The work detailed in this thesis is presented and discussed in three distinct chapters, which constitute a general and progressive study into polyoxometalate (POM) chemistry. This began with the development of a new synthetic strategy towards a family of transition metal-substituted POMs (TMSPs), continued through the study of POM physical properties in solution, and culminated in the empirical analysis of a new family of structures. During this work, the focus was primarily on crown-type POMs and their function as supramolecular inorganic hosts, both as discrete ‘zero-dimensional’ structures, and as an integral part of porous multi-dimensional frameworks. Four iso-structural triple Wells-Dawson-type phosphotungstate compounds, which incorporate six transition metal (TM) centres are discussed, with two of the compounds presented for the first time. An in-depth comparative study of the structures of the four TMSPs has been conducted, and related back to the synthetic conditions which gave rise to their formation. Electrochemical and electrocatalytic studies of the four compounds are also detailed. Although a great number of TMSPs of various shapes, sizes and composition is already known, the establishment of iso-structural TMSP families is still rare. In the second chapter, the application of isothermal titration calorimetry to assess the binding properties of the crown-type POM, [P8W48O184]40- ({P8W48}), is discussed. To facilitate these studies, {P8W48} was prepared in the absence of potassium to give two new mixed lithium/ammonium salts. Distortion of the {P8W48} ring, previously only observed in compounds with TM substitution, was observed both in solution and in the solid state, whilst this investigation also revealed ‘super-crown’ behaviour of the compound. {P8W48} is also an ideal building block for the construction of inherently-porous framework materials. However, the coordination of 1st-row TMs to this POM ring has so far proven unpredictable, and established compounds are often difficult to reproduce. Comprehensive analysis of {P8W48}-based frameworks was therefore performed to unite a group of previously disparate compounds. This class of inorganic framework materials is termed POMzites due to members’ all-inorganic POM scaffolds, their oxygen-rich and anionic nature, and their micro-scale porosity

Biological macromolecules are becoming increasingly important as a target for pharmaceutical research. Structural examination of this class of compounds is vital, both in terms of understanding the three-dimensional structures these molecules form as well as for quality control of bio-pharmaceutical products. UV polarised spectroscopy, such as circular dichroism (CD) is a powerful tool for this form of analysis, rapidly providing the user with structural information on the sample. The ease of data analysis combined with its non-destructive nature make UV polarised spectroscopy an ideal tool for this purpose. However, limitations in the current instrumentation, especially in terms of sample handling have placed significant barriers in the way of fully realising the potential of these techniques. To address the weaknesses of the currently available UV polarised spectroscopy accessories, new devices have been designed and tested to increase the utility of such techniques. A low volume capillary sample holder has been developed which significantly reduces the sample requirements for circular dichroism without loss of signal quality. This advance has been coupled with an HPLC auto-sampler to create a device that can process 96-well and in some cases 384- well plates. This device opens up a host of new applications for polarised UV spectroscopy, including refolding screening as well as freeing up user time. Additionally, a high precision demountable micro scale cuvette has been developed that reproducibly assembles to the same path length every time. The percentage error of path-length for this new cuvette is of the same order as currently commercially available 1 mm cuvettes. This new accessory should prove highly advantageous for the bio-pharmaceutical industry, as it allows accurate path-length CD analysis for high concentration samples. Additionally, the first confirmed linear dichroism (LD) spectrum of a bacterium and flagella are reported, opening up the potential for real time UV spectroscopic analysis of living bacteria. By using the work contained within this thesis, it should be possible to construct a new form of high path-length accuracy, low volume, multiple-sample UV polarised spectroscopy accessory that could be used for both CD and LD analysis.

