The aims of this project were to investigate the surface chemistry and morphology of processed tea leaves the techniques of atomic force microscopy (AFM), scanning electron microscopy (SEM) and time of flight secondary ion mass spectrometry (ToF-SIMS). Data from the spectra obtained by ToF-SIMS was also analysed using principal component analysis (PCA). Further experimentation was performed on tea leaves by the addition of diluted samples of aromas, methyl salicylate, trans-2-hexenal and linalool and examining these leaves using depth profiling to discover how far into the leaf the aroma had penetrated and if there was any connection between the chemistry and size of the aromas and how far they penetrated. A general characterisation of the tea leaves was performed in Chapter 3 where layers of waxes of a comparable size were observed on both green and black tea leaves with AFM, as were micro-crystals on black tea and areas showing two distinct types of interaction between the cantilever tip and the surface of a green tea leaf indicating different surface properties. SEM images revealed a visual difference between green and black tea leaves, where the black tea leaves had more debris on the surface and greater changes in topography due to the different processing methods. The presence of lipids and epicuticular waxes were observed on the surface of the tea leaves using the ToF-SIMS. In Chapter 4 the effects of infusion in hot water on the morphology and surface chemistry of the tea leaves are examined. SEM revealed structural damage to the leaves from 30 seconds of infusion and this increased with infusion time, resulting in the formation of holes in the cutin on the adaxial surface of the tea leaf. By examining positive and negative ToF-SIMS spectra and using PCA, a change in surface chemistry could be detected from 15 seconds of infusion. The intensity of C3H5O2+ peaks in the spectra increased as infusion time increased, indicating that the waxy cuticle of the leaf surface had been removed revealing the underlying epidermal cell layer. Peaks associated with octadecenoic and octadecanoic acids were shown to have a reproducible effect on the positioning of the different infusion times within the PCA plots. Though chemical changes can be detected at 15 seconds, the first 30 seconds of infusion were found to be responsible for the majority of the chemical changes on the surface. Taken together these data indicate that the melting of the cutin layer, primarily within the first 30 seconds of infusion may be related to the release of flavour, aroma and constituents such as polyphenols. The penetration into the leaf of aroma molecules was examined in Chapter 5. Diluted solutions of methyl salicylate, linalool and trans-2-hexenal were added to tea leaves and then examined using depth profiling with ToF-SIMS. For the first time a leaf was depth profiled using a C60. The presence of trans-2-hexenal was detected in the palisade mesophyll layer of the leaf as was methyl salicylate, but to a smaller intensity. Methyl salicylate showed partitioning in diffusion across the cuticle with a large intensity in the cuticle and also in the interface between the epidermis and palisade mesophyll layers. Linalool was present on the surface of the leaf and showed partitioning in the cuticle of the tea leaves. As trans-2-hexenal was the smallest and least lipophilic of the three aromas examined it is theorized that the smaller the size of the aroma molecule plays a key role in the penetration of the dehydrated leaves.

This thesis details the synthesis and study of molecular species designed to form supramolecular assemblies, in particular for surface deposition purposes. The first chapter gives a brief introduction to supramolecular chemistry concepts and the basis on which this project is built. The importance of non-covalent bonding interactions to form complex architectures capable of self-assembly is discussed, in particular hydrogen bonds and pi-pi interactions with a series of examples from the literature to illustrate the work that has been accomplished over the past few years in various fields of supramolecular chemistry and nanotechnology in particular. The present project aims at the design, the synthesis and the characterisation of two different groups of compounds, namely p-terphenyl tetracarboxylic acid derivatives and manganese based single molecule magnets. The former are dealt with in the second chapter of the present thesis. The scientific background and the recent results obtained following the surface deposition of p-terphenyl-3,5,3',5'-tetracarboxylic acid are explained and discussed in the introduction. The focus of the research is to design and synthesise similar derivatives, i.e capable of self-assembling to produce similar ordered arrays on surfaces as observed for the parent molecule, but bearing some specific functional groups that are anticipated to either induce a change in the observed assembly process or even impart the molecular functionality upon the assembly. The third chapter of the thesis describes the synthesis and functionalisation of manganese-based single molecule magnets, which are believed to be promising candidates for future applications such as high-density data storage. The crystal structures of some derivatives are discussed and a crystallographic comparative study between the as-synthesised derivatives and literature examples is detailed. In addition, the magnetic properties of selected complexes are discussed and compared. Finally, the results resulting from surface deposition studies that have been carried out in collaboration with the School of Physics and Astronomy at the University of Nottingham are presented in the last section of this chapter.

