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The need for light-weight, high capacity energy stores is driven by the necessity for a more sustainable approach to reducing the global dependency on fossil fuels. Storing hydrogen in the solid state is an attractive method in which the safety, sustainability and performance requirements for the automotive and aviation sectors may be met. Mechanochemical methods have been exploited in this work to modify and synthesise inorganic materials for hydrogen storage based on Group I and Group II metal compounds. The properties of un-milled and milled commercial MgH2 have been examined and milling conditions optimised to obtain desirable hydrogen desorption characteristics. Subsequently, inexpensive, non-toxic, non-oxide catalyst materials were considered for enhancing the hydrogen release properties and three catalysed hydride systems were examined; MgH2-xSiC, MgH2-xgraphite and MgH2-xSiC:graphite (x = 1-20 wt%). The hydrogen desorption properties of the 1:1 molar SiC:graphite doped MgH2 system are shown to exhibit improved hydrogen release properties relative to the carbide and graphite systems alone, suggesting a synergistic effect. The Ea for hydrogen desorption from MgH2 could be decreased from 144±5 kJ/mol to 84±5 kJ/mol in the MgH2-10 wt% SiC:graphite system, maintaining a desirable hydrogen capacity >5 wt%. A recurring artefact of thermal analysis profiles for MgH2, in this work and in literature, indicates a two-step decomposition process under relatively mild milling conditions. Therefore, beyond the investigations described for optimisation of hydrogen release conditions, the effect that the aforementioned catalysts have on the two-step desorption anomaly using milder milling has also been investigated. This has given insight in to how the tuning of MgH2 may be made possible by selection of catalysts which have a more prominent effect on the low temperature desorption step relative to the higher temperature feature. Direct synthesis of ternary hydrides from their corresponding binary hydrides has been investigated by mechanical alloying of stoichiometric and non-stoichiometric binary hydride mixtures. High purity NaMgH3 powder (Orthorhombic space group Pnma, a = 5.437(2) Å, b = 7.705(5) Å, c = 5.477(2) Å; Z = 4) was prepared in 5 h at high ball:powder ratios using a stoichiometric mixture of the respective binary hydrides. The dehydrogenation behaviour of the sub-micron (crystallites typically 200 – 400 nm in size) ternary hydride was investigated by thermal analysis. The nanostructured hydride releases hydrogen in two-steps with an onset temperature for the first step of 240 °C. ii Using a range of initial binary hydride stoichiometries, a series of potentially new cubic ternary (Ca1-xMgxH2)n hydride phases has been proposed, such that the initial stoichiometry of Ca:Mg results in (non-)stoichiometric Ca-Mg-H phases relative to the known Ca19Mg8H54 phase. The crystallographic properties of the (Ca1-xMgxH2)n series have been examined by both lab and in-situ synchrotron X-ray diffraction experiments, and the Rietveld method employed to establish detailed structure information. The thermal properties of the (Ca1-xMgxH2)n hydrides have also been determined and their relative hydrogen desorption and gravimetric capacities compared. This work demonstrates that as the proportion of Mg increases, the thermal stability of the Ca-Mg-H system is lowered and higher hydrogen capacities are obtained. The effect of small alkali metal vs. larger alkaline earth metal inclusion on the Mg-H system is explored through this work. With a focus on new solid state synthesis routes to hydrides, mechanochemical metathesis reactions have been examined. Complex and ternary halides were selected as halide precursors, towards the synthesis of complex and ternary hydrides. The halides; LiAlCl4, NaMgCl3 and NaAlCl4, were synthesised using mechanochemical alloying of stoichiometric mixtures their respective binary metal halides. Their structures and thermal properties were determined and comparisons drawn between conventional synthesis in literature and the mechanochemical method employed in this work. The halides were then milled in appropriate stoichiometric ratios with alkali metal hydrides to determine whether a proposed metathesis reaction may result in the formation of the respective ternary/complex hydride. The products of the mechanochemical metathesis reactions were evaluated using powder diffraction and then thermal analysis, where low temperature hydrogen release corresponding to the desired hydride product was found. One metathesis route in particular highlights the potential of this approach, where analysis of the product suggests that the elusive “LiMgH3” hydride has been formed with hydrogen release at 316.6 ºC. This work illustrates that the solid state metathesis route is a suitable means for materials synthesis and design, where tailored reactions can yield exciting results.

