The fully regio-controlled synthesis of C1a-C12a mono-seco colchicine 133, as well as a number of structurally interesting analogues, has been achieved. The key feature employed in our approach to troponoid compounds of this type has been the incorporation of synthetic equivalents for α-tropolone anions 84 and 87 via dehydrobrominative ring expansion of C7-substituted7-bromobicyclo[4.1.0]heptan-2,3- and -3,4-diones respectively. The hydroxyl functionality present in tropolone 143 has been found to be a suitable progenitor for the C7-acetamido group in mono-seco colchicine 133. Studies directed towards the enantio-controlled introduction of the C7-acetamide moiety via asymmetric reduction of the prochiral ketone 152 are discussed. Various strategies to effect B-ring closure in mono-seco colchicine 133 and its congeners are presented. The novel preparation and dehydrogenative dimerisation of desacetamido mono-seco colchicine 174 is reported. An efficient synthesis of the naturally occurring tropone nezukone (16) has been accomplished via the novel rearrangement of bicyclic methylene cyclopropane 209. Evidence for the intermediacy of heptafulvenes in this conversion is described.

A series of structures of light atom molecules is presented. The molecules, in the main, are physiologically active or potentially active. The molecules have been divided into five broad categories. Their structure and properties are discussed. Section 1 presents some organic natural products largely isolated during the chemotaxonomic investigation of coastal marine organisms from New Zealand and Australian waters including the first porphyrin isolated from a sponge. Also presented are the structures of an isostegane and an intermediate in the synthesis of potentially odoriferous compounds. Section 2 presents compounds related to the drug amsacrine m-AMSA, of known chemotherapeutic use and other compounds produced in the study of chemotherapeutic agents, some as templates for elaboration into bis- and tris- intercalators. Section 3 presents anthraquinone derivatives related to the synthesis of compounds of known chemotherapeutic activity. One of these is a stable ozonide. Section 4 presents the study of 4, 4'-bipyridinium cations, compounds related to paraquat and exhibiting interesting electrical properties. Section 5 presents two compounds related to the study of colchicine, the most commonly used drug in the treatment of gout and a compound of other biological interest. One is an active analog the other is an intermediate in the regiocontrolled synthesis of colchicine itself.

