NUCLEAR MAGNETIC SHIELDING DENSITY

Molecular charge density maps have been widely used to characterize the bonding in a molecule, the facilitation or opposition of nuclear motion or the changes which occur in hydrogen bonding, and other intermolecular effects. In a similar fashion, nuclear magnetic shielding densities may be useful in providing a physical interpretation of gross differences between molecules in magnitudes of the nuclear shielding constants, their dependence on nuclear configuration, as well as more subtle differences or shifts which are observed in NMR. We explore the use of shielding density difference maps for the interpretation of chemical shifts which occur upon molecule formation. This concept appears to have great promise in providing a physical basis for interpretation of NMR shifts. © 1979 American Chemical Society.