Lithium-ion high voltage cathode materials are discussed within this thesis, with LiCoPO4 as a composite electrode evaluated for use as the active compound within lithium half-cells. A comprehensive literature review on lithium containing cathode materials with a focus on high voltage materials is provided. The majority of the materials within this work were synthesised using solvothermal techniques, which were characterised through XRD and SEM. Composite type electrodes were prepared through mainly using PTFE as the binder material, and different electrolytes were also investigated. Composite electrodes were electrochemically evulated with competitive capacites obtained compared to the literature. The performance of the LiCoPO4 composite electrodes was found to be significantly different and attributed to the use of different synthesis solvents and heating conditions used for synthesis. The rate performance and electrochemical cycling was found to depend highly on the surface area and particle size of the composite electrode. XANES and in-situ XRD was performed at Diamond Light Source (UK synchrotron), where the LiCoPO4 charge profile was fully characterised. It was found that LiCoPO4 undergoes transient lattice parameter changes during charging, and that phase recovery during any relaxations was observed.

In this thesis, the development of a new methodology for the C–H oxidation of a variety of organic substrates using a bimetallic vanadium-titanium molecular sieve, VTi AlPO-5, is presented. Preliminary studies using model substrate propylbenzene were conducted to elucidate trends in catalytic activity by varying a wide array of reaction and catalyst parameters. Following that is a series of studies documenting the uses of VTi AlPO-5 in the oxidation of other substrates, in which different types of reactivity were probed. The catalyst is highly active and capable of redox- as well as acid catalysis due to the inclusion of its vanadium and titanium centres, the combination of which has been found to be capable of effecting two-step syntheses in the same pot, or enhancing selectivity to very high levels in several reactions. The physicochemical nature of the material as well as spectroscopic investigation of the V and Ti centres in the catalyst has been investigated using a variety of techniques. This data, combined with the catalytic data obtained during reactions, led to the proposal of structures for the metal ions and a preliminary reaction mechanism.

Kohn-Sham density functional theory (DFT) is an extraordinarily powerful and versatile tool for calculating the properties of materials. In its conventional form, this approach scales cubically with the size of the system under study. This scaling becomes prohibitive when investigating larger arrangements such as biomolecules and nanostructures. More recently linear-scaling approaches have been developed that overcome this limitation, allowing calculations to be performed on systems many thousands of atoms in size. An example of such an approach is the ONETEP code which uses a plane wave-like basis set and is based upon the use of spherically-localised orbitals. A simple yet common calculation performed using ab initio codes is the total (ground state) energy calculation. By comparing the energy of isolated parts of a system to the energy of the combined system, we are able to obtain the energy of interaction. This quantity is useful as it provides a relative measure of the enthalpic stability of an interaction which can be compared to other systems. Equally, however, this quantity gives little indication of the driving forces that lead to the interaction energy we observe. A number of approaches have been developed that aim to identify these driving forces. Energy decomposition analysis (EDA) refers to the set of methods that decompose the interaction energy into physically relevant energy components which add to the full interaction energy. Few studies have applied EDA approaches to larger systems in the thousand-atom regime, with the vast majority of investigations focussing on small system studies (less than 100 atoms in size). These methods have shown varying degrees of success. In this work, we have evaluated the suitability of a selection of popular EDA methods in decomposing the interaction energies of small biomolecule-like systems. Based on the results of this review, we developed a linear-scaling EDA approach in the ONETEP code that separates the intermolecular interaction energy into chemically distinct components (electrostatic, exchange, correlation, Pauli repulsion, polarisation, and charge transfer). The intermediate state used to calculate polarisation, also known as the absolutely localised molecular orbital (ALMO) state, has the key advantage of being fully antisymmetric and variationally optimised. The linear-scaling capability of the scheme is based on use of an adaptive purification approach and sparse matrix equations. We demonstrate the accuracy of this approach in reproducing the energy component values of its Gaussian basis counterparts, and present a remedy to the limitation of polarisation and charge transfer basis set dependence that is based on the property of strict localisation of the ONETEP orbitals. Additionally, we show the method to have mild exchange-correlation functional and atomic coordinate dependence. We have demonstrated the high value of our method by applying it to the thrombin protein interacting with a number of small binders. Here, we used our scheme in combination with electron density difference (EDD) plots to identify the key protein and ligand regions that contribute to polarisation and charge transfer. In our studies, we assessed convergence of the EDA components with protein truncation up to a total system size of 4975 atoms. Additionally, we applied our EDA to binders that had been partitioned into smaller fragments. Here, we accurately quantified the bonding contributions of key ligand moieties with particular regions of the protein cavity. We assessed how accurately the ligand binding components are reproduced by the fragment contributions using an additivity measure. Using this measure, we showed the fragment binding components to add up to the full ligand binding component with overall minimal additivity error. We also investigated the energy components of a series of small thrombin S1 pocket binders all less than 30 atoms in size. In this study, we demonstrate the EDA and EDD plots as tools for understanding the relative importance of different binder structural features and positionings within the pocket. Overall, we show our EDA method to be a stable and powerful approach for the analysis of interaction energies in systems of large size. The application of this method is not limited to biomolecular studies, and we expect that this approach can be readily applied to analyses within other fields, for example materials, catalysts, and nanostructures.