Polymers have been used as biomaterials for nearly a century and have recently become the material of choice for use in tissue engineering. However, the classes of biodegradable and biocompatible polymers available for use in biomedical devices and as tissue engineering scaffolds are limited. This lack of available polymers with suitable properties could inhibit the development of biomedical devices with improved biocompatibility and hinder the growth of the fledgling tissue engineering field. Researchers in the polymer and biomaterials fields have tried to remedy this problem by applying combinatorial and high throughput methods developed in drug discovery to the search for new polymers. A recent advance has been the development of combinatorial polymer libraries printed as microarrays. This format allows the polymers to be readily screened for their cell adhesion and differentiation properties, allowing ‘hit’ materials with ideal properties to be identified. However, without knowledge of the surface properties of these novel polymers it is impossible to rationalise their biological properties. The surface characterisation of such microarrays presents numerous practical problems included small sample size, sample number and even analysis of such large amounts of data. It is the aim of this thesis to develop methods for the characterisation of the surface chemistry, wettability and protein adsorption properties of polymers in situ in microarray format and within realistic timeframes. The thesis will explore multivariate statistics in the form of PCA and PLS as methods of analysing the large amount of data acquired. The first part of this thesis describes the surface chemical analysis of a polymer microarray using ToF-SIMS and XPS. A comparison of the polymers’ surface to bulk chemistries by XPS indicated that 64 % of the polymers had a surface chemistry which differed from the bulk. This reinforces the need for characterisation of the polymers’ surface chemistries, as it is obvious that this can not be inferred from their bulk chemistries. ToF-SIMS imaging was shown to be an ideal method of studying the distribution of specific ion species across the array and to confirm that the microarray was printed in the intended layout. Principal component analysis is shown to be an ideal technique to analyse both ToF-SIMS and XPS spectral data from the arrays, allowing similarities and differences in the surface chemistry of the polymers to be easily visualised. To estimate the surface energies of the arrayed polymers it is necessary to use picolitre volume droplets to make contact angle measurements. In Chapter 4 it is shown that contact angle measurements taken from picolitre volume water droplets are equivalent to those measured from more conventional microlitre droplets. In Chapter 5 picolitre contact angle measurements are used to estimate the polar and dispersive surface energies of a polymer microarray, which has been specifically designed to exhibit a maximum range of surface energy values. The analysis shows that there is indeed great variation in the WCA and polar surface energies of the polymers, demonstrating the power of intelligently designed combinatorial libraries. To understand the chemical basis of this large range of surface energies the results are compared to surface chemical data from ToF-SIMS and XPS. Surface atomic and functional data from XPS is unable to provide any definitive explanations for the range of surface energies observed. However, information about the molecular structure of the surface from ToF-SIMS gives an insight into what surface functionalities are responsible for high and low surface energies. In Chapter 6 PLS regression is investigated further as a method for investigating surface structure-property relationships in large polymer libraries. Specifically two issues are investigated: the influence of sample number on the results obtained and the ability of PLS to make quantitative predictions. The ToF-SIMS and surface energy dataset discussed in Chapter 5 is used for this task. It is demonstrated that the results obtained from PLS models of large polymer libraries are equivalent to those obtained from much smaller datasets, in terms of the ions identified in the regression vector. Using various test sets of polymers it is shown that there is a limit to the predictive ability of PLS: specifically, as the difference between the training and test sets increases, the quality of the predictions decreases. Potential problems with data pre-processing and re-scaling are also identified. In the final experimental chapter two methods are described for investigating protein adhesion and adsorption to micro-arrayed polymers using AFM and fluorescently labelled proteins. Both methods indicate a wide range of protein adsorption properties within the group of polymers analysed. A good correlation between the two sets of data was observed which appears to validate both methods. In summary the work described in this thesis has demonstrated the feasibility of the characterisation of the surface chemistry, energetics and protein adsorption properties of a micro-arrayed polymer library within realistic time-frames. PCA and PLS have been shown to be useful tools for analysing the data obtained. It is hoped that the methods described in this thesis will allow the biological data from polymer microarrays to be rationalised using the surface properties of the polymers, allowing the design of new biomaterials.