Molecules containing transition metal-carbon multiple bonds have been recognised as active species in catalytic reactions and key intermediates in stoichiometric reactions. It is therefore important to gain an understanding of the reactivity of these functional groups. The metal-carbon double bond is introduced in Chapter 1 with a literature review and the following two chapters are concerned with the synthesis and properties of a new class of Group VIII metal carbene complexes containing the prototype carbene ligand, =CH2. The synthetic route to the first of these complexes involves a new low-valent osmium complex OsCl(NO) (PPh3)3. The synthesis of this complex from a reformulated complex containing the novel peroxycarbonyl ligand is discussed in Chapter 2, followed by simple reactions including the synthesis of a range of acetylene, allene and heteroallene π-adducts. The reactions establish that OsCl(NO)(PPh3)3 reacts as the osmium analogue of IrCl(CO)(PPh3)2. The methylene-ligand synthesis involves the addition of diazomethane to OsCl(NO)(PPh3)3 to give the structurally characterised Os(CH2)Cl(NO)(PPh3)2. The reaction has been extended to give the first isolable ruthenium and iridium methylene complexes. The reactions of these complexes establish the nucleophilicity of the double bond and two Lewis acid adducts, Os(CH2AuI)Cl(NO)(PPh3)2 and [Os(CH2S(O)O)Cl(NO)(PPh3)2]ClO4, have been structurally characterised. The reaction with CO and isocyanides to form ketene and ketenimine ligands illustrates a different mode of reaction that is interpreted in terms of the non-innocent participation of the nitrosyl ligand. The change from nucleophilicity to electrophilicity of the double bond with a reduction of metal electron density is illustrated by reactions of Os(CH2Cl)Cl2(NO)(pph3)2 which implicate [OS(CH2)Cl2(NO)(PPh3)2]+ as an intermediate. Os(CH2Cl)Cl2(NO)(PPh3)2 is formed by addition of Cl2 to Os(CH2)Cl(NO)(PPh3)2. In Chapter 4 a different type of metal-carbon double bond is discussed. The complexes contain the relatively uncommon dichlorocarbene ligand and the synthesis of the first such iridium complex, Ir(CCl2)Cl3(PPh3)2 is described. The utility of the dichlorocarbene ligand in the synthesis of a range of carbene ligands including monochlorocarbene complexes is illustrated. The most useful single reaction of the dichlorocarbene complexes is that forming a metal-carbon triple bond. A review of the literature concerning carbyne complexes is presented in Chapter 5 and the synthesis and reactions of a number of carbyne complexes is discussed in Chapter 6. Like the methylene complexes, the carbyne complexes such as Os(CPh)Cl(CO)(PPh3)2 contain nucleophilic metal-carbon bonds and Os(CHPh)Cl2(CO)(PPh3)2 resulting from HCl addition has been structurally characterised. However, just as the reactivity can be changed with the methylene complexes, the reduction of metal electron density in complexes such as [Os(CR)Cl2 (CNR')(PPh3)2]ClO4 (R = C6H4-4-NMe2, R' = C6H4-4-Me) makes the triple bond electrophilic. Two methods for synthesising these octahedral carbyne complexes are described. One, involving a reaction of complexes such as Os(CPh)Cl(CO)(PPh3)2 with oxygen and the formation of another peroxycarbonyl ligand, the other a reaction with iodine to give complexes such as Ru(CPh)ClI2(PPh3)2. Reactions with chlorine by contrast lead to a group of reactive chlorophenyl carbene complexes. Where appropriate, the reactivity of the complexes described is interpreted in terms of frontier-orbital and charge controlled reactions using the current models for the carbene and carbyne complexes.

The reactions and transformations of atmospheric primary particles have been studied using the surface analysis techniques of X-ray Photoelectron Spectroscopy (XPS), Auger Electron Spectroscopy (AES), Scanning Electron Microscopy (SEM) and Secondary Ion Mass Spectrometry (SIMS). Particles emitted from a steel mill were studied at their point of emission, during transport through the atmosphere and after deposition. The mill was located in a coastal region removed from other major industrial particle sources which made the identification of the mill particulate emissions possible in ambient samples. The mill utilizes indigenous titanomagnetite ironsand and coal as the raw materials. There is evidence of the surface enrichment of volatile trace elements such as Zn, S, Na, K and P from the raw materials in the particulate emissions. Particle samples were collected from sites within the mill which represented different stages in the iron-making process, including the rotary kilns, electric melting furnaces and the vanadium recovery plant. This established an inventory of particulate emissions. Mill sourced particles were then identified and studied in air samples collected downwind of the mill on silver-coated nucleopore filters. AES and SIMS depth profiling studies indicated the mill particles became surface enriched in sea salt components such as S, predominately as sulfate, Cl- and Na+ after atmospheric aging. This was attributed to their coagulation with the marine derived ambient aerosol. SIMS ion imaging and mass spectral analysis suggested a characteristic "fingerprint" of the mill emissions could be distinguished in the ambient aerosol up to 8 km downwind of the mill. An experimental rig was constructed to model the interaction between the mill particles and the natural marine aerosol. A bubble nebuliser was developed to produce an artificial sea salt aerosol which was reacted with a metal powder in the fluidised bed of the rig. The metal powder was then aged under controlled relative humidity (RH) conditions. It was shown that an iron powder, after reaction and aging at 75% RH, developed an aqueous surface layer which quickly led to electrochemical corrosion, dissolution and oxidation of the particle surface. Evidence of this corrosion of metal particles occurring in the environment was found in a SEM-EDX study of the mill particles deposited on pine needles downwind of the mill. It was argued that these reactions would increase the bio-availability of the particle components. A model which incorporated these observations was developed to describe the morphogenesis of atmospheric primary particles during aging in the New Zealand environment. XPS was used to study ambient aerosols deposited on both botanical and artificial passive sampling surfaces. Plant leaves were shown to be excellent collectors of particulate material and were suited to analysis by XPS. Site differences in the atmospheric aerosol load and composition were detected on vine leaves located on a hill side (high NaCl) and at a roadside (high sulfate and silicates) in a rural area. Zn and Fe species were detected by XPS on pine needles up to 2 km downwind of the steel mill.

