diameter with a narrow particle size distribution. Key experimental procedures that are often overlooked in the literature have been highlighted to facilitate successful reactions. The resultant materials can be used for future column packing’s or as starting materials for the production of superficially porous materials. The use of microwave irradiation was shown to dramatically improve surface functionalisation reaction times whilst incorporating reduced solvent volumes and reduced energy expenditure. Reaction times of five minutes were shown to produce packing’s possessing the level of surface coverage associated with commercially produced phases (3 μmoles/m2 ) which traditionally use disordered heating methods such as reflux with long reaction times. The use of microwave “superheating” or slightly longer reaction times of 20 minutes further increased the overall bonding density. Computer simulation of commercial packing’s showed the influence of large particles within the distribution on bed formation. Larger particles are pushed towards the top of the column chamber by the sedimentation of smaller particles. This effect is completely analogous to the phenomenon of “The Brazil nut effect”. More uniform packing’s would reduce the overall impact. This work improves our understanding of the complex nature of HPLC column phase synthesis as well as provides new tools for future research.

Since its discovery, the Heck reaction has received great attention from academic research. As a result, many advances have been made, making the Heck reaction one of the most widely adopted methods for the construction of carbon-carbon bonds in modern organic chemistry. Chapter 1 presents a brief history of the Heck reaction, from its initial discovery to current day applications. This is followed by a brief overview of the different classes of cross-coupling reactions catalysed by palladium. Chapter 2 describes the synthesis of alkyl aryl ketones from aryl chlorides and aldehydes by the development of a novel Heck-type acylation reaction. The aldehyde first condenses with pyrrolidine to form an enamine intermediate, which acts as an electron-rich olefin and undergoes a regioselective Heck coupling with the aryl chloride. Additional experiments such as in-situ¬ IR spectroscopy were carried out in order to probe the reaction mechanism. Chapter 3 is an extension of Chapter 2. The scope of the newly developed acylation reaction is extended beyond commercially available aliphatic aldehydes. The palladium catalysed Heck arylation-isomerisation reaction of aryl bromides and allyl alcohol leads to the generation of aldehydes which, by intervention of pyrrolidine and the same palladium catalyst, undergo the acylation reaction with a second aryl bromide. This leads to the one-pot synthesis of functionalised dihydrochalcones from readily available starting materials. Chapter 4 presents the development of a second one-pot methodology, based on the same principle of design, whereby the reactive C=C double bond is generated in situ. A Keggin-type heteropolyacid is employed to catalyse the¬ formation of styrenes from secondary aryl alcohols which, following addition of palladium, base and an aryl bromide, undergo regioselective Heck arylation. Interesting stilbene products are obtained in good to excellent yields.

Conjugated microporous polymers (CMPs) are a class of materials that have advantageous properties, such as extended π-conjugation, tuneable micropore size and surface area, and the ability to swell. Owing to the limited solubility and the amorphous nature of CMPs, little information is known about their structure and characterisation is dominated by solid-state NMR spectroscopy. NMR is a technique which is sensitive to both molecular level structure and dynamics. An increase in understanding of these networks is required to give an overall picture of their physical properties and origins of flexibility, ultimately leading to the design of such materials for specific applications. In addition to the challenges with characterisation, a considerable disadvantage of CMPs is the cost of their synthesis. Many of the current routes to CMPs involve the use of heavy metal catalysts. Development of methodologies that use cheap monomers and do not require metal catalysts would increase the viability of CMPs for use in industrial applications. In this work advanced structural elucidation and investigations of network flexibility and porosity were achieved using two approaches. The first involves identification of a reaction mechanism for the formation of CMP-1 by examination of the products of reaction after incremental time periods. The second involves employing advanced solid-state NMR techniques, specifically deuterium NMR, to probe the molecular motions of deuterated versions of CMP-1 and CMP-2. Swelling experiments of CMP-1 and CMP-2 with benzene-d6 were also used to investigate changes in porosity for swollen and non-swollen networks. A new synthetic route to CMPs was also developed by exploiting the reaction between aldehydes and amines. In particular the formation of aminal linkages shall be explored, as this would allow preparation of branched networks from bi-functional monomers. Newly synthesised materials are to be fully characterised and their gas sorption properties will be analysed.