The self-assembly of two-dimensional molecular systems is of significant interest, offering an insight into the fundamental interactions which drive the formation of complex supramolecular structures. A careful choice of the molecular 'building blocks' for such self-assembled systems potentially allows the design and production of nanoscale architectures with pre-determined geometries and specific chemical functionalities. Within this thesis the two-dimensional structures formed by the self-assembly of complex organic molecules, deposited on an Au(111) surface held in an ultrahigh vacuum (URV) environment, are studied using a combination of scanning tunnelling microscopy (STM), photoelectron spectroscopy (PES), molecular dynamics (MD), and density functional theory (DFT) techniques. A UHV electrospray deposition (URV-ESD) technique is employed to facilitate the introduction of thermally labile molecules into the URV environment. Bi-molecular networks, formed from perylene tetracarboxylic diimide (PTCDI) and melamine, have previously been observed to assemble on the Au(111) surface. Several more complex phases are reported here, as characterised by S'I'M, with the balance between isotropic and anisotropic interactions giving rise to a variety of structures. Chemical functionality may be added to these networks by incorporating functionalised derivatives of PTCDI. Alternative structures produced by altering the shape of the molecular 'building blocks' are also discussed. The URV-ESD technique is demonstrated here to be compatible with the deposition of the fullerene C60,the single molecule magnet Mn12012(02CCR3h6(H20)4 (Mn12(acetate)16), and porphyrin based oligomers (P4 and P6) and polymers (Pn). The URV-ESD of C60on the clean AU(ll1) surface, and on a surface prepatterned with a PTCDI/melamine network, results in similar structures to those previously observed to be produced by sublimation. Mn12(acetate)16 and the porphyrin oligomers and polymers represent complex molecules which are thermally labile and possess, respectively, novel magnetic and electronic properties. Mn12(acetate) 16is observed to form filamentary aggregates due to the anisotropic nature of the molecule-molecule and molecule-substrate interactions, while P4, P6 and Pn form highly ordered close-packed domains driven by the interdigitation of the alkyl chains attached to the porphyrin cores. The findings presented within this thesis demonstrate that self-assembled molecular structures can be understood in terms of intermolecular interactions, and that for systems containing complex molecules the molecule-molecule interaction potential can lead to the formation of novel structures.

CHAPTER 1: A background to the techniques of matrix isolation, liquid xenon solution and flash photolysis with fast IR detection is presented. The application of infrared spectroscopy in structural studies of metal carbonyl compounds is also discussed. Chapter 2: Photolysis of((nu5-C5R5)Pt(CO))2 (R=H, Me) in frozen gas matrices results in production of ((nu5-C5R5)Pt2(mu-CO)). 13CO enrichment and polarised photochemistry show that the photoproduct contains a single symmetrically bridging CO group. Photolysis of (CpNi(mu-CO))2 in frozen gas matrices results in formation of CP2Ni2(CO) with a terminal CO ligand. The stability these dinuclear photoproducts in room temperature solution has been investigated using fast TRIR spectroscopy. Photolysis in CO matrices leads to M-M bond cleavage and reaction with CO to give Pt(CO)4 or Ni(CO)4 as the final product. CHAPTER 3: Photolysis of Os2(CO)9 or OS2(CO)8- - (mu-nu1, nu1-C2H4) in frozen gas matrices leads to formation of Os2(CO)8, which has only terminal CO groups. The thermal and photochemical reactivity of Os2(CO)a towards CO, N2 and C2H4 is investigated. Photolysis using plane polarised light provides confirmation of the C2v structure of Os2(CO)9, and gives evidence favouring a D2h structure for Os2(CO)8. Prolonged UV photolysis of Os2(CO)9 in CO matrices leads to cleavage of the Os-Os bond and production of Os(CO)5. CHAPTER 4: The mechanism of the photochemical deoligomerisation of FpSiMe2SiMe3 is investigated using a variety of techniques. The reaction is shown to proceed via two photochemical steps. Primary CO-loss is followed by intramolecular trapping to give a silyl(silylene) intermediate. The second step involves expulsion of an SiMe2 fragment and coordination of a ligand. L. to give CpFe(CO)(L)SiMe3 (L = CO, PPh3,C2H4 or N2). CHAPTER 5: A study of the photochemistry of Fp-disilyl complexes containing beta-silyl hydrogens implies beta-H transfer from Si to Fe as the dominant process following photodissociation of CO. The product, a metalladisilacyclopropane or nu2-disilene complex, is implicated as an intermediate in the photochemical formation of FpH in this system. CHAPTER 6: The experimental techniques and spectrometers used in this research are described. along with a discussion of the theory and advantages of FTIR spectroscopy.