This thesis deals with the nucleation, growth and defect structure of anodic oxide films formed on bismuth in aqueous electrolytes. The early stages in the formation of continuous anodic layers of bismuth oxide were studied using the technique of cyclic voltammetry. During this period, the oxide, Bi2O3, covered the surface by a process of simultaneous thickening and spreading of patches. The study of oxide nucleation classified the metal surface into two different areas with different kinetics of oxide nucleation. The ratio of the two areas varied according to the history and original preparation of the surface. Film nucleation was also studied by the galvanostatic step and potentiostatic step methods. The rate of spreading of the oxide patches over the surface was shown to be controlled by the magnitude of the surface area still uncovered. Film thickening was studied using both galvanostatic and cyclic voltammetric techniques. The high field growth law i = Ā exp (BĒ) where i is the current density and Ē the field in the oxide layer, was found with parameters Ā = (1 ± 0.5) x 10-5 A cm-2 B = (2.0 ± 0.5) x 10-6 cm V-1 This value of B gives an activation distance for high-field ion transport, a* = 0.2 nm, comparable to the radius of a lattice site. These parameters were determined for very thin films in strongly alkaline electrolyte (pH 13; thickness <30 nm). At greater film thickness, cracking of the film gave a porous layer on top of a continuous barrier layer, and the apparent value of the parameter B increased to 1.7 x 10-5 cm v-1. All previous work on the bismuth anodic film thickening process has been affected to some extent by cracking of the film. In this work, cracking of the film was confirmed by microscopic observation, including scanning electron microscopy. Dissolution of the film, giving breakdown of the oxide layer and pitting of the metal, was an important phenomenon. It became particularly significant for pH <8. The thickness attained by the anodic bismuth oxide layer was limited by this process to only 4 nm at pH 5, increasing to over 200 nm at pH 13. The cathodic reduction of the oxide proceeded from the outer surface inwards, and a rough, porous metal surface resulted. A model involving electron injection from the metal into the oxide, diffusion of electrons through the film and their reaction at the outer surface has been proposed. Microscopic observation confirmed the porous nature of the electro-reduced surface. The transient conductivity of the bismuth anodic film has been investigated, and the effects of standing at open-circuit in the electrolyte or of heating in air studied. The galvanostatic method was used. The observed effects could be adequately explained as being due to the presence ofanon-stoichiometric, n-type (excess metal) layer at the film-solution interface. Cyclic voltammetry was used to investigate the possibility of nucleation of anodic bismuth oxo-halides from solutions containing halide ions. Solutions containing fluoride, chloride, bromide or iodide at pH 4-9, phosphate and phosphate with added methanol at pH 8.5 were used. Consideration of thermodynamic stability would indicate the formation of new phases, but results showed that, in the comparatively short time scale of the experiments, kinetic factors resulted in the formation of anodic Bi2O3, except when the solution contained iodide at low pH, when the oxo-iodide, BiOI, was probably formed. Room lighting had no effect on the cyclic voltammetric or galvanostatic measurements. The transient response of anodic films on bismuth to an intense flash of white light was studied. In the case of a thick anodic oxide film (240 nm), the results were interpreted in terms of photo-excitation of the film, producing electron-hole pairs which were separated by the applied field. The recombination process was best described as rate-limiting thermal excitation of trapped electrons. The lifetime of an electron in the conduction band of anodic Bi2O3 was determined: τc = 23 ms. The photo-response of a very thin anodic oxide film (4 nm) involved internal photo-emission of electrons from the metal into the oxide. Formation of a positive space charge by the injection of extra cations from the metal into the film followed. The transient photo-potential (galvanostatic experiments) or photo-current (potentiostatic experiments) showed the decay of both excess electronic and ionic space charges. The density of electron traps in the anodic oxide film was determined as NT > 3 x 1018 cm-3. When the anodic film was formed in a solution containing bromide or iodide at pH 5, an inversion of the sign of the primary photo-effect from that observed in the absence of additives (4 nm thick film) was seen, and interpreted in terms of the photo-excitation of halide ions incorporated in the film. The lifetime of a conduction electron in anodic BiOI was determined as 1.5 ± 0.2 ms, much less than in anodic Bi2O3 (23 ms). In all the studies of the photo-effect, Gauss' theorem was used to relate the observed photo-potential (galvanostatic experiments) to the photo-induced charge separation. An approximate value of the conduction electron mobility in anodic Bi2O3 was thus obtained: μ ≃ 5 x 10-8 cm2 V-1 s-1. Parameters for the evolution of hydrogen on the bare bismuth metal surface, were obtained: b = 0.11 V, log10(i0/Acm-2) = -10.3 and (∂(log10i0)/∂(PH))η = 0 where η = E – 60 pH mV.

