The DCIF NOE Page

The Nuclear Overhauser Effect

	Introduction:
	NOE (Nuclear Overhauser Effect) difference spectroscopy provide an easy straightforward method in determining many of the problems involved with stereochemical assignment. These problems, such as differentiating between E and Z double bonds or between endo and exo groups in bicyclic compounds, cannot be solved simply by using spin coupling constants if no suitable protons are available. In the NOE experiment, irradiation of one group of protons causes a change in intensity signals, which is proportional to the inverse 6^th power of the distance between the spins.

	References:
	*D. Neuhaus and M. Williamson, The Nuclear Overhauser Effect, VCH, Weinheim, 1989.* *J. K. M. Sanders and B. K. Hunter, Modern NMR Spectroscopy, 2nd Edition, Oxford University Press, Oxford, 1993, Ch. 6.*