Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Aluminium smelters emit upwards of 6 kg of gaseous hydrogen fluoride per tonne of aluminium metal produced. Since the 1960's, many aluminium smelters have used the dry scrubbing process to capture the HF on the surface of smelter grade alumina. In this way, dispersion of the emitted HF is prevented and the fluoride is returned to the aluminium electrolysis cells. The surface adsorption reactions on which the dry scrubbing process relies have been studied by various researchers. It is common knowledge that there occurs a relatively strong bond between HF and alumina and that the quantity of water in the gas effects the maximum fluoride adsorption capacity of the alumina. It has also been considered that FIF adsorption is a combination of strong chemisorption and reversible physisorption at the temperatures at which the dry scrubbing process operates. Some researchers have postulated the formation of Al-F bonds at the alumina surface, while others have postulated the existence of hydrogen bonds between surface fluoride or hydroxyl ions and molecular H2O and HF. However, these models do not agree with the experimental data which was gathered during the course of researching this thesis, nor do they agree with much of the experimental data presented earlier. The major finding of this research was that hydrogen fluoride adsorption is irreversible under the temperature and gas composition conditions of the dry scrubbing process. The maximum fluoride adsorption capacity of smelter grade alumina depends on the relative humidity during adsorption, as well as the specific surface area of the alumina. Both factors indicate that HF adsorption is a surface process. The most likely product of reaction is a thin layer of crystalline aluminium hydroxyfluoride, AIFx(OH)3-x 6H2O, formed in an aqueous reaction at the alumina surface. The reaction mechanism involves the steps of: H2O adsorption to form an aqueous layer on the alumina surface; HF adsorption to acidify the surface water layer; dissolution of the alumina surface to form AlO2- and AlO2-; precipitation of AlFx(OH)3-x.nH2O. The overall adsorption rate appears to be controlled by the rate of the surface chemical reactions rather than by transport phenomena such as fluid phase mass transfer and intraparticle diffusion. At relative humidity greater than 35% the adsorption capacity of smelter grade alumina increases dramatically and small crystallites of AIFx(OH)3-x.6H2O and AIF3.3H2O are formed. Under these conditions the reaction mechanism is similar, except that water-filled pores provide an environment which is conducive to the formation of larger crystallites of product. At temperatures below 450°C the aluminium hydroxyfluoride hydrate phase dehydrates, and at temperatures above 450°C hydrolysis of aluminium hydroxyfluoride results in the release of HF. Samples which are produced under dry scrubbing conditions and aged under ambient conditions, are indefinitely stable. However, when aged at high humidity the product layer is transformed into distinct crystallites of aluminium hydroxyfluoride by a dissolution/re-precipitation mechanism involving water filled pores. Samples which are hydrofluorinated at greater than 35% humidity show continued growth of A1Fx(OH)3-x 6H2O and AlF3.3H2O under all storage conditions due to residual water condensed within the alumina pores.

