ENHANCEMENT OF THE NMR-SPECTRA OF INSENSITIVE NUCLEI USING PENDANT WITH LONG-RANGE COUPLING-CONSTANTS

The recently reported NMR pulse sequence PENDANT. that enables-the sim ultaneous detection of all insensitive nuclei (S), of a given type, in a compound and the enhancement of the signals arising from those nucl ei coupled to sensitive nuclei (I). is developed further. The sequence has been modified to enable the detection of spin-spin coupled multip lets without phase distortions. Its normal form, for use with short ra nge coupling constants has been adapted to facilitate the S-N enhancem ent of insensitive nuclei through the use of long range coupling const ants. The developments are illustrated by reference to {H-1}-C-13 and {H-1}-Si-29 spectra.