Work in this thesis involves manipulating the interaction between light and matter in order to retrieve important information from adsorbed molecules, such as their structure and/or function, and henceforth, to gain insight into highly sensitive detection capabilities for biosensor applications. Such manipulation might be achieved via rationalising the surfaces of optically active metamaterials by taking full advantage of the recent growth in a variety of nanotechnology disciplines. As such, the possibility of characterising biomolecules adsorbed on the surface of chiral and achiral plasmonic metamaterials, referred to as chiral and achiral plasmonic nanostructures, have been investigated. Also, illustration and applications for the so called `Superchiral Field`, which has been generated via circular polarised light (CPL), are presented. Microscopic origin of the chiroptical second harmonic generation (SHG) signal that originates from the surface of the chiral nanostructures has been investigated. Practical visualisation via femtosecond laser beam of regions of intense plasmonic activity, i.e., hot-spot mapping, has been performed. In general, the work described in this thesis involved the use of several linear and non-linear chiroptical techniques namely as extinction (absorption and scattering), CD, ORD and SHG spectroscopy, in addition to scanning imaging namely SEM and AFM microscopy. Given that most biomolecules contain either chiral molecules or adopt chiral structures, the plasmonic nanostructures presented in this work could be used to study a wide range of biological problems, from the structure of biomolecules associated with neurodegenerative illnesses such as Alzheimer’s disease and Parkinson’s disease, to DNA and viruses. As a regard, general classifications for aspects of chirality are presented in order to emphasise the association of the samples used in this chapter with some of these aspects. All samples are fabricated via Electron Beam Lithography (EBL) in JWNC cleanroom/UK; the associated fabrication techniques, the instruments and the experimental methods are described.

Taxol is one of the world’s most successful drugs used in the treatment of cancers. Isolated from the bark of the Pacific yew tree (Taxus brevifolia), it is a molecule of great interest within organic chemistry; with six total syntheses and a number of synthetic works having been published since its discovery. A semi-convergent synthesis of an intermediate in Holton’s synthesis was planned. The overall synthetic plan is shown below. The A ring would be installed by an intramolecular pinacol condensation. The BC bicycle would be closed by ring-closing metathesis at C10-C11. The ketone at C12 would be protected as an alkyne and the BC bicycle precursor would be obtained by coupling fragment A and the C ring. This thesis describes the preparation of a model C ring, without the oxygenated functionality at C7, was successfully synthesised along with fragment A. Metathesis precursors were synthesised and gold hydration reactions were attempted.

This thesis describes the use of titanium carbenoids for the synthesis of piperidinone alkaloids, in particular pipecolic acid derivatives, and the development of a new titanium-based strategy for the methylenation of carbonyl compounds including carboxylic acid derviatives.

Steam reforming of CH4 is an established industrial process for the formation of synthesis gas. It takes place in two reversible stages: CH4 reforming reaction (1) followed by the water-gas shift (2). (Fig. 3599A) The biggest worry to the steam reforming industry is the formation of carbon which is produced favourably via three side-reactions: (Fig. 3599B) In this project, the behaviour of eight supported noble metals (Rh, Pt, Ru and Ni supported on La-ZrO2 and Al2O3) during reactions (3)-(5) at 20bar and 873K was investigated. It has been shown previously that noble metal catalysts can be more active than Ni during steam reforming and are more carbon resistant. More significantly, noble metal catalysts do not form whisker carbon. High pressure reactions (3) and (4) combined with a series of low pressure pulses followed by mass spectrometry revealed the greater stability of the La-ZrO2 supported catalysts due to strong metal support interactions (SMSI) and a faster rate of O-transfer. Ni was always the more reactive catalyst although it was not compared at high pressure for risk of potential damage. Common mechanisms were proposed for all catalysts involving interaction of surface OH-groups with reactant species on all La-ZrO2 and Al2O3 catalysts. The reactivity of the Al2O3 catalysts was related to percentage metal dispersion although this was not apparent for the La-ZrO­2 catalysts. Deactivation studies revealed the likely first and second order behaviour of reactions (4) and (3) respectively. These studies also showed how the rate of deactivation was greater over Pt than Rh. Each noble metal catalyst produced a unique reaction profile during reaction (5) and the greater reactivity of the La-ZrO2 catalysts was attributed to interfacial metal-support interactions (IMSI). The reaction profile was clearly affected by the nature of the metal and the support and so a mechanism was proposed with an explanation of each catalysts' behaviour in terms of type of metal and support. An excess of steam can be used to prevent carbon formation and likewise, CO2 can be used for the same purpose. An investigation of different CO/CO2 ratios was made and it was apparent that ratios of approximately 1:1 were necessary for carbon prevention. A pre-treatment of each catalyst with CO/CO2 changed the product selectivity during reaction (5).

This thesis describes the incorporation of a flavin unit into a range of systems spanning photovoltaics and biomimetic self-assembly. The flavin unit is better known as a cofactor in a range of enzymes. However, the unique physical and self-assembly properties were exploited in this research programme to develop new systems with photovoltaic and biomimetic self-assembly applications. In Chapter 1 a general introduction relating to flavins and photovoltaics is provided. In Chapter 2, the aim was to explore the effect of the addition of fullerene to a range of acceptors in the expectation of forming new acceptor materials with a wide range of LUMO energies. In Chapter 3, the aim was to investigate the effect of coupling a flavin unit to a naphthalenediimides (NDI) unit in the expectation of forming hybrid materials for solar energy conversion. Chapter 4 describes the formation of conjugated polymers featuring a flavin moiety, in the expectation that these materials will have photovoltaic properties. Chapter 5 describes the synthesis of push-pull flavin systems with pH dependent visisble light absorption characteristics. Finally Chapter 6 describes the synthesis of water soluble ammonium salts to furnish new micelle based systems with hydrogen bonding recognition properties.

