Pulsed field gradient 'inverse' HOESY applied to the isotope pairs H-1,P-31 and H-1,Li-7

For many heteronuclei, inverse (H-1 detected) heteronuclear Overhauser effect spectroscopy (HOESY) should be superior in theory over heteronucleus detected HOESY. In practice, strong t(1) noise artifacts completely cancel the benefits of inverse HOESY. However, pulsed field gradient (PFG)-enhanced inverse HOESY yields 2D spectra without any t, noise, consisting only of genuine cross peaks. The applicability of the method is demonstrated for thymolphthalein monophosphate hydrate using 3(1)P,H-1 PFG-HOESY and for n-butyllithium using Li-7,H-1 PFG-HOESY. In addition to the absence of t(1) noise, the merit of PFG-inverse HOESY is improved digital resolution in the usually crowded H-1 domain.