One of a synthetic organic chemists‟ greatest challenges is to create step-efficient routes toward compounds with high molecular complexity. Therefore, reactions such as the meta photocycloaddition of an olefin to a benzene derivative, which provide more than one bond in a single step are of significant importance. It this remarkable reaction three new σ bonds, three new rings and up to six new stereocenters are formed simultaneously. Additional complexity can be added by tethering the two reacting partners together and this form of the reaction has found many uses in natural product synthesis. In this work a remarkable double [3+2] photocycloaddition reaction is reported that results in the formation of a complex cis, cis, cis, trans-[5, 5, 5, 5] fenestrane derivative from a simple flat aromatic acetal with two branching alkenes. During this dramatic transformation four carboncarbon bonds, five new rings and seven new stereocenters are created in a single one-pot process using only UV light. The reaction occurs in a sequential manner from the linear meta photocycloadduct, via a secondary [3+2] addition of the alkene across the cyclopropane of the adduct. In addition, an angular meta photocycloadduct also produced in the initial addition step, undergoes an alternative fragmentation-translocation photoreaction to afford a silphinene-like angular tricyclic compound. In this work the investigation of this newly discovered process is discussed via the synthesis and subsequent irradiation of a series of photosubstrates containing different functional groups in the arene-alkene tether. In addition, attempts toward the synthesis of alternative structures using the same double [3+2] photocycloaddition are reported.

Steam reforming is a well established industrial process for the formation of synthesis gas. It takes place in two reversible stages: the reforming reaction (1) followed by the water-gas shift reaction (2). (1) CnH2n+2 + nH2O nCO + (2n+1)H2 (2) CO + H2O CO2 + H2 Reaction (1) is highly endothermic and is favoured at high temperatures and low pressure, while reaction (2) takes place at as low temperature as possible. One of the major problems affecting the steam reforming industry is catalyst deactivation due to sulphur poisoning. Sulphur is present in the hydrocarbon feedstock and even after desulphurisation steps some sulphur still remains, from ppb to ppm levels. Such low levels of sulphur can still poison the catalyst due to the catalyst having a significant time on stream. It is therefore desirable to produce a catalyst that exhibits sulphur resistance to prolong the lifetime of the catalyst. In this project the behaviour of precious metal catalysts (Rh and Pt supported on La-ZrO2, Al2O3 and SiO2) towards sulphur was examined. Two major aspects were studied, the catalysts’ adsorpitive behaviour towards sulphur and the effect of sulphur during the steam reforming reaction. Low pressure pulses of H2S and CH3SH over the catalysts followed by gas chromatography revealed that sulphur is a very strong adsorbing species, similar to CO, and could not be displaced by the adsorption of another species as there was no mechanism to desorb the sulphur species. The alumina supported catalysts offered some protection from sulphur poisoning, evidenced during co-adsorption experiments with CO, because the support was acting as a ‘sulphur sink’. Adsorption mechanisms were proposed for H2S at the different adsorption conditions tested: a 3-site adsorption mechanism producing surface sulphides at room temperature and at higher temperatures bulk sulphides were formed. High pressure steam reforming reactions of ethane were carried out at three different temperatures (600oC, 550oC and 500oC) to act as standards to the poisoned reactions, but also revealed interesting insights into the reforming of ethane. Each catalyst produced a unique reaction profile during steam reforming, with the La-ZrO2 catalyst exhibiting greatest activity. The Rh catalysts showed high selectivity towards the formation of CH4 due to the hydrogenolysis of C2H6, which was not occurring over the Pt catalysts. The Pt catalysts were the least active and deactivated considerably as the result of carbon formation. Sulphur species, hydrogen sulphide and methanthiol, were introduced into the reaction by dissolving them in the feed water. It was found the identity of the sulphur species had a significant impact upon the extent of catalyst deactivation, with methanthiol having the most detrimental effect, which was attributed to the molecule decomposing and laying down carbon. None of the catalysts tested exhibited particularly high sulphur resistance, particularly with regard to methanthiol, however Rh/ZrO2 did recover a lot of its original activity once the poison was removed from the feed. This was due to the removal of surface carbon rather than the removal of sulphur from the catalyst, because La-ZrO2 has a faster rate of oxygen transfer and therefore a mechanism to remove surface carbon.