Organometallic chemistry is concerned with the study of metal-carbon bonded species. A wide variety of bonding modes have been discovered ranging from simple σ- through to more complex π- and μ-interactions. This thesis deals with the synthesis and chemistry of just three classes of compound, those containing formal TM-C single, double and triple bonds. These species are normally referred to as transition metal alkyl (σ-aryl), carbene and carbyne complexes respectively. The material is divided into five chapters and each is introduced by a relevant review. In chapter 1 the syntheses of σ-alkyl and -aryl complexes of ruthenium and osmium are described. These species are produced from organomercury reagents either by oxidative addition to the zerovalent complex Ru(CO)₂(PPh₃) ₃ or by reaction with the hydrido complexes MClH(CO)(PPh₃) ₃ (M = Ru, Os). This latter reaction provides a new route to organotransition metal complexes and some possible mechanisms are discussed. The organo-complexes formed by this latter method are coordinatively unsaturated and the structure of RuCl(p-tolyl)(CO)(PPh₃)₂ has been obtained by X-ray crystallography. The migratory insertion and reductive elimination reactions of these new compounds are discussed in chapters 2 and 3. Predictably, the Lewis base CO rapidly adds to these 16 electron species and the expected octahedral derivatives are formed. In some cases these are in equilibrium in solution with the corresponding dihapto-acyl complexes. The positions of the equilibria, the rates of interconversion and the relative solubilities of the two forms are such that in each case either essentially pure dicarbonyl or essentially pure dihapto-acyl can be isolated from solution. The dihapto-mode of bonding has been confirmed by X-ray crystallography for two of the derivatives. CNp-tolyl also adds to the 16 electron organo-compounds in an analogous fashion and equilibrium with the corresponding dihapto-iminoacyl compounds is attained in some cases. The dihapto-iminoacyl formulation has been confirmed by X-ray crystallography. Factors affecting the positions of all these equilibria are discussed and the possible relevance of these dihapto-acyl and -iminoacyl complexes as models for the proposed intermediates in the CO and CNR insertion reactions is noted. Compounds containing cis-H,R ligands are rarely stable since reductive elimination of R-H usually occurs very readily. Species of this type, therefore, appear to be ideal precursors for reactive, low valent complexes which are unobtainable by other means. A synthetic route has been developed by which an hydrido ligand can be incorporated into the coordination sphere of the new organo-derivatives described in chapter 1. The key step involves the thermal decarboxylation of a dihapto-formate ligand. In this way remarkably stable cis-H, tolyl complexes of osmium have been prepared. Toluene is eliminated from these derivatives only under forcing conditions. In contrast, reductive elimination from the analogous ruthenium complexes proceeds much more rapidly and in only one case has a stable hydrido, aryl complex been isolated. Other compounds that have been formed by this route are the zerovalent complex Ru(CO)(dppe)₂ and the ortho-metallated complex Ru(C6H₄PPh₂)H(CO)(PPh₃)₂. Factors affecting the rates of all these reactions are discussed. Some reactions of Ru(C₆H₄PPh₂)H(CO)(PPh₃)₂ have been investigated, and most notably a methyl, formate complex is produced with formaldehyde and a small amount of a dichlorocarbene complex with CCl₄. The reactions of this ortho-metallated compound may proceed via the intermediate "Ru(CO)(PPh₃)₃". Extension of the synthetic procedure described in chapter 1 has led to the production of the dichlorocarbene complex OsCl₂ (CO)(CCl₂)(PPh₃)₂, the structure of which has been determined by X-ray crystallography. This compound, which formally contains an Os-Ccarbene double bond, provides the subject matter for chapter 4. The carbene carbon atom is attacked by nucleophiles and the chloride substituents are easily displaced. This species therefore behaves as a remarkably versatile synthetic intermediate. Reaction with the chalcogen hydrides HX⁻ (or H₂X) leads to the corresponding chalcocarbonyl derivatives and OsCl₂ (CO)(CTe)(PPh₃)₂ is the first tellurocarbonyl complex to be isolated. Characterization of this complex includes an X-ray crystallographic analysis. Primary mines react with OsCl₂ (CO)(CCl₂)(PPh₃)₂ to form the corresponding coordinated isocyanides and reactions with other nucleophiles are also discussed. The most important of these, however, is the reaction with Li(p-tolyl). This produces the monomeric carbyne complex, Os(Cp-tolyl)Cl(CO)(PPh₃)₂, the structure of which has been determined by X-ray crystallography. This compound has an extremely short Os-Ccarbyne bond length and this is consistent with a triple bond formulation. The synthesis and chemistry of this compound is discussed in chapter 5. Although other carbyne complexes