The synthesis of branched copolymers with precise composition, specifically the ratio of methacrylic acid (MAA) to ethylene glycol (EG) has been demonstrated. These polymers were used to stabilise dodecane oil-in-water emulsion droplets. It was demonstrated in the literature that branched copolymers containing a 1:1 ratio of MAA:EG formed pH-responsive emulsions, capable of triggered inter-droplet hydrogen bonding to form engineered emulsions (EE). The effect of varying this ratio on the rate of engineered emulsion formation, and the resulting strength and stiffness of the emulsion droplet aggregates was investigated. This control over systems is exemplified by the demonstration of selective acid-triggered assembly of binary mixtures of droplets stabilised by polymer containing only EG functionality with droplets stabilised by polymers containing only MAA functionality. EEs stabilised using a branched copolymer containing a 1:1 ratio of MAA:EG were produced and allowed to dehydrate, leading to the removal of water from droplet interstitial sites. The resulting single-phase materials are known as polymer-structured oils (PSOs), held structurally by the inter-droplet polymer-polymer interactions. These polymer boundaries provide enough of a barrier between droplets to prevent coalescence upon the removal of water, allowing reversible hydration of PSOs to reform EEs. The production of large volume, well-defined EEs produced via the hydrolysis of glucono-δ-lactone (GδL) to gluconic acid in an emulsion’s water phase was investigated. This process provides a homogeneous pH trigger for the formation of EEs, eliminating the slow diffusion of HCl. A homogeneous pH trigger also allows the formation of EEs to be studied in situ using rheology. A comparison between GδL and a conventional HCl trigger is presented. Branched copolymer-stabilised ethyl acetate o/w emulsions were used as templates in the production of both pH-responsive, surface-functionalised poly(methyl methacrylate) (PMMA) colloidal nanoparticles and non-responsive PMMA particles via an emulsion-solvent-evaporation technique. Lowering of the solution pH can trigger the reversible aggregation of these highly dispersed pH-responsive colloids into 3D structures with internal macroporosities dictated by the method of dehydration employed. The colloids can also co-encapsulate various hydrophobic molecules without any effect on particle stability and pH-responsiveness. The production of multi-responsive emulsion droplets via the encapsulation of oleophilic, magnetic Fe3O4 nanoparticles within a stable, surface-functionalised dodecane o/w emulsion was investigated. Droplet surface functionality allowed the formation of EE on lowering the pH, and encapsulated nanoparticles gave both the free-flowing and aggregated emulsions magnetic-responsiveness. The rate of aggregation and gel strength of multi-responsive EEs is compared to that of a standard pH-responsive emulsion.

The adsorption of thymine and melamine on Cu(110) has been investigated using a combination of experimental and theoretical techniques. These techniques have allowed the development of an extensive picture of how these molecules may orient on this surface. Many Density Functional Theory (DFT) calculations using the latest version of the Vienna Ab-Initio Simulation Package (VASP) have allowed the production of a series of models which have, in general, corroborated the experimental data. The additional utilisation of semi-empirical techniques (like those used by Grimme), which seek to simulate long-range inter-molecular vdW interactions, have allowed the creation of a firm foundation of, not only how the individual molecules bond to the Cu(110) surface, but of how they arrange themselves into long-range structures. With thymine, two long-range phases were observed; a room temperature structure, which aligned along the [001] direction in 1-D chains, one molecule thick and with the cyclic plane roughly parallel to the [110] direction. The higher temperature phase occurred after annealing between 350-400K and consisted of two distinct 1-D chains, two molecules thick and angled at ~±20o to the [001] direction. In both cases the thymine was deprotonated at the N(1) atom. With melamine, only the room temperature phase is discussed and this consisted of a 2-D “hexagonal” structure arranged on a (6x2) unit cell. Although structural relaxation techniques give good indications of the stability of the models, the technique of Scanning Tunneling Microscopy (STM) simulation has been used extensively with both thymine and melamine systems in order to verify their validity. Although it is not yet possible to directly observe individual atoms in such small molecules it is possible (with STM) to observe their electronic “footprint” and to then re-create this observed image. The similarity of this “simulated STM” to the “experimental STM” combined with a relaxed stable model is a strong indication that the model is in good accordance with the observed (static) system. Combining this analysis technique with experimental data, models are proposed for both the room temperature thymine and melamine phases as well as the annealed thymine phase.

