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Alkane elimination reaction of Hf(CH2SiMe3) 4 with a zwitterionic salt 1-Me2NHCH2CH2 -1,3-C2B10H12 has resulted in the isolation and structurally characterization of the first example of half-sandwich group 4 metallacarborane alkyls of the C2B10 system. This is also a new route to high-valent group 4 metallacarboranes. / Alkane or amine elimination reactions are also effective methods for the preparation of half-sandwich group 4 metal] acarboranes of the C 2B9 system. The Lewis base functionalized sidearm can effectively stabilize half-sandwich group 4 metallacarborane alkyls through intramolecular coordination. These novel metallacarborane alkyls undergo insertion reaction with alkyne and intramolecular hydrogen atom abstraction reactions. / High-valent group 4 half-sandwich metallacarboranes incorporating an eta 7-carboranyl ligand have been prepared and structurally characterized. The heteroatom-containing pendant sidearms on the carborane cage are both electronically and entropically necessary for the formation of such complexes. / Reaction of [(Me2NCH2CH2)C2B 10H11]Na2 with YCl3 gives eta 1:eta6-[(Me2NCH2CH2)C 2B10H11]YCl(THF)3 containing an exopolyhedral Y-Cl bond, which offers an important intermediate for the preparation of lanthanacarboranes bearing the Ln-C or Ln-X (X = heteroatoms) bonds. On the other hand, it implies that Lewis base functionalized carboranes can stabilize half-sandwich metallacarboranes via the coordination of heteroatom from the sidearm. Silylamine elimination reactions of the neutral ligand 7-Me2NHCH2CH2-7,8-C 2B9H11 with Ln[N(SiHMe2)2] 3(THF)2 are effective method for the preparation of half-sandwich lanthanacarboranes. / Reactions of alkali metal salt of these carboranes with LnCl3 in the presence of excess alkali metal afford a novel class of 13-vertex closo-metallacarboranes incorporating eta7-carboranyl ligands [{eta1:eta1:eta7-[(DCH 2CH2)RC2B10H10]Ln}{Na(solvent) x}]n. Structural studies show that the Lewis base functionalized sidearms have some effects on the coordination environments of the central metal atom, but do not change the gross structures of the 13-vertex closo-metallacarboranes. The reactivity patterns of these 13-vertex closo-metallacarboranes have been studied for the first time. / Several mono- and bisfunctional carboranes (DCH2CH2)RC 2B10H10 (R = H, DCH2CH2, D = MeO, Me2N) have been designed and successfully synthesized. They can be conveniently converted into the monoanions, the dianions and the tetraanions by treatment with suitable reagents. Their applications in organolanthanide and group 4 organometallic chemistry have been studied. / Cheung Mak-shuen. / "June 2005." / Adviser: Kevin W. P. Leung. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0258. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 169-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Ren, Zhiyuan. / "March 2001." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 137-143). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Wong, Man Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 173-188). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.v / Table of Contents --- p.vii / List of Tables --- p.xi / List of Figures --- p.xiii / List of Plates --- p.xv / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Definition of Rare earth elements --- p.1 / Chapter 1.2 --- Discovery of REEs --- p.5 / Chapter 1.3 --- Physical and chemical properties of REEs --- p.6 / Chapter 1.4 --- Abundance of REEs on earth --- p.10 / Chapter 1.4.1 --- Bastnasite --- p.11 / Chapter 1.4.2 --- Monazite --- p.14 / Chapter 1.4.3 --- Xenotime --- p.16 / Chapter 1.5 --- Reserves and resources --- p.16 / Chapter 1.5.1 --- World reserves --- p.16 / Chapter 1.5.2 --- REE resources in China --- p.18 / Chapter 1.6 --- Production and demand of