This thesis explores the “crystal engineering” of the solid-state behaviour of a series of alkali metal TCNQ salts. This can exhibit a variety of electronic and magnetic properties, depending on the solid-state architecture. TCNQ is a good one-electron acceptor and the resulting radical anion salt is quite stable. The architectural behaviour of TCNQ salts is very dependent on the nature of the counter-cation and the stoichiometry of the material. In the present study, the effect of ionophore-encapsulation of the cation (M = Li, Na, K, Rb and Cs) has been explored using single crystal X-ray diffraction, IR, Raman, EPR and pressed discs conductivity measurements. In addition, the effect of changing the ionophore:metal cation ratio and the presence of additional TCNQ0 has been investigated. 25 new crystal structures have been obtained and analysed in detail and this has grown new insight into the impact of the effect of controlling ion pair interactions through ionophore complexation and of steric factors on the nature of TCNQ assemblies adopted. A range of solid-state motifs have been observed including some novel solid-state behaviour. In addition, the solid-state behaviour of two hydrated lanthanide TCNQ salts has been investigated.

Compositionally graduated films of a SrTi1-xFexO3-y (STFO) perovskite electrocatalyst were successfully prepared by High Throughput Physical Vapour Deposition (HT-PVD). X-ray diffraction measurements confirmed a cubic perovskite structure for all values of x as well as an increase in the cubic lattice parameter with increasing x from 0.392 ± 0.001 nm for SrTiO3 to 0.386 ± 0.001 nm for SrFeO3 in accordance with Vegard’s Law. A Raman mode corresponding to an O-stretching vibration was observed which is disallowed by symmetry in the cubic structure and suggests a localised lattice distortion. The films were highly resistive, < 7 x 10-8 S cm-1, at low x but conductivity increased with increasing x before reaching a plateau at 0.041 S cm-1 for x > 0.75.High electrocatalytic activity towards the oxygen evolution reaction (OER), characterised by over-potentials below 0.2 V, was found for STFO electrode compositions with x > 0.5. The high OER activity was however found to correlate with low electrode stability, consistent with the participation of lattice oxygen in the OER mechanism. This was supported by the observed redox electrochemistry which showed evidence of reversible oxygen intercalation. An optimal electrode composition of SrTi0.5Fe0.5O3-y is recommended as OER activity showed no significant increase for higher Fe content whilst electrode stability decreases. Low electrocatalytic activity towards the oxygen reduction reaction (ORR) was observed for all compositions. The ORR did not occur until after surface reduction of the films suggesting that the surface reduction is required for the creation of active surface sites. The STFO perovskite system was also investigated on Fe doped STO (110) surfaces. A series of reconstructed surfaces were prepared and characterised by low energy electron diffraction (LEED) in agreement with the literature. X-ray photo-electron spectroscopy (XPS) and low energy ion scattering spectroscopy (LEISS) confirmed that Fe doping was successful in incorporation of Fe into the perovskite structure. Fe incorporation was observed to improve the ORR electrocatalytic activity of the surface however no OER electrocatalytic activity was observed.

