This thesis details the synthesis of novel Rh(I) and Rh(III) bis-phosphine fragments, and their use, along with other known rhodium species, to investigate the reactivity of amine-boranes, with a particular focus on the dehydrocoupling of the secondary amine-borane H3B.NMe2H (DMAB). Chapter 2 utilises the new mixed phosphine, PtBuiBu2, to investigate the role of the phosphine with regard to the corresponding low-coordinate organometallic species isolated. Their coordination and reactivity with amine-boranes is studied, leading to the development of a mechanism for an alkene hydroboration catalyst that employs H3B.NMe3 (TMAB). The final section of the chapter studies several fluxional processes pertinent to rhodium and iridium complexes of the model amine-borane TMAB using H/D exchange and low temperature NMR experiments. In Chapter 3, the mechanism of dehydrocoupling of DMAB is investigated in detail, employing catalysts based on the cationic bis¬-phosphine Rh fragment, {Rh(PCy3)2Ln}+. A series of stoichiometric and catalytic reactions are probed using NMR spectroscopy and mass spectrometry, revealing a complex mechanistic landscape. Subtleties include: the product of dehydrocoupling, [H2BNMe2]2, acting in an autocatalytic role; and parallel dehydrogenation of DMAB by a neutral catalyst present in a low but constant concentration. The mechanism was additionally interrogated through kinetic simulations conducted by Prof. Guy C. Lloyd-Jones (University of Bristol). From this, a generic mechanistic scheme has been suggested, aspects of which can be applied to transition metal and main group systems reported to catalyse the dehydrocoupling of DMAB. The final chapter moves on from cationic rhodium fragments to investigate the reactivity of the neutral rhodium species, Rh(H)2(PCy3)2Cl and [Rh(PCy3)2Cl]2, with amine-boranes. The mechanism by which Rh(H)2(PCy3)2Cl catalyses the dehydrogenation of DMAB has been investigated through initial rate and H/D exchange experiments, leading to the proposal of a reaction scheme. Additionally, the formation and characterisation of a base-stabilised boryl species has been reported resulting from the reactivity of an amino-borane with [Rh(PCy3)2Cl]2.

The purpose of this project has been to expand the η8 binding mode of the permethylpentalene ligand into uranium, zirconium and hafnium chemistry. All three of these elements have shown intriguing, high-hapticity carbocyclic chemistry and, because of their relatively large size, are excellent candidates for the development of organometallic permethylpentalene chemistry. Chapter one of this thesis will review previous work on η n carbocyclic ring chemistry of these elements, where n = 6 - 8. This introduction will include the unsaturated rings systems where all the ,carbons are bonded to the metal centre, specifically η6 arene systems, η 7 cyclohept.atriene systems, and η 8 cyclooctatetraene and pentalene systems. Species of lower hapticity (e .g. the η 6 binding mode of cycloheptatriene) will not be covered but reviews, where available, will be referenced. Chapter two documents the successful synthesis and characterisation of η 8 permethylpentalene uranium (IV) species. Initially, the uranocene equivalent, UPn*2 was synthesised and characterised structurally, magnetically and electrochemically. From here, a half-sandwich synthon [U Pn*CI4][Li(TMEDA)h was synthesised which was used for further salt metathesis chemistry in order to make a number of mixed sandwich complexes. Chapter three is an account of the synthesis and characterisation of zirconium and hafnium η 8 permethylpentalene species. Initial work focused on the synthesis of a suitable synthon analogous to that used for the previously synthesised titanium species. However, this route was unsuccessful and an alternative species was formed, [MPn*(μ-Cl)3/2]2(μCl)2[Li(THF)x(Et2O)y]. This species could be made on a multi-gram scale and proved to be a sui table synthon for further synthesis. Salt metathesis reactions were undertaken and a number of new species were synthesised and characterised including mixed-sandwich, alkyl, aryl and allyl species. Chapter four reports the results of polymerisation testing that was undertaken for selected synthesised compounds. All compounds catalysed the formation of poly(ethylene), with the group 4 mixed sandwich species being particularly active catalysts. Two of the zirconium species, ZrPn*CpCI and ZrPn*Cp2 were therefore used for further optimisation experiments which were somewhat limited due to the high activity of the compounds. These were useful in gaining insight into conditions that should be investigated on a larger reaction scale. Chapter five gives the full experimental details for all the syntheses described in chapters two and three as well as details of instrumentation used for characterisation, and also gives the respective loadings of catalyst and co-catalyst employed in the polymerisation testing reported in chapter four. Chapter six presents the full characterisation data obtained for the compounds synthesised and the electronic appendix attached as a CD at the back of the thesis contains the crystal data .cif files and the DFT output files (.out). ,

