Magnetic Inequivalence

Magnetic Inequivalence can occur within sets of chemically equivalent nuclei

• For two nuclei that are chemically equivalent to be magnetically equivalent, they must couple in the same fashion to all other magnetic nuclei in the molecule.
• Nuclei are magnetically inequivalent to each other if they couple differently to at least one other magnetic nucleus in the molecule.
  
  Viewing tools:
  
  The Example: The following pair of protons are chemically equivalent because they are equivalent through a C₂ operation
  If we differentiate between the two H_a protons and label them
  And use to test H_a1 and H_a2 against
  We ask the following question:
  If the two H_a protons are magnetically equivalent, they will each couple to H_b in the same fashion.
  This is clearly not the case: H_a1 couples to H_b in a geminal (adjacent to each other on the same carbon atom: H_a1 - C - H_b) relationship
  However H_a2 couples to H_b in a viscinal relationship (H_a2- C - C - H_b)
  
  We conclude that H_a1 and H_a2 are magnetically inequivalent
  and by convention we label them H_a and H_a'
  
  Your mission: Test to see if the
  
  1. protons are magnetically equivalent to each other
  2. And if within the H_c subset and the H_d subset of protons you expect to see magnetic inequivalence
  
  Reference: CCDC Structure HARBAD; R.J. Geve, L.M. Englehardt, J. M. Harrowfield
  A.M. Sargenson, A. H. White Aust. J. Chem. Vol 46, 1993, p. 1485