Many of the highlights in the surface science field in the last years have arisen from the study of organic molecules adsorbed upon, but physically decoupled from, metallic substrates. When adsorbed on bare surfaces like Cu, the strong interaction between the two can have a number of different effects on the chemistry, functionality and assembly of the adsorbates. These effects can be reduced or even prevented by incorporating an ultra-thin insulating film between the molecule and the metal, enabling the retention of the desired molecular properties. Previous studies have almost exclusively used films of inorganic material, such as alkali halides and metal oxides. In this work, an all-organic alternative approach has been developed, which should allow a greater degree of control over the nature of the decoupling film and its corresponding interactions. To demonstrate the potential impact of the molecule-substrate interaction on the formation of molecular nanostructures, the adsorption and assembly of a prototypical molecular tecton, terephthalic acid (TPA), has been explored on Cu(110) and Cu(111). On Cu(110), the TPA is deprotonated and goes on to form a range of metal-organic or all-organic monolayer films. The exact structure obtained is determined by the total molecular coverage, which is rationalised by consideration of the TPA adsorption energies and the molecular density in each phase. On Cu(111), TPA adsorbs intact, and assembles into a brickwork-like structure characterised by both uncharacteristically short and elongated hydrogen bonds. This unusual assembly is the result of the oft-cited, but in general poorly understood, ‘interplay of intermolecular and molecule-substrate interactions’. In a bid to understand the observed supramolecular assembly of TPA on Cu(111), a simple algorithm has been developed that is capable of predicting both its quantitative and qualitative aspects. Moreover, this analytical model can be readily expanded to more complex assemblies, such as those using more complex molecules and surfaces. In addition, the formation of Cu- and Fe-terephthalate complexes has been explored. Oxalic acid (OA) monolayers have been investigated as prototype organic decoupling layers for the Cu(110) and Cu(111) surfaces. This molecule was chosen as, in previous work, it had been reported to adsorb in an upright orientation and assemble into a densely packed monolayer on Cu(110). In this work, a flat-lying, low density film has been obtained on Cu(110), which later proved to be incapable of supporting molecular ‘overlayers’unless it was cooled to low temperature prior to the deposition of molecular overlayers. In contrast, a densely-packed, upright monolayer was obtained on Cu(111). This decoupling layers was effective even at room temperature, and moreover appears to plays a significant role in determining the assembly of the overlayer species. These studies indicate the potential of vertically standing organic films as both decoupling layers and also as a tool with which to directly modify and control the assembly of organic nanostructures.

The objective of this work was to synthesise water-soluble polymers bearing desirable functionality, particularly to improve water-solubility of phthalocyanines by incorporation of hydrophilic polymers for personal oral care applications. Prior to preparation of water-soluble polymers containing phthalocyanine, the second chapter described the synthesis of ferrocenyl initiator for polymerisation of tert-butyl acrylate by SET-LRP, followed by acidolysis of tert-butyl group yielding poly(acrylic acid) containing ferrocenyl end group. The resulting polymer could be used as the scale inhibitor for a potential oil drilling application, and further detected by cyclic voltammetry due to the presence of the ferrocene end group. The majority of the thesis is focussed on an investigation of novel approaches for covalently attachment of water-soluble polymers to (copper or zinc) phthalocyanines. The initial PEGylated CuPc complexes were obtained via DCC/EDC coupling reactions, and the resulting blue powder showed excellent solubility in water; however, it revealed a broad molecular weight distribution due to the presence of mono-, di-, and tri- substitutions of PEG chains as confirmed by GPC analysis. PEGylation of phthalocyanines were further improved via a combination of Mitsunobu reaction and CuAAC “click” reaction. In this approach, the substituted macrocycles were prepared from 4,5-bis-(4-hydroxyphenoxy)phthalonitrile as a precursor. The final PEGylated CuPcs or metal-free Pcs with different PEG chain lengths were prepared by two different routes. The incorporation of the (Cu)Pc core with the polymer chain was confirmed and distinguished by THF-GPC equipped with a PDA detector, and also showed an increase in hydrodynamic volume with increasing the PEG chain length with a narrow dispersity remained. PDMAEMA, as a dual responsive polymer was also introduced to ZnPc using a core-first approach by a combination of ATRP and CuAAC reaction with sharing the same CuBr/PMDETA catalyst, yielding the star-shaped water-soluble polymer. The polymer solution represented tuneable LCSTs in range between 83 and 33 oC with increasing the pH of the buffer solution from 7 to 10. The polymer was further transformed into highly polyelectrolyte stars with ZnPc core by quaternization of the pendant amino groups with either methyl iodide or 1,3-propanesultone. The resulting zwitterionic star after quaternized with propanesultone, ZnPc-PMEDSAH, exhibited a UCST value 17 oC, compared with the quaternized salt, ZnPc-PMETAI with no obvious phase transition observed. In addition, their optical properties and aggregation behaviour in water were investigated by UV-Vis spectroscopy. The final study involved the synthesis of water-soluble zinc phthalocyanines conjugated to poly(galactose) by an arm-first approach. The well-defined protected galactose oligomer arm was synthesised by SET-LRP with a desirable ω-chain end as confirmed by MALDI-ToF MS analysis which were ready for postfunctionalisation. Following a click reaction and deprotection of the acetal groups, the isolated green powder achieved good water-solubility and emitted a sharp fluorescent band at approximate 695 nm via excitation at 610 nm in DMF. The GPC analysis also showed that a narrow molecular weight distribution remained after deprotection and confirmed the presence of ZnPc core by the PDA detector.

