The aim of the thesis was to study the phase behaviour of aqueous polyacrylonitrile/NaSCN solutions using a variety of nuclear magnetic resonance techniques. Polyacrylonitrile (PAN) is the basis of the acrylic fibre industry, as such fibres contain at least 85% PAN. Despite this industrial importance, the available literature describing the phase behaviour of PAN in solution is far from comprehensive. Bulk 1H NMR relaxation measurements were carried out over a wide range of concentrations and temperatures to probe the molecular dynamics of the PAN and water molecules. Both the T1 and T2 relaxation data was found to be bi-exponential decay for all samples, the relative amplitudes of which were shown to be equal to the ratio of PAN protons to water protons. Both species were found to be in the regime of rapid molecular motion. Bulk 1H NMR self diffusion measurements, using the PFGSTE technique, exhibited a bi-exponential decay of the echo amplitudes. By careful selection of the observation time, Δ, it was possible to independently probe the water and PAN translational diffusion. A background gradient, resulting from inhomogeneities of the magnetic field, complicated the analysis of the data and a novel polynomial least squares fitting procedure was devised to overcome this effect. The measured attenuation of the water diffusion coefficients (D~10-6-10-5 cm²s-1) with increasing PAN volume fraction was modelled according to various theories, including free volume and scaling laws. The study of the PAN diffusion coefficient (D~10-7-10-6 cm²s-1) was limited by the experimental constraints of the NMR spectrometer. A 1H NMR one-dimensional imaging technique was used to study the nonsolvent induced phase separation (coagulation) of a PAN solution. The time dependence of the measured profiles allowed observation of the coagulation process. A diffusion model was developed to fit the experimental data using a semi-infinite diffusion framework. The fitting parameters represented the diffusion coefficients of the water molecules in the solution/ coagulated PAN network, and in the bulk non-solvent/solvent. PAN films were cast at a range of temperatures in non-solvent baths. This was a scaling up of the dimensions of the fibre spinning process and was used to investigate the range of morphologies which can be formed in the wet-spinning of acrylic fibres. Before any drying processes, water molecules were confined in the porous structure of the saturated films, and their NMR relaxation and self diffusion behaviour was investigated. Parameters describing the pore size and the tortuosity were derived from these studies and scanning electron microscopy was used as a comparative technique. The pore sizes predicted from the NMR data span a smaller spatial range than those observed from SEM. This is explained by the fundamental differences between the two techniques.

The work presented in this thesis is primarily concerned with the structural aspects of bridging and chelation in organoantimony(V) chemistry. The thesis may be essentially divided into two main parts. The first part examines the reactions of a number of halogenated oxo-bridged organoantimony compounds (themselves subject to a study in Chapter 2) with a range of potentially bidentate groups (arsinates, phosphinates and carboxylates) to assess the capability of these groups to bridge between antimony centres. Spectroscopic and crystallographic results illustrate that arsinate groups were successfully employed in the formation of quadruply bridged compounds, whereas both arsinate and phosphinate groups enabled the preparation of several triply bridged compounds. In contrast, the shorter 'bite-length' carboxylate groups were unable to span across antimony centres in an analogous manner, although reactions between [Ph2SbBrO]2 and acetate or trimethylacetate groups led to formation of the carboxylate bridged tetra-antimony compounds, [Ph8Sbil4(mu-O)4(mu-O1.2)2(mu-O2CR3 )2]. The second part is concerned with antimony(V) stereochemistry. Incorporation of the chelating 2,2' -biphenylylene group led to manipulation of the coordination geometry at antimony and the preparation of compounds of the type, PhSb(2,2' -C12H8)X2,with square pyramidal monomeric units. The compounds, however, possess weak intermolecular connections, giving rise to dimers in the solid state and an increase in the coordination number at antimony. In addition, the related compound, PhSb (o-02C6Cl4)Cl2, also showed distinct Lewis acidity at antimony and was isolated as a diethyl ether adduct. An additional area of work is also briefly investigated in Chapter 6. This work examines reactions between halogenated phenylantimony compounds and transition metal anions, to yield complexes incorporating the Ph2Sb or PhSb moieties.