This thesis describes selected reactivity studies of group 15 Zintl anion [E7]3– (E = P, As) derived cages towards a series of unsaturated organic molecules. The synthesis and characterization of forty-two compounds derived from [E7]3– cages are detailed herein. A high yielding procedure for the synthesis of [HE7]2– (E = P, As) from the K3E7 Zintl phase has been developed. This solves prior issues with poor solubility and variable purity of the Zintl phases. The conditions required for the deprotonation of the phosphorus congener to [P7]3– are described. The reactivity of both [P7]3– and [HP7]2– towards carbon dioxide and isolobal isocyanates and carbodiimides was explored. This yielded a series of monofunctionalized [E7R]2– cages, via a net hydropnictination of a C=N double bond of the organic substrate. The protonation chemistry of these anions was further investigated, resulting in the formation of the protic [HP7C(NHDipp)(NDipp)]– cluster. This anion is capable of further hydrophosphination chemistry to give a series of difunctionalized heptaphosphide cages. The reaction of [E7]3– with alkynes results in the formation of the relatively unusual 1,2,3-tripnictolide anions. A series of such anions have been prepared, encompassing all of the previously reported anions and several novel species. Investigation of the coordination properties of these cyclopentadienyl analogues shows that they are superior π acceptor ligands. A synthetic route to [P5]– as a compositionally pure solid, and some initial studies on its protonation chemistry are also additionally presented.

This thesis explores the area of the intermolecular hydroacylation reaction, catalysed by rhodium diphosphine complexes. A range of latent low-coordinate rhodium diphosphine complexes have been synthesised, and their catalytic activity for the hydroacylation reaction has been investigated. In particular, emphasis has been placed on understanding how subtle changes in diphosphine steric properties affect, and can be used to control, selectivity of this catalysis. Chapter 2 presents investigations into rhodium complexes incorporating the potentially hemilabile P-O-P ligands: POP’, XANTphos and Xphos. The resulting complexes have been fully characterised and their activity for the catalytic intermolecular hydroacylation of aldehyde I (HCOC₂H₄SMe) and alkene II (H₂C=CHCO₂Me) established and compared to the DPEphos system. Further reactivity of Xphos for aromatic aldehyde V (HCOC₆H₄SMe) and alkene II, and aldehyde V and alkyne XI [HC≡CC₆H₃(CF₃)₂] has also been explored, and compared with the catalytic activity of {Rh(PPh₃)₂}⁺. Focus moved from potentially hemilabile ligands to chelating diphosphine ligands of the type PPh₂(CH₂)nPPh₂ (where n = 2-5), and then on to ortho-substituted bulky analogues of the type P(₀-C₆H₅R)₂(CH₂)₂P(₀-C₆H₅R)₂ (where R = Me and ⁱPr) complexed to rhodium. Chapter 3 outlines the complexes synthesised, and their activity for the catalytic intermolecular hydroacylation of aldehyde I and alkene II, aromatic aldehyde V and alkene II or aldehyde V and alkyne XI. Possible explanations for the observed switch in selectivity from alkene to aldehyde hydroacylation, and linear alkyne to branched alkyne hydroacylation, have been explored and are detailed. The final chapter concerns the structure of an interesting catalytic intermediate: the branched alkenyl species for the {Rh(DPEphos)}+ catalysed hydroacylation of aldehyde V and alkyne XI. Investigations into the kinetic and catalytic behaviour of this system were carried out, and a reaction scheme has been proposed which correlates well with kinetic modelling undertaken by Prof. Guy Lloyd-Jones of the University of Bristol.

This thesis is concerned with structure-reactivity relationships in metallocene chemistry. In particular new ansa-metallocenes of Groups 5-7 have been prepared. The structure and reactivity of these ansa-metallocenes is compared to the corresponding nonbridged metallocenes.