have been isolated previously this is a relatively new area of organometallic chemistry and reports of the chemistry of these species are restricted mainly to compounds of the GpVIa and VIIa metals. Os(Cp-tolyl)Cl(CO)(PPh₃)₂ displays a rather different chemistry from these compounds and some new reactions have been observed. Electrophiles such as H₊ and Cl₂ readily attack Ccarbyne and the corresponding carbene complexes are formed. This suggests that Ccarbyne is nucleophilic. The elements S, Se and Te add to the Os-Ccarbyne triple bond under ambient conditions to give the corresponding dihapto-chalcoacyl complexes. Adducts of the Os-Ccarbyne triple bond are also formed with the GpIb metals and the structure of Os(C{p-tolyl}AgCl)Cl(CO)(PPh₃)₂ has been determined by X-ray crystallography. Analogues of all these reactions are to be found in acetylene chemistry. In contrast to the cationic carbyne complexes of the GpVIa and VIIa metals, Ccarbyne in [Os(Cp-tolyl)(CO)₂ (PPh₃)₂]ClO₄ is not attacked by nucleophiles. Instead LiBHEt₃ preferentially attacks the para-carbon atom of the Ccarbyne p-tolyl substituent and an Os(O) vinylidene complex is formed. The structure of this compound has been confirmed by X-ray crystallography. Although the aromatic ring is destroyed in this reaction it is replaced by an extensively conjugated system which reaches through to the osmium atom. Further reactions of this species and the cationic carbyne complex [Os(Cp-tolyl)(CO)(CNp-tolyl)(PPh₃)₂]ClO₄ are also discussed. / Note: Whole document restricted due to copyright restrictions, but available by individual request use the feedback form to request access.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Mammalian liver and skeletal muscle glycogens were extracted using mild procedures and characterised according to their fine structure, molecular weight distribution and electron microscopic appearance. The role of protein in their structure was investigated. Rat, rabbit and mouse liver and muscle glycogens were polydisperse ranging in size up to more than one thousand million daltons. Whilst there are reports of liver glycogen covering such a size range, skeletal muscle glycogen of this size has not been previously reported. The glycogens contained a significant level of protein, some of which could be removed without altering the molecular weight distribution. The residual protein accounted for approximately 1% by weight of the purified glycogen, and it was concluded that this protein was covalently bound. Protease or concentrated alkali treatment of the glycogen digested the protein and resulted in a dramatic lowering of the molecular weight of glycogen, indicating that it was covalently bound protein which was responsible for the formation of high molecular weight material. Disulphide bond reduction also caused a lowering of molecular weight, indicating that high molecular weight glycogen arises by disulphide bridging between the protein backbones upon which the low molecular weight glycogen is synthesised. Thus liver and skeletal muscle glycogens are constructed in a similar manner. The fine structure of the glycogens was typical of that previously reported. When observed by electron microscopy the material appeared as spherical β-particles and large aggregates of these, the α-particles, thus confirming the presence of a high molecular weight component of skeletal muscle glycogen. The sizes of the products of TCA or KOH extraction of tissue glycogen were explained by the effects of these agents upon the glycogen molecule. Alkali digests the protein backbone and splits the glycogen β-particles, while TCA causes insolubility of the high protein content, high molecular weight glycogen. The protein backbone of rat liver glycogen was isolated. It had a molecular weight of 60,000 daltons and was rich in serine, glutamate, and the hydrophobic amino acids. Lysosome-enriched fractions were isolated from rat liver and skeletal muscle. Both contained glycogen; approximately 10% of tissue glycogen for the liver fraction and approximately 5% for the muscle fraction. The lysosomal glycogen of both tissues was enriched in the high molecular weight component. Thus in both tissues glycogen metabolism is compartmentalised, and degradation is via both phosphorolytic and hydrolytic pathways. The lysosomal acid α-glucosidases showed a preference for low rather than high molecular weight glycogen as substrate. A model for the regulation of lysosomal breakdown of glycogen was proposed. High and low molecular weight liver and muscle glycogens showed inhomogeneous responses upon starvation and rapid post mortem glycogenolysis. Both phosphorolysis and hydrolysis were involved. The increase in glycogen level upon refeeding following starvation was inhomogeneous with respect to glycogen size, in both tissues. The metabolic inhomogeneity of glycogen was related to its structural inhomogeneity and the association of the high molecular weight component with the lysosome.

