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The aim of the study was to heterogenise existing tetramerisation catalysts by supporting the bis(diphenylphosphino)amine ligands on polymer. The polymer of choice was Merrifield’s resin which was functionalized to enable attachment of the ligands. These supported ligands were characterized via ATR, solid-state NMR, SEM and TGA-DSC. In order to compare activity of the supported and unsupported ligands, homogeneous bis(diphenylphosphino)amine ligands were synthesized and characterized via NMR, elemental Analysis, ATR and GC-MS. Tetramerisation reactions were carried out in a Parr pressure reactor using Cr(acac)₃as the precursor and MMAO-3A as the activator. The homogeneous ligands proved active in the tetramerisation of ethylene, with the selectivity of 1-octene in the C8 fraction being comparable with that mentioned in literature (> 98 wt%). When comparing the homogeneous ligands with their heterogeneous counterparts, the heterogeneous ligands performed poorly due to steric effects caused by the polymer chain. The activity dropped by more than four times that of their homogeneous counterparts and the selectivity towards the main product, 1-octene, was very low (< 10 wt%). These ligands seemed to create a system that favoured the formation of the C6 products more than any other product, with the C6 cyclics being the most dominant. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2010.

The synthesis, characterisation and X-ray structure detenninations of homonuclear nickel, palladium and platinum complexes with bis(phosphino)amine ligands is reviewed in Chapter 1. Particular attention is given to the mode of coordination that these ligands may adopt when coordinating to a transition metal i.e., as a monodentate (n'-), chelating (n2-) or bridging (u-) ligand. The Chapter is concluded with a brief summary of (i) The dependence of the 31P chemical shift for the bonded phosphorus atom(s) on the mode of coordination and (ii) The dependence of key, ligand-based, structural parameters on the mode of coordination. The synthesis and characterisation of the bis(diphenylphosphino )-ethylamine, Ph2PN(Et)PPh2, ligand and its subsequent reactions with various palladium precursors is described in Chapter 2. Reaction with the Pd(II) precursor, [PdCI2(PhCN)2], afforded the mononuclear complex cis-[PdCI2{ n2-Ph2PN(Et)PPh2}]1; when the same reaction was carried-out in the presence of the Pd(0) species [Pd2(dba)3] (dba = dibenzylideneacetone) the dinuclear ligand-bridged complex [Pd2C12 {u-Ph2PN(Et)PPh2}2] was formed. Reaction of 2 with I2 afforded 1, as well as the mononuclear di-iodo species cis-[PdI2 {n2-Ph2PN(Et)PPh2}] 3, and the mixed-halogeno complex [PdClI{n2-Ph2PN(Et)PPh2}] 4. Direct reaction of the ligand with [Pd2(dba)3] afforded, in the first instance, [Pd2{u-Ph2PN(Et)PPh2}3] 5, an extremely air-sensitive red compound, that readily reacted with oxygen in the solution to afford palladium metal and a yellow clathrate species that contained the oxidised ligand i.e., Ph2P(O)N(Et)P(O)PPh2. dba. H2O. Apart from 4, all compounds were characterised by means of elemental analysis, 1H and 3IP{1H} NMR spectroscopy and, in the case of 1, 2, 3 and Ph2P(O)N(Et)P(O)PPh2. dba. H2O, by means of single crystal X-ray structure determinations. The structures of the palladium complexes are, as expected, dominated by the requirement that the coordination geometry at the Pd atom is square-planar. In the case of the dinuclear ligand-bridged complex 2, this is achieved through formation of a Pd-Pd bond of length 2.600(1)A. Of particular interest is the crystal structure of the clathrate, which has the oxidised ligand and dba molecules stacked in alternating lines approximately parallel to the [c ]-axis of the unit cell. The synthesis and characterisation of the bis(2-pyridyl)phenylphosphine, PhP(py)2 ligand and its subsequent reaction with [PdCI2(PhCN)2] to afford the mononuclear complex cis-[PdCI2{n1-PhP(py)2}2] 6 is decribed in Chapter 3. The latter reacted with [Pd2(dba)3] to afford the dinuclear ligand-bridged species [Pd2CI2{u-PhP(py)2}2] 7. The 1H and 31P{1H} NMR spectral data, as well the results of single crystal X-ray structure determinations are reported for 6 and 7. The square-planar coordination at each palladium atom in 7 is achieved through the formation of a Pd-Pd bond of length 2.586(1)A. The synthesis and characterisation of the 2,5-(diphenylphosphino)thiophene, Ph2P(C4H2S)PPh2 ligand is described in Chapter 4. Reaction of the ligand with [PdCI2(PhCN)2] afforded the dinuclear ligand-bridged species [Pd2C14 {u-Ph2P(C4H2S)PPh2}2] 8. Characterisation of 8 was by means of elemental analysis, 1H and 31P{1H} NMR spectroscopy. Reaction of 8 with Ag+ in acetonitrile afforded a compound isolated as a yellow solid and formulated as [Pd2CI3(MeCN){u-Ph2P(C4H2S)PPh2}2] 9. Evidence for this formulation is based on the 31P{1H} NMR spectrum which shows two closely-spaced singlets, consistent with two sets of phosphorus atoms in different chemical environments, and too far separated (by 4 bonds) for magnetic coupling. Unfortunately, single crystals of these thienylphosphine ligand-bridged compounds could not be grown. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