The work presented in this Thesis describes the modular design and spectroscopic study of polynuclear systems based on ruthenium (II) and rhenium (I) complexes. A combination of UV/vis, luminescence and TRIR spectroscopies, electrochemistry, spectroelectrochemistry and conformational analysis have been employed to understand the electronic structure of the ground and excited states of these compounds. Chapter I gives an introductory background to this Thesis. An overview of transition metal photophysics and excited states, and the typical spectroscopic and electrochemical techniques used in their study is presented. Previous studies of the ground and excited state properties of the complexes [Ru(bpy)3]2+ and [ReCl(CO)3bpy)] which are used as supramolecular building blocks in this Thesis are presented and a number of relevant studies of supramolecular systems are described. Chapter 2 contains a study extending the known family of [Ru(CN)4(NN)]2- complexes and describes their unique advantages over [Ru(bpy)3]2+. The results obtained are discussed alongside previous studies. This completes the introduction of the molecular building blocks used in Chapters 3 and 4. Chapter 3 details a study of through-space PEnT in bimetallic systems constructed from the complexes introduced in Chapters I and 2, bridged by a saturated alkyl linker between bpy ligands on either metal. This Chapter demonstrates the solvent-switchable nature of the direction and gradient of PEnT, using ps-TRIR spectroscopy to directly probe these processes in real time. Chapter 4 describes a study of bimetallic systems bridged by conjugated the ligand 2,2'- bipyrimidine. Monometallic, homobimetallic and heterobimetallic systems are studied and questions arising from limitations of previous studies are addressed. In particular ps-TRIR spectroscopy gives new insight into the numerous ultrafast processes occurring. Chapter 5 summarises the achievements of this Thesis and suggests promising directions for extending this work in the future. Chapter 6 describes the experimental and theoretical techniques used in this Thesis.

This thesis aims to expand our knowledge of block copolymer synthesis, particularly in supercritical CO2 (scCO2) and to study the microphase separation behaviour occurring within block copolymer microparticles during the synthesis. For these purposes, a new synthesis strategy was proposed and a high pressure X-ray autoclave was built and tested to facilitate the in situ microphase separation investigation by X-ray scattering. The success of this project has significantly broaden our understanding of the block copolymer synthesis and its phase separation mechanism in scCO2 dispersion, which are highly important to generate self-organised nanostructures. For the synthesis of block copolymers, a two-stage method has been successfully applied to add flexibility to the existing synthesis method, by allowing each block to be synthesised in independent steps. The results indicated that this method can be used for synthesising a variety of poly(methyl methacrylate)-based block copolymers. Importantly, these block copolymers can be prepared in a much shorter timeframe, since the polymerisation of the second block can be decoupled from the first. Different internal morphologies of the block copolymers were observed, including body centred cubic packing of spheres (SPH), hexagonally packed cylinders (CYL), bicontinuous gyroid (GYR), and lamellae (LAM). These morphologies were obtained by changing either the block copolymer pairs or the block volume fractions. A new design of high pressure X-ray autoclave has been constructed and successfully applied in the monitoring of time-resolved Small-Angle X-ray Scattering (SAXS) during the Reversible Addition-Fragmentation Chain Transfer (RAFT) dispersion polymerisation in scCO2 using synchrotron radiation. During polymerisation of styrene using PMMA macro-RAFT agent, the microphase separation of PMMA-b-PS block copolymers developed with reaction time resulted in more distinct domains and an increase in the domain spacing. The investigation revealed that the nanostructured morphologies remain invariant from the initial formation. However, the ordering of the nanostructures was found as the polymerisation proceed. We then sought to expand the potential of the two-stage synthesis method for preparing polymer/metal nanoparticle hybrid materials. Nanostructured PMMA-b-PDMAEMA block copolymer was selected as the host polymer. In this approach, the second block, PDMAEMA, can be synthesised while generating silver nanoparticles (AgNPs) in one-pot process. Importantly, the AgNPs can be located in the PDMAEMA domain selectively since the tertiary amine groups of the growing PDMAEMA chains anchored the AgNPs. This synthesis method produces a clean material as the solvent is readily removed on depressurisation and there was no additional reducing agent.