Polyoxometalates (POMs) are anionic oxides of the early transition metals in their highest oxidation state (i.e. V(V), Nb(V), Ta(V), Mo(VI) and W(VI)) which possess a wide structural diversity and an equally broad range of physical properties. Transition metal substituted polyoxometalates (TMSPs) are the subset of the POM family which members can be described as metal complexes of purely inorganic, highly nucleophilic, POM based ligands and oxophilic transition metals. TMSPs are usually synthesized in solution via multi-step reaction procedures; however the processes controlling their formation are poorly understood and usually described as "self-assembly". Hence, the design of synthetic methods aimed at producing a desired structure is based on a mixture of empirical observations and general considerations about the reactivities of both ligand and transition metal in solution. The judicious exploration of the synthetic parameter space (e.g. pH, added electrolytes, etc.) have resulted in the discovery of a high number of complexes, a process which contributes to a better understanding of the relationship between synthetic conditions and final structure. However, and despite the vast number of TMSPs reported in the past couple of decades, this connection between synthetic variables and the structure of the cluster is far from being fully established. In particular, the effect of high pH values of the reaction mixture and the presence of alkaline metal ions does not seem to have been fully explored and therefore a potentially high number of clusters may lay undiscovered. A section of this thesis is devoted to that exploration of the parameter space of TMSP synthesis involving four different lacunary POM ligands ({γ-SiW10}, {γ-GeW10}, {A-α-PW9} and {α-P2W15}) and late first-row transition metal ions. The synthetic variables scanned during this programme were primarily two: the increase of the pH, by means of the addition of several inorganic bases, and the addition of alkaline metal salts to the reaction mixtures. A number of novel TMSPs were thereby discovered which, thanks to their relevant structural features, represent a significant contribution to the final goal of rationally design pathways to produce these complex inorganic architectures. The remarkable physical properties of POMs can be exploited by their integration into suitable composite materials. In particular, their ability to undergo several reversible electrochemical reductions whilst retaining their structural integrity, a property which is usually coupled to a pronounced change of optical absorbance, make these clusters ideal candidates for electrochromic applications. However, their performance in terms of optical contrast and switching time is typically lower than state-of-the-art electrochromic materials. A strategy employed to exploit and enhance the electrochromic response of POMs is to disperse them in an electrochromic organic polymer and hence produce an improved material in terms of its optical contrast. However, mostly classic POMs, with just one type of transition metal in their elemental composition and of relatively simple structure, have been examined for this application while only a small number of TMSPs have been evaluated for the same purpose. V(IV/V)-substituted POMs, for example, have not been used to fabricate this type of materials in spite of their electrochromic properties. A section of this thesis is devoted to the deposition and characterization of a number of TMSP-based hybrid films in terms of morphology, electrochemistry and electrochromic response. Electrodeposited films containing an electrochromic organic polymer and a dimeric V(V) TMSP, {V(V)6P4W30}, showed a higher optical contrast than films containing the monomeric equivalent, {V(V)3P2W15}, or POM-free films. This result constitutes a significant insight into the effect of the structure of the cluster on the electrochromic performance of POM-based hybrid materials.