Photovoltaic devices have emerged as a promising and efficient technology to address rising global energy demands as the current energy source, which depends on fossil fuels is running out. This technology has the ability to directly convert sunlight to electricity. Inorganic photovoltaic devices exhibit relatively high power conversion efficiencies from 8 to 29%. However, the high cost of these devices has impeded their widespread usage. Intensive research has been done in order to find different approaches to explore less expensive materials to maintain a technology path for photovoltaic devices. Organic photovoltaic devices based on conjugated polymers have gained a large amount of attention from researchers and academicians owing to their potential characteristics when compared with inorganic solar cells. The potential characteristics of organic photovoltaic devices are as follows: they are economical, light weight, and their roll to-roll production is fast and inexpensive. Several types of π-conjugated polymers have been synthesized and applied as electron donor materials in organic photovoltaic devices, either as homopolymers or alternating donor-acceptor copolymers. In this project, different type of donor-acceptor conjugated polymers, consisting of pyrene as the electron donor and benzothiadiazole or thieno[3,4-c]pyrrole-4,6-dione as the electron acceptor, have been prepared via palladium catalysed cross-coupling reactions such as Stille or direct arylation. The purity and identity of all monomers were confirmed by 1H and 13C NMR spectroscopy, GC-MS and elemental analysis. The structures of all synthesised polymers have been confirmed by 1H NMR spectroscopy and elemental analysis. The thermal, optical and electrochemical properties of all polymers have been investigated using TGA, UV-vis, CV and XRD in order to evaluate their suitability for application in organic photovoltaic devices. The optical band gap of all polymers ranged between 1.76 and 2.06 eV. Bulk heterojunction devices were fabricated from all polymers using PC70BM as the electron acceptor. Preliminary studies indicated that the power conversion efficiencies of the polymers ranged from 0.33 and 2.06 %.

The project aimed to reveal mechanistic details of the Pd-catalysed direct arylation reaction involving fluoroarenes. Direct arylation methodologies have rapidly developed over the last decade as cost-effective, eco-friendly and sustainable alternatives to cross-coupling reactions. Fluoroarenes are attractive substrates due to the fluorine-substitution effect as well as the ability to control the regioselectivity of C–H bond activation by the ortho-fluorine effect. Understanding the reaction mechanisms are crucial for making improvements to the C–H bond functionalisation field and provides access to unique reactivities. A literature reaction condition and the setup for the direct arylation reaction of iodoarene with fluoroarene was tailored for monitoring the progress by in situ FT-IR spectroscopic analysis. Kinetic information regarding the relationship between the reaction rate and factors such as concentrations, temperature, C–H bond strength and the electronic properties of the substrates were established. The catalytically relevant species were identified by in situ NMR spectroscopy, and ex situ MS. The reactivities of these species were confirmed by stoichiometric reactions and the ability to act as a catalyst.

This Thesis describes the development of novel catalytic dearomatisation methodologies of indolyl and pyridyl systems for the synthesis of spirocyclic and annulated products. Chapter 1 provides an introduction to this area of research and reviews related reactions, as well as setting out the research objectives. Chapter 2 describes the cyclisation of indole-alkyne systems I, using Ag(I) or Au(I) catalysis, to selectively form either spirocyclic indolenines III or carbazoles IV in high yield through a common vinyl metal intermediate II. An efficient and reusable heterogeneous catalyst system was also found for the synthesis of indolenines III. A high-yielding asymmetric spirocyclisation methodology was later developed by using the silver salt of a BINOL-derived chiral phosphoric acid V to furnish spirocycles in up to 89:11 er. Finally, these methodologies were applied in brief studies towards the natural product spirobacillene B VI and in an accidental synthesis of actinopolymorphol B VII. Chapter 3 details the cyclisation of indole α-diazocarbonyls VIII, using Rh(II)-, Pd(II)-, Cu(II)- and SiO2-based catalysts to selectively form 6 different products, namely spirocyclic indolenines IX, oxindoles X and XI, as well as annulated indole isomers XII, XIII and XIV. This work is, to the best of our knowledge, a record number products prepared through catalyst-selective synthesis. A number of diverse mechanistic pathways were proposed in this work, including a surprising reaction involving atmospheric oxygen. Finally, Chapter 4 describes the cyclisation of pyridine-, pyrazine- and isoquinoline-ynones XV to generate annulated products XVII, which are presumed to form via a vinyl silver species such as XVI. This work ultimately led to a high-yielding 5 step dearomative synthesis of the alkaloid (±)-lasubine II XVIII.