Chlorpropham, also known as isopropyl-N-(3-chlorophenyl) carbamate or CIPC is a sprout suppressant and plant growth regulator of the chemical class derived from carbamic acid (NH2COOH). The substance was first developed as a pre-emergence herbicide, and it was quickly identified as a useful potato sprout suppressant for long-term tuber storage (Marth & Schultz 1952). Today CIPC is the major sprout inhibitor used in the potato industry (UK Potato Council 2013c). As a consequence there is environmental concern about CIPC reaching the aquatic environment from potato washing plants. An RP-HPLC method for the analysis of CIPC and IPC in methanol solvent with an automatic integration method was developed and validated. The correlation coefficients for CIPC and IPC regression lines at all calibration levels (0.001–100 mg/L) were (R2>0.999) while IPC exhibited a slightly less linear calibration curve (R2>0.98) at the lowest concentration range of (0.001–0.1 mg/L). An acceptable precision of 10% based on 10 injections was obtained at the limit of quantification of 0.001 mg/L for both analytes. The 3CA was excluded at this stage as it overlapped with an extra peak which required extensive investigations. The identification led to the conclusion that the artefact peak was a methanol-oxygen peak and elimination of the methanol-oxygen peak was not possible. The evaluation of five different columns and conditions in separating the methanol-oxygen peak from 3CA in a mixture containing 3CA, IPC and CIPC was studied. For the four peaks, the best separation at low eluant concentration was obtained at 55% methanol, but the run time was considerable. In contrast, the best separation at high eluant concentration was obtained at 75% methanol; however, the methanol-oxygen peak was still incompletely separated from the IPC peak due to the high size of the methanol-oxygen peak. Further investigations were conducted to reduce the size of the methanol-oxygen peak by changing the mobile phase pH which had no effect. Changing detection wavelength from 210 – 260 nm reduced the peak size, but considerable loss in sensitivity was observed. Five different instruments were tried and at the end the Thermo HPLC system was chosen because it provided a smaller methanol-oxygen peak along with temperature control to enhance the methanol-oxygen and 3CA peak separation at 60% methanol eluant, but the run time was still very long. Therefore, to enable a compromise between baseline peak resolutions as well as high-throughput separations; two separate methods for 3CA and CIPC, including IPC were developed and validated. The precision for both analytes at two levels of 0.01 and 1.0 mg/L based on 10 injections was ≤ 1%, the calibration curves at all levels were (R2>0.999) and the limit of quantification was 0.001 mg/L. Preparation of CIPC, IPC and 3CA standards in water from stock solutions in methanol and directly by dissolution in water was investigated. The peak areas were not affected even at 0% methanol concentration and the peak shapes were sharper than that in methanol without affecting the peak area. This validated the use of water as sample solvent to carry out the analysis by HPLC. To successfully prepare CIPC, IPC and 3CA in 100% water, it was necessary to develop methods for preparation and handling aqueous solution of CIPC, IPC and 3CA. The solubility of CIPC and IPC were studied. Both CIPC and IPC have low solubility in water while 3CA has higher solubility and dissolved quite rapidly. The solubility time curve for CIPC showed a gradual concentration increase from initial time until day 3 stirring but after that the solubility was consistent and values of 106, 89 and 61 mg/L CIPC were obtained at 25°C, 22°C and 4°C respectively. IPC exhibited similar solubility behaviour and the corresponding values were found to be 222, 200 and 140 mg/L at same temperatures respectively.The solubility results agreed with the literature values. Stock solutions and standards in aqueous solution were found to be stable on storage at 4°C (refrigerator) and ~20°C (lab temperature) for up to 90 days.For this work it was necessary to investigate possible CIPC, IPC and 3CA adsorption from aqueous solutions by glassware and filters. All plastic glassware were avoided as they have measurable adsorption (20-40%) for the analytes, except high clarity polypropylene. In contrast, glass materials particularly borosilicate and soda glass provided nearly zero adsorption for all three analytes. Although it was possible to identify suitable glassware that did not adsorb CIPC, IPC and 3CA it was necessary to discard the first 25 mL of filtrate to overcome adsorption onto filters (Cellulose, Glass microfiber, PTFE and Nylon). The Glass microfiber, type GF/B