Nuclear magnetic resonance measurement

Nuclear magnetic resonance measurements have led to the conclu-sion that 2-pyridones have about 35% of the aromaticity of benzene and that the formally related l,2-dihydro-2-methylenepy-ridine is not aromatic. A substantial contribution by such resonance is indicated by the electronic spectrum of 2-quinolone, which is... 

J. D. Seymour, B. Manz, P. T. Callaghan 1999, (Pulsed gradient spin echo nuclear magnetic resonance measurements of... 

Nuclear magnetic resonance measurements of methane adsorbed to various coverages on titanium dioxide have been made by Fuschillo and Renton 16). At a coverage of 0.95 monolayer and at 20.4°K, the X-point for solid bulk methane, these authors observed an abrupt change in the proton resonance line width, presumably due to translational and rotational diffusion of methane molecules. For pure, bulk methane no change has been observed in the line width at the X-point. 

Changes In nuclear magnetic resonance measurements of an extensive suite of Australian coals on heating and exposure to pyridine are used to elucidate the molecular conformation of coal macerals Two types of fusible material are Identified In these coals One Is associated with llptlnltes of all ranks and Is typified by fusion commencing at temperatures below 475 K. The other Is associated with vltrlnltes and some Inertlnltes of bituminous coals only and Is characterized by a sharp onset of fusion at temperatures above 625 K. The temperature of onset of fusion Increases with rank for both types The effect of pyridine on the molecular stability of bituminous coals at ambient conditions Is strongly dependent on maceral composition at 86% C and on rank at higher carbon contents ... 

Takahashi, S., Saboungi, M.-L., Klingler, R. J. et al, Dynamics of room-temperature melts Nuclear magnetic resonance measurements of dialkylimidazolium haloaluminates, Faraday Trans., 89, 3591,1993. 

The three unknown parameters y, r, and SI in Eq. (11-41) for / = 3 were obtained by nuclear magnetic resonance measurements, which yield the phosphorous concentrations with zero, one, two, or three Cl atoms, for each R. It was found that the extent of cyclization, a, is about 10% at the gel point SI = 1.05 (f.s.s.e. is weak) and the value R at the gel point is shifted — mainly due to cyclization — from 1.5 (random reaction without cyclization) to 1.1—1.2 which is in agreement with the value found experimentally.,The extent of ring formation in the l.p.g.f. theory is... 

Taylor, J. Deutsch, C. (1988). 19F-nuclear magnetic resonance Measurements of [02] and pH in biological systems. Biophys. J. 53,227-233. 

The existence of dynamical inhomogeneity also explains certain measurements for self-diffusion in ILs that have previously been attributed to ion pairing. Watanabe and co-workers [165-170] conducted studies on a range of ILs, comparing the molar conductivities calculated via PGSE-NMR (nuclear magnetic resonance) measurement against those obtained via electrochemical... 

Samyn, F., Bourbigot, S., Jama, C., Bellayer, S., Nazare, S., Hull, R., Castrovinci, A., and Camino, G. (2008) Crossed characterisation of polymer-layered silicate (PLS) nanocomposite morphology TEM, x-ray diffraction, rheology and solid-state nuclear magnetic resonance measurements, European Polymer Journal 44(6) 1642-1653. 

Miller B Gesner BD (1965) Conformation of cyclotriveratrylene by nuclear magnetic resonance measurements. Tetrahedron Lett 6 3351-3354... 

T. F. Havel and K. Wiithrich, Bull. Math. Biol., 182, 673 (1985). A Distance Geometry Program for Determining the Structures of Small Proteins and Other Macromolecules from Nuclear Magnetic Resonance Measurements of Intramolecular >H- H Proximities in Solution. 

To avoid these pitfalls two different techniques have recently been used to measure the intracellular pH in intact A. nigra blood cells97. One technique combines a measurement of the ratio of intracellular to extracellular concentration of amine with measurement of the extracellular pH to yield the intracellular pH. Another technique involves intracellular 31P-NMR (nuclear magnetic resonance) measurements. These methods led to a determination of pH7.39 0.10 for unfractionated cells, and 7.2 for the vanadocyte fraction. 

Nuclear magnetic resonance measurements show that the hydrogen atoms of NH3 rapidly exchange with those of water by the process... 

Because the mutarotation reaction in methyl sulfoxide is slow, nuclear magnetic resonance measurements in this solvent are par-... 

Nuclear magnetic resonance measurements show ftiat the 2,3-carbonate of D-lyxose has the furanose structure. Thus, the C-5 methylene protons show coupling, with a hydroxyl group, that is removed on addition of DjO, and so, the primary alcohol group is free. 

Composition of Sugar Solutions as Determined by Nuclear Magnetic Resonance Measurements ... 

Studies, by means of nuclear magnetic resonance measurements with pertrimethylsilyl ethers, of the behavior in solution of glycol-aldehyde and related substances formed by periodate oxidation gave striking results. Products formed under mild conditions showed that the original material was composed of dimers having p-dioxane structures products separated after complete mutarotation showed eight dimeric forms. ... 

Studies of the nonaqueous chemistry of xenon fluorides have also been initiated. Whereas xenon tetrafluoride is only sparingly soluble in hydrogen fluoride, xenon difluoride and xenon hexafluoride are very soluble indeed. Electrical conductivity, absorption and Raman spectroscopy, and nuclear magnetic resonance measurements have been employed in studying these solutions. The observations have been interpreted in terms of dissolution without appreciable dissociation for xenon difluoride and xenon tetrafluoride, and dissolution with extensive ionization for xenon hexafluoride. The extensive solubility and ionization of xenon hexafluoride contrast strikingly with the behavior of other hexafluorides (e.g., uranium hexafluoride). 

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