The ability of 2,2':6',2"-terpyridine (terpy) to chelate to a wide variety of metal ions has led to the synthesis of different metal-terpyridine complexes. In addition, there are different synthetic strategies have been improved, allowing 2,2':6',2"-terpyridine and its derivatives to find a wide range of applications assensors and catalysts. This thesis concerns the synthesis of a series of Pd(terpy) complexes with different para- and meta-substituted pyridine ligands and their properties are studied by X-ray crystallography. In order to extend the experimental observations and the range of applicability of the proposed interpretation, another system involving the tridentate aromatic nitrogen donor 4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine (tBu3-terpy) has been examined. A range of N,N-bidentate ligandsare introduced in next section. These can be potentially used to bridge two metal centres. The reactivity of [Pd(terpy)(NCCH3)](CF3SO3)2 was investigated with a wide range of N,N-bidentate ligands. Substitution of the acetonitrile ligand of [P(terpy)(NCCH3)](CF3SO3)2 with these ligands was found to be efficient and facile with reactions occurring at room temperature. Extension of this reaction to meso-tetra (4-pyridyl)porphyrin results in tetranuclear Pd(terpy) complex and affords [{Pd(terpy)}4(H2T(4-Py)P)](CF3SO3)8. In Chapter 6, similarly to terpyridine, 2-phenyl-4,6-bis(2-pyridyl)-1,3,5-triazine (pbptz) is coordinated to palladium as a tridentate ligand and no complex was seen to adopt any of the other potential binding modes for this molecule.

Electrophoretic displays (EPD) show several advantages over other display screen types including being easy on the eye, low power consumption, good visibility in bright daylight and a wide viewing angle. However, conventional EPDs only offer black and white images. One possible approach to colour EPD is the use of coloured particles. Here, the colours that can be displayed are dictated largely by the colour of the colloidal particles dispersed within the screen, which are traditionally carbon black and titanium dioxide white. In this thesis, dispersion polymerisation of methyl methacrylate (MMA) in supercritical carbon dioxide (scCO2) is investigated as a simple route to producing functional particles for application in colour EPDs. First, using a commercially available poly(dimethyl siloxane) PDMS based stabiliser, multi-stage injections are used in order to allow greater particle size control than previously published for any single stabiliser, producing particles between 309 and 3966 nm in diameter. Particle size distributions (PDI) of ~1.5 were consistently obtained for particles synthesised using this process. The method was then adapted in order to allow the incorporation of acid and base functionalised monomers in order to aid particle charging as well as acrylic dyes for colour. Analysis of these particles revealed that various core-shell structures were achieved and could be influenced by solvent and monomer choice. Finally, dyed particles synthesised using the techniques developed during this project were assessed for their ability to function in EPDs. Colour switching was successful and synthesis in scCO2 was shown to yield better separation of the white and coloured states of the test cells than those produced by analogous synthesis in conventional media.

This Thesis reports some advances in the preparation and metal catalysed reactions of diazo compounds. After an introduction presenting the synthesis routes and the main transformations of this class of compound (Chapter I), the focus is placed on the dehydrogenation of unsubstituted hydrazones as a route to diazo compounds. A review of the reagents previously used for this transformation is followed by the description of the development of the use of potassium N-iodo p-toluenesulfonamide (iodamine-T) as a new reagent for this reaction and its application to a number of hydrazones (Chapter II). After presenting the advantages offered by the handling of diazo compounds in a flow environment, the preparation of a N-iodosulfonamide functionalised resin and its application to the generation of diazocarbonyl compounds in flow are described (Chapter III). A number of examples for the further reaction of diazo compounds generated by this protocol in various in-line reactions (O-H and N-H insertion, cyclopropanation and C H insertion) are described. In particular, the synthesis of spiro-β-lactones by C-H insertion and their further conversion to oxetanes are presented. Moving away from the preparation of diazocarbonyl compounds towards their metal catalysed insertion reactions, the recently described concept of diverted insertion reaction of metallocarbenes into X-H bonds (X = O, N) is first presented and the features of this process are reviewed in light of recent examples (Chapter IV). Following its fortuitous discovery, the diverted insertion reaction of metallocarbenes derived from diazocarbonyl compounds into β-hydroxyketones to give highly functionalised and stereodefined tetrahydrofurans is described (Chapter V). Based on this process, efforts towards the synthesis of naturally occurring hyperlactone C and related compounds are discussed in the same Section. Finally, the application of a diverted insertion strategy to the preparation of functionalised and stereodefined pyrrolidines products from diazocarbonyl compounds and various β aminoketone derivatives is described (Chapter VI).

