Spin Decoupling Homonuclear, 1-D

This is probably the oldest of the instrumental techniques but it is still very useful even today. It enables the user to determine which signals in a spectrum are spin-coupled to each other. It can be an extremely useful aid to assignment and can in some cases, even be used to facilitate conformational studies. 

In practise, a powerful secondary radio frequency is centred on the signal of interest whilst the spectrum is reacquired. This causes the irradiated proton(s) to become saturated which effectively destroys any spin coupling from the protons giving rise to this signal. By comparing the resultant spectrum with its un-decoupled counterpart, it should be easy to work out which protons couple to the signal of interest. This is demonstrated in the following example. Note that this technique is applicable to both FT 

Essential Practical NMR for Organic Chemistry S. A. Richards and J. C. Hollerton 

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