WINDOWLESS DIPOLAR RECOUPLING - THE DETECTION OF WEAK DIPOLAR COUPLINGS BETWEEN SPIN-1 2 NUCLEI WITH LARGE CHEMICAL-SHIFT ANISOTROPIES/

A new homonuclear dipolar recoupling technique is described which uses a sequence of phase-shifted, windowless irradiations applied synchron ously with sample spinning. Experiments performed on a series of doubl y labeled dicarboxylic acids, alanine-1,3-C-13(2), and 2'-deoxythymidi ne-4,6-C-13(2) demonstrate that this new windowless dipolar recoupling pulse sequence can accurately determine internuclear distances from p olycrystalline solids in cases where the coupled spins have large chem ical shift anisotropies and large differences in isotropic chemical sh ift.