A series of complexes of the type [Rh(diphos)(C(_7)H(_8))](BF(_4)) (1) have been synthesised and two of these species [diphos = Bu(^1)(_2)P(CH(_2))(_2)PBu(^1)(_2), Cy(_2)P(l,2-trans-cyclopentane)PCy(_2)] have been characterised by X-ray crystallography. The influence of the chelating diphosphine on the structural characteristics and NMR parameters of these compounds has been investigated. Complexes of the type (1) are active catalysts for the hydroformylation of l-hexene(120ºC, 450psi 2:1 H(_2):C0). However, they are inactive for the related hydroesterification process and this is attributed to the stability of [Rh(diphos)(CO)(_2)]^ under the reaction conditions. Detailed studies of the reactions of type (1) complexes with H(_2) have been undertaken. The products from these reactions are dependent on both the diphosphine and the solvent employed. In THF and CD(_2)Cl(_2), dimeric hydrides were observed, whilst in CDCl(_3) hydrido-chloro-complexes of the type [Rh(_z)(diphos)(_2)(|µCl)H(_2)](^2+) were formed. In the former solvents, three types of hydrides have been identified by NMR studies, namely [Rh(_2)(diphos)(_2)H(_6)], [Rh(_2)(diphos)(_2)H(_4)] and [Rh(_2)(diphos)(_2)H(_4)](^2+). The oxidative-addition reactions of alkyl-, acyl- and formyl-halide with Rh(I) complexes have been investigated. The reaction with ClCO(_2)Me with [Rh(dppe)Cl](_2) and [Rh(dppe)](_2)(BF(_4))(_2) led to the formation of diphosphine-rhodium(III)-halide species (H(_3)NOH)[Rh(dppe)Cl(_4)] and [Rh(_2)(dppe)(_2)(µ-Cl)(_3)Cl(_2)](BF(_4)) respectively. Alternative routes to these complexes have been investigated starting from RhCl(_3).3H(_2)O/diphosphines and a series of the novel halide bridged dimers have been characterised, including by X-ray crystallography and their reaction chemistry explored. In the synthesis of the cationic rhodium complexes from neutral chloro-complexes with AgBF(_4), the novel silver complexes [Ag(_2)(µ-Bu(^t)(_2)P(CH(_2))(_3)PBu(^t)(_2))(_2)](BF(_4))(_2), [{Ag(H(_2)O)}(_2)(µ-Bu(^t)(_2)P(CH(_2))(_2)PBu(^t)(_2))](BF(_4))(_2), and [Ag(C(_6)D(_6))(_3)BF(_4)] have been isolated as by-products and characterised by X-ray crystallography.

The analytical advantages of some novel approaches to atomisation using gaseous sample transport and slurry nebulization have been investigated and applied to the determination of trace metals in coal. A cold vapour atomic fluorescence spectroscopic method for the determination of mercury using a gas-sheathed atom cell and front surface illumination was developed. With a manual injection technique the detection limit was 0.01 ng. Replacement with a continuous flow system yielded a more rapid and precise method with a detection limit of C.045 ng.ml-1. Quantitative recoveries of mercury from a standard coal were obtained through liberation of the analyte using nonoxidative pyrolysis. Continuous hydride generation methods for the determination of arsenic and selenium using atomic absorption and atomic fluorescence spectrometry were developed.