The application of supercritical C0₂(scC0₂) as a solvent for the synthesis of fine and bulk chemicals has been well documented; however its application as a solvent for the synthesis of pharmaceuticals is yet to be exploited fully. To address this issue, two synthetically important reactions have been investigated in scC0₂; chemoselective N-debenzylation and diastereoselective hydrogenation. Chapter 3 details the study of catalytic N-debenzylation in the presence of sensitive functional groups (COMe and Cl). It has been shown that selective N-debenzylation in the presence of a carbonyl (COMe) is difficult to achieve due to the high operating temperatures that are required to facilitate continuous flow debenzylation. N-debenzylation in the presence of chloro- substituents was also investigated. Dechlorination can be a major problem during this reaction however several different strategies were developed to suppress dechlorination including: (i) the correct selection of catalyst support; (ii) selective poisoning of a Pd catalyst; (iii) the addition of acids, such as H₂S0₄ to the reactant stream; (iv) the use of an aprotic co-solvent, such as THF. Chapter 4 covers progress made on the diastereoselective hydrogenation of the pharmaceutical intermediate, rac-sertraline imine. It has been shown that the hydrogenation reaction can be performed with excellent levels of chemo- and diastereoselectivity (cis:trans ratio of 97:3, 0.7 % by-product formation) by performing the reaction as a continuous flow process in the presence of scC0₂ All details of the apparatus, experimental and synthetic procedures are reported in Chapter 2.

Intramolecular vibrational energy redistribution (IVR) is a commonly-observed phenomenon whereby vibrational energy can be transferred between different parts of a polyatomic molecule. This process has profound implications for the understanding of chemical reactivity. In this work, IVR is studied in the S1 electronic state of toluene using time-resolved and frequency-resolved techniques. Both experiments are based upon laser photoelectron spectroscopy in the collision-free environment of a molecular beam. The time-resolved experiments employ laser pulses of ~1 ps duration and ~15 cm^-1 bandwidth. In a pump-probe scheme, the molecule is first excited to a chosen superposition of vibrational states in the S1 manifold and then ionised by a second photon. The photoelectrons produced by the probe laser pulse are detected using velocity map imaging in order to obtain a vibrationally resolved photoelectron spectrum. Changes in the spectrum as a function of time give a direct view of the evolution of the vibrational state. The use of a two-colour ionisation scheme substantially improves the resolution compared with previous work. High resolution zero kinetic energy (ZEKE) photoelectron spectra have also been obtained for the first time from excited vibrational levels in the S1 electronic state of toluene. These experiments employed laser pulses of ~5 ns duration and ~0.3 cm^-1 bandwidth, allowing the excitation of individual S1 vibrational levels rather than a superposition. The nanosecond and picosecond experiments therefore give complementary information. A Fermi resonance at ~460 cm^-1 above the S1 origin in toluene is shown to be more complicated than previously thought, and provides the first demonstration of the use of time-resolved photoelectron spectroscopy to gain quantitative measurements of vibrational coupling matrix elements. Lifetimes of dissipative IVR have been determined following the preparation of high-frequency vibrations, and at intermediate energies several "doorway states" which mediate the IVR mechanism have been identified for the first time.

The performance of X-ray spectroscopy techniques has been advanced by recent reviving in X-ray sources. These techniques that involve the excitation of core electrons can provide an atom specific probe of electronic structure and provide powerful analytical tools that are used in many fields of research. Theoretical calculations can often play an important role in the analysis and interpretation of experimental spectra. In this thesis, I report a recent developments in quantum chemical calculations of X-ray absorption spectra, focusing on the use of time-dependent density functional theory to study core excitations. The practical application of these calculations is illustrated with examples drawn from surface science,and the application of these methods to study X-ray emission spectroscopy is also explored.