Malaria remains one of the greatest problems facing developing nations, especially in sub-Saharan Africa. Part of the problem stems from increased resistance to current treatments hence there is a large drive to develop novel antimalarial compounds. Several chelating compounds, including 8-hydroxyquinoline (8-HQ), 1,10- phenanthroline (1,10-phen) and 2,2.6,2-terpyridine (terpy), have disputed activities (8-HQ and 1,10-phen) or are untested (terpy). Furthermore the mechanism(s) by which these ligands and/or their complexes with metal ions exhibit their toxic effect is unknown. In order to resolve these issues, a study of the antimalarial activities of the free ligands, the ligands complexed with metal ions (Au 3+, Cu 2+, Fe 3+, Pd 2+ and Pt 2+), and the ligands with free metals in solution were measured. The ligands, complexes and metals were also tested for their ability to inhibit β-haematin formation, the mode of action ascribed to the most widely used antimalarial, chloroquine. The background toxicity levels of the various metal ions (previously unreported) were also measured and are reported here. None of the ligands were found to have particularly high activity (all approximately 1μM). In general the metals in were found to have no beneficial effect on activity whether complexed or freely available in solution. None of the ligands were found to inhibit β-haematin formation. The complexes however, with the exception of those of Cu 2+, all inhibited β-haematin formation. Upon further investigation it was found that the each of the metal ions with the exception of Cu 2+ had an innate ability to inhibit β-haematin formation. Thus the mode of action of the ligands and the complexes is likely to be via different mechanisms. In an attempt to enhance the activities of the ligands they were modified by covalently linking them to nutrients essential to the malaria parasite (adenosine and pantothenic acid). These six novel compounds however, showed no improvement in action. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2008.

Chiral crown ethers have recently been shown to be useful asymmetric catalysts in many carbon-carbon bond forming reactions. The design and synthesis of new chiral macrocycles and ligands for use in asymmetric catalysis is of great interest in the field of synthetic chemistry. Catalytic asymmetric Michael additions have been studied using chiral crown ethers as phase transfer catalysts. Many chiral crown ethers have been synthesised and tested in asymmetric catalysis but the design of these systems is still an area of much interest. The attempted synthesis of a new class of novel macrocycles such as 1 is described (chapter 2). The synthesis of a new class of chiral cage annulated macrocycles such as 2 is reported (chapter 3). The testing of these macrocycles as catalysts in the Michael addition of 2-nitropropane to chalcone was carried out with poor enantioselectivity being observed Recognition events in chemistry occur on a molecular scale that is difficult to monitor without the use of molecular devices. Photoinduced Electron Transfer (PET) systems have been the subject of much research over the past three decades. The attempted synthesis of the first chiral PET sensor 3 is described (chapter 4). / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2006.

This Thesis describes the synthesis and characterisation of titanium hydrazido(2-) and alkylidene hydrazido(2-) complexes and their reactivity towards unsaturated molecules. Exploration of the bonding in titanium hydrazido(2-) and alkylidene hydrazido(2-) complexes is performed through structural and computational studies. Chapter 1 introduces current Group 4 hydrazido chemistry in comparison to Group 4 imido and mid/late metal hydrazido examples. Current Group 4 alkylidene hydrazido chemistry is also described. Chapter 2 describes the synthesis, bonding and the novel reaction chemistry of titanium hydrazido(2-) half-sandwich complexes. Novel reactivity at the Ti=N, bond is presented with the mechanisms of some of these transformations probed by Density Functional Theory (DFT) calculations. Chapter 3 describes the novel reaction chemistry of Cp*Ti{MeC(Nipr)2} (NNMe2) in comparison to its imido and diphenyl hydrazido analogues. Novel reactivity at both Ti=N, and Na-N~ bonds is presented with the mechanisms of some of these transformations probed by Density Functional Theory (DFT) calculations. Chapter 4 describes the synthesis and characterisation of a new titanium alkylidene hydrazido(2-) complex. The bonding of the alkylidene hydrazido(2-) ligand is explored through structural and computational studies. Novel reactivity at Ti=N, and Na-N~ bonds is presented. Chapter 5 presents full experimental procedures and characterising data for the new complexes reported. CD Appendix contains .cif files for all new crystallographically characterised complexes described.

by Lam Fung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 70-75). / Acknowledgements --- p.i / Abbreviations --- p.ii / Abstract --- p.iii / Introduction --- p.1 / Results and Discussion --- p.16 / Conclusion --- p.55 / Experimental --- p.56 / References --- p.70 / Appendix --- p.76 / List of Spectra --- p.80