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Showing 1 to 17 of 17 for “"VT NMR"”.
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Spectroscopic analysis and synthesis of nucleoside analogs for lethal mutagenesis
… how KP1212 induces lethal mutagenesis, VT NMR studies were conducted on KP1212. These experiments revealed that the enol tautomers of KP1212 are more prevalent than the keto tautomers, in contrast to native 2'-deoxycytidine (dC) which is predominately found in the keto-amino tautomer. …
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Squaramide-Naphthalimide Conjugates as Potential Self-Assembled Materials and as DNA Binders
… compound was characterised with room temperature NMR and it was concluded that after VT-NMR studies were performed, which clearly indicated self-assembly properties of these novel compounds. Chapter 3 describes the self-assembly properties of the novel squaramide containing bis-naphthalimides, …
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Effects of different ligands on the binding of a palladium center in a pyridyl spaced dicarbene
… These compounds have been characterized by NMR and IR spectroscopies. Furthermore, X-ray crystallography has permitted the solid-state structures of these complexes to be determined. VT-NMR and IR experiments have allowed for the thermodynamics and kinetics of small molecule binding by this …
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LINEARLY EXTENDED PYRYLIUM SALTS (LEPS) AND LINEARLY EXTENDED THIOPYRYLIUM SALTS (LETS) AS ORGANIC SEMICONDUCTORS
… X-ray diffraction, ESR and variable temperature NMR (VT-NMR) experiments.</p> <p>The LEPS and LETS compounds described here show moderate to high solubilities in organic solvents like acetonitrile and dichloromethane. While they are resistant to oxidation due to their electron-deficient …
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Sintesi e coordinazione di leganti Ciclopentadienilici O-Multifunzionalizzati
… by their spectroscopic features (ESI-MS, IR, 2D NMR, n.O.e.). The X-ray diffraction studies of 1a reveal the occurrence of one couple of enantiomeric pairs in the crystal structure, whilst the crystal packing shows an interesting self-organization in chains of dimeric units of 1a, promoted by …
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Studies on Methylaluminoxane Catalyst Activators
… of TMA with H2O. This was attempted by using 1H VT NMR spectroscopy and by combining infrared spectroscopy with the matrix isolation technique. Low temperature NMR experiments successfully led to the identification of the AlMe3·H2O adduct as the first intermediate, followed by formation of …
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Arene bridged diuranium compounds supported by amide and ketimide ligands
… solution behavior based on variable temperature, VT, NMR data), spectroscopic (X-ray absorption near-edge structure, XANES, and electronic absorption - UV- vis-NIR) and magnetic properties are discussed and interpreted with reference to results of density functional theory (DFT) calculations …
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Beiträge zur Chemie des höherkoordinierten Siliciums: Synthese, Struktur und Eigenschaften neuer Silicate mit SiO 3 C 2 -, SiO 4 C -, SiO 5 - und SiO 6 -Gerüst, Beiträge zur Chemie des tetrakoordinierten Siliciiums: Synthese, Struktur und Eigenschaften von Silanen, Silanolen und Siloxanen
… an dem bereits bekannten l5Si-Silicat 1 durch 1H-VT-NMR-Experimente die Energiebarriere für die Enantiomerisierung im Sinne einer Berry-Pseudorotation in Lösung bestimmt werden. Durch Hydrolyse von 1 — gefolgt von Kondensationsreaktionen — wurde das neuartige Oktasilsesquioxan 2 dargestellt. Die …
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Polymer drug dispersions: understanding structure and dynamics
… model drugs. We aimed to develop solid-state NMR methods to provide invaluable information on molecular mobility; to ultimately use NMR for the prediction of crystallisation outcomes from stability studies, leading to quicker prediction of potential storage issues, since mobility is a key …
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Computational and experimental studies of acenes, starphenes and [60]fullerene derivatives
… CH -- pi interactions by variable temperature NMR (VT-NMR) are described. Diels-Alder cycloadducts of [60]fullerene were generated from substituted o-quinodimethane derivatives to give compounds that may or may not engage in an intramolecular CH -- pi interactions. Evaluation of the …
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Synthesis and analysis of siloranes for use as a biomaterial and extended twisted molecular ribbons
… on the aromatized isopropyl acenes utilizing VT-NMR spectroscopy. Coalescence of the methyl peaks in the 1H NMR spectrum was not observed at temperatures up to 408 K. Utilizing this method, the barrier to enantiomerization of these compounds was found to be greater than 24.0 kcal/mol. The …
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NOVEL ETHYLENE-BRIDGED HEXADENTATE BIS(AMIDINES), BIS(AMIDINATES), AND MULTINUCLEAR COINAGE METAL BIS(AMIDINE) COMPLEXES
… be observed in the solid state and <sup>1</sup>H NMR spectroscopy. Accompanying low-temperature VT-NMR studies of <strong>1</strong> and <strong>2</strong> indicate that the NH···Cl–M–N' hydrogen bonds are retained in solution. The free energies of activation of the hydrogen bonds/molecular motion …
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Novel Magnetic Resonance Techniques as Applied to Metallic Phases in Lithium-Ion Battery Electrodes
… Resonance (EPR), Nuclear Magnetic Resonance (NMR) and Dynamic Nuclear Polarisation (DNP), as well as magnetic property measurements, all at variable temperature (VT). In addition to providing insight about these materials’ electronic structures, the body of work presented here describes novel …
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Multinuclear NMR Investigations of Local Structure, Distortions and Redox Mechanisms in Layered Lithium Ion Battery Cathode Materials
… implementation impractical. Solid state NMR is a powerful tool to study local structure and ^{6/7}Li NMR has been used extensively to probe many aspects of local structure and dynamics in Li-ion batteries. Less commonly studied nuclei, such as ^{59}Co and ^{17}O can also offer …
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NMR Studies of the Electronic Structure, Lithium-Ion Dynamics, and Prelithiation of Lithium-Ion Battery Anode Materials
… improve cyclability and then use solid-state NMR (ssNMR) to understand the differences in the lithiation mechanism during two different prelithiation techniques, electrochemical and chemical. Although much progress has been made on Si and Li metal anodes, graphite remains the major active …
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Solid-State NMR of Metallic and Paramagnetic Systems
Solid-state nuclear magnetic resonance (ssNMR) is a powerful element-specific technique to study local atomic environments in many different classes of materials; however, ssNMRbased methodologies have primarily focussed on diamagnetic systems without any unpaired electrons. In paramagnetic or …
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Metal complexes with ω-alkenyl ligands. synthesis, structure, reactivity, and applications in chemical vapor deposition (CVD) and hydrosilylation catalysis
… is correlated with deshielding of the 1H NMR resonances of the olefinic hydrogen atoms. DOSY and NOE measurements show that (2,2-dimethylbut-3-en-1-yl)lithium and (2,2-dimethylpent-4-en-1-yl)lithium remain tetrameric in cyclohexane and that the lithium-olefin interactions persist in …