This thesis will focus on two main research areas with the aim of developing and exploring the solar photochemical reactivity of quinones. In Chapter One, a review of quinone photochemistry is presented; this includes both cycloaddition reactions and hydrogen abstraction reactions. After a review of the relevant literature, the aims of the research are outlined and placed into context. Chapter Two details the development of a green photo Friedel-Crafts acylation for the preparation of acylated hydroquinones, which serve as versatile precursors for the synthesis of numerous biologically active quinone natural products. After a review of the relevant literature, the results of the research are discussed. Key achievements include the development of an accessible and ‘greener’ synthetic protocol employing a ‘sun-mimicking’ light source and trifluorotoluene as solvent. The factors influencing the regiochemical outcome of the acylation are also discussed. In Chapter Three, the photochemical oxidising ability of p-benzoquinone in both stoichiometric and substoichiometric quantities is investigated. In the introduction, a short review of the oxidising ability of the quinones - particularly DDQ - is presented and the enhanced oxidising ability of p-benzoquinone upon irradiation is discussed. The potential breadth of this underexploited oxidising ability is then investigated in the use of alcohol oxidation and C-H functionalisation protocols. Chapter Four summarises the results obtained in the thesis and outlines scope for further research in the area. In Chapter Five, full experimental details for the research are presented.

Chapter 1. Introduction. An introduction to the detection of reactive intermediates by various spectroscopic techniques is given, as well as a brief introduction to perfluorinated solvents, which are used throughout the work presented in Chapters 2 to 4. Chapter 2. Time-Resolved Studies of Spin-Forbidden Reactions of Transition Metal Carbonyls with Weak Ligands. The photolysis of a series of first-row transition metal carbonyl compounds which have been previously reported to form 16-electron coordinatively unsaturated intermediates was examined in a series of perfluorinated solvents using TRMPS (time-resolved multiple probe spectroscopy) and TRIR (time-resolved infrared) spectroscopy. In the case of Fe(CO)5, CpMn(CO)3, (MeCp)Mn(CO)3 and CpV(CO)4, the rate of reaction of the 16-electron intermediate with the perfluorinated solvent was found to be slower than that previously reported for weakly coordinating solvents (e.g. alkanes). Addition of cyclopentane, CO2, Xe and C2H6 to a solution of CpMn(CO)3 in perfluoro(methylcyclohexane) was shown to change the rate of this spin-forbidden reaction, as well as the (CO) band positions of the resulting 1CpMn(CO)2X (X = solvent or dopant) complex. Other perfluorinated materials (perfluoro(hexanes) and perfluoro(triethylamine)) are also shown to allow formation of such weakly-coordinated alkane and noble gas complexes in room-temperature liquid solution. Chapter 3. Further Time-Resolved Studies of Alkane and Noble Gas Complexes in Room Temperature Perfluoroalkane Solutions. The photochemistry of various model transition metal compounds in perfluoroalkane solutions was examined with TRMPS and TRIR spectroscopy. 266 nm photolysis of CpRe(CO)3, Cp*Re(CO)3 and CpRe(CO)2(N2) in perfluoro(methylcyclohexane) solution was found to result in the formation of two distinct dicarbonyl species of the form CpRe(CO)2X, the first of which decay completely on the nanosecond timescale to form the second. The rate of formation, rate of decay and (CO) band positions of this second dicarbonyl species were found to be dependent on the nature of the the solvents or dopants including Xe or cyclopentane present in solution. Similar results were observed for complexes of the form M(CO)6 (M = Cr, Mo, W). DFT calculations were used in conjunction with spectroscopic studies to attempt to confirm the structure of the initially formed species following photolysis of CpRe(CO)3 and M(CO)6 in PFMCH solution. Good agreement was observed between the calculated (CO) band positions of coordinatively unsaturated species and the unknown initially formed CO loss species. Doping of CH4 or C2H6 into a solution of CpRe(CO)3 or Cp*Re(CO)3 resulted in observation of a C-H activated alkyl hydride complex, with the amount of observed C-H activation vaying in the order: CpRe(CO)3 with ethane < Cp*Re(CO)3 with ethane < CpRe(CO)3 with methane < Cp*Re(CO)3 with methane. Photolysis of CpRh(CO)2 in perfluoroalkane solvents was shown to lead to formation of a monocarbonyl solvent complex, followed by the dimeric species Cp2Rh2(CO)3, as well as another species, very tentatively assigned to a C-F activated oxidative addition product. Addition of Xe to the above solution was shown to slow formation of the dimeric species, with no evidence of C-F activation observed, indicating formation of CpRh(CO)Xe in room temperature solution. Chapter 4. Time-Resolved Spectroscopic Studies of Organometallic Triethylsilane Complexes. TRMPS studies of CpMn(CO)3, CpRe(CO)3 and Cp*Re(CO)3 were undertaken in neat HSiEt3 solvent. Photolysis of CpMn(CO)3 resulted in initial formation of 3CpMn(CO)2, following by both direct and indirect formation of the Si-H activated speciesin both cases. Photolysis ofW(CO)6 was found to result in initial formation of the ethyl-boundW(CO)5(EtSiHEt2), which interconverted to form the Si-H-bound speciesW(CO)5(H−SiEt3). Preliminary time-resolved x-ray absorption fine structure spectroscopic studies are also presented. Photolysis of W(CO)6 and CpRe(CO)3 in neat HSiEt3 was observed to cause subtle changes in the absorption edge compared to ground state XAFS spectra, indicating possible formation of transient species in both cases. Chapter 5. Experimental. The experimental techniques utilised in this Thesis are described.

