Nuclear magnetic resonance spectroscopy signal averaging

Nuclear magnetic resonance spectroscopy gives precise information on complexation in solution. Equilibrium is rapidly established on an NMR time scale, hence only an average spectrum is observed and it is difficult to determine the spectrum of a pure complex. When complexation of a sugar or polyol with a diamagnetic ion occurs, all of the signals shift downfield. Equation (11.1) allows the variation of the shielding constant Ao- of the proton to be calculated when the nucleus is subjected to an electric field E whose projection on the C-H bond is... 

Nuclear Magnetic Resonance (NMR) Spectroscopy This techni-que85-89 utilizes solid-state NMR to analyze nanoscale dispersion for the overall sample. The iron in the montmorillonite structure facilitates the relaxation of nearby protons, which provides information on the dispersion of the clay in the polymer matrix. In the cases reported, a signal in the polymer is identified and its relaxation time (fy) is measured the relaxation time depends on how close the proton is to a paramagnetic iron atom. On average, the protons of the polymers will be closer to the iron in the clay in a well-exfoliated system and... 

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