This thesis describes synthetic work directed towards the synthesis of the dimeric pyranonaphthoquinone antibiotic crisamicin A 1.46 and its regioisomer 2.77. The synthetic strategy adopted is based on a double furofuran annulation/oxidative rearrangement strategy that has been successfully used by this research group to prepare a related dimeric pyranonaphthoquinone based on the actinorhodin skeleton. The retrosynthesis that was adopted (see Scheme 1.47, page 59) required the initial preparation of a key bis-naphthoquinone 1.267 which in turn is available from bisnaphthalene 1.268 that bears acetyl groups at C-7 and C-7’. Initial work concentrated on the construction of the biaryl linkage of bis-7- acetylnaphthalene 1.268 using a palladium(0)-mediated Suzuki-Miyaura homocoupling of the key triflate 1.269 (prepared in 10 steps from vanillin 1.271) using bis(pinacolato)diboron 1.179. This coupling method successfully afforded binaphthyls 2.8b and 2.8d which were subjected to attempts to effect either double bromination, double acetylation or double Fries rearrangement to a more functionalised biaryl system. Disappointingly, none of these methods allowed introduction of the key acetyl group at C-7 and C-7’ onto the initial biaryls 2.8b and 2.8d. Attention then turned to the synthesis of the bis-7-acetylnaphthalene 1,268 that was required for the ensuing furofuran annulation reaction starting from triflate 2.7 that already contained an acetyl group at C-7, then effecting formation of the key biaryl linkage. Attempts to prepare 7-acetyltriflate 2.7 via either Fries rearrangement of acetates 2.33a or 2.9a, or via bromination of acetate 2.33a, naphthol 2.56 or benzyl ether 2.6 were unsuccessful. An alternative approach for the preparation of 7-acetyltriflate 2.7 involved the preparation of 2-acetylcarbamate 2.74 from carbamate 2.64 via a directed ortho-metalation, followed by reaction of the derived ortho-lithiated species with N-methoxy-N-methylacetamide 2.71. However, this strategy resulted only in low yields of the desired 2-acetylcarbamate 2.74, although initial model work did provide methodology for the successful conversion of carbamate 2.68 to 2-acetyl-l-naphthol 2.73. The synthetic target of this thesis shifted to the regioisomer of crisamicin A 2.77 when attempts to introduce an acetyl group atC-7 of triflate 2.9 failed. However formation of the 6-acetyltriflate 2.81b was successful from triflate 2.9b. A subsequent one-pot in situ Suzuki-Miyaura homocoupling of triflate 2.81b with boronate 2.89 furnished dimmer 2.76b. Oxidation of dimer 2.76b to bis-naphthoquinone 2.80 was then accomplished using silver(II) oxide and 6 M nitric acid. With the key bis-6-acetylnaphthoquinone 2.80 in hand, an efficient double furofuran annulation reaction was carried out using 2-trimethylsilyloxyfuran 1.88 affording the desired bis-furonaphthofuran adduct 2.79 as an inseparable l:l mixture of diastereomers 2.79a and 2.79b. However, initial experiments to effect the double oxidative rearrangement of bis-furonaphthofuran adducts 2.79 using either silver(Il) oxide and 6 M nitric acid or with ceric ammonium nitrate in aqueous acetonitrile to the bisfuronaphthopyran 2.7 8 were unsuccessful. Attention then turned to the preparation of bis-furonaphthopyran 2.78 from the 6-acetyltriflate 2.81b via initial oxidation of triflate 2.81b to naphthoquinone 3.3 followed by furofuran annulation and then oxidative rearrangement. Attempts to effect the key Suzuki-Miyaura homocoupling of furonaphthofuran 3.2 to bis-furonaphthofuran 2.79, or of furonaphthopyran 3.1 to bis-furonaphthopyran 2.78, using catalyst PdCl2(dppf) and ligand dppf were unsuccessful. The work achieved herein constitutes the synthesis of an advanced intermediate for the synthesis of the crisamicin analogue 2.79. The final synthesis of the regioisomer of crisamicin A 2.77 can be completed by preparing bis-furonaphthopyran bis-lactol 2.78 using more powerful palladium(0) catalysts and ligands for the Suzuki-Miyaura homocoupling of the monomeric furonaphthopyran 3.1. Subsequent reduction af 2.78 using triethylsilane and trifluoroacetic acid will then afford the bis-cyclic ether 3.15, which can undergo deprotection of the methyl ether and epimerisation at C-5 upon treatment with excess boron tribromide to finally furnish the regioisomer of crisamicin A 2.77. An investigation into the double oxidative rearangement of bis-furonaphthofuran 2.79 to the bis-lactol 2.78 could also be carried out by the use of several alternative oxidising agents, such as phenyliodine(III) bis(trifluoroacetate) (PIFA), phenyliodine(III) diacetate (PIDA), polymer-supported (diacetoxyiodo)benzene (PSDIB), Fremy's salt, iron trichloride or CrO3.