filter, has a pore size of 1.0 µm and is often used as a prefilter. However, the 25 mL discarding from filtrate was suitable only for filtering sample larger than 25 mL. For small scale filtration, a much smaller 0.2 µm PTFE filter in a 17 mm chemically resistant polypropylene housing disk attached to 3 mL BD syringe was used and only 1.5 mL of the sample was required to saturate the filter. A liquid-liquid extraction method with vortex mixer (LLE-Vortex) was successfully developed and validated for the extraction of CIPC and 3CA from dilute soil–water suspensions (0.001 g/mL) with a high recovery 98%–100% and RSD% less than 1.34%. In addition, the method was reliable for extraction from high soil suspensions formed with 0.02 g/mL of soil and for 0.1 g/mL of soils with low adsorption capacity. The average precision of extracting CIPC at 0.02 g/mL and 0.1 g/mL soil content was 1.6% and 3.2% while more precise extraction observed for 3CA of about 0.91% and 1.86%, respectively. However, the extraction method did not work for soil suspension with the highest organic matter content and concentration equal or more than 0.1 g/mL. Investigations were carried out to examine the adsorption- desorption behaviour of CIPC and 3CA from aqueous solutions onto different clay and sandy air dried soils. The suitable contact time of two days using 1 g material size was determined. At all temperatures, CIPC and 3CA were strongly adsorbed in clay soils while only slightly adsorbed in sandy soils. A paired t-test was used to compare between the adsorption at 5°C and 30°C for CIPC and 3CA and concluded that there was a statistically significant difference between the two temperatures for both analytes (p-value < 0.05). The effect of pH was also studied and it was found that the soil pH had a negligible impact on the adsorption of CIPC, while for 3CA the adsorption at low and high pH was significant (p-value <0.05). The data was fitted to a Langmuir isotherm (R2=0.91-0.98) and adsorption maxima calculated. The maximum adsorption capacities for CIPC in Downholland 1A, Downholland 2A, Midelney 2A, Midelney 1A, Midelney 1B, Dreghorn 1A, Dreghorn 1B, Quivox A and Quivox B were 1583, 668, 714, 927, 215, 325, 243, 355 and 194 µg/g respectively and for 3CA were 1024, 1104, 550, 651, 292, 278, 317, 239 and 162 µg/g respectively. The main determining factor was soil organic matter. Desorption for CIPC and 3CA from soils increased with reducing both carbon and LOI percentage. In addition, investigations were extended to study the adsorption of CIPC and 3CA in oven dried plant waste materials. The data was also fitted to a Langmuir isotherm (R2=0.96-1.00) and adsorption maxima calculated. The maximum adsorption capacities for CIPC in mixed bark, B&Q garden peat, Miracle-Gro compost, Pine needles, Scots pine bark and Birch bark were 3090, 2968, 2973, 3636, 3004 and 2581 µg/g respectively and for 3CA were 2914, 2724, 2953, 2787, 2358 and 2568 µg/g respectively. The removal of chlorpropham from two river water types was studied in laboratory incubation experiments at two temperatures and different treatments of carbon, nitrogen, phosphorus, Fulvic acid and soil extracts.

TaxolTM and its derivatives are the largest selling anticancer drugs of all time. Numerous synthetic works and total syntheses have been published since its discovery, but to date no high yielding synthesis with less than 37 steps has been achieved. In this thesis is presented our synthetic efforts toward such a robust and efficient synthesis of Taxol. The optimisation of the Shapiro coupling fragments syntheses were investigated to enhance the robustness of our strategy. Then the C7-deoxy model ABC tricycle ring-system of Taxol, which lacks the oxygenated substituent at C7, has been efficiently synthesised by a dienyne ring-closing metathesis cascade (RCDEYM). This cascade closed the AB 6/8 membered ring system in a single operation. Other dienyne ring-closing metathesis cascades with similar substrates were also performed, assessing the influence of ruthenium catalysts, C1-C2 diol protecting groups (R1, R2), and substitution of the alkene at C13. Synthetic efforts were also devoted to apply such a powerful method toward a formal synthesis of Taxol from an intermediate Holton and co-workers synthesised. During our studies, the C7-oxy group was found to be critical to access the ABC tricyclic core of Taxol by metathesis cascade. Understanding of the importance of this C7-oxy group was undertaken and led to the conception of a metathesis cascade prediction model. Once the metathesis cascade was optimised, differentiation of the three trisubstituted alkenes present on the ABC tricyclic ring system was studied and elaboration of a formal synthesis was endeavoured.

