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This thesis describes the synthetic, structural and reactivity studies of η- cycloheptatrienyl-molybdenum and -tungsten chemistry. Chapter 1 presents an overview of the chemistry of η-cycloheptatrienyl derivatives of transition metals, in particular group 6 metals. The functional group properties of the η-cycloheptatrienyl ligand are also discussed. Chapter 2 describes the synthesis of [Mo(η-C₇H₇)(η⁵-C₇H₉)] from Mocl₅ or [MoCl₄(thf)₂], which provides a convenient route to η-cycloheptatrienyl-molybdenum compounds, such as [Mo(η-C₇H₇)LX₂] and [Mo(η-C₇H₇)L₂X], where L = tertiary phosphines or acetonitrile and X = halogen, [NBu₄] [Mo(η-C₇H₇)I₃], [Mo(η-C₇H₇)(η- C₅H₄R)] (R = H or Me) and [Mo(η-C₇H₇)(η⁵-C₉H₇)]. The X-ray crystal structures of [Mo(η-C₇H₇)(MeCN)I₂], [NBu₄][Mo(η-C₇H₇))I₃] and [Mo(η-C₇H₇)(η-C₅H₄Me)] are presented. The compound [Mo(η-C₇H₇))(MeCN)I₂], mixed with Me₃SiCH₂MgCl, is a catalyst for ring-opening polymerisation of norbornene giving trans polymer exclusively. The electron-transfer complexes [Mo(η-C₇H₇)(η-C₅H₄Me)][tcne] and {[Mo(η-C₇H₇))(η- C₅H₅}₂[tcnq]} and the intercalation compound {ZrS₂[Mo(η-C₇H₇)(η-C₅H₄Me)]o.22} are also described. An extension of these synthetic pathways to tungsten is described in chapter 3. Reduction of WCl₆ with sodium amalgam in the presence of cycloheptatriene gives [W(η- C₇H₇)(η⁵-C₇H₉)], which is a precursor to the compounds [W(η-C₇H₇)(MeCN)I₂], [W(η- C₇H₇)(PMe₃)X₂] (X = Br or I), [W(η-C₇H₇)(dmpe)I], [W(η-C₇H₇)(η-C₅H₄R)] (R = H or Me) and [Mo(η-C₇H₇)(η⁵-C₉H₇)]. The [W(η-C₇H₇)(MeCN)I₂] / Me₃SiCH₂MgCI system is an active catalyst for ring opening polymerisation of norbomene. The electronic structures of [W(η-C₇H₇)(η-C₅H₄R)] (R= H or Me) are discussed on the basis of their He I and He II photoelectron spectra. The intercalation of [W(η-C₇H₇)(η-C₅H₄Me)] into ZrS<suv>2</sub> is also described. The magnetic properties of the 17-electron compounds [Mo(η-C₇H₇)(MeCN)I₂], [Mo(η-C₇H₇)(PMe₃)I₂], [W(η-C₇H₇)(MeCN)I₂], [W(η-C₇H₇)(PMe₃)I₂] and [W(η-C₇H₇) (PMe₃)I₂] are discussed in chapter 4. They behave as one-dimensional antiferromagnets which was suggested by magnetic model fittings and the crystal structure of [Mo(η-C₇H₇)(MeCN)I₂]. Chapter 5 comprises of two parts. The first part describes a new series of binuclear thiolato-bridged molybdenum complexes [(η-C₇H₃R¹₄)Mo(μ-SR²)₃ Mo- (η-C₇H₃R¹₄)][BF₄] (R¹ = H or Me; R² = Et, Pr, Bu, Ph or CH₂Ph). Dynamic NMR studies reveal that all of these complexes (except for R² = Ph) are fluxional due to inversion at the pyramidal sulfur centre. Cyclic voltammetric studies show that they undergo two reversible one-electron reductions. Second part of this chapter describes the new bridging-imido compound [(η-C₇H₇)Mo(μ-NAr)₂Mo(η-C₇H₇)] (Ar = 2,6- diisopropylphenyl). Chapter 6 discusses the η-l,2,4,6-tetramethylcycloheptatrienyl-molybdenum system. The new η-tetramethylcycloheptatriene molybdenum compounds [M'(η-C₇H₄Me₄- 1,3,5,7)],[M'(η-C₇H₄Me₄-l,2,4,6)] and [M'(η-C₇H₄Me₄-l,3,4,6)], M' = Mo(CO)₃, and new η-tetramethylcycloheptatrienyl-molybdenum compounds [M"(CO)₃]+, [M"(CO)₂C1], [M"(dmpe)Cl], [M"(η-C₆H₅Me)]+ and [M"(acac)(PPh₃)], M" = Mo(η- CC₇H₃Me₄-1,2,4,6), and [Mo(η³-C₇H₃Me₄-l,2,4,6)(dmpe)(CO)₂Cl] are described. Chapter 7 gives the experimental details for the work described in preceeding chapters. Appendix A presents characterising data for all the new compounds and previously unreported data for known compounds. Crystallographic details for the X-ray structure determinations and X-ray powder diffraction data are listed in Appendix B and C respectively.

Sustainable fusion power is within reach; however, more research is needed in the field of material science and engineering. One critical component of a fusion reactor is the plasma facing material. Very little literature exists on the sustainability of tungsten as a plasma facing material (PFM). During operation, PFM must withstand harsh conditions with combined effects from high temperature, mechanical stress, irradiation, transmutation, and the production of hydrogen (H) and helium (He) from nuclear reactions. Therefore, this thesis will focus on co-implantation of H and He into tungsten to investigate the mechanical and microstructural material response. For the first part of this study, Molecular Dynamics (MD) was used to qualitatively understand defect migration and mechanical property changes in tungsten. A Brinell hardness test was simulated using MD in tungsten to study the dependence on void size and void density hardness. It was found that hardness changes vary as the square root of the void size and void density. Also the movement of dislocations and its interaction with voids were investigated. For the second part of the study, H and He were co-implanted into tungsten to look at the mechanical and microstructural changes. Hardness changes were measured using a nano-indenter ex-situ on post-irradiated specimen. Results show that the hardness of tungsten after co-implantation is proportional to the square root of the fluence. Additionally, the microstructure of irradiated tungsten samples was investigated by using a Transmission Electron Microscope (TEM). It was observed that the defect microstructure in tungsten, after co-implantation, is quite complex, with a number of intriguing features, such as the presence of the nano-bubbles and dislocation loops. Also it was observed that there was an effect that H has on the nucleation of He nano-bubbles. The results from this work suggest that the effect of co-implanting H and He into tungsten is crucial to fully understand its viability as a PFM.

Thesis (M. Sc.)--University of Adelaide, 1984. / Some mounted ill. Includes bibliographical references (leaves 123-141).

Thesis (M.S.)--Brigham Young University. Dept. of Chemistry and Biochemistry, 2006. / Includes bibliographical references.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "August 2007." Includes bibliographical references (leaves 65-66). Online version available on the World Wide Web.

Thesis (Ph. D.)--State University of New York at Binghamton, Dept. of Mechanical Engineering, 2007. / Includes bibliographical references.

Thesis (M.S.)--University of Nevada, Reno, 2007. / "December 2007." Includes bibliographical references (leaves 54-58). Online version available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [225]-233).

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.