Nuclear magnetic resonance measurements, solution

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. 

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). 

Relative basicities of cyclic ethers have been determined by several methods [146,152,153]. By one method Wirth and Slick [152] obtained relative basicities by infrared from a study of the equilibrium constant at 27°C for the distribution of BF3 between two ethers in benzene solution. In another case, Yamashita et al. [146], following a method similar to that of Gordy and Stanford [154], measured the infrared absorption spectra of cyclic ethers in the presence of 0.1 mole r methanol-d. They then calculated the basicity of the monomers from the shift value of O—D stretching band. Nuclear magnetic resonance measurements of the equilibrium constant between BF3. Et O and the cyclic ether were also used [146]. 

The effect of the solvent on the proportions of the anomers for sugars in solution has also been studied by Perlin and coworkers by nuclear magnetic resonance measurements (see p. 46, Part I). These workers suggested that, in aqueous solutions of D-fructose, the pyranose form is stabilized by hydrogen-bonding with water molecules. Additional data supplied by Perlin are given in Table XVII. 

Smith, B. C., Chou, L. C., and Zakin, J. L., Measurement of the orientational binding of counterions by nuclear magnetic resonance measurements to predict drag reduction in cationic surfactant micelle solutions, J. RheoL, 38, 73-83 (1994). 

In many cases, the equilibrium constants can also be determined by nuclear magnetic resonance measurements. For example, in analogy to Equation (22-69), the chemical shift of the acceptor protons in the uncom-plexed state (6 ), in the pure CT complex (6ct), and for the corresponding mixture concentration (6ohs) is given for ideal solutions as... 

In a nuclear magnetic resonance measurement in solution, the direct dipolar interaction Xo actually disappears because, due to rapid molecular motion, the interspin (internuclear) vectors are rapidly space-averaged within the time-scale of a measurement. Hence, the terms Xs and Xj are detectable as sharp lines or splittings in a high-resolution spectrum of H or and they can be related to detailed molecular structure or conformation of the substance investigated. In a solid, on the contrary, the directions of the internuclear vectors are stationary even if they are distributed randomly in space. Then, X gives a very wide linewidth to the zeroth-order absorption line and completely masks all lines due to Xs and Xj. 

Glowinkowski S, Gisser DJ, Ediger MD (1990) C-13 nuclear-magnetic-resonance measurements of local segmental dynamics of polyisoprene in dilute-solution— nonlinear viscosity dependence. Macromolecules 23(14) 3520-3530. doi 10.1021/ma00216a021... 

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... 

Iwahashi, M. Hayashi, Y. Hachiya, N. Matsuzawa, H. Kobayashi, H., Self-association of octan-l-ol in the pure liquid state and in decane solutions as observed by viscosity, selfdiffusion, nuclear magnetic resonance and near-infrared spectroscopy measurements, J. Chem. Soc. Faraday Trans. 89, 707-712 (1993). 

---