This thesis describes the study of a series of platinum complexes, with particular emphasis towards hydrosilation. Platinum bis(phosphine) azodicarbonyl complexes Pt(PRI 3)2(R20CNNCOR2) (RI = Ph, Me; R2 = Ph, Me, OEt, Pri) were synthesised and studied. Multinuclear NMR spectroscopy on Pt(PRI3)2(R20CNNCOR2) revealed that the dicarbonyl substituted azo ligand is co-ordinated asymmetrically, consistent with a five membered, Pt-N-N-C-O ring. The crystal structure of Pt(PPh3)2(Pri02CNNC02Pri) shows that the co-ordination sphere of platinum is essentially square planar and co-planar with the five-membered, Pt(1)-0(1)-C(5)-N(2)-N(1) ring. The Pt(PRI 3)lR20CNNCOR2) complexes show sensitivity towards chlorinated solvents (CH2CI2, CHCI3) under photolysis conditions forming the corresponding platinum bis(phosphine) dichloride complexes; the same products are formed in a slower thermal reaction but only for complexes with azodicarboxylate ligands. Complexes with azodicarboxylate ligands also react photochemically with ethylene in ds-THF yielding Pt(PPh3)2(C2H4) but the azodiacyl analogues are inert in this respect. Azodicarboxylate compounds R02CNNC02R (R = Et, Pri, But) are inhibitors of the catalytic activity of [(Pt {174 _(CH2=CHSiMe2hO }h {.u-( CH2=CHSiMe2)20}] for the hydrosilation reaction. The inhibited species can be decomposed thermally or photoch~mically to give active hydrosilation catalysts. It was found that the bulky azo compound But02CNNC02But was the least effective inhibitor of [(Pt{ 174 - '(CH2=CHSiMe2hO} )2(P-( CH2=CHSiMe2)20)]. The photochemistry of platinum bis(phosphine) malonates and phthalates was found to be limited, and their reactivities were much lower compared to the analogous oxalate complexes. Silyl hydride complexes, cis-Pt(PCY3)2(H)(SiR3), were synthesised from the reaction of Pt(PCY3)2 and the corresponding silane. These complexes were undergo dynamic exchange in solution. Two exchange processes were identified; the first involves mutual phosphine exchange, i.e. positional interchange between the hydride and the silyl ligands. The second process occurs at higher temperatures (above 290 K) and involves the elimination and re-addition of the silane ligand HSiR3. Thermodynamic and activation parameters are obtained for cis-Pt(PCY3)2(SiR3) (R = Ph, SiR3 = SiMe2CH2CH=CH2, SiMe2Et). The reaction of Pt(PCY3)2 with the disilane HSiMe2(l,2-C6~)SiMe2H is thought to form a Pt(IV) bis(silyl) dihydride trigonal bipyramidal species of the form, Pt(PCY3)(H)2[SiMe2(1,2-C6~)SiMe2]' where the hydride ligands are in the axial positions. All of the platinum silyl hydride complexes studied degrade thermally to form trans-Pt(PCY3)2(H)2 at, or above, room temperature.