Synthesis of a photoactivated uncoupler I was completed and subsequently used by collaborators to demonstrate mitochondria uptake. The synthesis of a ratiometric, targetable calcium sensor was completed up to intermediate II (9 steps), alongside a thiohydantoin heterocycle III synthesised in 5 steps. A co-worker has subsequently completed the probe synthesis based on this route, with the resulting probe showing good binding and optical responses in testing. Numerous routes to 5,6-disubstituted phenanthridinium salts were investigated towards the synthesis of a mitochondrially targeted superoxide probe and hydroxylated standards. In the course of this work a novel cyclisation was developed based on intramolecular SNAr giving access to 9-benzyloxyphenanthridinium salt V. Rapid and high-yielding access to 5,6-disubstituted phenanthridinium salts IX was then achieved through forming benzophenones VIII via Suzuki coupling and converting these to imines with the alkylamine. The nitrogen atom of the imine then undergoes cyclisation onto the aryl fluoride in an intramolecular SNAr upon heating. This transformation was shown to have good steric and electronic tolerance in the synthesis of 13 phenanthridinium analogues with 6 structural diversification points. Subsequent DFT calculations by a colleague showed this reaction proceeds in a concerted fashion and as such represents a considerable mechanistic novelty. Efforts towards a new probe for mitochondrial superoxide led to the synthesis of 3-tertbutyl-dihydrophenanthridine X, which does not intercalate into DNA upon oxidation. This concept was refined and lead to the development of neopentyl ethidium XI and the targeted analogue MitoBNH XII and its deuterated analogue XIII.

This thesis describes the preparation and characterisation of potential ‘modular’ solid state hydrogen storage solutions for on-board applications. The systems investigated throughout this work are based on reactions between light weight hydroxides and hydrides. In many senses light metal hydroxides can be seen as attractive candidates for hydrogen storage: they are low cost, present negligible toxicity and it is not possible to poison the fuel cell with decomposition products, unlike in nitrogen or boron containing systems. However, as the dehydrogenation products are the respective oxides, the major drawback of such systems lays in the fact the thermodynamics of rehydrogenation are not favourable for onboard applications. Hence, the system must be considered as a ‘charged module’, where the regeneration is performed ex-situ. Dehydrogenation can be achieved through reaction with light metal hydrides such as LiH or MgH2. A wide range of ‘modular’ release systems can be studied, however the most interesting in terms of theoretical gravimetric capacity, kinetics and thermodynamics within reasonable temperature range (RT - 350°C) use magnesium and lithium hydroxide and their hydrate forms. The present work focuses on the full investigation of three main systems: · Mg(OH)2 – MgH2 system · Mg(OH)2 – LiH system · LiOH(·H2O) – MgH2 system (both anhydrous and monohydrate LiOH were used) Mixtures of hydroxides and hydrides were prepared by manually grinding stoichiometric amounts of the starting materials. Further, nanostructuring the reactants was investigated as a means to control the dehydrogenation reaction and enhance the kinetics and thermodynamics of the process. Nanostructured Mg(OH)2 and LiOH(·H2O) have been successfully obtained using both novel and conventional synthetic routes. Reduction of the particle size of both hydrides was effectively achieved by mechanically milling the bulk materials. As detailed throughout Chapters 3, 4 and 5, promising results were obtained when employing nanosized reactants. The onset temperatures of hydrogen release were decreased and the overall systems performances enhanced. Particularly interesting results were obtained for the LiOH – MgH2 system, which exhibit a dramatic decrease of the onset temperature of H2 release of nearly 100 K when working with milled and nanostructured materials with respect to bulk reagents. All systems were characterised mainly by Powder X-ray diffraction (PXD) and simultaneous thermogravimetric analysis (TG-DTA) mass spectroscopy (MS). TG-DTA2 MS experiments were performed to obtain information on the onset and peak temperature of hydrogen release, weight loss percentage and nature and amount of the gases evolved during the reaction. Ex-situ PXD studies have been performed for each system in order to try and identify any intermediate species forming during the dehydrogenation process and ultimately propose a mechanism of H2 release. Since two fundamentally different types of reaction pathway could be proposed for the Mg(OH)2 – LiH system, powder neutron diffraction (PND) was employed for following the reaction in-situ. Developing a complete model of the dehydrogenation process in terms of mechanistic steps was found to be pivotal in order to understand and enhance such systems further.

