Fields of Research, NMR of Oriented Molecules

Dipole-Dipole Couplings

  • Origin of Direct Couplings
  • Theory of Dipole-Dipole Interactions
  • Calculations of Dij
  • Determination Methods of Dij
    • from different temperature spectra
    from different concentration spectra
    by use of molecular symmetry
  • Comparison of Methods
  • Quadrupolar Couplings Data
    • Deuterium
    Nitrogen-14
    Boron-10, boron-11
  • Comparison with Theory
  • Separation of Isotropic and Anisotropic Interaction
  • ?
  • ?
    		•

    Origin of Dipole-Dipole Couplings

    Dipole-Dipole Couplings

    The direct dipolar coupling is defined as follows
    Dij=-KijSij/rij3
    where
    Kij=-
    depends upon the gyromagnetic ratios of the nuclei i and j.
    Kij may be split into the individual nuclear contributions Kij=kikj. For Sij=1 and rij=0.1mm, the ks and Kij are summarized in Table.
    Table 1. The value of ki=?? for various nuclei.
    Nucleus kij(kHz1/2pm3/2) Nucleus
    1H 346.506 Nucleus
    2D 53.190 Nucleus
    13C 87.123 Nucleus
    14N 25.034 Nucleus
    15N -35.118 Nucleus
    19F 325.989 Nucleus
    31P 140.276 Nucleus
    57Fe 11.24 Nucleus
    107Ag 14.01 Nucleus
    Table 2. Relative value of direct couplings for Sij=1 and rij=0.1nm
    Nuclear Pair Kij(MHz pm3) Dij
    1H 1H 120067 Nucleus
    1H 2D 18431 Nucleus
    1H 13C 30188 Nucleus
    1H 15N -12169 Nucleus
    1H 31P 48606 Nucleus
    1H 57Fe 3895 Nucleus
    1H 107Ag 4855 Nucleus
    2D 2D 2829 Nucleus
    13C 13C 30188 Nucleus

    Return to "NMR of Oriented Molecules"

    Last Update: April 22th, 1997
    By: Alexan Shahatuni (msrc@moon.yerphi.am)