The molecular structures of [κ³-S₂H-Tmᴮᵘᵗ]Na(THF)₃ and [κ³-S₂H-Tmᴬᵈ]Na(THF)₃ have been obtained, which is significant as these are the first two examples of monomeric κ³-S₂H coordinate sodium compounds to be reported. Based on an extensive structural analysis of all of the [Tmᴿ]M compounds listed in the Cambridge Structural Database, a set of criteria has been generated that can be used to classify [Tmᴿ] ligands according to their coordination modes. Compounds exhibiting κ³-S₃ coordination are found to be the most prevalent, as are compounds exhibiting 0:3 conformation modes. A series of [Tmᴮᵘᵗ]CdO₂CR complexes (R = C₆H₄-4-Me; C₆H₄-4-F; C₆H₃-3,5-F₂; C₆H₃-2,6-F₂; C₃H₆Ph; 9-An; and tridecyl) has been prepared via the reaction of [Tmᴮᵘᵗ]CdMe with the corresponding carboxylic acids. [Tmᴮᵘᵗ]ZnO₂CR (R = C₆H₄-4-Me; C₆H₄-4-F; C₆H₃-3,5-F₂; C₆H₃-2,6-F₂; 9-An) have been prepared by an analogous method. In addition, two thiobenzoate complexes, [Tmᴮᵘᵗ]MSC(O)Ph (M = Zn, Cd), have been obtained via the treatment of [Tmᴮᵘᵗ]MR (R = Me) with thiobenzoic acid. An extensive structural analysis of the [Tmᴮᵘᵗ]MO₂CR and [Tmᴮᵘᵗ]MSC(O)Ph complexes has been provided, based on single crystal X-ray diffraction and NMR spectroscopy. In addition, degenerate benzoate exchange between [Tmᴮᵘᵗ]MO₂C(4-C₆H₄-F) and 4-fluorobenzoic acid has been investigated by ¹⁹F-NMR lineshape analysis over a large temperature range (195-262 K). The acid concentration dependence of the rate for the exchange process supports an associative exchange mechanism. [Tmᴮᵘᵗ]MO₂C(4-C₆H₄-F) benzoate exchange is extremely rapid on the 19F NMR timescale at 25˚, and has been observed to be faster for [Tmᴮᵘᵗ]CdO₂C(4-C₆H₄-F) than for [Tmᴮᵘᵗ]ZnO₂C(4-C₆H₄-F). The reactivity of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) towards different thiols, ArSH (Ar = C₆H₄-4-F, C₆H₄-4-Buᵗ, C₆H₄-4-OMe, C₆H₄-3-OMe), has been investigated using various NMR techniques. In contrast to the results of our degenerate benzoate exchange studies, thiolate exchange between [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) and ArSH is slow on the ¹H NMR timescale. Even at elevated temperatures, the NMR signals for the reaction species remain resolved with minimal linebroadening. The equilibrium constants for the reactions of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) with ArSH (Ar = C₆H₄-4-But, C₆H₆-4-OMe, C₆H₄-3-OMe) have been calculated and determined to be indistinguishable, with equilibrium favoring the [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) and ArSH species. Additionally, the reactivity of [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) toward phenols, ArOH (Ar = Ph, 2,6-diphenylphenol), has been investigated. While [Tmᴮᵘᵗ]CdS(C₆H₄-4-F) has been found to be unreactive toward ArOH, [Tmᴮᵘᵗ]CdSOAr (Ar = 2,6-diphenylphenol) reacts immediately (C₆H₄-4-F)SH, resulting in complete conversion to [Tmᴮᵘᵗ]CdS(C₆H₄-4-F). Two monomeric [Tmᴮᵘᵗ]CdE(2-C₅H₄N) complexes (E = S, Se) have also been prepared, and structurally characterized. A monomeric, terminal zinc hydride complex, [Tmᴮᵘᵗ]ZnH, has been prepared via the reaction of [Tmᴮᵘᵗ]ZnOPh with phenylsilane. The molecular structure of [Tmᴮᵘᵗ]ZnH has been obtained by single crystal X-ray diffraction techniques, and the reactivity of [Tmᴮᵘᵗ]ZnH towards various reagents has been investigated. [Tmᴮᵘᵗ]ZnH reacts rapidly with ArEH (EAr = OPh, S(C₆H₄-4-F), SePh) to form [Tmᴮᵘᵗ]ZnEA via H₂ elimination. [Tmᴮᵘᵗ]ZnH reacts with CO₂ to form [Tmᴮᵘᵗ]ZnO₂CH via CO₂ insertion into the Zn-H bond. [Tmv]ZnO₂CH can also be prepared by the reaction of [Tmᴮᵘᵗ]ZnH with formic acid. [Tmᴮᵘᵗ]ZnH reacts rapidly with ZnEt₂ to form [Tmᴮᵘᵗ]ZnEt. The reaction of [Tmᴮᵘᵗ]ZnH with CpMo(CO)₃H resulted in the formation of a metal-metal bonded complex, namely [Tmᴮᵘᵗ]Zn-MoCp(CO)₃. A series of [Tmᴮᵘᵗ]M-M'Cp(CO)₃ heterobimetallic complexes (M = Zn, Cd; M' = Cr, Mo, W) has been prepared via the reaction of [Tmᴮᵘᵗ]MR (R = Me) with CpM'(CO)₃H. An extensive structural analysis of these complexes is provided, based on X-ray diffraction and NMR spectroscopy. Each of these complexes features a direct M-M' bond, which is supported by two partially bridging carbonyl ligands. Only a few complexes featuring an M-M' bond have been structurally characterized, and the molecular structures of [Tmᴮᵘᵗ]Zn-CrCp(CO)₃ and [Tmᴮᵘᵗ]Cd-WCp(CO)₃ represent the first two structures reported for compounds featuring either a Zn-Cr or Cd-W bond. The coordination chemistry of [tpyᴬʳ] (Ar = p-tolyl, mesityl) and [bppᴮᵘᵗ] with various main group and transition metals has been investigated. [tpyᴬʳ]MX₂ complexes (M = Co, Zn; X = Cl, I) are prepared by the reaction of [tpyᴬʳ] with the dihalide MX2 complex. [bppᴮᵘᵗ]MX2 (M = Fe, Co, Zn, Cd; X = Cl, I) complexes are prepared by an analogous method. Each of these [tpyᴬʳ]MX₂ and [bppᴮᵘᵗ]MX₂ complexes have been characterized by single crystal X-ray diffraction. The [bppᴮᵘᵗ]LiI compound was unexpectedly obtained from the reaction of [bppᴮᵘᵗ]FeCl₂ with MeLi, which is significant as it is the first example of an alkali metal complex featuring a [bppᴮᵘᵗ] ligand that has been structurally characterized.