A series of 3-acyl(thio)chromones has been prepared. These compounds were acetalised with a variety of diols, with p-TsOH catalysis, under azeotropic conditions, to give the corresponding 3-acyl(thio)chromone acetals. A new rearrangement accompanies the formation of acetals from 3-acetyl- or 3-benzoyl- chromone giving a 2-methyl- or 2-phenyl- 3-formylchromone acetal. The rearrangement is initiated by conjugate addition of the diol to the chromone ring. The C-2 lithio derivatives of 3-acyl(thio)chromone acetals are generated by treatment with lithium diisopropylamide or lithium 2,2,6,6-tetramethylpiperidide (LTMP) in THF at low temperature. The anions have been intercepted with a variety of electrophiles. It was found that metallation with LTMP proceeds more efficiently. A number of novel 3-acyl-2-(1-hydroxyalkyl)(thio)chromone acetals has been prepared by electrophilic trapping with aldehydes. Three novel self-condensation dimers were obtained from lithiations of 3-acyl(thio)chromone acetals; the structures of two were established by X-ray crystallography. Mechanisms for their formation are presented. Whilst C-2 lithiation of 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane with n-BuLi does occur, the reaction is complex and leads, ultimately, to a benzofuranone derivative. The structure and relative stereochemistry of this compound, which possesses two 1,4-disposed stereogenic centres, was established by X-ray crystallography. The reaction also provides another compound, derived from 1,2-addition of n-BuLi to 2-(4-oxo-4H[1]benzopyran-3-yl)-1,3-dioxane. Lithiation of 2-(hydroxymethyl)chromone with LTMP initiates reduction ofthe pyranone ring, probably via a Single Electron Transfer mechanism. Electrophilic trapping of the intermediate anion with CICO2Et proceeds in a regio- and diastereospecific manner. Unmasking of the acetal function in 3-acyl-2- (1-hydroxyalkyl)(thio)chromone acetals is facile (p-TsOH in toluene) and proceeds with concomitant cyclisation to give novel 9H-furo[3,4-b][l]benzo(thio)pyran-9-ones. Cycloaddition reactions of the furobenzo(thio)pyranones have been investigated. When 3-methyl-9H-furo[3,4)[1]benzopyran-9-onereacts with methyl propiolate a pincer Diels-Alder reaction prevails, to give an octacyclic 2:1 adduct with complete regio- and stereo- specificity. The stereochemistry was established as syn exo-endo by X-ray crystallography. Dimethyl acetylenedicarboxylate reacts with 3-(4-methylphenyl)-9H-furo[3,4-b][1]benzopyran -9-one to give a mixture of the 1:1 and the anti exo-exo 2:1 adducts. 3H,9H-Furo[3,4b[1]benzopyran-1,9-dione has been obtained via a tandem acylation-SnAr reaction of ethyl 2-fluorobenzoylacetate. Protolysis of dimethyl 1,4-dihydro-1,4-epoxy4-(4-methylphenyl)-9-oxo-9H-thioxanthene-2,3-dicarboxylate gives the expected 1-hydroxythioxanthone derivative. However, the analogous 1,4-epoxyxanthene underwent an unprecedented hydrolytic cycloreversion to dimethyl 2-(4-methylphenyl) furan-3,4-dicarboxylate and 4-hydroxycoumarin. The acylation of 3-pyrrolidinodihydrothiophenes with 2-fluorobenzoyl chloride has been investigated as an entry to the 9H-thieno[3,4-b]benzopyran-9-one system. An unexpected product, 2,4-bis(2-fluorobenzoyl)-3-pyrrolidino-2,5-dihydrothiophene is formed predominantly.

The targets of this thesis were the selective oxidation of hydrocarbons under mild conditions, using cheap and environmentally friendly oxidants and initiators. Three projects are treated; the oxidation of an alkane using O2 and a co-oxidant, the oxidation of toluene using TBHP (tert-butyl hydroperoxide) and finally the oxidation of propane using hydrogen peroxide. C-H bond activation, O2 activation and high conversion with high selectivity were essential points to investigate. In the first project, alkane oxidation was studied in presence of a co-oxidant. The co-oxidant has for purpose to initiate the activation of the alkane and O2, as well as prevent the over-oxidation of the alkane. The co-oxidation of octane using benzaldehyde has been investigated using 1 wt. % AuPd/ C catalyst; the hypothesis is that benzaldehyde oxidation would use a radical mechanism able to activate octane to octanol. Also, the coupling of octanol with activated benzaldehyde would prevent the over-oxidation of octanol by the formation of an ester; octylbenzoate. The aim of the second study was to investigate the selective oxidation of toluene using TBHP at 80 °C with supported noble metal nanoparticle catalysts prepared by sol-immobilisation techniques. Au, Pd and Pt have been use to form mono, bi and trimetallic catalysts of different morphology supported on C and TiO2. These catalysts have been tested for toluene oxidation. The catalyst showing the best activity has been used for further investigation such as reuse test, using H2O2 as oxidant or O2 activation. The third project target was to oxidise propane using H2O2 in mild conditions. 2.5 wt. % Fe/ ZSM-5 (30) has been used to investigate reaction conditions in order to optimise the system. This catalyst has been acid treated; standard and treated catalysts were characterised and analysed to identify the structure and active sites. Role of supports and metals (mono and bimetallic) has been explored in order to improve this system.