Progress in catalyst development for reactions such as Fischer-Tropsch synthesis (FTS) has been impeded by the time consuming characterisation and catalytic testing of new formulations. Hence, this thesis discusses the development of high-throughput (HT) techniques for studying the deactivation of cobalt based catalysts under simulated FTS conditions. Libraries were rapidly synthesised by incipient wetness methods utilising robotic platforms and then treated in arrays under conditions designed to cause rapid ageing. HT X-ray diffraction (XRD) was performed before and after the ageing test to monitor the deactivation of the catalysts by sintering of the active metal particles or loss of metallic cobalt. HT thermogravimetric analysis in 5 % H2 was utilised to probe the reducibility of the catalysts and this information was then combined with results from XRD to inform decisions on which formulations to scale-up for further testing. This approach led to the discovery of highly stable Co/Ru/Mg/γ-Al2O3 catalysts. Thorough characterisation of selected hits was carried out to understand the phase assemblage. In addition to the high stability of Co/Ru/Mg/γ-Al2O3 catalysts, there was also a lowering of intrinsic activity. The degree to which the intrinsic activity was decreased was dependent on the amount of Mg in the catalyst and more specifically, the amount of Mg in close proximity to Co as identified by the amount of Mg incorporated into MgxCo3-xO4 phases prior to activation. In addition to incipient wetness synthesis, a method was also developed to perform HT co-precipitation synthesis with the aid of robotic platforms. HT synthesis was coupled with HT XRD to determine synthesis conditions giving rise to high surface area, phase-pure magnesium aluminate supports.

The work in this thesis is split into three experimental chapters: The first section involves the development of the directional freezing and frozen polymerization method to prepare crosslinked aligned porous polymers with improved mechanical stability. Monomer solutions were directionally frozen in liquid nitrogen to orientate the growth of solvent crystals and the frozen samples are polymerized by UV irradiation. The solvent is removed under vacuum at room temperature to produce aligned porous structure. The mechanical stability is improved by two orders of magnitude compared to the usually freeze-dried porous materials. The materials are modified with graphene and a conducting polymer to make conducting monoliths, whilst maintaining the aligned porous structure. The aligned porous monolith is also assessed by high performance liquid chromatography (HPLC), showing fast separation of hydrocarbon compounds with low back-pressure. The second section uses directional freezing and frozen UV initiated polymerization to prepare aligned porous stimuli-responsive hydrogels. Oligo-ethylene glycol methacrylates and dimethylamino ethyl methacrylate monomers were used to produce temperature and pH-responsive hydrogels respectively. Aligned porous morphologies are observed in both dry and hydrated states. The hydrogels exhibit stimuli-responsive behaviour in aqueous conditions and anisotropic compressive strength and diffusion behaviour with respect to freezing direction. Section three uses directional freezing and frozen UV polymerization method to prepare aligned porous monoliths containing silica. The surface of the materials was post-functionalized to make two different types of aligned porous composites. Hydrothermal synthesis using Teflon lined autoclaves was used to functionalize monoliths separately with silver and metal organic frameworks (MOFs). The MOF composite materials were used as a stationary phase to try and separate a mixture of organic compounds.

We investigated the adsorption and reactivity of substituted hydrocarbons on Si and Cu surfaces using Grimme’s vdW–corrected DFT, CI–NEB and STM simulations. Halogenated hydrocarbons on surfaces are systems of particular interest. These molecules adsorb and self–assembly at surfaces and many experimental works show that, if one provides energy to the complex, in the form of heat, light, or electrons dropped with an STM tip, they easily react resulting in single, or patterns of, chemisorbed atoms at specific and controllable sites. For instance, 1–chloropentane forms asymmetric (A) and symmetric (S) pairs on Si(001)–2×1. The rate of thermal reaction of A is greater than S in chlorinating room-temperature silicon. The energy threshold for electron–induced reaction is also different. We have used DFT and NEB tools to explain the features of this system and we simulated STM images in agreement with the experiments. On the other hand, diiodobenzenes physisorbed on Cu(110) can act as molecular calipers. We have computationally modelled the adsorption of 1,3-diiodobenzene (m–DIB) on Cu(110) and simulated STM images for the four most stable configurations using the Tersoff–Hamann approach at different bias voltages. We find that all the adsorption orientations have comparable energy and we discuss the relative probabilities of experimental observation as well as the structural details. We have furthermore compared the electronic ground–state reactivity of 1,3– and 1,4–diiodobenzene in order to show that the different symmetry of the initial adsorbed state greatly affects reactivity. Since the studied systems provide a means to surface functionalization via site–specific imprinting of single atoms, we also propose a model for Cu nanoclusters on Cu(110) supported by one or two chemisorbed S (or Cl) atoms.

