Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"metal-oxo"”.
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Kinetics and mechanisms of oxidation of organic and inorganic substrates by transition metal oxo complexes
… activates H2O2 through formation of a mono-peroxo-Re(VII), A, and a bisperoxo-Re(VII), B, species. Both species are active toward olefin epoxidation with very similar reactivities and are about 105 times more reactive than free H2O2. Epoxides, the initial products from these reactions, undergo …
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Ligand field considerations for the reactivity of high valent metal-oxo complexes and of bimetallic HX splitting photocatalysts
… the O-O bond formation process, terminal metal oxo complexes of pseudotetrahedral geometry were synthesized and studies focused on determining the electronic structure of these complexes as well as reactivity patterns. A novel series of low coordinate tris(alkoxide) complexes of divalent …
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O-O bond formation and the transition metal chemistry of [beta]-diketiminate, siloxide, and triamide ligands
… reaction, which can be catalyzed by transition metal species with varying degrees of efficiency. This thesis examines the characteristics of oxygen bonding that complicate the 0-0 bond formation reaction, and examines ligand platforms that can stabilize high valent metal oxo intermediates. …
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Synthesis, Kinetic and Photocatalytic Studies of Porphyrin-Ruthenium-Oxo Complexes
Macrocyclic ligand-complexed transition metal-oxo intermediates are the active oxidizing species in a variety of important biological and catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in Nature, namely the cytochrome …
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Thiophene derivatives of rhenium and titanium
… strides have recently been made involving organometallic modeling of hydrodesulfurization (HDS). These studies have typically utilized late transition metals with high d-electron counts. This thesis focuses on three areas, (i) the synthesis of high oxidation state metal-oxo derivatives of …
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Bioinspired Mo/W-Oxo Complexes: Synthesis and Reactivity Across Multiple Ligand Scaffolds
… model for understanding how high-valent metal-oxo centers and sulfur- rich ligand environments work together to control structure and reactivity. Molybdenum and tungsten complexes were investigated as bioinspired models of these active sites, with particular focus on ligand platforms …
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Biologically inspired materials for electro-responsive coatings and the photo-oxidation of water
… sequences that bind to electrode materials and metal oxides. As in nature, it is observed that the context of a particular peptide dramatically influences its properties. While a peptide sequence may exhibit good adhesion to a particular surface when displayed on yeast, the same peptide may have …
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Synthetic and Post-Synthetic Methods towards Fine Tuning the Chemical and Physical Properties of Metal-Organic Frameworks
… the chemical and physical properties of metal-organic frameworks (MOFs), with a particular emphasis on modulating redox activity, framework composition, and ionic conductivity. The first part of the work focuses on leveraging MOF-embedded polynuclear metal clusters for multi-electron …
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Kinetic Studies of the Sulfoxidation of Aryl Methyl Sulfides by Trans-Dioxoruthenium(VI) Porphyrin Complexes
… with well-characterized <i>trans</i>-dioxoruthenium(VI) porphyrin complexes were studied by rapid stopped-flow spectroscopy. The substituent effect in sulfides and in dioxoruthenium(VI) complexes were also kinetically investigated. The low-reactive <i>trans</i>-dioxoruthenium(VI) …
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Catalytic Activity of Tungsten-dioxo and Tungsten-diimido Complexes
… the design, development, and synthesis of d0 dioxo-W(VI) complexes bearing a bulky phenolate ligand which were active towards the dehydration and deoxydehydration of polyols. The selective homogeneous dehydration of 1-phenyl ethanol to styrene was performed at low catalytic loading with high …
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Photochemical Oxidation Studies of Porphyrin Ruthenium Complexes
<p>In nature, transition metal containing enzymes display many biologically important, attractive and efficient catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in nature, namely, the cytochrome P450 enzymes. Ruthenium …
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Selective Catalytic Oxidation of Organic Sulfides by Iron (III) Porphryin Catalysts and Generation of Iron (IV)-OXO Prophyrin Radical Cations
<p>Macrocyclic ligand-complexed transition metal-oxo intermediates are the active oxidizing species in a variety of important biological and catalytic oxidation reactions. Many transition metal catalysts have been designed to mimic the predominant oxidation catalysts in nature, namely the …
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A reevaluation of distortional isomerism.
… chlorine electron density on the derived metal-oxo bond lengths. A calibration curve of Mo-Cl bond length versus composition calculated from these models resulted in a favorable comparison of this present theoretical work with other experimental X-ray studies of the MoOCl₂(PMe₂Ph)₃ system. …
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Selective Oxidations by Metalloporphyrins and Metallocorroles
<p>Highly reactive transition metal-oxo intermediates are important active oxidant involved in numerous enzymes such as cytochrome P450 monooxygenases as well as in many useful metal-catalyzed oxidations. Many transition metal catalysts are designed for biomimetic studies of the predominant …
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Synthesis and characterisation of lanthanide and other inorganic framework materials
… (NH4)[CeIVF2(PO4)].<br/><br/>The use of metal tetra-fluorides (MF4; M = Zr, Hf) in hydrothermal reactions, has led to the production of new structures that incorporate either phosphate or arsenate oxotetrahedra linking metal oxo-fluoro polyhedra. This new synthetic pathway has provided a …
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Rhenium and technetium-labeled progestins, the development of receptor-directed agents for diagnostic imaging or therapy
… prepared in which a progestin is linked to a metal chelate system. These are bis-amino bis-thiol (BAT or N$\sb2$S$\sb2$) systems and are linked through carbon-21 of progesterone or the 17$\alpha$- or 11$\beta$-position of a nortestosterone type progestin. As a model for technetium-labeled …
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Revealing Structural and Spin-state Dependent Reactivity of Single Atom Catalysts (SACs) with Systematically Improvable Computational Tools
… active site configurations and the impact of the metal's local environment on their properties and catalytic activity. This thesis presents a combined effort utilizing computational methods to explore the design and optimization of SACs for methane-to-methanol conversion and the ORR. In this …
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Electronic structure of transition metal ions and clusters
… and reaction mechanisms of open-shell transition metal ions and clusters. The early part of the thesis (Chapters 2 and 3) is devoted to high-valent metal-oxo species, both mono- and bimetallic, while Chapter 4 describes some aspects of copper-catalysed carbon-carbon bond formation. Finally, …
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Enhancing chemoselectivity and predicting site-selectivity in manganese catalyzed C–H oxidation
… of oxidation. The highly reactive carboxylate-oxo active oxidant in PDP catalysis enables strong C–H bond oxidation but remains incompatible with many functional groups. Moreover, increased molecular complexity introduces a greater number of potential oxidation sites, making heuristic …