To be published in the book "Methods in Bioinorganic Chemistry" Que, L., Jr. Ed.


Li-June Ming
Department of Chemistry and
Institute for Biomolecular Science
University of South Florida
Tampa, Florida 33620-5250

I. Basic NMR Principles for Paramagnetic Molecules
     A.  NMR transition
     B.  Chemical Shift
          1.  Fermi Contact interaction
          2.  Dipolar Interaction and Molecular Structure
     C.  Nuclear Relaxation
          1.  Dipolar Relaxation
          2.  Curie Relaxation
          3.  Contact Relaxation
          4.  Application of Nuclear Relaxation
     D.  NMR Properties of Multinuclear Paramagnetic Metal Centers
          1.  Magnetic Coupling
          2.  Chemical Shift
          3.  Electron and Nuclear Relaxations
II.  Practical Aspects:  Acquiring NMR Spectra of Paramagnetic Molecules
     A.  I just want a spectrum!
          1.  Spectral width—the window in the frequency domain
          2.  Radio Frequency Pulse
          3.  Free induction decay—the window in the time domain
          4.  Choice of window function
          5.  Baseline correction
          6.  Water suppression
          7.  Temperature control
          8.  Relaxation times
     B.  Nuclear Overhauser Effect
     C.  2D NMR
          1.  Bond Correlation (COSY, TOCSY, and HMQC)
          2.  Internuclear Distance (NOESY and ROESY)
          3.  Chemical Exchange (EXSY)
III.  Perspectives


Appendix I. Derivation of Fermi Contact Shift
Appendix II. Nuclear Overhauser Effect (NOE)
      A.  Steady-State NOE
      B.  Transient NOE and NOESY
      C.  Rotating Frame NOE
Appendix III. Chemical Exchange

I.  Basic NMR Principles for Paramagnetic Molecules
    Nuclear magnetic resonance (NMR), a versatile tool for the study of molecular structure and dynamics, has been used to solve problems in bioinorganic chemistry, despite the fact that many systems of interest contain a paramagnetic metal center.  The basic principles of NMR in diamagnetic species can be applied, in principle, to the understanding of the NMR properties of paramagnetic species by taking into account the significant influence of electron magnetic moment (which is 658 times larger than that of the proton).  The unpaired electrons in these paramagnetic molecules present some challenges and require some adaptation of approaches used for NMR studies of diamagnetic molecules.  Nevertheless useful information can be extracted from the NMR spectra of paramagnetic metal complexes and metalloproteins.  This chapter is intended to serve as an illustration how NMR can be applied to the investigation of paramagnetic systems.
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