The following thesis discusses the combined use of electron paramagnetic resonance (EPR) spectroscopy, electron nuclear double resonance (ENDOR) spectroscopy and density functional theory (DFT) calculations to investigate a number of transition metal catalyst systems the binding of epoxide molecules by a vanadyl analogue of the catalytically important metallosalen class of compounds the binding of a chiral aryl amine by a copper salen complex and the incorporation of copper(II) ions in aluminophosphate materials. Two classes of epoxide selectivity by a vanadyl salen derivative are presented here, the discrimination of the geometric isomers of 2,3-epoxybutane, cw-2,3-epoxybutane and /ra 5-2,3-epoxybutane by Ar,Ar'-bis(3,5-di-tert-butylsalicylidene)-l,2-diaminocyclohexa- ne-vanadium(IV) oxide ( VO(l) ) 1 and the stereoselectivity of epoxypropane, 1,2- epoxybutane, chloromethyloxirane and fluoromethyloxirane by VO(l) . In both cases it is shown that hydrogen-bonding interactions, including interactions between the epoxide oxygen atom and a hydrogen atom bonded to a stereocentre carbon atom of the complex are important in determining the binding mode, thus implicating the given stereocentre carbon atom in the transfer of chirality. In the geometric isomerism of 2,3-epoxybutane, steric arguments regarding the obstruction caused by the methyl groups made on the basis of the DFT structures explain the selectivity observed in the EPR/ENDOR spectra. In the chiral selectivity of the other epoxides, more complicated reasoning, based on tripodal weak hydrogen-bonding configurations involving the hydrogen atoms of the epoxide ring and the oxygen atoms of the complex ligand is required to fully explain the selectivity observed, with different selectivity effects in the more electronegative halogenated epoxides compared to the alkyl cases. The coordination of methyl benzyl amine to a series of analogues of Cu(l) with various levels of tert-butylation, to model the steric effects in this interaction is studied here using DFT methods to explain the coordination preference for heterochiral pairings observed in the EPR spectra. Reasoning based on the preference of each enantiomer of the MBA to become involved in % - n interaction with alternate benzene rings of the complex, along with a slightly increased crowding of one ring over the other caused by the same hydrogen atom as implicated in determining selectivity in the epoxide study (above), namely the hydrogen atom bonded to one of the stereocentre C atoms, explains the selectivity observed in terms of n n interactions, also identifying the role of the stereocentre C atoms in conferring chirality. In combination, these studies demonstrate the importance of weak interactions, namely hydrogen-bonding andn-n interactions, in determining the binding configurations, and by extension the selectivity of these transition metal complexes. They also describe the nature of the involvement of the stereocentres of the complex in directing that selectivity, delineating a link between the chirality of the complex and that of the bound species in each case. The importance of using both EPR/ENDOR and DFT techniques in such studies, namely of explaining selectivity observed by EPR in terms of ENDOR and DFT derived geometry parameters is further explored in this thesis in the development of genetic algorithm routines to modify DFT-derived structures, by means of the ENDOR spectra simulated with the hyperfine parameters derived from a simple point-dipole model applied to the coordinates. The application of this process to a sample axial system, VO(acac)2, demonstrates the effectiveness of exploiting the complementary nature of the ENDOR and DFT techniques in this manner. Finally, a second copper study is reported here. This example is of a microporous aluminophosphate material, and concerns the incorporation of Cu11 ions into framework vs. extra-framework sites, a subject of some controversy. Here, evidence is presented for the ability of copper to distort the tetrahedral lattice into a distorted octahedral and a square- based pyramidal environment in which one or both of the remaining coordination sites is/are occupied by the templating molecules and water molecules, without rendering the lattice unstable, arguing in favour of framework site incorporation.

