Identification of Two Isomers from an Organic Mixture by Double-Stimulated-Echo NMR and Construction of the DOSY Spectra by the Regularized Resolvent Transform Method

DOSY‐NMR experiments were used to characterize two structural isomers that have different shapes, but identical mass fragmentation patterns, from an organic mixture. It is shown that the spherical molecule diffuses faster than the ellipsoidal one. This distinct behaviour is tentatively explained in terms of microfriction effects from the solvent. Finally, to increase the resolution and efficiency of the 2D DOSY map construction, the data were treated with the regularized resolvent transform method. This method provides good separation for mildly overlapped peaks and requires fewer points than other classical DOSY processing methods. Shape sorter: Two structural isomers with different shapes but identical mass fragmentation patterns can be characterized by DOSY‐NMR spectroscopy, with data processing by the regularized resolvent transform method (iRRT; see picture). The ellipsoidal isomer (green) diffuses more slowly than the quasi‐spherical one (red), in agreement with the Stokes–Einstein theory.