The aim of this thesis was to accurately simulate the dynamic nature of known porous organic cage molecules, with a view to understanding the diffusion of different gases through their pore structures. Initial calculations showed that, due to their unique chemical structure, no ‘off-the-shelf’ force field (FF) was accurate enough to describe their dynamic motion. Therefore, a cage specific force field, (CSFF), was developed to be transferable across the first three cage systems, CC1-CC3. CSFF was subsequently used to rationalise the ‘on’/‘off’ porosity observed in two different polymorphs of CC1. A combination of computational simulations, including simulated surface area calculations, grand canonical Monte Carlo (GCMC) adsorption isotherms, and molecular dynamics (MD) simulations, for hydrogen and nitrogen in CC1α and CC1β, helped to confirm experimental results, as well as to provide further insight into why the polymorphism of CC1 alters the porosity of the molecule. In addition, CSFF was used to study the diffusion of a range of gases through crystalline CC3. Seven gases were chosen: hydrogen, nitrogen, carbon dioxide, methane, sulfur hexafluoride, krypton and xenon. A detailed understanding of the diffusivity within CC3 was accomplished by combining MD simulations with new methodologies and techniques, for example analysis of the dynamic connectivity. This helped to rationalise why CC3 showed good experimental uptake of gas, as well as highlighting potential separation capabilities. In summary, the development of CSFF has made it possible to simulate the diffusion of small gases through porous organic imine cages, and it has been shown that this diffusion is dependent on the relative size of the gas to the cage window, assuming that there is a suitable diffusion pathway. Using MD simulations, we have unlocked phenomena such as gas selectivity, rare-event hopping and the diffusion of gases to regions previously thought inaccessible. This has aided the rationalisation of existing experimental observations, and is a significant step forward for a priori prediction of porous organic cage systems, and their properties. This work has also led to new experiments that were prompted by my simulations. Finally, a new way to visualise the connectivity of a system has been introduced. This is achieved by monitoring how the surface area evolves with respect to time, during a MD simulation. This suggests how the pore channels of various systems, previously thought too small for gas adsorption, are actually suitable candidates for separations.

The applicability of aqueous, mixed addenda polyoxometalates with the general formula [PMo12-xVxO40](3+x)- as catalysts for FlowCath® technology has been demonstrated. These compounds were used as a platinum substitute in the PEM fuel cell cathode for the indirect reduction of oxygen. The effect of increased vanadium substitution within the Keggin structure upon the diffusion coefficient (Do) and the standard rate constant for electron transfer (ko) was investigated via simulation and electrochemical analysis. The apparent decrease in electrode kinetics linked with increased vanadium substitution is explained via simulation modelling, with the VxPOMs systems demonstrating multiple redox processes. The effects of solvent and electrode material upon the voltammetry are also discussed. Self supporting conditions analogous to the in fuel cell were employed to the VxPOM catalysts and their behaviour compared to the [Fe(CN)6]4-/3- redox couple via CV, simulation and RDE analysis. The resulting self-supported [Fe(CN)6]3-/4- system demonstrated significantly increased currents, but less than theoretically expected due to increases in cell resistance. The self-supported VxPOM system electrode processes are hindered due to the formation of a VO20 driven blocking layer reducing the actual potential experienced by the redox active species at the electrode surface. The resulting blocking layer prevented the VxPOM from approaching the electrode surface thus not experiencing the actual potential applied at the electrode surface. Tafel plots based upon the VxPOM systems showed characteristics not resembling ‘classical’ Tafel analysis with curvature preventing extrapolation for exchange current density. An ‘alternative’ analysis method involving the interpolation of the raw rotating disc electrode data to determine the required overpotential to generate a desired current was developed. The regeneration of the V4POM catalysts was investigated which demonstrated a possible change in speciation and a more ordered structure based upon single crystal X-ray analysis. The effects of formulation development of the lead V4POM catalyst upon its electrochemical and fuel cell performance were investigated. Substitution of Na+ counter ions with H+ (HV4POM) showed a decrease in charge transfer resistance (Rc) as well increase in membrane resistance (Rs) and cathodic current. The affects of adding stoichiometric quantities of H3PO4, HBF4 and VOSO4 were investigated with RDE and fuel cell testing indicating improved performance for the HBF4 formulation at fuel cell conditions. The effects of current developments in FlowCath® technology upon the H3PO4 formulation are also discussed.