Proton magnetic resonance high resolution

High resolution proton magnetic resonance (PMR) spectra were recorded on a Perkin-Elmer R-10, 60-megacycle per second spectrometer fitted with a decoupling unit, a temperature probe, and a computer averaging attachment. Unless specified otherwise, spectra were obtained at 33.5°C. Chemical shifts in the high resolution NMR spectra are expressed as usual in parts per million relative to the protons of tetra-methylsilane at 10 p.p.m. (t scale). 

Figure 2. High resolution proton magnetic resonance spectra...

Figure 4. High resolution proton magnetic resonance spectra of lysolecithin and membrane fragments dispersed with lysolecithin in Dg0 (4)...

Resonance spectroscopies have an important role in determining electronic configurations and protein conformations. High resolution proton magnetic resonance may provide information on conformations in solu-... 

Figure 2 shows the proton magnetic resonance spectrum for moxalactam disodium. The spectrum was recorded on a 60 MHz instrument. An interpretation of the spectrum is presented in Table 2. The spectrum is complex, for the configuration at site a undergoes rapid equilibrium and the proton at a is exchanged with deuterium. At high resolution such as at 360 MHz every resonance is split except for that of HQ. 

Nicholson, J.K. Wilson, I.D. (1989). High resolution proton magnetic resonance spectroscopy of biological fluids. Progr. Nucl. Magn. Reson. Spectrosc. 21,449-501. 

For the label of specificity, criterion (2), we must appeal to a more limited area of study, to spectroscopic and diffraction data. The most definitive data are, no doubt, those which indicate atom positions in the molecular aggregate. Thus, x-ray diffraction, neutron diffraction, and certain nuclear resonance studies of solids can provide more or less direct evidence that there are H atoms which occupy positions of close approach (hence bonding distance) to two other atoms. Electron diffraction spectra can yield the same information for gaseous species. More easily obtained, however, are IR and Raman spectra, which reveal specific involvement of H atoms by peculiarities in their vibrationeil degrees of freedom in the molecular aggregate. Finally, high resolution proton magnetic resonance studies provide a sensitive index of the electronic environment of the H atoms. 

J.R. Ebdon, The characterization of diene polymers by high resolution proton magnetic resonance, in K. J. Ivin (Ed.), Structural Studies of Macromolecules by Spectroscopic Methods, John Wiley ns, London, 1976, p. 241. 

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