The infra red, Raman and nuclear quadrupole resonance (n.q.r) spectra of several complexes of copper(I), silver(I) and gold(I) are reported. These are interpreted in terms of the structures of the complexes and the various possible bonding schemes for these d10 transition elements. To interpret the n.q.r. spectra the contributions to the field gradient at the copper nucleus of the various orbitals in the copper atoms are calculated and the Townes and Dailey approximations are revaluated. From this the s-d mixing theory of Orgel is chosen as the most satisfactory description of the bonding in these complexes. This theory is extended to cover several other geometries besides the D∞h geometry for which it was originally derived.

This thesis describes the single crystal x-ray analyses of six novel organometallic osmium complexes and three complexes of the tridentate dentate ligand 1,6-bis(diphenylphosphino)-trans-hex-3-ene with the transition metals iridium, rhodium and ruthenium. The complexes of carbon monosulphide and carbon monotelluride with osmium, OsCl2(CO)(CS)(PPh3)2 and OsCl2(CO)(CTe)(PPh3)2, exhibit linear thio- and telluro-coordination similar to that of the carbonyl. The -CS and -CTe ligands exert strong trans-bond weakening influences. In the dihapto-thioacyl complex of osmium, Os(η1-o2CCF3)[C(S)-(p-tolyl)](CO)(PPh3)2, the bidentate thioacyl is coordinated to the osmium through the carbon and sulphur atoms. This bonding involves a considerable degree of π-interaction between the C, S and Os atoms, concomitant with a lengthening of the C-S bond. The dichlorocarbene complex, OsCl2(CO)(CCl2)(PPh3)2 is disordered in the crystalline state. Consequently, while the presence of the dichlorocarbene is verified, no unambiguous conclusions can be drawn from the associated geometry. In the carbyne complex of osmium, Os(C-p-tolyl)Cl(CO)(PPh3)2, the osmium is in a trigonal bipyramidal environment with an approximately linear arrangement of the Os-C-R group. The Os-Ccarbyne bond is short (corresponding to a bond order of ca. 3), confirming the formation of the C-p-tolyl group as a carbyne. The formaldehyde ligand in the osmium complex, Os(η2-CH2O)(CO)2(PPh3)2, is bonded to the osmium centre via both the carbon and oxygen atoms. The C-O bond of the formaldehyde lengthens considerably upon coordination, resulting in a bond order apparently less than 1. Also present in the crystal structure are molecules of water which are hydrogen bonded into pairs (O…O separation 2.56 Å). The (H2O)2 units do not hydrogen bond to any other atoms, but rather occupy hydrophobic interstices in the structure. The three complexes of 1,6-bis(diphenylphosphino)-trans-hex-3-ene, (BDPH), IrIIICl3(BDPH), RhIIICl3(BDPH), and RuIICl2(CO)(BDPH) are isomorphous. The ruthenium complex is, however, disordered in the crystalline state. In each of the three structures the olefin of the BDPH moiety is only weakly bound to the metal, leaving the C-C double bond virtually unchanged from that of the free ligand. The olefin exerts a stronger trans-bond weakening influence than do the chlorine ligands in these complexes.

