Through-bond interactions with other nuclei

Through-bond interactions with other nuclei... 

A ID nuclear overhauser experiment (NOE) (Gaggelli and Valensin, 1993) is an important and valuable variation on the simple ID NMR experiment that provides spatial relationship between each nucleus in the structure. Coupling constants observed in a ID H NMR spectra provide connectivity for directly bonded nuclei whereas, a ID NOE experiment identifies nuclei that are close in space (<6A). Briefly, a ID NOE experiment requires the addition of a second lowpowered rf pulse that selectively saturates a specific peak in the NMR spectrum. The saturated peak becomes a null in the spectrum and any other nuclei that are coupled through space via a dipole-dipole interaction to the saturated peak will experience a change in peak intensity. A ID NOE experiment requires collecting two NMR spectra, with and without saturation, to monitor changes in peak intensity. A summary of common ID NMR experiments and their applications are listed in Table 12.6. 

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