Previous studies of single-molecule magnets (SMMs) have interpreted their low-temperature (below 8 K) magnetic measurements on the basis of X-ray crystal structures measured at 100 K or even room temperature. The work presented herein describes the first structural measurements performed on SMMs in the temperature regime in which magnetisation studies are performed. The ultra-low temperature (2 K) crystal structure of the prototypical SMM [Mn12O12(O2CMe)16(H2O)4]⋅2MeCO2H⋅4H2O (Mn12-acetate, 1) was determined by using single-crystal X-ray and neutron diffraction. We have observed an additional hydrogen-bonding interaction in the disordered region of 1 that backs up the link between solvent disorder and disorder in the position of an acetate ligand. Two new desolvated species [Mn12O12(O2CMe)16(H2O)4]⋅4H2O (2) and [Mn12O12(O2CMe)16(H2O)4] (3) were formed from 1 by single-crystal to single-crystal (SCSC) transformations and lead to the conclusion that the acetic acid of crystallisation in 1 is responsible for positional disorder in an acetate ligand. Another new {Mn12} derivative [Mn12O12(O2CMe)16(CH3CH2OH)4]•CH3CH2OH (4) is formed by exposing the desolvated species to ethanol vapour. The structure of the SMM [Mn3O(Et-sao)3(ClO4)(MeOH)x(H2O)3-x] (5, Et-saoH2 = C6H4-1-CH(C2H5)N(OH)-2-OH) at 2 K is also reported from a combination of single-crystal neutron and X-ray diffraction experiments. There is linked disorder in the identity of the coordinated solvent (methanol or water) and in the position of the ethyl substituent in the Et-sao2- ligand. This leads to a number of possible isomers present in a single-crystal and is consistent with the observation of transverse anisotropy in 5 previously recorded by high-frequency- and high-field-electron paramagnetic resonance (HF-EPR) spectroscopy. The crystal structure of the triangle intermediate [Mn3O(O2CEt)6(py)3](ClO4) (6, py = pyridine) formed during the synthesis of the SMM [Mn4O3Cl4(O2CEt)3(py)3]⋅4MeCN (7) is reported for the first time. Additionally a related new compound [Mn4O3Cl7(O2CEt)3](C5H5NH)3 (8) that crystallises in the same space group as 7 is also reported. The structure of the SMM [Ni4(dea)4Cl4]⋅4MeCN⋅0.6H2O (9, deaH = (HOCH2CH2)2NH) is reported at 1.7 K by using single-crystal neutron diffraction. The isostructural bromide complex [Ni4(dea)4Br4]⋅6MeCN (12) was synthesised for the first time and its structure is reported at 30 K. Methanol solvates of each species are also reported (10 and 13) and crystallise in the lower symmetry P-1 space group. 13 displays similar low-temperature (sub-3 K) magnetic behaviour to that reported for 9, as well as an additional slow relaxation process at 4-6 K. Mass spectrometry is consistent with the formation of {Ni4} cubanes with N-substituted diethanolamine ligands, N-phenyl-deaH and triethanolamine (teaH); the former with chloride ligands and the latter with bromide ligands. Another new solvothermally-derived {Ni4} cubane species is described with a slightly different cubane core, [Ni4(dea)4Br2(H2O)2]Br2 (14). We attempted to investigate two species based on a {Ni10} supertetrahedron (16 and 17); unfortunately the single-crystal neutron diffraction experiment carried out on these compounds was unsuccessful. The structure of the SMM (C(NH2)3)8[Co4(cit)4]⋅4H2O (18, H4cit = (HO2CCH2)2C(OH)CO2H) was determined at 2 K using high-resolution neutron powder diffraction, single-crystal X-ray diffraction and single-crystal neutron diffraction. The former two measurements offer some evidence for disorder in the hydrogen bonding between the {Co4} clusters, guanidinium cations and solvent of crystallisation; however, the latter measurement does not support this. A series of inelastic and polarised neutron scattering measurements are presented for a deuterated sample of 18 (denoted 19) and allow observation of scattering related to magnetic excitations.

The Ajudazols A and B are secondary metabolites, isolated in 2004 and exhibit anti-fungal and cytotoxic activity. The primary objective of the work presented in this thesis was to expand and develop our novel isobenzofuran oxidative rearrangement methodology for generation of isochromanones, and to apply this methodology towards the total synthesis of the ajudazols. An efficient, high yielding, regio- and diastereoselective oxidative rearrangement sequence has been developed, allowing for the generation of elaborately-functionalised isochromanone structures, from transient isobenzofuran intermediates. A flexible route to the synthesis of the ajudazol B eastern section was achieved, and this research culminated in the synthesis of ent-8-epi-ajudazol B.