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 38 for “"Single electron transfer"”.
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Photochemical Rearrangements of Tetraarylborate Salts: Direct Irradiation, Triplet Sensitization, and Single Electron Transfer
… irradiation, triplet sensitization and under single electron transfer conditions. Irradiation of sodium tetraphenylborate at 254 nm in either acetonitrile or THF produces 2,7,7-triphenyl-7-boratabicyclo (4.1.0) hepta-2,4-diene. The rearrangement was also observed to occur with other …
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New explorations in visible-light mediated energy and single electron transfer for nitrogen heterocycle synthesis
… containing heterocycles, investigating both single electron transfer and energy transfer methods. The results section of this thesis is presented in three chapters, each focusing on a different ring size, namely 4, 5 and 6 membered nitrogen heterocycles. Chapter two explores the use of …
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The elucidation of single electron transfer (SET) mechanisms in the reactions of nucleophiles with carbonyl compounds
… that the rate limiting step is heterogeneous electron transfer. Ring opening of the radical anion generated from <b>20</b> results in a 9:1 ratio of the 3° and 1° distonic radical anions. The rate constant for ring opening has been estimated to be k ≥ 10⁷s⁻¹ with a calculated (AM1) enthalpy of …
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Evaluation of 1,1-Dimethyl-5,7-Di-T-Butylspiro[2.5]Octa-4,7-Dien-6-One as a Mechanistic Probe for Single Electron Transfer
Single electron transfer (SET) mechanisms are becoming ubiquitous in modern organic chemistry. However, it is often difficult to distinguish SET mechanisms from polar mechanisms. Kinetics, products and product distributions, and response to perturbation in solvent and substituents are often …
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Hydrodynamically modulated voltammetry in microreactors
… (FTACV) under microfluidic conditions. Single electron transfer reactions with different kinetics were studied first by using potassium ferrocyanide and ferrocenecarboxylic acid (FCA). Dual electron transfer reactions with different pathways were investigated by using …
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Controlling kinetic branching in C0₂-to-fuels catalysis
… activation of CO₂ over H+ to form the two-electron reduced CO product; and (2) the requirements for the accumulation of surface-bound CO species that can be reduced to higher order products beyond CO. Using model Au and Cu electrocatalysts, we uncover mechanistic insights into these branch …
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The Photochemistry of 3- and 4-Nitro Phenyl Azides
… rate and reacts with the tertiary amine by single-electron transfer. The rate constant of the reaction of triplet nitrenes with O$\sb2$ is ca. 10,000 fold slower than the dimerization. The precursors of the triplet nitrenes can be trapped by secondary amines. The mechanisms of these …
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Mechanophore-Linked Polymers for Studying Mechanochemical Response
… acrylate) in an efficient manner using single electron transfer living radical polymerization (SET-LRP). The utility of this method was demonstrated with a spiropyran (SP) mechanophore that was found to undergo a mechanically induced 6pi-relectrocyclic ring opening. The mechanokinetics …
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Quantitative structure activity relationships of monoamine oxidase catalyzed oxidation of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine analogs
… correlations with lipophilic, steric, and electronic factors. Compounds studied were 4-aryloxy analogs, 4- aromatic heterocycle analogs, and 4-phenyl analogs. The conformer with phenyl ring to tetrahydropyridine dihedral angles similar to a low energy conformer of …
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ARYL-HETEROATOM CROSS-COUPLING WITH DUAL NICKEL/PHOTOCATALYST PROTOCOLS : THEORY, APPLICATIONS AND RECENT DEVELOPMENTS
… different relaxation pathways, the difference of singlet and triplet states, and parameters used to predict reactivity are first disclosed. The general components used in dual nickel/photocatalyst protocols are presented followed by the discussion on reactivity trends. The reactivity trends are …
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Synthesis of Dimeric Pyrrole-Imidazole Alkaloids
… synthetic studies support the possibility that a single-electron transfer (SET) reaction and a pinacol-type rearrangement may be used in nature as a way to produce ageliferin and massadine.
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Binding Affinity of Flavins to the Dehydrogenase Domain of SpNOX
… catalyze the production of superoxide through single electron transfer. This superoxide production leads to the production of other reactive oxygen species (ROS). ROS affect many metabolic processes throughout the body that can cause several different diseases, making this an ideal target for …
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The nickel-catalyzed Mizoroki-Heck reaction : high regioselectivity in Olefin migratory insertion and photoredox-enabled indoline formation
… high selectivity in the Heck reaction of electronically unbiased alkenes has been a longstanding challenge. Using a nickel-catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for branched products (>/=19:1 in all cases) over a wide range of aryl electrophiles …
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Chloro-arylation of Alkenes via Cooperative Photoredox and Atom-transfer Catalysis
… study demonstrated broad-spectrum tolerance to electron-deficient alkenes, styrene derivatives, and unactivated alkenes. Elucidation of the key mechanistic steps and intermediates revealed a unique inner-sphere single electron transfer (iSET) mechanism when [CuI(dpp)2]+ and [BPA.CuI]+ were used …
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On the reactions of ortho-positronium and inhibition of positronium formation
… be correlated with the free energy change for single electron transfer, ΔG⁰, however, no such correlation was found for solutions containing a series of complexes of Hg(II), HgCl₂, and Fe(III). The rates of reaction of these complexes were found to be influenced by the nature of the ligands and …
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Photoredox C–C Cross-Coupling Reactions using Boronic Acid Derivatives
… tool for small molecules activation via single-electron transfer mechanisms. Despite their ubiquity as reagents in organic synthesis, the use of boronic acid derivatives to generate carbon-centred radicals remains elusive. This dissertation explores the utilisation of photoredox catalysis …
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Oxidation of Tetrahydropyridines by MAO B Biomimetics: Mechanistic Studies
… been debated for just as long. Proponents of the single electron transfer (SET) pathway of oxidation faced severe critiques in that the hypothesized radical intermediates arising from the SET pathway were never directly observed. Work performed herein provides that exact evidence using biomimetics …
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Metabolic Studies on 1-Cyclopropyl-4-phenyl-1,2,3,6-tetrahydropyridinyl Derivatives by HPLC and LC-ESI/MS
… of MAO-B which presumably is processed by a single electron transfer (SET) pathway to generate a bioalkylating species. These results have prompted us to study how the cytochromes P450, the major liver drug metabolizing oxidases, interact with N-cyclopropyl analogs of MPTP. HPLC with diode …
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Mechanistic Studies on the Monoamine Oxidase B Catalyzed Oxidation of 1,4-Disubstituted Tetrahydropyridine Derivatives
… amines. The overall process involves a two electron oxidation of the amine to the iminium with concomitantreduction of the flavin. Based on extensive studies with a variety of chemical probes, Silverman and colleagues have proposed a catalytic pathway for the processing of amine substrates …
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