DOI: 10.1063/1.1744645 ISSN:
Calculation of Nuclear Magnetic Resonance Spectra of Aromatic Hydrocarbons
C. E. Johnson, F. A. Bovey- Physical and Theoretical Chemistry
- General Physics and Astronomy
The free electron model of Pauling is used to calculate the magnetic field around a benzene ring which is rotating rapidly about all axes in an external magnetic field. It is assumed that the π electrons precess in two circular paths, one on each side of the ring, equal in radius to the C–C distance in the benzene ring. The separation of these rings is taken as 1.28 A, which gives a calculated value for the nuclear magnetic resonance shielding value for benzene protons equal to the observed value. The field thus calculated is employed to predict shielding values for other aromatic compounds. Agreement with experiment is in general good, but there are some exceptions.