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 20 of 40 for “"radical chemistry"”.
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Development and Evolution of ‘Ene’-Reductases for Selective Radical Chemistry
… engaged in single-electron transfer events for radical initiation, offering the capability to generate high-energy open-shell intermediates in the controlled environment of the enzyme active site. This feature has been used to effect various radical-mediated transformations, offering exceptional …
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Mass spectrometric characterization of peptide radical ions and implication for radical chemistry
<p>Gas-phase radical ion chemistry has attracted increasing research interest from the mass spectrometry (MS) society because it provides new capabilities in bio-analysis which often complements traditional MS methods developed from even-electron ions. Fundamental studies of biomolecule related …
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New Strategies in Radical Chemistry and Their Application to the Construction of C(sp3)–C(sp3) Bonds in the Giese Reaction
… a unique platform to access C(sp³)-centred radicals, and their subsequent addition into electron deficient olefins to build saturated hydrocarbon frameworks (the Giese reaction), is investigated. The transformation merges two electrophilic components (an alkyl halide and an acceptor) in the …
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Structural and functional investigations of mechanisms of iron-utilizing enzymes
… as reservoirs from which to initiate enzymatic radical chemistry. Here, I discuss efforts to study the allosteric mechanisms of an essential human iron and free radical utilizing enzyme: ribonucleotide reductase (RNR), and efforts to elucidate the radical based mechanism of isonitrile formation …
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Catalytic Reactions of Organoboranes
… quantities. We proposed that 1 electron radical chemistry can be used to generate new organoboranes under catalytic systems to allow for more controllable and efficient processes. Herein we report our efforts towards developing new catalytic methodologies for the synthesis of …
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MEASUREMENTS OF ATMOSPHERIC RADICALS IN AMBIENT AND INDOOR ENVIRONMENTS: OUTDOOR-INDOOR RELATIONSHIPS, INDOOR FORMATION MECHANISMS, AND INSTRUMENTAL ANALYSIS
… (OH), hydroperoxy (HO2), and peroxy (RO2) radicals are key to atmospheric oxidation, critically altering the chemistry of the air we breathe. Radical reactions initiate oxidation of volatile organic compounds (VOCs), which in the presence of nitrogen oxides (NOx) can form ozone and …
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Structural studies of radical enzymes in bacterial central metabolism
… gut microbiome. The absence of oxygen limits the chemistry that bacteria can perform; however, these organisms do make use of organic radical cofactors that are oxygen sensitive. This thesis presents a structural analysis of three enzymes that utilize a glycyl radical cofactor to perform …
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Structural insight into the assembly of iron-sulfur clusters and their function in radical generation
… areas in the study of iron-sulfur cluster biochemistry: bioassembly of iron-sulfur clusters, and their involvement in initiation of radical chemistry. The structure of a cysteine desulfurase involved in cluster bioassembly in the cyanobacterium Synechocystis PCC sp. 6803 was solved by X-ray …
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The Exploration of a Strategy for Regioselective Arene Amination Utilising Non-Covalent Interactions
… methods which utilise reactive N-centred radicals for the synthesis of anilines from arenes have recently been developed. However, regiochemical control is a major challenge associated with these methods, with mixtures of regioisomers commonly obtained in most protocols. Non-covalent …
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Radical methods for the synthesis of aliphatic amines
… This thesis details the development of three new radical reactions for the synthesis of aliphatic amines. Following an introduction to radical chemistry and a summary of previous advances in amine synthesis, chapter 2 will describe a general carbonyl alkylative amination reaction, a successful …
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Methodology investigations for the synthesis of biologically important nitrogen-containing heterocycles
… the development of a novel, Mn(OAc)3-mediated radical cyclisation-dimerisation cascade sequence for the synthesis of sterically challenging 3,3'-bisoxindoles using two complementary simple, acyclic starting materials; β-oxoanilines and β-oxoacids. This method proved amenable to a variety of …
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Atmospheric chemistry and aerosol associated with the coastal urban environment
… at night, likely associated with nitrate radical chemistry. Substantial differences in particle compositions and concentrations were observed on NPF and non-NPF days. PM1 mass concentrations were 7% to 76% lower on NPF days compared to non-NPF days across all sites. However, the fractional …
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MEASUREMENTS AND MODEL PREDICTIONS OF HYDROXYL RADICAL, PEROXY RADICALS, AND NITROUS ACID: EVIDENCE OF MISSING SOURCES OR SINKS IN FORESTED AND INDOOR ENVIRONMENTS
The hydroxyl radical (OH) is the dominant oxidant in the atmosphere, controlling the lifetimes of volatile organic compounds (VOCs) and contributing to the formation of ozone (O3) and secondary organic aerosols (SOA). The oxidation of VOCs by OH propagates a radical cycle between OH, the …
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Exploring the origins of DNA using synthetic biology Alannah Marie
… ribonucleotide reductase, performs complex free radical chemistry, so is believed to have occurred late in evolution. If DNA is instead able to be produced through an alternative and simpler pathway, it is possible that the transition could have occurred far earlier in evolution than previously …
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The roles of redox active cofactors in catalysis : structural studies of iron sulfur cluster and flavin dependent enzymes
… determined to aid in electron transfer and redox chemistry. However, additional activities for these cofactors continue to be discovered. The study of FAD in the context of rebeccamycin and staurosporine biosynthesis has yielded another role for this cofactor in the enzyme StaC. A homolog of this …
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Development of a Novel TiO2-polymeric Photocatalyst for Water Purification both under UV and Solar illuminations
… process is based on aqueous phase hydroxyl radical chemistry and couples low energy UV light with semiconductors acting as photocatalyst. The slurry form of TiO2 though being efficient has several disadvantages (particularly, post treatment expensive separation steps) which brings the …
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Molecular genetics and microbiology of bioremediation using methane-oxidising bacteria
… toward a range of substrates, and indicated that radical chemistry at this position is not xviii essential for monooxygenase activity toward a number of aliphatic and aromatic hydrocarbons. Results from other mutations included stabilising a previously unstable mutant (C151Y) with a secondary …
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Water-Soluble Redox Materials and Their Applications in Aqueous Batteries
… battery. In the third project, a non-persistent radical precursor, N-hydroxyphthalimide (NHPI), is reported for the first time as a low-cost, high-potential organic cathode with rapid kinetics in a semi-aqueous redox battery. A novel combined strategy is proposed in stabilising non-persistent …
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Indirect Detection of Explosive Vapours by Thermal Dissociation Cavity Ring-Down Spectroscopy
… second explosive detection technique exploited radicals generated during the thermal decomposition of triacetone triperoxide (TATP), a peroxide explosive, for detection. These radicals were amplified via a peroxide radical chemical amplification scheme (PERCA) that required the addition of NO …
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Studies on Critical Proton Pathway Residues in the Aa3-Type Cytochrome C Oxidase From Rhodobacter Sphaeroides
… steps. However, the coupling of the oxygen chemistry to proton pumping is not yet understood at a molecular level and several grey areas like proton/water-exit channel, residues controlling the unidirectionality of the pump and a universal proton pumping mechanism are being actively …
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