PART I A general introduction is given to the mechanisms of olefin-forming β-elimination. The development of mechanistic criteria and their application to the various reactions is discussed. Conflicting theories concerning the nature of the transition states of E2H reactions in protic solvents as well as the Winstein-Parker E2C-like transitions states for elimination by weak bases in dipolar aprotic solvents are described. PART II The use of primary deuterium isotope effects: structure-reactivity relationships, and rate-acidity correlations as mechanistic criteria for the E2 mechanism and the variants of the E1cB mechanism is reviewed. These criteria have been applied to the dehydrochlorination of the 1,1-diaryl-2, 2, 2-trichloroethanes (DDT-type compounds) with methoxide-methanol and t-butoxide-t-butanol. Literature comparisons indicate that the kinetic evidence for these two systems is in accord with an "irreversible" E1cB elimination pathway. PART III Characteristics of weak base-promoted eliminations in dipolar aprotic advents are reviewed. The evidence is not entirely consistent with either E2C or the E2H mechanism. Deuterium isotope effects and equilibrium constants are reported for the chloride ion-promoted elimination of the 1, 1-diary1-2,2,2-trichloroethanes in dimethylformamide and acetone respectively. The results are in accord with an E2H mechanism.

The results to be described and discussed in this thesis concern synthesis and reactivity of iridium(I) and (III) complexes containing thiocarbonyl or selenocarbonyl ligands. Chapter 1 comprises: a review of Vaska's compound, IrCl(CO) (PPh3)2 and related species, covering syntheses, structure and bonding and reactions of this very widely studied moiety; and brief reviews of metal-thiocarbonyl syntheses and reactions and metal-selenocarbonyl chemistry. These three reviews background the themes developed in this work; of preparations and reactions, particularly ligand reactions, of thiocarbonyl and selenocarbonyl analogues of Vaska's compound and species derived from IrCl(CE)(PPh3)2, E = S, Se. A new synthesis of IrCl(CS)(PPh3)2 is described in Chapter 2. The route employed involves preparation of dithioester complexes and facets of the reactivity of these species have been considered and a number of metallocycle derivatives prepared. Reductions of coordinated-thiocarbonyl groups have been considered; IrH(CS)(PPh3)3 was transformed into IrH2(SMe)(PPh3)3 by treatment with hydrogen, while the thiocarbonyl cation complexes [IrClX(CO)(CS)-(PPh3)2]+ were treated with borohydride to afford thioformyl species. Iridium alkyl, thiocarbonyl complexes have been prepared, and transformed by reaction with dithiocarbamate ion to yield monohapto-thioacetyl derivatives. The preparation of IrCl(CSe)(PPh3)2, the selenocarbonyl analogue of Vaska's compound is reported in Chapter 3. The synthesis utilizes carbon diselenide as the selenocarbonyl source, and involves a four-step conversion of a dihapto-carbon diselenide adduct complex to the iridium(I) selenocarbonyl species. Reactions of a range of iridium(I) complexes with carbon diselenide are described, including the preparation of a complex including three CSe2 groups. Reactions of IrCl(CSe)(PPh3)2 have been studied and several iridium(I) and (III) selenocarbonyl compounds prepared. The ready reduction of IrCl(CSe)(PPh3)2 (in the presence of phosphine) by borohydride to give IrH2(SeMe)(PPh3)3 is described and comparisons are drawn between the relative reactivities of iridium thiocarbonyl and selenocarbonyl groups, in analogous species, with nucleophiles. It is concluded the Ir-CSe system is more reactive under similar conditions. Metallocycle derivatives of iridium selenocarbonyl, diselenomethylester complexes have been characterised.