REEs --- p.20 / Chapter 1.6.1 --- Production and demand in US --- p.21 / Chapter 1.6.2 --- Production and export in China --- p.23 / Chapter 1.6.3 --- Production in other countries --- p.24 / Chapter 1.7 --- Separation of REEs --- p.24 / Chapter 1.7.1 --- Classical methods --- p.24 / Chapter 1.7.2 --- Modern methods --- p.25 / Chapter 1.7.2.1 --- Ion exchange separation --- p.25 / Chapter 1.7.2.2 --- Solvent extraction --- p.25 / Chapter 1.8 --- Applications --- p.26 / Chapter 1.8.1 --- Alloys --- p.26 / Chapter 1.8.2 --- Permanent magnets --- p.28 / Chapter 1.8.3 --- Catalysts --- p.29 / Chapter 1.8.4 --- Glass additives --- p.30 / Chapter 1.8.5 --- Phosphors in television screens and similar fluorescent surfaces --- p.31 / Chapter 1.8.6 --- Fertilizers and feed additives --- p.32 / Chapter 1.9 --- REEs in the environment --- p.33 / Chapter 1.9.1 --- REEs in soil --- p.33 / Chapter 1.9.2 --- REEs in plants --- p.35 / Chapter 1.10 --- Overview of toxicological studies of REEs --- p.36 / Chapter 1.11 --- Current study --- p.38 / Chapter 1.11.1 --- Thesis outline --- p.3 8 / Chapter 1.11.2 --- Objectives --- p.38 / Chapter 1.11.3 --- Significance --- p.39 / Chapter Chapter 2 --- Phytotoxicity of rare earth elements / Chapter 2.1 --- Introduction --- p.41 / Chapter 2.1.1 --- Ecotoxicity of REEs --- p.41 / Chapter 2.1.2 --- Toxicity tests using higher plants --- p.43 / Chapter 2.1.3 --- Advantages of seed germination and root elongation test --- p.44 / Chapter 2.1.4 --- Selection of species --- p.46 / Chapter 2.1.5 --- Endpoint of test --- p.47 / Chapter 2.1.6 --- Median effect estimates --- p.50 / Chapter 2.1.7 --- Objective --- p.50 / Chapter 2.2 --- Materials and methods --- p.50 / Chapter 2.2.1 --- Test species --- p.51 / Chapter 2.2.2 --- Test chemicals --- p.51 / Chapter 2.2.3 --- Range finding test --- p.51 / Chapter 2.2.4 --- Definitive test --- p.52 / Chapter 2.2.5 --- Statistical analyses --- p.52 / Chapter 2.3 --- Results --- p.53 / Chapter 2.3.1 --- Range finding test --- p.53 / Chapter 2.3.2 --- Definitive test --- p.53 / Chapter 2.3.2.1 --- Germination rate --- p.53 / Chapter 2.3.2.2 --- Root length --- p.55 / Chapter 2.3.2.3 --- Germination index --- p.58 / Chapter 2.3.3 --- The median effective concentration --- p.61 / Chapter 2.4 --- Discussion --- p.62 / Chapter 2.4.1 --- Dose-response curves of REEs --- p.62 / Chapter 2.4.2 --- Relative toxicity of the four REEs --- p.63 / Chapter 2.4.3 --- Mechanism of effect of REEs on seed growth --- p.67 / Chapter 2.4.4 --- Comparison between different endpoints --- p.68 / Chapter 2.4.5 --- Comparison between different species --- p.70 / Chapter 2.4.6 --- Limitations and improvement --- p.71 / Chapter 2.4.7 --- Methods of measuring root length --- p.72 / Chapter 2.5 --- Conclusions --- p.73 / Chapter Chapter 3 --- Growth of tree seedlings in soil treated with rare earth elements / Chapter 3.1 --- Introduction --- p.75 / Chapter 3.2 --- Materials and methods --- p.77 / Chapter 3.2.1 --- Soil --- p.77 / Chapter 3.2.2 --- Tree seedlings --- p.77 / Chapter 3.2.3 --- REEs --- p.78 / Chapter 3.2.4 --- Greenhouse experiment --- p.78 / Chapter 3.2.5 --- Soil analysis --- p.80 / Chapter 3.2.5.1 --- Initial properties --- p.80 / Chapter 3.2.5.2 --- Post harvest analysis --- p.81 / Chapter 3.2.6 --- Plant analysis --- p.83 / Chapter 3.2.7 --- Statistical analysis --- p.83 / Chapter 3.3 --- Results --- p.84 / Chapter 3.3.1 --- Growth --- p.84 / Chapter 3.3.1.1 --- Height --- p.84 / Chapter 3.3.1.2 --- Basal diameter --- p.87 / Chapter 3.3.1.3 --- Biomass --- p.89 / Chapter 3.3.1.4 --- Standing leaf number --- p.92 / Chapter 3.3.1.5 --- Chlorophyll fluorescence --- p.95 / Chapter 3.3.2 --- Tissue contents --- p.97 / Chapter 3.3.2.1 --- REEs concentrations --- p.97 / Chapter 3.3.2.2 --- Nitrogen concentrations --- p.99 / Chapter 3.3.2.3 --- Phosphorus concentration --- p.101 / Chapter 3.3.2.4 --- Mineral concentrations --- p.102 / Chapter 3.3.3 --- Soil --- p.104 / Chapter 3.3.3.1 --- Initial properties --- p.104 / Chapter 3.3.3.2 --- REEs concentrations --- p.106 / Chapter 3.3.3.3 --- Nitrogen and phosphorus concentrations --- p.107 / Chapter 3.3.3.4 --- Mineral concentrations --- p.109 / Chapter 3.4 --- Discussion --- p.110 / Chapter 3.4.1 --- Effects of REEs on growth --- p.110 / Chapter 3.4.2 --- Mechanisms of the effect of REEs --- p.112 / Chapter 3.4.3 --- Nutrient uptake --- p.114 / Chapter 3.4.4 --- Soil nutrient contents --- p.116 / Chapter 3.4.5 --- Comparison between REEs --- p.118 / Chapter 3.4.6 --- Comparison between species --- p.121 / Chapter 3.5 --- Conclusions --- p.123 / Chapter Chapter 4 --- Bioavailability and accumulation of rare earth elements / Chapter 4.1 --- Introduction --- p.124 / Chapter 4.2 --- Materials and Methods --- p.126 / Chapter 4.2.1 --- Soil --- p.126 / Chapter 4.2.2 --- Tree seedlings --- p.126 / Chapter 4.2.3 --- Pot experiment --- p.127 / Chapter 4.2.4 --- Chemical speciation of soil --- p.129 / Chapter 4.2.5 --- Statistical analysis --- p.130 / Chapter 4.3 --- Results --- p.130 / Chapter 4.3.1 --- Plant performance --- p.130 / Chapter 4.3.2 --- Tissue contents of La --- p.144 / Chapter 4.3.3 --- Soil --- p.144 / Chapter 4.3.3.1 --- Soil final pH --- p.146 / Chapter 4.3.3.2 --- Soil La contents --- p.146 / Chapter 4.3.4 --- "Association between pH, organic matter and La contents in soil and plant" --- p.149 / Chapter 4.4 --- Discussion --- p.151 / Chapter 4.4.1 --- Growth performance of tree seedling on different soil conditions --- p.151 / Chapter 4.4.2 --- Comparison between growth parameters --- p.152 / Chapter 4.4.3 --- Speciation in soils --- p.154 / Chapter 4.4.4 --- Bioavailability of REEs in soil --- p.155 / Chapter 4.4.5 --- Factors affecting bioavailability of REEs --- p.158 / Chapter 4.4.6 --- Distribution of REEs in plants --- p.162 / Chapter 4.5 --- Conclusions --- p.165 / Chapter Chapter 5 --- General conclusions --- p.167 / Chapter 5.1 --- Summary of major findings --- p.167 / Chapter 5.2 --- Suggestions for further investigation --- p.171 / References --- p.173

Typescript. / Digitized by Kansas Correctional Industries

The corrosion protection of aluminium alloys is of high importance, particularly in the aerospace industry. The most widely used technologies utilise Chromium(VI) compounds for conversion coatings and primer additives in paint systems to provide corrosion protection to these alloys. These compounds are highly toxic, carcinogenic and detrimental to the environment, therefore the identification of alternative systems that are safe and environmentally benign, that meet or exceed the current levels of corrosion protection is vital. This research program examines the corrosion inhibition effectiveness of selected rare earth diphenyl phosphates (RE(dpp)3). These compounds incorporate known inhibitor species, namely rare earth metals, organics and phosphates into a single complex, with the aim of achieving synergistic inhibition in corrosive environments. A screening study utilising immersion and weight loss experiments identified Cerium diphenyl phosphate (Ce(dpp)3) and Mischmetal diphenyl phosphate (Mm(dpp)3) as the most effective inhibitors of corrosion for AA2024-T3. The inhibiting efficiency, mechanism of inhibition and surface interaction of these complexes on aluminium alloy AA2024-T3 was characterised using a range of electrochemical and surface techniques. A similar study was carried out using AA7075-T6 to assess the adaptability of the RE(dpp)3 compounds to protect different alloy compositions. The complexes were effective in significantly reducing the corrosion rate of the alloys, with both the cathodic and anodic corrosion processes being suppressed. This mixed inhibition was not