Nuclear magnetic resonance spectroscopy shielded proton

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 spectroscopy is such a powerful tool for stracture determination because protons in different environments experience different degrees of shielding and have different chemical shifts. In compounds of the type CH3X, for example, the shielding of the methyl protons increases as X becomes less electronegative. Inas-... 

JG Oldenziel, NJ Trappeniers. High resolution nuclear magnetic resonance spectroscopy in liquids and gases at pressures up to 2500 bar, HI. Density dependence of the proton magnetic shielding constants in the polar liquids methanol and ethanol. Physica A 83 161-172, 1976. 

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