The crystal structure of the bromo derivative of a cyclic diterpene has been determined. The crystals are of orthorhombic symmetry with a = 9.00Å, b = 31.46Å, c = 7.31Å. The structure was solved by the normal heavy atom procedure, and refined by least-squares to a residual of R = 0.064. The molecule is shown to be phyllocladan-15-yl bromoacetate, rather than to be a neo-atisirane derivative, as had been expected.

The ketoester, 3-ethoxycarbonyl-12-methoxy-5βH-18,19-bisnor-podocarpa-8,11,13-trien-4-one(80). The numbering used throughout this thesis is that proposed by J.W. Rowe (personal communication to Dr. R. C. Cambie) in 'The Common and Systematic Nomenclature of Cyclic Diterpenes', 3rd Revision, Oct. 1968, to be submitted to the IUPAC Commission on Organic Nomenclature has been prepared from 12-hydroxypodocarpa-8,11,13-trien-19-oic acid (1), via the C4 ketones (76) and (77). Both of these isomers were obtained from the methoxyalkene (11), which was isolated in a pure form during selective epoxidation of the methoxyalkene mixture (11 - 13) obtained from the decarboxylation of 12-methoxypodocarpa-8,11,13-trien-19-oic acid (2) with lead tetraacetate. This reaction has been investigated, and a mechanism accounting for the formation of nondecarboxylation products is proposed. The unsaturated ketoester (102) was prepared in low yield via the saturated C12 ketone (24), obtained from 12-hydroxypodocarpa-8,11,13-trien-19-oic acid (1) by Birch reduction of the aromatic ring. A number of ring A epoxide derivatives of the acid(1) were prepared and cleaved by a variety of reagents to give the 3-oxygenated derivatives (145), (146), and (152), together with compounds possessing a contracted ring A. Some ring B lactone derivatives of the acid (1) were prepared, and their stereochemistry and conformation were determined by n.m.r. spectroscopy. The conformation of some ring B-substituted derivatives was also determined by n.m.r. methods. The bromination of some 7-ketopodocarpa-8,11,13-triene derivatives was investigated, and reasons are advanced for the non-stereospecific reactions observed in some cases.

The first part of this thesis describes the use of several diterpenoids which are readily available in New Zealand for the synthesis of compounds possessing ambergris-type odours. Homologues and analogues of known odorants have been prepared with a view to correlating their odour properties with molecular structure. A new series of 1,3-dioxa-compounds has been found to exhibit odour properties characteristic of this class of odorants. In the second part a simple procedure for the conversion of totarol into a C-12 oxygenated derivative is reported. This derivative has been oxidatively degraded using ozone, and the degradation product has been converted into a possible intermediate for the synthesis of a ring-C system found in naturally occurring nagilactones. The rearrangement of several aryl phosphates under the action of n-butyllithium is reported.

This thesis describes the chemical, physico-chemical and structural studies of two types of copper compounds which interact with molecular oxygen in their formation. The first type is an intensely coloured species based on the ligand oxalyldihydrazide. The divalent metal and the ligand react together with simple carbonyl compounds and molecular oxygen in basic conditions to form blue species the nature of which has been the subject of conjecture for many years. This work shows that the metal is trivalent in the highly coloured states and that it acts as an oxidative catalyst with ascorbic acid. The copper (III)/copper (II) potential has been established as +0.244V by polarography. Compounds including acetaldehyde and acetone as the carbonyl component have been crystallized in monoclinic space groups. In both instances X-ray diffraction studies show that the metal is co-ordinated to a 6-5-6-5 macrocycle formed by a condensation reaction between two oxalyldihydrazide molecules and two carbonyl moieties. The co-ordination is via four deprotonated 'amide' nitrogen atoms and is of square-planar geometry. A structural study of oxalyldihydrazide has also been undertaken and comparisons are made with the co-ordinated species. The second type of compound studied is a Cu4OX6L4 cluster. It was made from a copper(I) precursor and studies with oxygen-18 gas show that formation requires oxidation to copper(II) followed by hydrolysis. Infrared evidence based on the Cu-O stretch (500-580 cm-1) is presented. Attempts to include both fluorine and iodine as the halogen component suggest that only chlorine and bromine may fill such a role.