Latent Image formation made apparent by double decomposition with AgNO(3) and ordinary development has been studied In thallous bromide-gelatin systems. The plates prepared were found to be much faster than those previously made(11), relatively stable latent Image formation and no reduction in capacity for such formation with time being features noted. The type of gelatin used was found to be largely responsible for the speed Increases. The speed of the emulsion was found to be increased by large amounts of bromine acceptors, but small amounts apparently had little effect. Contrary to previous work (11), the presence of Iodide In Increasing amounts decreased the sensitivity of the plate to blue light. The thallous bromide plates were found to be directly sensitive to green light. Reversal was found to take place with red,green and low intensity blue light, but In the case of the blue light such reversals were only found at much higher primary densities and lower intensity values than In previous work. The straight line relation between the bleaching limit and the primary density was confirmed, A general desensitisation effect was found when malachite green and and methylene blue were aided to finished emulsions and an increase of the intensity of light at which the bleaching limit occurred, was observed. A study was made of the latent image distribution in thallous bromide grains, using dichromate bleachers, surface and total developers, and another reversal effect was observed, which was dependent on the Internal image? The Gurney-Mott mechanism of latent image formation is considered to be applicable in general to the thallous bromide system. An approximate general equation was extended and developed. Finally, some preliminary work was done on the possible latent image formation in lead bromide, antimony oxybromide and bismuth oxybromide. In the last case latent image fomation was shown to be present but was capable of development to a much smaller extent than in the thallous bromide system.

This thesis describes investigations into the coordination- and thermo-chemistry of metal-uronide complexes (namely alginates). The work probes the importance of such metal-saccharide interactions in the thermolysis of kelp, with a view to deriving valuable fuels and chemicals from this aquatic bioresource. In this regard, Chapter 1 justifies the model-compound approach adopted in this thesis, and outlines the wider context in which the work is set. Chapter 2 describes the isolation of the composite monosaccharides of alginate (D-mannuronate and L-guluronate) and their characterisation by NMR spectroscopy. A combination of 1- and 2-D 1H and 13C experiments were utilised to provide the most comprehensive assignments of algal mono-uronates to-date. Subsequently, the well-defined mono-uronate spectra were used to probe the conditions that favour hydrothermal uronolactone formation. Chapter 3 probed the response of the algal mono-saccharides (prepared and characterised in Chapter 2) to a range of metal ions (Na+, K+, Mg2+, Ca2+, Sr2+, Ba2+, Zn2+, and Cu2+) to explore the validity of the well-known “Egg-box model” of metal ion/alginate coordination. By observing changes to anomeric equilibria, α-L-gulopyranuronate was found to coordinate (via an axial-equatorial-axial arrangement of hydroxyl groups) to large, divalent cations, in a manner consistent with “Egg-box binding”. In contrast, in the presence of Na+, Mg2+, Zn2+, and, Cu2+ α-L-gulopyranuronate interacted via its carboxylate moiety (and possibly ring oxygen), demonstrating the unsuitability of these ions for Egg-box binding. Chapter 4 describes the impact of the metal ions discussed in Chapter 3 on the subsequent pyrolysis behaviour of alginates (and related mono- and poly-uronides). Thermogravimetric analysis (TGA), pyrolysis-gas chromatography mass spectrometry (Py-GCMS), and solid-state studies of the post-thermolysis chars were all conducted. The uronides were generally found to demonstrate unfavourable thermal behaviour (high yields of char, CO2, and H2O, and low yields of condensable hydrocarbons). Complexation of Cu2+, however, had a beneficial impact on subsequent thermolysis, by increasing the low-temperature, selective formation of 2-furfural. The presence of Cu0 in the alginate char is indicative of Cu(II)-mediated alginate decomposition occurring via a Hofer-Moest type decarboxylation. Chapter 5 tested the validity of the model compound approach by enriching samples of kelp with either Cu2+ or Ca2+ ions and studying the thermal degradation of the resulting materials by TGA and Py-GCMS. The thermochemical outcomes for the whole biomass mirrored those found for the model compounds studied in Chapter 4. Finally, in Chapter 6, the results of Chapter 2 – 5 are analysed synoptically, and the success of the model compound approach is appraised. Ultimately, it is concluded that the ability of a metal ion to inhibit or promote thermal decarboxylation of a uronide (in isolation or within kelp) is more important in dictating pyrolysis behaviour than any differences in coordination to various hydroxyl groups around the saccharide ring. The results could find application in the development of a phytoremediative kelp-based thermal biorefinery.