This thesis is concerned with a study of the oxidation of ring-A aromatic steroids using either chromium trioxide-aqueous sulphuric acid-acetone or chromium trioxide-aqueous acetic acid mixtures. It was found that chromic acid oxidation of ring-A aromatic steroids substituted with a strong electron-donating group, gives rise to products with the site of oxidation being predominantly that para to the activating group. Thus C-3 methoxy ring-A aromatic steroids give the corresponding 9b-hydroxy-11-oxo and 9-oxo-9,11-seco-11-oic acid derivatives as the major products and the 6-oxo derivative as a minor oxidation product. However, a ketol was not formed if a C-3 methoxy ring-A aromatic steroid also contained a substituent at C-1. The C-1-methoxy-4-methyl ring-A aromatic steroids give the 4-carboxy derivative as the major product and again the 6-oxo compound as a minor neutral product. The acetoxy and methyl substituted ring-A aromatic steroids, however, all give rise to the 6-oxo derivatives as the major products. The usual oxidation product of a ring-A aromatic steroid is therefore the 6-oxo product unless it is substituted with a methoxy group in a position which will stabilise an electron deficiency at a site other than C-6. Oxidation will then occur predominantly at the stabilised site unless it is sterically blocked.

The modified reactivity observed when a substituted arene is complexed to a cycIopentadienylruthenium moiety has been exploited to prepare a range of synthetically interesting target molecules. Activation of nitrogen- and halogen- substituted arenes has been achieved by compIexation to the cyclopentadienylruthenium moiety. Double nucleophilic substitution reactions between substituted (7 6- 1,2-dichlorw benzene)RuCp+ salts and substituted 1,2-benzenediols were carried out under mild conditions to prepare substituted (q6-dibenzodioxin)ruthenium complexes. Both mono- and di-substituted dibenzodioxin complexes were prepared. The dibenzodioxin ligands were subsequently liberated by photolysis. The complexation of a range of substituted benzimidazoles to the cyclopentadienylruthenium moiety has been studied. Several complexes were isolated and structures proposed. The metal moiety has been used to influence the stereoselection achieved in the reduction of carbonyl substituted arenes. A number of keto-arene complexes were prepared and reduced with sodium borohydride. The resulting alcohol complexes were characterised and the observed diastereoselectivity rationalised. Yanovsky-like adducts were prepared by nucleophilic addition to the cationic ruthenium salts to produce neutral (n5-cyclohexadienyl)ruthenuim complexes. A comparison between lithium, silicon and tin enolates was undertaken.

Polarographic chemical analysis, although invented only twenty-five years ago, has already become a standard method ror the research worker and industrial analyst alike. The variety or topics in pure, bio- and commercial chemistry which may be investigated easily with the polarograph, as well as its application to microchenistry, has found it a place in laboratories throughout the world. The invention offthe method, and much or the pioneer development are due to Jaroslav Heyrovsky and his colleagues at Charles University, Prague, (Phil. Mag., 1923, 45, 303; Trans. Faraday Soc., 1923, 19, 692 et seq.) Kucera, also of Charles University, noticed peculiar inflections in the electrocapillary curve of mercury under certain conditions, and devised the "dropping mercury electrode", now commonly used; to investigate these, (Ann. Physik., 1903,11, 529). Further work on this subject by Heyrovsky led ultimately to the development of polarography, (Ohemo Listy, 1922, 12, 256.)