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Showing 1 to 20 of 31 for “"KIE"”.
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Palladium-Catalyzed Alkenylsilanol Cross -Coupling Reactions: Method Development and Mechanistic Analysis
… abundance 13C NMR kinetic isotope effect (KIE) studies. This provided evidence for either palladium-olefin complexation or a Heck-type carbometalation as the turnover-limiting step for these cross-coupling reactions.
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Lewis Base Catalyzed Enantioselective Aldol Additions: Preparative and Mechanistic Studies
… abundance 13C NMR kinetic isotope effect (KIE) studies have determined aldolization to be rate limiting.
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Understanding non-precious metal catalysts for the oxygen reduction reaction and investigating corrosion and surface properties of carbon-doped aluminum alloys
… study utilizing the kinetic isotope effect (KIE) to compare the ORR pathway on NPM catalysts with precious metal catalysts Pt and Pd. The use of KIE in this case is able to provide information on the role of protons (H+) in the ORR mechanism. This study indicates that there is a KIE observed …
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Borenium Cations as Catalysts for the Reduction of Organic Molecules and Mechanistic Investigations into their Mode of Operation
… and produced a high kinetic isotope effect (KIE = kH/kD = 6.6 ± 0.2). This high KIE strongly indicates that hydride delivery is the rate limiting step in the catalytic cycle. With this knowledge an asymmetric model is discussed and the beginnings of the development of an asymmetric borenium …
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Mechanistic Studies of Peptidylglycine Alpha-Amidating Monooxygenase (PAM)
… mechanism for improved catalytic function. The 1°KIE showed a linear decrease with increasing chain length. Neither the minimal kinetic mechanism nor the maximal rate for substrate oxidation was observed to be altered by substrate hydrophobicity. It was concluded that KIE suppression was a …
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Pin1: WW domain ligands, catalytic inhibitors, and the mechanism
… measured a secondary kinetic isotope effect (2º KIE) to study the Pin1 catalytic mechanism of proline isomerization. The ratio of kH/kD for unlabeled and [d₃]Ser-labeled substrate gave a SKIE value of 1.34 ± 0.01. The normal 2º KIE value indicates that carbonyl-serine hybridization is not …
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The Reactivity of Ditetrelenes Towards Organophosphorus Oxides
… through deuterium labelling studies and KIE experiments. The mechanism for the formation of disilyl and digermyl phosphinites and phosphites was determined to proceed through a nucleophilic addition. An exchange phenomenon between the OP(pentyl)2 moiety of 32 and an OPPh2 group from …
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Mechanochemistry: Redefining the Paradigm of Organic Chemistry
… studies such as kinetic isotope effect (KIE) and Hammett analysis, combinedly verified the importance of mechanochemistry for green organic synthesis.
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SHAPING ORGANIC SYNTHESIS WITH LIGHT-DRIVEN PROCESSES
… a method to analyze the kinetic isotope effect (KIE) through Raman spectroscopy in flow conditions.
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Mechanistic investigations of enzymes in phosphonate metabolism
… incubations, site-directed mutants, and 18O KIE studies. Additionally, this thesis presents a study on an alcohol dehydrogenase that reduces phosphonoacetaldehyde (PnAA) to 2-HEP; the implications for the biosynthetic pathway for fosfomycin are discussed. Finally, observations made while …
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Photochemical Oxidation Studies of Porphyrin Ruthenium Complexes
… the well-known 3a under identical conditions. A KIE at 298K was found to be larger than those observed in autoxidation processes, suggesting a nonradical mechanism that involved the intermediacy of ruthenium(V)-oxo species as postulated. The reactivity order in the series of ruthenium(IV) μ-oxo …
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Home range use by Southern Ground-Hornbills (Bucorvus leadbeateri) - quantifying seasonal habitat selection and vegetation characteristics
… Moorcroft et al. 1999; Mitchell, 2007; Rodgers & Kie, 2011). Patterns of differential use of space within an animal's home range are the result of competing demands and trade-offs. In this study, a kernel technique was used to determine the home range of four satellitetracked groups of Southern …
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Observation and Nature of Non-statistical Dynamic Effects in Ordinary Organic Reactions
… free energy surface. Kinetic isotope effects (KIEs) were measured for three DA reactions. We envision that the entropic barrier may have several experimental consequences such as unusual isotope effects due to extensive recrossing. Preliminary results for the organocatalytic reaction show an …
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Kinetics and dynamics controlling proton-coupled electron transfer in ribonucleotide reductase
… , and a lower bound of 7 for the associated 1° KIE. The pKa of proton acceptor(s) at the subunit interface, and the relative energies of individual radical intermediates were determined, revealing matched tuning to the surrounding environment and highlighting the subtlety of precision control …
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Interrogating electrocatalytic mechanisms and developing nano-porous catalysts for energy conversion reactions: I. Oxygen evolution reaction, and II. Carbon dioxide reduction reaction
… The OER Tafel slope and kinetic isotope effect (KIE) calculated from electrochemical data shows that both Ni and Co exhibits inverse secondary KIE, which is never observed before in an electrochemical experiment. These results contribute to a more complete understanding of the OER mechanism and …
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Synthesis, Kinetic and Photocatalytic Studies of Porphyrin-Ruthenium-Oxo Complexes
… <b>3a</b> under identical conditions. A KIE at 298K was found to be larger than those observed in autoxidation processes, suggesting a nonradical mechanism that involved the intermediacy of ruthenium(V)-oxo species as postulated.
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Investigating the rate-limiting step of mitochondrial complex I catalysis
… displays a solvent kinetic isotope effect (KIE), signifying that the rate-limiting step involves a proton transfer. This isotopic sensitive step is dependent on Q-chain length, Q binding-site mutations, and Qconcentration, but not dependent on Δp, suggesting that this step is Q-reduction. …
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Ideology, welfare mix and the production of welfare : a comparative study of child daycare policies in Britain and Hong Kong.
This is a study of the inter-relationship between welfare ideology, welfare mix and the production of welfare. It has been hypothesized that the welfare ideology of a state is likely to affect its choice of welfare mix and the kind of social relations produced in the wider society. In this study, …
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What does the analysis of copper-alloy brooches reveal about the social and economic landscapes of Early Anglo-Saxon Cambridgeshire and Suffolk?
This thesis examines the social and economic landscape of the Early Anglo-Saxon period by analysing copper-alloy brooches using X-ray fluorescence spectroscopy. Two clusters of cemeteries, one in Cambridgeshire and the other in Suffolk, were chosen to have their brooches analysed. The results of my …
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From Homological Algebra To Topology via Type B Zigzag Algebra and Heisenberg Algebra
We construct a faithful categorical action of the type $B$ braid group on the bounded homotopy category of finitely generated projective modules over a finite dimensional algebra which we call the type $B$ zigzag algebra. This categorical action is closely related to the action of the type $B$ …
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