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Sibrina Collins, The Charles H. Wright of Museum of African American History
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Joined: 01/17/2009 - 10:29pm

Paramagnetic Metal Complexes and NMR

Dear Colleagues,

I hope all is well. I had a question about NMR and paramagnetic metal complexes. I understand that paramagnetic metal complexes often goes significant broadening and loss of splitting with NMR peaks. But, what is happening at the molecular level that actually causes the broadening of the peaks? I don't have a good understanding of this concept.

Adam R. Johnson, Harvey Mudd College
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Joined: 11/17/2007 - 10:55am
My understanding is that the electron spin provides a very low energy pathway for nuclear relaxation.  The rapid relaxation causes you to observe all of the instantaneous signals from all of the possible orientations of the molecule in solution instead of the averaged signal you would observe for a long relaxation event.