Part 1 of this thesis describes the continued development of a new method for the synthesis of olefins from sulfur reagents and carbonyl compounds. The proposed catalytic olefination investigated the reaction of sulfur ylides or sulfines with carbonyl compounds to produce the corresponding alkene, catalysed by a transition metal oxo complex. A variety of literature trioxo rhenium and molybdenum di-oxo and oxo-imido complexes were reacted with dimethylsulfoxonium methylide and generally led to degradation. The reaction of diphenylsulfonium benzylide with the rhenium and molybdenum oxo complexes gave no reaction or led to degradation. Diphenylsulfine was also reacted with the metal-oxo complexes and produced benzophenone and degradation of the metal oxo complex. Part 2 of this thesis describes the investigation into the novel complex MoO(NtBu)(2,6-R2C6H3O)2py [where R = iPr (72a) or Me (72b)], which was developed in the Anderson group, as an epoxidation catalyst. The initial epoxidation conditions were optimised for trans-stilbene. The optimised conditions were used to epoxidise a variety of alkenes. The catalyst 72 is effective at epoxidation of electron rich alkenes, will selectively epoxidise allylic alcohols and does not epoxidise electron deficient alkenes. The rate of epoxidation of cis-stilbene using catalyst 72a and 72b were compared and showed that 72b had a faster rate of epoxidation than 72a. The rate of reaction for catalyst 72b was also compared with MoO2(2,6-Me2C6H3O)2py2 98 for the epoxidation of cis-stilbene and found to be similar, indicating that the catalytically active species may be common to both. Part 3 of this thesis describes an investigation into the synthesis of (-)-dysibetaine using the aza-[2,3]-Wittig rearrangement-cyclisation protocol. The initial retrosynthesis led to a -lactone enolate 57 in the aza-[2,3]-Wittig rearrangement cyclisation. However the desired cyclised product 58 was not obtained and instead ring opening of the -lactone to the acrylic acid 80 was observed. A revised route used a phenyldimethylsilyl amino acid 106 as a masked hydroxyl group to mimic a serine amino acid that would not undergo -elimination. The aza-[2,3]-Wittig precursor 109 was prepared and subjected to the standard aza-[2,3]-Wittig rearrangement-cyclisation protocol and the desired cyclised product 110 was obtained in 43% yield. This product contained the correct dysibetaine skeleton and would require functional group transformations to complete the synthesis.

The 3s, 3d and 4s Rydberg states of nitric oxide (NO), bound to a rare gas (Rg) atom in a van der Waals complex (NO-Rg), are probed using resonance-enhanced multiphoton ionisation, in order to investigate the effect of electronic excitation on these complexes. The spectroscopy is interpreted in terms of interactions between the Rydberg electron, the nitric oxide (NO+) core and the Rg atoms. Larger NO-Rgx clusters are investigated offering the prospect of bridging the spectroscopic gap between van der Waals dimers and the bulk. The spectroscopy is determined by an NO+-Rg2 moiety and formation of the Rydberg state provokes a dynamic response from the Rgx cluster, similar to that observed in matrix studies. High-resolution zero electron kinetic energy spectroscopy is employed to derive vibrational frequencies of the para-fluorotoluene cation and assignments for previously unidentified (or in some cases, erroneously assigned) features have been presented. The first electronically-excited state of para-fluorotoluene (pFT), where a pFT chromophore is bound to several pFT molecules in a van der Waals cluster, has been studied. The effects of laser power and the internal temperature of the clusters on the fragmentation are considered. A model potential analysis is carried out to determine whether binding in metal cation/rare gas (M+-Rg) complexes is physical (due to electrostatic, dispersion and induction interactions), or whether a chemical component (classical covalent interactions) must be considered. For alkali metal (Alk+)/Rg complexes, the model potential successfully describes the binding (the interaction is purely physical). For Au+-Rg, the model potential analysis reveals the emergence of a chemical component to the interaction, which becomes more significant as Rg gets larger.