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This thesis focuses on the structure, reactivity and spectroscopy of metal complexes, as investigated using both DFT and ab initio methods, with a particular emphasis on the elucidation of experimental data. The first results chapter. Chapter 3, describes the electronic structure and spectroscopy of [Zn(pyridine)₄]²⁺, as calculated using TDDFT, to aid the interpretation and assignment of the first recorded state-resolved gas-phase photofragmentation spectrum of a dicationic transition-metal complex.

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This thesis describes the development of new methods towards the stereoselective synthesis of oxazolidinones and [3,3] sigmatropic rearrangements to allylamines from allylic carbamate starting materials. Unlike previous protocols found in the literature the oxazolidinones formed do not have a protected nitrogen atom. The stereoselective formation of chlorohydroxylated products is demonstrated with the view to utilise this reaction as part of an alternative to the tethered aminohydroxylation. A novel diastereoselective iodine mediated cyclisation of allylic carbamates and allylic ureas to oxazolidinones and imidazolidinones respectively is described. The reaction has also been telescoped from an aldehyde completing three reactions in a one pot environment. The use of palladium (II) catalysis for oxazolidinone formation is also shown in an attempt to devise an enantioselective reaction analogous to the highly acclaimed tethered aminohydroxylation. Palladium (II) catalysis is also utilised for the diastereoselective conversion of allylic carbamates to allylic amines. Chapter 1: An overview to the uses of osmium and palladium in the activation of alkenes described in the literature. Chapter 2: Highlights our research into the formation of oxazolidinone rings from and [3,3] sigmatropic rearrangements of allylic carbamates. Chapter 3: Provides experimental data for our studies.

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For industrial objectives, synthesis of akaganéite ffl-FeOOH) and goethite ((X-FeOOH) iron oxyhydroxides with nanometre particle size and acicular morphology was targeted. Both P & a-FeOOH particles were generated via forced hydrolysis of Fe" ions in acidic media. Templated syntheses of these particles were carried out in surfactant lyotropic liquid crystal media and in aqueous glyme solutions. Partial phase diagrams for different commercial surfactantIH20 systems (Neodol (1-5E), Brij 97 and CTAB) have been examined for stability to the iron oxyhydroxide synthesis conditions (pH, ionic media and iron cations), with only CTAB/water system losing lyotropic phase integrity in the presence of iron cations. The Neodol (I-SE) maintained an ordered lamellar (L4 phase for a surfactant molar ratio between 0.035 and 0.1, and up to 50°C. The Brij 97 gave a stable hexagonal phase from 0.014 to 0.025 mol/mol (up to about 45°C) and a lamellar phase from 0.047 to 0.1mol/mol (up to about 65°C). The stability of these polyethylene oxide non-ionic surfactant materials was examined against the different conditions that can be used for the synthesis of 13- & a-FeOOH such as pH, ionic species, Fe" and Fe" ions. The addition of Cr, NO3, S042, and P043 anions and Nat, C2t Mg2 and Cr3 cations induced a noticeable destabilisation effect at the high concentration end of the lyotropic liquid crystal phases. Small angle x-ray diffraction was used to determine the spacing available for templated reaction. The d-spacing of the L. phase of Neodol (I-SE) varied between = 4.8 and 7 nm with concentration, which was found to be equivalent to water layer thickness of =3.3 - 5.5 nm. The Brij 97 provided a minimum templating distance of about 1.4 nm in the hexagonal phase and 1.95 nm in the lamellar. In the Neodol (l-SE)/water surfactant system, f3- & a-FeOOH particles were characterised using FT-IR, UV-VIS, PCS, TEM and AFM techniques. The -FeOOH formed cigar-shaped acicular particles both in free solution and in the lamellar phase. The size of particles from free solution ranged between 300 - 500 nm in length and 30 to 60 nm in width. The size of particles grown in Neodol (I-SE) / water system ranged from 25 to 40 nm in length and 4 to 7 nm in width and showed narrower size distribution, using PCS, compared to their counterparts prepared in aqueous solution. The a-FeOOH particles produced in aqueous and Neodol (1-5E) surfactant medium appeared as aggregates. The aggregates produced in aqueous solution were not uniform in shape with sizes ranging from 100 to 200 nm. The aggregates formed from the ordered surfactant phase were elongated in shape with sizes ranging from SO to IOU nm. PCS also showed smaller size distribution of u-FeOOH from templated synthesis compared to ct-FeOOH prepared in aqueous solution. Also, the 13-FeOOH iron oxide prepared in the Brij 97 / water system appeared as aggregates under the TEM. The effect of the ethylene oxide species, the surfactant head group, on the hydrolysis of Fe" ions and the consequent production of 13-FeOOH particles has been examined using, a series of glymes, organic molecules containing ethylene oxide species. The glymes were observed to induce faster precipitation and templating effects on 3-FeOOH particles produced. Glymes also showed evidence of possible chelating effects influencing the hydrolysis mechanistic processes.

