Pure shift 1H NMR, a robust method for revealing heteronuclear couplings in complex spectra

We investigate the utility of pure shift techniques in revealing heteronuclear couplings in complex H-1 NMR spectra. The results show the technique to be a robust and valuable complement to the standard H-1 spectrum, and an attractive alternative to heteronuclear decoupling since the technique is independent of the size of the heteronuclear couplings and the chemical shift range(s) of the heteronuclei involved. We highlight some possible artefacts, and the subtle effects due to the presence of C-13 nuclei in otherwise symmetric molecules when bilinear rotational decoupling (BIRD) elements are present in the pulse sequence.