Nuclear magnetic resonance interactions

Solid-state nuclear magnetic resonance Interaction between nuclear magnetic Polymerization kinetics, time evolution of... 

Basic theory and nuclear magnetic resonance interactions 216... 

BASIC THEORY AND NUCLEAR MAGNETIC RESONANCE INTERACTIONS... 

Lauterbur P C 1973 Image formation by induced local interactions examples employing nuclear magnetic resonance Nature 242 190-1... 

Alexander S 1962 Exchange of interacting nuclear spin in nuclear magnetic resonance. I. Intramolecular exchange J. Chem. Phys. 37 967-74... 

Nuclear Magnetic Resonance 2.1.1.3.A Electron Paramagnetic Resonance 2.1.1.4 Thermal/Mechanical Energy Interaction... 

Infrared, ultraviolet, and nuclear magnetic resonance spectroscopies differ from mass spectrometry in that they are nondestructive and involve the interaction of molecules with electromagnetic energy rather than with an ionizing source. Before beginning a study of these techniques, however, let s briefly review the nature of radiant energy and the electromagnetic spectrum. 

Mathematical models are the link between what is observed experimentally and what is thought to occur at the molecular level. In physical sciences, such as chemistry, there is a direct correspondence between the experimental observation and the molecular world (i.e., a nuclear magnetic resonance spectrum directly reflects the interaction of hydrogen atoms on a molecule). In pharmacology the observations are much more indirect, leaving a much wider gap between the physical chemistry involved in drug-receptor interaction and what the cell does in response to those interactions (through the cellular veil ). Hence, models become uniquely important. 

Nuclear magnetic resonance spectroscopy of the solutes in clathrates and low temperature specific heat measurements are thought to be particularly promising methods for providing more detailed information on the rotational freedom of the solute molecules and their interaction with the host lattice. The absence of electron paramagnetic resonance of the oxygen molecule in a hydroquinone clathrate has already been explained on the basis of weak orientational effects by Meyer, O Brien, and van Vleck.18... 

Abscisin II is a plant hormone which accelerates (in interaction with other factors) the abscission of young fruit of cotton. It can accelerate leaf senescence and abscission, inhibit flowering, and induce dormancy. It has no activity as an auxin or a gibberellin but counteracts the action of these hormones. Abscisin II was isolated from the acid fraction of an acetone extract by chromatographic procedures guided by an abscission bioassay. Its structure was determined from elemental analysis, mass spectrum, and infrared, ultraviolet, and nuclear magnetic resonance spectra. Comparisons of these with relevant spectra of isophorone and sorbic acid derivatives confirmed that abscisin II is 3-methyl-5-(1-hydroxy-4-oxo-2, 6, 6-trimethyl-2-cyclohexen-l-yl)-c s, trans-2, 4-pen-tadienoic acid. This carbon skeleton is shown to be unique among the known sesquiterpenes. 

The change in the electronic properties of Ru particles upon modification with Se was investigated recently by electrochemical nuclear magnetic resonance (EC-NMR) and XPS [28]. In this work, it was established for the first time that Se, which is a p-type semiconductor in elemental form, becomes metallic when interacting with Ru, due to charge transfer from Ru to Se. On the basis of this and previous results, the authors emphasized that the combination of two or more elements to induce electronic alterations on a major catalytic component, as exemplified by Se addition on Ru, is quite a promising method to design stable and potent fuel cell electrocatalysts. 

Gakh, E.G., Dougall, D.K., and Baker, D.C., Proton nuclear magnetic resonance studies of monoacylated anthocyanins from the wild carrot part 1. Inter- and intramolecular interactions in solution, Phytochem. Anal., 9, 28, 1998. 

These special features are explained by an interaction between the proton and one of the water molecules, which is not merely electrostatic but also covalent. This yields a new chemical species, the hydroxonium ion, HjO. The existence of such ions was demonstrated in the gas phase by mass spectrometry and in the solid phase by X-ray diffraction and nuclear magnetic resonance. The H -H20 bond has an energy of 712kJ/mol, which is almost two-thirds of the total proton hydration energy. 

Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool that can provide the binding sites of Ugand-DNA interactions at the molecular level. A prerequisite for the examination of ligand-DNA complexes is assignment of all resonances in the NMR spectra of the free DNA and the ligand and of both components in the complex. 

Balaram, P., Bothner-By, A. A., Breslow, E. Nuclear magnetic resonance smdies of interaction of peptides and hormones with bovine neurophysin. Biochemistry 1973, 12, 4695 704. 

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