Polarization transfer between two scalar-coupled systems of arbitrary numbers of nuclei of arbitrary spins

A five-pulse sequence is studied theoretically, with experimental support, which can be used for the controllable transfer of nuclear magnetization from a system S ( l 2 ) n of the n nuclei of spin l 2 , to a different system I ( l 1 ) m . of m nuclei of spin l 1 , when the scalar coupling between the two systems can be characterized by a single constant. It is found that the polarization transfer signal is governed by a remarkably simple formula of universal validity for all values of l 1 , l 2 , n , and m , which is applicable for all initial conditions. Consequently, the sequence is called a universal polarization transfer (UPT) sequence. It is easily seen that three previous sequences, EPT, DEPT, and inverse-DEPT, which have been shown to be of considerable value for editing spectra, are merely special cases of the UPT sequence. Like these sequences, the UPT sequence should also prove to be a valuable tool for spectral editing, but with a much improved versatility.