New chiral half-sandwich Ru hydride enantiomers with asymmetric disubstitution on the Cp ligand have been successfully synthesized and resolved. An enantiopure thiolate ligand was installed on the Ru center to form a pair of diastereomers, which were separated by crystallization via vapor diffusion of pentane into their saturated Et2O solution. Racemization occurred at elevated temperatures, but a room temperature conversion pathway was developed to remove the chiral thiolate ligand and generate the enantiopure hydride complex. Two new Rh(III) hydride complexes and their Ir analogues have been synthesized and characterized. The hydride complexes readily transfer H– to the N-carbophenoxypyridinium cation at room temperature, giving mixtures of 1,2- and 1,4-dihydropyridine products. In CD3CN, all four hydrides give nearly the same product ratio, demonstrating that the hydride transfer mechanism is outer sphere. In weak or non-coordinating solvents, the resulting 16-electron cations catalyze the isomerization of 1,2- to 1,4-dihydropyridine at rates that depend upon the cation and the solvent. The fastest isomerization was observed with the Rh(III) cation [Cp*Rh(2-(2-pyridyl)phenyl)]+, Acetonitrile can trap the 16-electron cations resulting from hydride transfer, dramatically slowing the isomerization process. The thermodynamics and kinetics of hydride, hydrogen atom and proton transfer reactions of the Rh(III) hydride, Cp*Rh(2-(2-pyridyl)phenyl)H, were studied both thermodynamically and kinetically. This hydride is both a good hydride and hydrogen atom donor, but a poor proton donor. This previously unobserved combination of properties is due to the high energy of the hydride’s conjugate base, [Cp*Rh(2-(2-pyridyl)phenyl)]−. Its exceptional hydride donor ability makes Cp*Rh(2-(2-pyridyl)phenyl)H a very efficient catalyst for the ionic hydrogenation of iminium cations.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 144-149).

Zirconium and its alloys are of technical importance, finding application as a structural material in the nuclear industry. Engineering components fabricated from zirconium slowly pick-up hydrogen as a result of in-reactor corrosion, degrading the components mechanical properties as a brittle hydride phase forms. This dissertation applies high energy X-ray diffraction to directly measure the mechanical properties of zirconium hydrides in the bulk and at stress concentrations in zirconium alloys. The current study is presented as a manuscript format dissertation comprised of three manuscript chapters. Chapter 3 reports the in-situ loading of hydrided Zircaloy-2 and discusses hydride/Zircaloy-2 matrix interactions as a function of applied load. Chapter 4 reports the mechanical behavior at a fatigue pre-crack in un-hydrided Zircaloy-2, comparing the results to finite element and polycrystalline plasticity models of the crack tip. Chapter 5 reports the effect of hydrides on the notch tip strain field. The three manuscript chapters are followed by a general discussion in Chapter 6 and conclusions in Chapter 7. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2009-09-27 20:32:01.455

Zirconium alloy pressure tubes are an important component in CANDU nuclear reactors. During operation these tubes can pick up hydrogen as a result of a corrosion reaction, which can eventually lead to the precipitation of a secondary, brittle zirconium hydride phase. Hydrides tend to first form at flaws (stress concentrations), and when they fracture can initiate a time-controlled crack growth mechanism known as delayed hydride cracking (DHC). Since DHC is a known failure mechanism for pressure tubes, and an ongoing concern in the nuclear industry, more fundamental knowledge is required about the behaviour of hydrides precipitated at flaws. Several approaches were employed in this thesis to better characterize the effects and behaviour of hydrides at such stress concentrations. High energy X-ray diffraction, as well as in-situ SEM testing coupled with digital image correlation, were used to map the strains around stress concentrations where hydrides were present. These studies highlighted important differences in the behaviour of the hydride phase and the surrounding zirconium. To gain greater insight into hydride morphology, neutron tomography was used in an attempt to measure the through-thickness hydride distribution at flaws. A finite element model was also developed and verified against the X-ray strain mapping results. This model provided greater insight into details that could not be obtained directly from the experimental approaches, as well as providing a framework for future modeling to predict the effects of hydride precipitation under different conditions. Taken as a whole, these studies provide important information for improving service guidelines and avoiding conditions that favour embrittlement due to hydride precipitation. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-01-17 20:39:25.621

Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 87-92). / viii, 92 leaves, bound ill. 29 cm

Thesis (doctoral)--Technische Universiteit Delft, 1997. / Vita. Includes bibliographical references.