The development of novel ligands for the complexation of transition metal ions in inorganic chemistry is a rapidly developing field of study. The broad objective of this work is to design novel tripodal transition metal based receptors of (TPA) frame work which can act as hosts for small molecules (guests) e.g. fluoride and succinate. In addition, investigation into the co-ordination chemistry of those receptors with first row transition metals were explored using variety of characterizing techniques such as: Infrared Spectroscopy (IR), Electronic transitions (UV-Vis), Mass Spectrometry (MS), Nuclear Magnetic Resonance (NMR), Cyclic voltammetry (CV) and Single Crystal Diffractometer (X-Ray). Mono, Bis and Tris thiourea tripodal ligands have been synthesised and their co ordination chemistry has been investigated (chapter 2, 3 and 4) as well as the binding studies of the bisthiourea (chapter 3) to bind: fluoride and succinate using *H NMR titration technique. The co-ordination chemistry of TPPA with some first row transition metals has been studied and it was expected to show high affinity for seven coordination sphere and indeed it has shown strong preference for mono capped octahedral geometry (chapter 5).

Additionally, some results are presented highlighting the use of three of the new diselenides as glutathione peroxidase mimics.

Hypervalent iodine compounds are molecules of increasing interest to the synthetic chemist. Their low toxicity when compared to heavy metal reagents and their ease of use in the laboratory are helping to establish them into the armoury of the synthetic chemist. More recently, research into chiral hypervalent iodine compounds has been the main focus. The work performed during this research tenure is based upon the development of new chiral hypervalent iodine reagents for use in stereoselective synthesis and this research can be summarised into three main sections: Synthesis of novel chiral iodine(III) compounds; Reactivity of chiral iodine(III) compounds; Novel oxididative procedure. The synthesis of new chiral iodine(III) compounds and their use in asymmetric oxidative functionalisations are described herein. The use of stoichiometric quantities of these iodine(III) reagents with 1 eq of pTsOHO in the a-oxytosylation of ketones and 2 eq of /7TSOH H₂O in the dioxytosylation of alkenes, have given the corresponding products in good yields, 57-76% (3-12% ee) and 48-75% (9-16% ee) respectively. Additionally, a new catalytic method is described in which the presence of a stoichiometric oxidant, 1 eq of /7TSOH H₂O and only catalytic quantities of the chiral iodine(I) reagent is necessary to afford a-oxytosylated ketones. The final aspect of the research has dealt with the problems associated with oxidizing iodine(I) compounds to iodine(III) compounds. The development of a new method to oxidise iodine(I) compounds to bis(trifluoroacetoxy)iodo arenes through the use of urea-hydrogen peroxide adduct and trifluoroacetic anhydride is also described.

The intermolecular base-stabilised haloboranes Ph3P.BPhCl 2, Ph3P.BCl3, 4-Pic.BCl3, and 4-Pic.BPhCl 2 represent useful examples of haloborane complexes containing PPh 3 and 4-picoline donors from which salt elimination chemistry might be used to make M-B bonds. The structures of Ph3P.BPhCl 2 and 4-Pic.BCl3 have been determined by single crystal X-ray diffraction and the structure of THF-BCl3 has been obtained for comparative purposes. The course of salt elimination chemistry with these boranes is highly dependent on the nature of the coordinated base; a bridging borylene complex [(C5H5)Fe(CO)2] 2 BPh has been synthesised and spectroscopically characterized using Ph3P.BPhCl2 as the boron-containing precursor.