The effects of precursor, support and calcination procedure on the physical and chemical properties of supported cobalt catalysts have been investigated. A multiple characterisation approach of thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and transmission electron microscopy was employed in order to gain understanding into the calcination and reduction processes. In addition, the catalysts were screened on a purpose built fixed bed reactor, under industrially relevant conditions, to determine effect of catalyst preparation on Fischer-Tropsch activity.

The opening chapter details investigations undertaken into heteroallylation methodology developed within the France group. The first section gives an overview of the existing strategies for palladiumcatalysed alkene difunctionalisation reactions which construct a new nitrogen-containing heterocycle. Particular attention is devoted to the construction of new carbon–carbon bonds and the relative lack of methods to construct new sp3–sp3 C–C bonds. The second section details the results of a mechanistic investigation into the previously developedoxyallylation ethodology. The investigation successfully provided evidence that an isohypsicpalladium(II) catalysed mechanism was operative. The third section discusses attempts towards the extension of the heteroallylation methodology to include the construction of nitrogen-containing heterocycles. Initial attempts focussed on the aminoallylation of tosylamides, from which four new heterocycles were synthesised. Further investigations with hydroxamates allowed the synthesis of three further heterocycles, but the results demonstrate the potential for a greater substrate scope in the future. The fourth section details experimental procedures and compound data. The second chapter details research undertaken towards the validation of a novel therapeutic target for the treatment of parasitic nematode infections. The first section details the current treatments and the growing levels of resistance to these treatments. Furthermore, previously published data concerning nematode astacins, the proposed new target, is presented, providing information which was utilised for the design of the new inhibitors. The second section discusses the design and synthesis of proposed nematode astacin inhibitors, and details the biological testing results gathered by our collaborators. Two compounds, in particular, were demonstrated to be the most potent known compounds against the new therapeutic target. Taken together, the results demonstrate a start point towards to goal of a new class of nematode-infection therapeutics. The third section details experimental procedures and compound data.

The research described herein involves the study of new approaches to alkenation and pinacol cross-coupling. The competition between modified Julia alkenation and Peterson alkenation was studied. Heterocyclic sulfides were oxidised to sulfones by dimethyldioxirane. Reactions between sulfones and aldehydes gave vinyl sulfones in good yields, rather than vinyl silanes, confirming that the Peterson alkenation is preferred in this system. Pinacol cross-coupling between an aldehyde or ketone in solution and a more easily reduced aldehyde immobilised on resin was attempted, but proved unsuccessful. However, aldehydes bearing the salts of tertiary amines were found to be good substrates for pinacol homo-coupling giving diols. The formation of salt avoided unwanted reduction of the aldehyde to a primary alcohol. A wide range of approaches to anisomycin using titanium reagents were investigated. These were based on the formation of the bond between C-3 and C-4 by alkylidenation of esters and ring-closing metathesis (RCM) or intramolecular alkylidenation or radical cyclization. The presence and position of the nitrogen atom proved an insurmountable obstacle to this strategy. The solid-phase synthesis of 4-amino-ketones was achieved. Resin-bound esters were alkylidenated using a novel titanium reagent generated in situ by reduction of a thioacetal with a low valent titanium reagent. Treating the resulting enol ethers with acid gave ketones in good yield and high purity because of the switch in the nature of the linker from acid-stable to acid-sensitive (a chameleon catch strategy). Amino-ketones are potential precursors of pyrrolidines.