attained with the constituent rare earth and diphenyl phosphate ions individually, indicating the need for the complex to remain intact in solution to achieve the high level of corrosion protection observed. The initiation and propagation of surface pits was effectively suppressed by the RE(dpp)3 complexes. The combination of electrochemical and surface characterisation techniques has for the first time allowed insights into the mechanism of action of these compounds on aluminium alloys, and indicated deposition was initiated at electrochemically active intermetallic particles. The mixed rare earth phases present in Mm(dpp)3 produced a synergistic effect, providing a greater degree of corrosion protection compared with Ce(dpp)3, particularly on AA2024-T3. In the final phase of this research project the RE(dpp)3 inhibitor compounds were incorporated into an epoxy coating system, and demonstrated that the initiation of filiform corrosion on AA2024-T3 could be reduced by up to a factor of 3 by their addition. The growth rate of filaments was also impeded.

Bibliography: leaves 132-147.

Thesis (Ph. D.)--Oregon Graduate Center, 1976.

Results of spin density functional theory (SDFT) calculations were used to construct and check features of a generally applicable semi-quantitative approach to understanding magnetic coupling in gadolinium-containing molecules, clusters, and solids. Using fragments based on structures of metal-rich lanthanide compounds, we have investigated molecular and low-dimensional extended structures, and have shown that open-d-shell clusters facilitate strong ferromagnetic coupling whereas closed-d-shell systems prefer antiferromagnetic coupling. The qualitative features can be interpreted using a perturbative molecular orbital (PMO) model that focuses the influence of the 4f 7- d exchange interaction on the d-based molecular orbitals. The f-d exchange interaction, mediated by spin polarization of both filled and partially-filled metal-metal bonding orbitals, is described for the model system Gd3I6(OPH3)12 n+ using basic perturbation methods. This approach is successful for predicting the magnetic ground state for Gd2Cl3, a semiconducting system for which calculations predict antiferromagnetic ordering of the 4f 7 moments in a pattern consistent with published neutron diffraction data. An attempt to account for the calculated magnetic energies of spin patterns using an Ising model was unsuccessful, indicating that the Ising model is inappropriate. Instead, the d-electron mediated f-f exchange interaction was interpreted using our basic perturbation theory approach. Computed density of states and spin polarization information was used to support the perturbation-theoretic analysis. This method has also been successful evaluating the ground state for Gd[Gd6FeI12]. Using the model [Gd6CoI12](OPH3)6, which has three unpaired electrons in the HOMO, the 4f moments prefer spin alignment with the unpaired electrons in the system and the ferromagnetic 4f 7 spin arrangement is the ground state. We have extended our analysis of R6X12 clusters to include nonmetal interstitial atoms, the bioctahedral cluster compounds Gd10Cl17C4 and Gd10I16C4, and Gd5(O)(OPri)5. Finally, we have shown that we can successfully predict the ground state magnetic structures of several metallic and semiconducting Gd-containing compounds, Gd2Cl3, GdB2C2,alpha-Gd2S3, Gd5Si4, and Gd5Ge4, using semi-empirical calculations which closely simulates the exchange effects exerted by the 4f electrons. In a more speculative vein, ideas concerning the incorporation of anisotropic rare-earth metal atoms to the cluster framework are touched upon.

Thesis (M.S.)--Miami University, Dept. of Geology, 2001. / Title from first page of PDF document. Document formatted into pages; contains viii, 150 p. : ill. Includes bibliographical references.