The adsorption of aniline at a clean and oxidised Cu(110) surface has been studied using STM and XPS at 295K. Adsorption at a partially oxidised surface results in formation of a phenyl imide. Co-adsorption of aniline and oxygen resulted in a closer packed surface. Concentrations calculated using XPS were twice that of concentrations calculated using unit cells determined by STM. Two models were proposed to account for this discrepancy. The first involved alternating parallel and perpendicular phenyl rings with respect to the surface. The favoured proposal on a basis of the steric hindrance involves parallel pi-stacking of the phenyl rings. The interaction of gaseous malonyl dichloride (C3H2CI2O2) with clean Cu(110) and partially oxidised Cu(110) surface has been studied. At low temperatures, malonyl dichloride physisorbed at the surface. Malonyl dichloride will only adsorb at a Cu(110) surface in the presence of oxygen at room temperature. This indicates that oxygen activates a reaction with malonyl dichloride at the Cu(110) surface. The interaction of melamine with clean and oxidised Cu(110) and clean Ag(111) has been studied. Melamine adsorption at a Cu(110) and Ag(111) surface resulted in molecular adsorption. Adsorption of melamine and malonyl dichloride at a Cu(110) surface resulted in a reaction occurring leading to CI adsorption but no effect on melamine. The binding energies do suggest that melamine is adsorbed molecularly at the surface but chlorine was also present. A co-adsorption of melamine and malonyl dichloride at an Ag(111) surface produced a surface with melamine molecularly adsorbed and also chlorine present. Pre-adsorbed melamine was exposed to cesium. Cesium atoms adsorbed on the supramolecular network created by melamine at an Ag(111) surface. The interaction of biphenyl dicarboxylic acid (BPDCA) with clean and oxidised Cu(110) and Ag(111) surfaces has been studied. Chemisorption occurred at a clean Cu(110) surface. Predominantly, the substrate-adsorbate interaction was too strong for any supramolecular structures to be formed. The adsorption of BPDC A at an Ag(111) surface resulted in various structures that were affected by concentration. Both the carboxylic groups and the phenyl rings played a part in the creation of the various supramolecular structures at the surface. The weaker substrate decreased the adsorbate-substrate interactions and allowed more freedom for intermolecular interactions.

Measurements with a molecular beam reactor show that the initial sticking probability of C₂H₄ on Fe(111) decreases with temperature from 0.35 at 373 K to 0.13 at 873 K. Steady state sticking commences above 573 K and only steady state sticking is observed above 723 K. Between 373 and 673 K the carbon deposits resulting from C₂H₄ dosing decrease O₂ sticking compared to the clean surface, since the surface now accommodates both species. Above this temperature O₂ sticking increase significantly compared to the clean surface as it reacts with surface C to form CO gas. Clean off experiments suggest that surface oxygen provides a driving force for C in the subsurface/bulk to segregate to the surface.

The work presented in this thesis is mainly concerned with crystal structures containing hydrogen bonds. Chapter 1 and 2 mainly discuss the background and basic concepts used in this study such as the importance of hydrogen bond in crystal engineering, co-crystals and polymorphism, and recent studies of urea co-crystals. Chapter 3 is a study about urea/oc,co-dihydroxyalkanes co-crystal structures. It begins with parameterising DMAREL to obtain lattice energy from a set of homologous co- crystals where DMA multipoles were generated from different method, GDMA and MOLPRO. The simulated lattice energy, structures and interaction energy were discussed and compared whether there is possibilities for the co-crystals to appear in different urea ribbon structures (parallel and anti-parallel) as these could not be crystallised experimentally. The energy data shows that urea/a,co-dihydroxyalkanes co-crystal of anti-parallel ribbon type structure are more thermodynamically favoured compared to the parallel structure. In latter part of this chapter, attempts to construct and simulate the anti-parallel urea ribbon co-crystal type structures from initial experimental structures were discussed. In Chapter 4, sulfur pair potential was modelled to fit for use in DMAREL for TTCA structure simulation. The original potentials were taken from Lennard Jones potential of a-S8 crystal structure. Initially, the potentials were modelled against a-Sg and thiourea crystal. Improved potentials were applied to a set of S-contained structure, specifically with similar environment to TTCA to validate the reliability of this potential against other molecules. Potentials works fairly well for 5 out of 10 molecules simulated, where TTCA shows poorest performance against the potential even though it has improved from the original sulfur potential. Contrasting crystal structure between TTCA and CA when substituted between each other is discussed. The final chapter, Chapter 5 is the continuation from work in Chapter 3. In urea co-crystal, it was found that urea structure was not exactly planar. We then continue on the search of different conformation of urea molecule in as and solid structure. First, the conformation of urea monomer were discussed and followed by calculation of larger planar urea clusters where one of the urea is substituted with either Cj or Cs conformers. Urea clusters were build systematically mimicking dense urea crystal structure. Planar structure was finally obtained by using 5 urea molecules involving four hydrogen bonds.

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