Today, CMOS-compatible Flash memory technology dominates the non-volatile memory storage market due to high density and low fabrication costs. However, with CMOS approaching fundamental scaling limits, research into novel emerging non-volatile memory storage technologies that exploit materials properties including resistance, spin and polarisation, has significantly progressed. The ideal non-volatile memory technology would compete with Flash, offering high-density memory storage at low costs, however it would outperform Flash due to its faster operating speeds, lower energy requirements, greater endurance and greater potential for scaling. Of all the emerging technologies, resistive RAM (RRAM) elements, in which reproducible (switchable) and distinct high and low resistance states are the basis of memory storage, are considered most advantageous due to their superior potential for scaling, fastest exhibited operating speeds and extremely low energy requirements. Despite progress in the field of RRAM research, the underlying mechanisms that allow a device to switch between high and low resistance states remains unclear in many materials systems and is the key motivation behind this work. Here, Pulsed Laser Deposited (PLD) RRAM devices that incorporate resistive switching transition metal oxide thin films were studied using Electron Energy Loss Spectroscopy (EELS). Basic metal/oxide/metal RRAM heterostructures that incorporated strongly oxidising titanium electrodes and polycrystalline ZnO and manganese-doped ZnO were investigated in Chapter 3. These devices were designed for direct comparison to a device in presented the literature which displayed the simultaneous co-switching of resistance and magnetisation states. In the devices fabricated here, EELS analysis revealed Mn-phase segregation both at grain boundaries both above and below the top and bottom electrodes, which supported the proposed co-switching mechanism. In Chapter 4, epitaxial single crystal perovskite oxide Pr0.48Ca0.52MnO3 was incorporated into a novel metal/oxide/tunnel-oxide/metal RRAM structure, where the thickness of the interfacial Yttria-stabilised Zirconia tunnel oxide varied the output current density. In both the ZnO and Pr0.48Ca0.52MnO3 devices, EELS analysis revealed that the observed resistive switching was mediated by the field-induced exchange of oxygen vacancies between the bulk oxide and an interfacial oxide. Despite this similarity, the overall device resistance was governed by different effects: for the polycrystalline ZnO-based devices, this was the oxygen-vacancy induced formation and dissolution of a highly resistive TiO2 interfacial layer; in contrast, for the epitaxial Pr0.48Ca0.52MnO3 device, this was the oxygen-vacancy induced charge accumulation and dissipation in the tunnel oxide, which modulated the tunnel barrier height.

This work investigates the hydrogen storage potential of a variety of solid state materials. The work has showed their synthesis, structure, morphology and hydrogen storage properties comprehensively. An MgH2 nanocomposite composed of 80% tetragonal α-MgH2 and 18% orthorhombic γ-MgH2 has been prepared for the first time without recourse to high pressure or temperature. By optimizing the ball milling conditions, addition of LiCl and use of THF solvent, the α-/γ-MgH2 nanocomposite so-produced is capable of releasing 6.6 wt% H2 with rapid kinetics, from ca. 260 °C without the use of a catalyst. Moreover, Ti-catalyzed MgH2 offering a capacity of 5.5 wt. % of H2 and superior hydrogen desorption kinetics has been successfully prepared by a novel wet chemical route. The MgH2 material, containing approximately 2~3 wt. % of Ti-additive exhibits hydrogen desorption at a temperature approximately 220 °C lower than pristine MgH2 where pure hydrogen evolution starts at ca. 420 °C via a synergetic effect of mechanochemical treatment and additives. Neutron scattering was employed to study the structure of activated MgD2 and for the first time local disorder in activated MgD2 has been verified using total neutron scattering (PDF fitting). Small angle neutron scattering (SANS) analysis indicates a surface fractal geometry, i.e high degree of surface roughness for activated MgD2 particles, in accordance with SEM analysis suggesting the morphological alteration introduced by mechanochemical treatment. A novel PANI-LiBH4 composite has been successfully fabricated through simple mixing. It is found that PANI-LiBH4 composites dehydrogenates from ca. 200 °C with over 10 wt.