Application of proton polarization transfer to a high-spin nucleus, germanium-73
Abstract
The application of proton polarization transfer (p.t.)via insensitive nuclear enhancement by p.t. pulse sequences to germanium-73 n.m.r is investigated for a variety of compounds. Despite the relatively short 73Ge relaxation times of this quadrupolar nucleus, and long, inhomogeneous radio frequency pulses, this method gives significant p.t. enhancements from compounds with hydrogen, methyl, or ethyl groups bonded to germanium. Signal enhancements range from 2- to 6-fold for proton-decoupled spectra and up to 20-fold for coupled spectra. Reductions in the time required to obtain a 73Ge spectrum range from 3- to 10-fold for a decoupled spectrum to 100-fold for a coupled spectrum. Applications of the technique are illustrated.