This thesis describes the synthesis and characterisation of several new metal-organic frameworks (MOFs). These frameworks have subsequently been used in gas sorption experiments to determine the selective adsorption of various guests. Chapter 1 An introduction to MOFs and the current research, including a description of the synthesis and characterisation process, various applications and some known MOFs from the literature. A general experimental techniques section is included describing the various techniques used in this research. Chapter 2 A series of isostructural Cu(II) frameworks, NOTT-150 – 153, have been synthesised containing different functional groups. The four functional groups (CH3, NH2, OH and COOH) have been chosen to investigate how they affect the selective adsorption of CO2 over other gases. The polarity of the functional groups is a key factor as the protons can form hydrogen bonds to guest molecules in the framework. The lone electron pairs on some of the functional groups also contribute to the selective adsorption of CO2 by binding to the C atom to form a T-shaped interaction. The selectivity of CO2 adsorption has been studied against CH4 and N2 at 298 and 273 K, with a specific focus on how each group binds to individual CO2 molecules, and the strength of these interactions, to determine the best functional group for CO2 selectivity. Chapter 3 Group II MOFs are rare in the literature due to their tendency to form dense 2D layered structures. A series of 3D MOFs containing Group II metal ions that feature 1D porous channels have been synthesised. NOTT-408(Ca) and NOTT-410(Ba) were synthesised with a tolyl-2,4,6-tribenzoate linker, and are stable to desolvation and exhibit permanent porosity upon activation. The porous frameworks are utilised in gas sorption experiments to determine which metal centre, Ca(II) or Ba(II), has the propensity for greater selective adsorption of CO2. Gas sorption experiments were performed at 298 and 273 K over a pressure range of 0 – 1 bar to determine the selective adsorption of CO2 over CH4 and N2; and both frameworks were compared to the selectivity exhibited in a Mg(II) MOF, Mg-MOF-74. Chapter 4 The MOFs synthesised in Chapters 2 and 3 were used to determine the selective adsorption of C2-hydrocarbons over CH4. The NOTT-150 – 153 series of frameworks have shown a small increase in selectivity depending on the choice of functional group. The lone electron pairs on the NH2 and OH functional groups interact with unsaturated C2-hydrocarbons, increasing their selective adsorption. The COOH functional group partially fills Cage A within the structure making diffusion through the pores more difficult for larger molecules. This is best shown in the selective adsorption of C2H2 vs CH4 which is significantly higher in NOTT-153 (191.9 at zero loading and 298 K), than in the other frameworks. NOTT-408(Ca) and 410(Ba) have shown good selectivity for the C2-hydrocarbons due to the narrow pore channels within the frameworks.