Aluminosilicates, especially zeolite A, Surrey powder and alumina, are efficient and mild catalysts for ligand substitution reactions of inert Cr(" and Co(ffl) complexes. The reaction kinetics for the aquation of chromium(1H) chloride and chromium(llI) bromide hexahydrates, the anation reaction of Cr(H 20)631 by Cl- and the aquation of [Co(NH3)5C1]C12 with and without aluminosilicate catalysts were studied using ion exchange chromatography. Rate constants were determined for each reaction by application of a least squares modelling in Excel. Experimental observations agreed with literature data, that under the conditions employed and without catalysts, the aquation reactions of trans-[CrCl 2(H20)4]Ct2H20 and lrans-[Cr]3r2(H20)4JBr2H20 to [Cr(H2O)6] 3 , follow an I mechanism with a conjugate base pathway, indicating that a weakening of the Cr-X bond is crucial for accelerating the aquation reactions. The aluminosilicate catalysed aquation studies of CrC! j6H2O and CrBr3'6H20 appear to indicate that accessible tetrahedral aluminium species are necessary for successful catalysis of the reactions and the greater the number of these sites the faster the aquation. The aluminosilicates act simultaneously as bi-functional catalysts, i.e. as proton acceptors (base catalysis) and as electron pair acceptors (Lewis acid catalysis). Thus, the two possible activation mechanisms that agree with the experimental observations, appear to be: i) association of a halide ion with an accessible Lewis site (e.g. Al—OH2 and/or (AJ-0)2Cr 4), which is developed from weak base site Al-OH on the surface of the catalyst, enabling the halide to dissociate more readily; ii) base catalysis where the catalyst absorbs H allowing the Cr cation to lose fbrther protons from its aquation sphere, reducing the charge on the complex, weakening the Cr—Cl bond and thus making the halide more labile to substitution. This bi-functional catalysis was confirmed by the anation of Cr(H 2O)63 by Cl- and the aquation of [Co(NH3)5Cl]C12 catalysed by Zeolite A and Surrey Powder. The base catalytic functionality can be classified into two types according to how they increase the pH of the solution environments. The first group including zeolite A and intact montmorillonite clays, has low pzc but high cation ion exchange capacity and so raises the pH to a relatively high degree by proton/metal cation exchange. The second group consists of oxides with high pzc such as y-alumina, which raise the pH of their surrounding solutions by reactions to form surface hydroxyls. For the Lewis acid catalysis function, the three possible anion absorption mechanisms on the clay edges that appear to occur under our experimental conditions (pH !9 4 and in Cr3 solution), are: i) formation of Al—OH2 at low pH, which can attract anions by acid—base ion pairing; ii) formation of AI—OCr2 or (Al-0)2Cr by metal cation binding reactions; and iii) the absorption of anions by exchange with the surface OH groups. The adsorbed Cr3 (e.g. [A]-0]2Cr4) on the edge of the catalysts appeared to be playing the more important role as the Lewis acid sites. Surrey Powder and 5A molecular sieve were successful catalysts for the direct syntheses of potassium and sodium tris(oxalato)chromate(ll1), potassium and sodium tris(malonato)chromate(Ill) and tris(ethylenediamine)chromium(ffl) chloride from chromium chloride hexahydrate in water at room temperature. Although no attempts at optimising these yields were made, all yields of the catalytic syntheses were improved over the un-catalysed reactions.