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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 50 for “"19F NMR"”.
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Probing Organometallic Reactions With 19F NMR
… the metallocene/MAO mixtures are analyzed using 19F NMR spectroscopy. Group 4 metallocene dimethides bearing pentafluorophenyl (C6F5) substituents were synthesized and treated with MAO in benzene-d6. 19F NMR spectroscopic analysis demonstrated reversible methide transfer to form "cation-like" …
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Development and Application of 19F NMR of Proteins
19F NMR studies of proteins provide unique insight into biologically relevant phenomena such as conformational fluctuations, folding and unfolding, binding and catalysis. While there are many advantages to the use of 19F NMR, experimental challenges limit its widespread application. The focus of …
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Progress Toward the Synthesis of 3-Methoxyflavones as Potential Antioxidants, Neuroprotective Agents, and Trifluoromethylated 19F NMR Probes
The total synthesis of polyhydroxylated flavones have proven to be challenging, due to the presence of more than one hydroxyl group. Direct cyclization was not successful in any of the attempts. However, by using a silyl protecting group, the cyclization was feasible. Other reactions like the …
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Pushing the Limits of the Lithium Indicator Carbon Acidity Scale Using Cyclopentadiene Chemistry and 19F NMR Spectrometry
… cyclopentadiene 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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Mechanistic Studies of Salt Effects on Bimolecular Electron-Transfer Reactions of Pentaamine Ruthenium Pyridyl Complexes Studied by 19F NMR Line-Broadening and T2 Spin-Echo Techniques
… have been measured using both <sup>19</sup>F NMR line-broadening and CPMG T<sub>2</sub> spin-echo relaxation techniques in H<sub>2</sub>O and D<sub>2</sub>O. Over the equimolar reactants concentration range of 0.10 mM – 8.00 mM there was a definite “self-salting” rate increase arising from the …
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Synthesis and solid state F-NMR studies on fluorine-labeled antimicrobial peptide RK-21
… peptide RK-21 was chemically synthesized and 19F-NMR studies were done. NMR studies were done at various peptide concentrations, on different lipid bilayer compositions and temperatures. 31P-NMR studies did not show any micellar fragments, eliminating the detergent-like mechanism for activity. …
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Characterisation of the conformational landscape of the β1-adrenergic receptor and development of a strategy towards NMR studies of the protease-activated receptor 1
… using solution state nuclear magnetic resonance (NMR) spectroscopy. The tβ1AR is a class A G-protein-coupled receptor (GPCR) and the human counterpart is an important drug target in diseases of the heart. In chapter 2, a wide range of constructs, labelling reagents and conditions were tested to …
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FLUORINATED RESPONSIVE LANTHANIDE COMPLEXES FOR MAGNETIC RESONANCE
… synthesised for use as responsive probes for 19F MRS and MRI. The careful positioning of the CF3 group within 6.5 Å from the metal ion caused the fluorine longitudinal and transversal relaxation rates to be strongly enhanced. This allows faster MR signal acquisition, reducing the sample …
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Amphiphilic BAB-triblock copolymers bearing fluorocarbon groups : synthesis and self-organization in aqueous media
… of the synthesized block copolymers via 1H-, 19F-NMR, and in some cases also UV-vis spectroscopy, were performed attaching suitable fluorinated moieties to the Z- and/or R-groups of the CTAs. Symmetric triblock copolymers of type BAB and non-symmetric fluorine end- capped polymers were …
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Chemical and Enzymatic Synthesis of Dehydropeptides and Their Fluoro Analogs
… L-Ala-Dha(F), respectively, as determined by 1H NMR, 19F NMR and MS (ESI).
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Structural And Functional Studies On Thrombin Allostery
… thrombin for solution based structural studies. 19F-NMR results indicate that α-thrombin is a highly dynamic and flexible molecule. Binding of Na+, an exosite I ligand, and an irreversible inhibitor induces significant and unique structural and dynamic changes. A zymogen form of thrombin, …
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Development of peptide-based 19F MRI agents and BPTF-bromodomain inhibitors
… the early detection of disease. In particular, 19F MRI shows promise for this development as the fluorine nucleus possesses many similar characteristics as the conventionally used proton but has the distinction of a lack of background signal found natively in biological systems. State of the art …
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Fluorinated Nanoparticles: A Novel Technology Platform for Multimodal Biomedical Imaging Applications
… for PET imaging, and as an imaging probe in 19F MRI. Additionally, fluorinated organic compounds generate a high ionization yield of fluorine in secondary ion mass spectrometry (SIMS), which is gaining recognition as an in vitro cellular imaging technique. This suggests that fluorinated SIMS …
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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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SCREENING FOR POTENTIAL ANTIBACTERIAL AGENTS AND THE APPLICATION OF ISOTOPIC LABELS FOR THE CHARACTERIZATION OF THEIR EFFECTS ON THE DYNAMICS OF THE BACTERIAL 16S RIBOSOMAL RNA
… new scaffolds using nuclear magnetic resonance (NMR) spectroscopy and identified compounds that bind weakly to a 27-nucleotide (nt) construct of the bacterial 16S ribosomal RNA (rRNA). We show that, at high concentration, these compounds interfere with bacterial growth. We also observed that the …
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Nuclear magnetic resonance studies of boron trihalide complexes of 1,1-BIS (dimethylamino) ethylene and related bases
… adducts of DME have been investigated by 1H and 19F NMR spectroscopy. Both nitrogen and the C-Q-H carbon of DME are possible donor a toms to boron trihal ides but complexation has been found to occur only at carbon of DME. The initial adduct acts as a Bronsted acid and gives up a proton to free …
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Mechanistic studies of rabbit muscle glycogen phosphorylase
… from solid-state magic angle spinning 31P NMR experiments of the native enzyme. The cofactor phosphate moiety, in both allosteric forms of the enzyme, exhibited axially symmetric shielding parameters. These results suggest that the PLP phosphate moiety exists as a dianion in both enzyme …
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Development of New Synthetic Approaches to Biologically-Active Peptides
… Finally, the use of fluorine as a reporter for 19F NMR analysis of biological molecules was investigated. Fluorinated prolines were used to explore protein-protein interactions and dynamics, specifically to study the peptidyl-prolyl isomerase cyclophilin D (CypD). First, short substrates were …
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A fragment-based approach towards understanding molecular recognition of 4’-phosphopantetheine adenylyltransferase from Mycobacterium abscessus
… 4 describes development of a ligand-based 19F NMR competition assay that enabled more complete characterisation of fragment binding affinities than previously possible for Mabs PPAT. The assay was validated by comparison with ITC and allowed ranking of affinities for several ligands for …
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