Recently Glenn Facey posted a nice example of resolution enhancement by decoupling 14N during 1H acquisition on the Ottawa NMR Blog.
Here’s another example, the 1H-{14N} (upper trace) and 1H (lower trace) spectra of formamide in DMSO-d6:
The restricted rotation about the C-N bond means that the two hydrogen atoms of the amide are in different environments with different chemical shifts (at 30°C). Both are broadened by the proximity of 14N and exchange. Decoupling 14N during acquisition removes the 14N effect and allows measurement of the H-H coupling constants between the formyl proton and the two different amide protons (notice the splitting in the signal of the formyl proton). The NH signals are still broad even with 14N decoupling because the exchange process between NH environments is unaffected by {14N}.
craigdgrimmer 