Disentangling complex mixtures of compounds with near-identical 1H and 13C NMR spectra using pure shift NMR spectroscopy

Abstract

The thorough analysis of highly complex NMR spectra using pure shift NMR experiments is described. The enhanced spectral resolution obtained from modern 2D HOBS experiments incorporating spectral aliasing in the 13C indirect dimension enables the distinction of similar compounds exhibiting near-identical 1H and 13C NMR spectra. It is shown that a complete set of extremely small Δδ(1H) and Δδ(13C) values, even below the natural line width (1 and 5 ppb, respectively), can be simultaneously determined and assigned.