The Swedish steelmaking industry produces large amounts of by-products. In 2008, the total amount of slag produced reached approximately 1,300,000 metric tons, of which 20% was deposited. Due to its strength, durability and chemistry, steel slag is of interest in the field of construction, since it has similar or better qualities than ordinary ballast stone, which makes it a competitive construction material. However, some steel slags face an array of quality concerns that might hinder their use. These concerns generally involve the following physical and chemical properties:Volume expansion Disintegration Leaching of metalsBy controlling and modifying process parameters during slag handling in liquid state, the physical and chemical properties of steel slags can be adequately modified to obtain a high-quality product for external application. The present work was undertaken as a research project within the Minerals and Metals Recycling Research Centre, MiMeR. The major goal of this work has been to investigate how different treatment methods including hot stage processing, cooling rates, ageing time and chemical composition influence the final properties of the slag. Analysis techniques used in this investigation include: thermodynamic calculations using FactsageTM, X-ray diffraction analyses (XRD), scanning electron microscopy (SEM), leaching tests (EN12457-2/3) and thermo-gravimetric analyses (TG).The results from this study show that it is possible to control/change the properties of the final product by additions to the liquid slag, thereby changing the chemical composition, as well as by varying the rate and method of cooling. The mineralogical composition, the size of the crystals and the composition of some solid solutions are affected by the cooling rate. The solubility of elements such as chromium and molybdenum varies, probably due to their presence in different minerals. The reactivity of the investigated slag samples increases as the cooling rate increases.When steel slags are aged, the leaching properties of the materials are changed. The total leachability and the pH decrease for all the investigated samples. All elements except magnesium decrease in leachability. As the slags are aged CaCO3 is formed on the slag surfaces. The degree of carbonation differs between different slags, due to the presence of different calcium-rich minerals in the slag. In order to form CaCO3, the calcium-containing mineral must be dissolved. This means that the solubility of the calcium-containing mineral will affect the outcome of the carbonation. The rate of dissolution for six typical slag minerals was investigated in order to distinguish the difference in solubility between the different minerals. Acidic to alkaline pHs (4, 7 and 10) were selected to investigate the solubility of the minerals under conditions comparable to those prevailing in newly produced slags and the potential future pH values obtained under acid conditions. It can be concluded that all six minerals behave differently when dissolving and that the rate of dissolution is generally slower at higher pH. At pH 10, the solubility of merwinite, akermanite and gehlenite is considered slow. The dissolution of γ-Ca2SiO4 is not affected in the same way as the other minerals when the pH is changed. / Godkänd; 2010; 20101213 (fren); DISPUTATION Ämnesområde: Processmetallurgi/Process Metallurgy Opponent: Professor Pekka Taskinen, Dept. of Materials Science and Engineering, Aalto University, Finland Ordförande: Professor Bo Björkman, Institutionen för TKG, Avd för mineralteknik och metallurgi, Luleå tekniska universitet Tid: Fredag den 4 februari 2011, kl 10.00 Plats: F341, Luleå tekniska universitet

This thesis is concerned with furthering our understanding of the basis of visible region photocatalytic activity exhibited by doped TiO2-based materials. A range of experimental techniques including high resolution X-ray photoemission spectroscopy and diffuse reflectance spectroscopy are used to investigate electronic structure and an attempt is made to link these results to the observed photocatalytic activity. Both anionic (N) and cationic (Rh and Sn) dopants are investigated. [See pdf file for full abstract].

This thesis describes the synthesis, characterisation and reactivity of diamide-amine and bis(cyclopentadienyl) supported Group 4 hydrazido(2-) compounds towards unsaturated molecules. The mechanisms of these transformations are probed using a range of structural, kinetic and computational methods.

Thesis (D.Sc.)--University of Adelaide, School of Chemistry and Physics, Discipline of Chemistry, 2005? / "December 2004" Includes bibliographical references.

This thesis describes selected reactivity studies of the N-heterocyclic carbene, IPr, towards a range of main group compounds. The synthesis and characterisation of sixty-three compounds, all of which incorporate IPr as a ligand in one of three coordination modes, are detailed herein. The deprotonation of IPr allowed for the isolation of an anionic source of the aIPr: ligand which was synthesised as a novel potassium salt and along with the previously reported lithium salt, was employed in reactions with group 12 and 14 bis(trimethylsilyl)amides and tetrahalides. The further chemistry of such novel products was investigated towards both electrophilic and nucleophilic reagents making use of both the pendant nucleophilic carbene functionality and the electrophilic main group centre. An alternative route to such species was investigated by the spontaneous isomerisation of IPr in the coordination sphere of group 14 tetrabromides and group 15 tribromides. The scope of this reactivity was subsequently investigated and was found to provide a simpler route to access the abnormal coordination mode of IPr. The aIPr ligand which is generated may be deprotonated by additional IPr thereby affording aIPr: ligands. The addition of halide abstracting agents allowed for the synthesis of cationic species stabilised by the coordination of either IPr or aIPr ligands. A unique, spontaneous reductive coupling of two phosphorus centres was discovered to take place upon heating a THF solution of (IPr)PBr₃. This allowed for the isolation of a bromide bridged P–P bond with reduced phosphorus centres. This facile reduction chemistry was further explored by reaction with mild reducing agents which provide access to low oxidation state phosphorus compounds in high yields. This chemistry was found to be possible (and more effective) due to the presence of the weaker phosphorus bond to bromine relative to the commonly employed chlorine ligands.