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The aim of this thesis is to develop novel receptors for the recognition of anionic, cationic and ion-pair species. The dithiocarbamate group is exploited in the metal directed selfassembly of the host molecules. Interaction between host and guest is analysed by a variety of spectroscopic methods including 1 H NMR, UV/visible and electrochemical techniques. Chapter One introduces the field of supramolecular chemistry. The underlying principles of molecular recognition are discussed, followed by a review of abiotic anion, cation and ionpair receptors reported in the literature. Various strategies for forming self-assembled architectures are presented and, in particular, the use of metal directed self-assembly highlighted. Chapter Two investigates a new type of acyclic receptor for anions, cations or ion-pairs. The anion receptor contains amide groups, the cation receptor crown ethers and the ion-pair receptor possesses both moieties. The binding of guest ions is investigated by 1 H NMR, UV/visible, ESMS and electrochemical techniques. The ion-pair receptor displays positive cooperativity upon binding ion-pairs via electrostatic and conformational effects. Chapter Three details the synthesis of macrocyclic host molecules which contain amide moieties and either one or two first row transition metal dithiocarbamate groups. Evidence for anion recognition is gained by a variety of techniques. A receptor containing a second row transition element is also investigated. Additionally, a more lipophilic receptor is synthesised and exhibits enhanced anion binding in a less competitive solvent. Chapter Four describes the self-assembly of macrocyclic transition metal dithiocarbamate molecules which contain pyridyl or phenol groups. Bulk liquid membrane transport studies reveal a macrocyclic effect for transporting the caesium cation. Chapter Five details the self-assembly of novel transition metal dithiocarbamate macrobicyclic anion receptors. The oxidation of a nickel(II) macrocycle to nickel(IV) affords a dicationic anionic host and the reaction of a substituted amide ligand with iron(III) creates a neutral host. Anions are sensed using a variety of techniques including electrochemistry and magnetic measurements. A new tripodal cryptand-like receptor displays a remarkable electrochemical shift upon the addition of dihydrogen phosphate. Chapter Six reports the experimental procedures and characterisation for all products. The Appendices provide information on experimental techniques, lists the crystallographic data and summarises all the receptors studied.

That there are a number of distinct ophiolitic belts separating some of the major tectonic zones of Greece and the eastern Mediterranean is generally well known. These have previously been interpreted as the remnants of back-arc basins, Mesozoic rifts, and supra-subduction zone type ophiolites. However mafic and ultramafic rocks present in the region of the Serbo-Macedonian Massif, northern Greece, do not appear to fit this model, and have generally been neglected in tectonic interpretations. The aim of this study is to determine how these bodies arrived at their current position, what is their true nature, and how do the answers to these questions help in the interpretation of the way that this section of continental crust was assembled. A multidisciplinary approach was taken to this problem. Structural and tectonic measurements and observations led to the conclusion that the main mafic and ultramafic bodies were accreted into the continental crust via a process of subduction accretion. Further to this, the continental crustal material between the main complexes is composed of tectonic melange material and not microcontinental fragments derived from the northern margin of Gondwana. A geochemical investigation of the Vavdos and Volvi Complexes demonstrates that the origin of these generally depleted lithologies was from a plume source, Volvi being thought to be a seamount, and the Vavdos Complex and associated along strike units, thought to be the disrupted remnants of an oceanic plateau. These conclusions have required the re-interpretation of current tectonic models for the region, and a new model is presented at the end of the thesis.

Infection with Human Immunodeficiency Virus type 2 (HIV-2) has been investigated in collaborative studies with the MRC unit, Fajara, in The Gambia, West Africa using virological, serological and molecular techniques. Serum antibody levels of anti-HIV-2 were measured with competitive serological assays using culture-derived viral antigens which were applied in field studies in West Africa. These were subsequently replaced with a recombinant β-galactosidase fusion protein of an immunodominant region of the transmembrane glycoprotein (gp36) of HIV-2. Competitive EIAs were demonstrated to be a specific and sensitive means of detecting anti-HIV-2 and, in most cases, for speciation of HIV-1 and HIV-2 infections and for the detection of related non-human primate lentiviruses. A recombinant HIV-2 p26 antigen was produced as a glutathione-S-transferase fusion protein by PCR amplification and cloning into the pGEX-3X expression vector. These studies yielded a soluble recombinant antigen which was used as an immunogen to raise a polyclonal anti-p26- specific reagent. An assay for the detection of p26 antigens was also developed. Partial nucleotide sequence of the p26 gene of four Gambian HIV-2 strains (CBL.20-23) indicated these to be subtype A strains. Nested PCR assays were applied to HIV-2 pro viral DNA detection using oligonucleotide sequences in the Long Terminal Repeat (LTR), pol, and vpx regions of the HIV-2 genome. In a cohort of Gambian seropositive individuals, HIV-2 provirus was detected in DNA extracted from PBMCs in 84/86 (97%) of individuals with LTR primers and 39/41 (95%) in a similarly conserved region of pol (integrase). LTR sequences and recombinant Pfu DNA polymerase, rather than Taq polymerase, were applied in a radiometric incorporation assay for quantification of HIV-2 proviral DNA and evaluated by an end-point limiting dilution method. A wide range of proviral DNA levels were found in HIV-2-infected individuals where increased proviral loads, expressed as copies per 105 CD4-positive lymphocytes, were strongly associated with CD4 depletion. Nested HIV-1 and HIV-2 PCR primers were also used to identify dual infections. Amplification and direct sequence analysis of the U3 region of the HIV-2 LTR, from either proviral DNA or viral RNA, indicated a high level of sequence conservation of four cis-acting elements in vivo. A PCR-based approach to genotyping HIV-2 strains was also developed, capable of differentiating HIV-2 subtype A strains from subtype B or SIV-like viruses based on U3 sequence-specificity. Subtype A viruses were found to predominate in the Gambian samples analysed.