% H2 released by 400 °C, significantly outperforming pristine LiBH4. Importantly, rehydrogenation can be achieved under conditions unprecedented for LiBH4 in isolation (200 °C; 100 bar H2 or 330 °C, 20 bar H2 vs. 600 °C, 350 bar H2). Moreover, the PANI-LiBH4 composite can be readily cycled and a new endothermic uptake event at 140 °C, a remarkably low temperature for LiBH4-based systems, suggests that the polymer thermodynamically alters the hydrogenation mechanism. PANI-NaBH4 and PANI-LiH also exhibit vastly improved dehydrogenation properties compared with the respective hydride materials alone. The structures of some first row transition metal halide hydrazinates, TMX2·2N2H4 (TM= Mn, Fe, Co, Ni, Cu and Zn; X= Cl and Br), have been revisited and detailed structural information of three typical complexes, MnCl2·2N2H4, ZnCl2·2N2H4 and MnBr2·2N2H4 have been accurately determined by using a combination techniques of PXD, FTIR and PND. It is also found that TMX2·2N2H4 decomposes at relatively high temperature ( > 250 °C) with massive weight loss due to the dissociation and decomposition of the N2H4 ligand. However the major gas evolution has been determined to be N2 and NH3 with only a minor amount of H2 (and undesired impurity N2H2) released, which makes TMX2·2N2H4 unsuitable for hydrogen storage. Our strategy to combine TMCl2·2N2H4 with LiBH4 to fabricate novel transition metal borohydride hydrazinates has been proven to be successful. Two novel complexes, Mn(BH4)2·2N2H4 and Zn(BH4)2·2N2H4 have been successfully prepared via a facile mechanochemical route with careful manipulation over the milling parameters. The crystal structure of Mn(BH4)2·2N2H4 has been determined using SR-PXD to be isostructural with its parent material MnCl2·2N2H4. The phase evolution behaviour of Zn(BH4)2·2N2H4 has been probed with evidence of various intermediate phases during preparation when various milling conditions were employed. The dehydrogenation properties of both complexes have been studied using DTA-TGA coupled with MS. Mn(BH4)2·2N2H4 and Zn(BH4)2·2N2H4 are very promising materials for off-board hydrogen storage due to their high hydrogen content and useful dehydrogenation properties.

This thesis describes the synthesis and characterisation of novel organic and organometallic materials with potential optoelectronic application. Chapter one provides a general introduction about the different types of solar cells and an overview of the working principle of two types of solar cells, DSSCs and BHJs, including examples of some molecular designs of the best performing dyes. Chapter two describes the successful synthesis and characterization of two organometallic molecules based on the porphyrin moiety (PorTh and PorFu). These dyes were employed to fabricate DSSCs devices, reporting a power converting efficiency of 4.2% as the best result. The same chapter reports the synthesis and characterisation of another metalloporphyrin dye (EDOT-Por), designed to be used as a sensitiser in DSSCs and synthesised by screening three types of one-pot C-H activation reaction protocols. Chapter three describes the synthesis and characterization of four novel ferrocene derivatives which were designed using a donor-π-acceptor architecture for DSSCs. The main advantage of these compounds would be the easy two-step synthesis, starting from cheap starting materials. The first part of chapter four describes the synthesis and characterization of a series of porphyrin derivatives containing a central transition metal ion (Zn (II), Pd (II), Ni (II) and Cu (II)), which were used as electron donor compounds in BHJs. The Zn-based porphyrin was chosen for photovoltaic device and blended with PC61BM, used as an acceptor, to give a power converting efficiency of 0.28%. The second part of this chapter describes the synthesis of a novel phthalocyanine derivative, which can be used as a donor unit in BHJs. Unfortunately, due to its very low solubility in most organic solvents, this compound could not be characterised. Chapter five describes the synthesis and characterisation of a family of organic conjugated polymers and the small molecules based on thieno[3,4-b]pyrazine (TP) unit, to be used as donor materials in BHJs. All polymers exhibit low solubility in most common organic solvents. The small molecules, however, were tested in as donor materials BHJs, showing low VOC ranging between 0.4 and 0.6 V, with the most performing device exhibiting a PCE of 0.62%. Chapter six describes the synthesis of new TTF derivatives designed to be used as a donor materials in BHJs. Different synthetic pathways were used to prepare these compounds, unfortunately it was not possible to synthesise the target materials.