This thesis presents new experimental techniques and utilizes these strategies in the analysis of solid organic inclusion compounds. This thesis also reports the production of a new series of co-crystals and examines their crystal structures. Chapter 1 acts as an introduction to the materials studied in this research. It explains the properties of inclusion compounds and lists the chemical materials used for these experiments. Chapter 2 explains the experimental techniques used in this research. Specifically it explains X-ray diffraction, X-ray birefringence and in-situ solid-state NMR. Chapter 3 presents a new technique for spatially resolved mapping of specific bond orientations in anisotropic solid materials using wide beam linearly polarized X-rays and an area detector. Earlier work with a focussed beam and a point detector showed the sensitivity of X-ray Birefringence to the orientation of specific energy-matching bonds inside a material, but these experiments only probed a small section of the crystal. Our wide beam imaging technique (X-ray Birefringence Imaging) shows similar sensitivity but allows us to investigate the full crystal simultaneously, which allows us to identify different domains within a single crystal. We apply this technique to a model material (1 bromocyclohexane/thiourea) which undergoes a low temperature phase transition and serves to demonstrate the usefulness of imaging techniques - in the high temperature phase the relevant C−Br bonds are isotropically disordered and no birefringence is observed, in the low temperature phase the relevant C−Br bonds are ordered but there are three possible orientations for the bromocyclohexane molecule so different regions of the crystal exhibit different birefringent signal. This behaviour is very clear on an imaging technique, but can appear highly confusing when using point-detector techniques. Chapter 4 utilizes X-ray Birefringence Imaging to investigate the dynamic rotational properties of guest molecules in a different set of solid organic inclusion compounds. By studying the known structures of 1,10-dibromodecane/urea and 1,8-dibromooctance/urea we have determined that XBI is a time-averaged and space-averaged technique. Additionally this chapter utilizes a Ge(555) analyzer instead of the Si(555) analyzer, which results in better spatial resolution and a different beam shape on the final images. Chapter 5 utilizes solid-state in-situ NMR to monitor crystallization processes as they occur and gain insight on competitive uptake of different guest molecules within the inclusion compound. These experiments use alkane and α,ω-dibromoalkane guest molecules inside urea inclusion compounds where the urea host structure (created in-situ) acts like a one-dimensional tunnel confining the guest. Every position within the urea tunnel is equivalent (a property of the incommensurate structure) which serves to simply the solid-state NMR spectra and means that for a given atom at the end of an alkane chain the only difference in NMR site comes from the neighbour molecule along the tunnel. This means in the solid phase we can observe peak splitting on certain atoms based on neighbour environment (e.g. the -CH3 in undecane will give a slightly different chemical shift if the neighbouring guest molecule is another undecane compared to if the neighbouring guest molecule is 1,8-dibromooctane) which in turn allows us to extract some information about the ordering within the inclusion compound. In these experiments we can also clearly distinguish between the same molecules in different phases, so as crystallization occurs we observe the loss of solution signal alongside the gain of solid signal. Additionally these experiments show no evidence of any intermediate structures or transition states. Chapter 6 describes a new set of organic co-crystals formed by reacting thiourea with α,ω-diiodoalkane chains and examines the crystal structures of these materials. Chapter 7 details further work and potential applications of this research. Digital data includes animated videos of the X-ray birefringence imaging data obtained in Chapter 3 and CIF files of the structures determined in Chapter 6.