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 15 of 15 for “"NMR spectrometry"”.
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Pushing the Limits of the Lithium Indicator Carbon Acidity Scale Using Cyclopentadiene Chemistry and 19F NMR Spectrometry
… and indene derivatives, using 19F NMR spectroscopy to determine the equilibrium constants of sequential acid-base reactions. This thesis describes the further extension of the SLI scale to ca. pK = −6. To achieve this result, a set of 11 tetrasubstituted cyclopentadienes were …
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Studies in the field of metal β-ketoenolate chemistry
… physical techniques including IR spectroscopy, NMR spectrometry, conductance determinations and magnetic susceptibility determinations. The NMR spectra of 42 variously substituted pyridines were determined. The results are used to discuss the nature of the bonding and structure of these …
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Challenging the Limitations of the Streitwieser Lithium Indicator Acidity Scale with Cyclopentadiene Derivatives
… to acidity measurements using 1H and 19F NMR spectrometry in CD3CN solution, bracketing their acidities between two "indicator" acids that were previously established on the SLI scale. This process revealed pKMeCN, pKTHF (SLI acidity) and pKa ("true" aqueous acidity) values for each …
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Bis-and tris (amidine) fluoroboron cations and related systems studies by Multinuclear NMR and fast atom bombardment mass spectometry
… species which were detected by 19p and 11B NMR spectrometry. The displacement reaction of CI- from these D.BFnCI3-n (n = 1 and 2) species by the second entering ligand is much faster than in other nitrogen donor containing systems which have been previously studied. Tetramethylguanidine, …
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Nanocrystalline Transition Metal Ferrites Synthesis, Characterization and Surface Functionalization
… transmission electron microscopy (TEM) and 1H-NMR spectrometry was performed in order to elucidate the composition and the morphology of the variable-sized iron oxide nanoparticles. Both finite size and interparticle interaction effects were identified to influence the magnetic behavior of the …
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In Vitro Methanogenesis From Formaldehyde. Identification of Three Carbon-1 Intermediates of the Methanogenic Pathway
… prevent inactivation by O(,2). ('1)H and ('13)C NMR spectrometry and ultraviolet spectroscopy was used to document the binding of C(,1) units of different oxidation states to FAF. Methanogenesis from each derivative of FAF (formyl, methylene, and methyl) was kinetically comparable to …
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Cyclopentadiene as a Platform for Polymer Synthesis and Modification of Macromolecular Systems
… characterized isomers, and with 1H NMR and 19F NMR spectrometry, including 1-D NOE, allowed five isomeric products to be identified. Diene CPD-1 is reactive toward nucleophiles (such as potassium 4-methylphenoxide) at the 4-positions of the C12F9 groups. Using this reactivity …
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Novel strategies for DNA detection and assay.
… was studied in the presence of lanthanide ions. NMR spectrometry was used to further improve the knowledge on the interaction, and this work was done in collaboration with King’s college London. The results obtained showed that about 1 lanthanide ion binds to 4 nucleotide bases. They bind first …
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Synthesis and characterization of precursors for chemical vapor deposition of metal oxide thin films
… analysis and proton nuclear magnetic resonance spectrometry (NMR). Purity of T8 was confirmed by proton NMR. Isothermal gravimetric analysis (TGA) was used to study volatility and thermal stability of the precursors. The Zr(thd)₄ isotherms ranged from 180-260 °C, the Pb(thd)₂ and Pb(fod)₂ …
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A metabolomics investigation of in utero antiretroviral exposure to neonates
… metabolomics [1H nuclear magnetic resonance (NMR) spectrometry] to analyse cord blood from HIV-ART exposed and unexposed neonates, as well as serum from healthy infants. Decreased levels of 3-hydroxybutyrate and alarming increase in hypoxanthine, indicators of metabolic stress, were observed …
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The synthesis of biologically active oxa-polyamine analogues, homologues and conjugates.
… were confirmed by IR spectrophotometry, NMR spectrometry and mass-spectral analyses. The chemistry developed to synthesise polyamine oxa-analogues, was used to prepare novel oxa-azamacrocycles bearing N-O moieties in the ring. A synthetic strategy was developed for the synthesis of …
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Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst
… and density. Gas chromatography and 13C-NMR spectrometry suggest that steam treatment affect the catalyst selectivity in the formation of CO, CO2, H2, CH4, C2-C5 hydrocarbons and aromatic hydrocarbons. The addition of ZSM-5 additive to the FCC catalyst was found to alter the …
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Influence of a Biodegradable Litter Amendment on the Pyrolysis of Poultry Litter
The effects of adding a biodegradable litter amendment (AmmoSoak), developed from steam exploded corncobs, to poultry litter prior to pyrolysis on the product yields and qualities were investigated. Mixtures of litter and AmmoSoak were pyrolyzed in a bench-scale fluidized bed reactor. The objective …
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Catalytic Pyrolysis of Cellulose, Hemicellulose and Lignin Model Compounds
… characterization of the oils using FTIR and ¹³C−nmr showed that, the VPISU001 HZSM-5 with and without NaOH pretreatment caused elimination of the levoglucosan fraction while increasing the aromatic fraction. The NaOH pretreated cellulose pyrolyzed on sand reduced the levoglucosan groups while …
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Validation and use of novel techniques to study the impacts of large-scale environmental changes on the health of wild waterfowl
… corticosterone and nuclear magnetic resonance spectrometry (NMR)- based metabolomics, and then used these approaches in field-based studies to investigate the impacts of a changing environment on stress responses or increased energetic demands on free-ranging migratory birds. Feather …