A simple and sensitive one-dimensional NMR technique for correlation of proton and carbon chemical shifts

A slightly modified version of the well-known selective population transfer (SPT) experiment (1-5) is described that is very easy to use and correlates ‘H and 13C or 15N chemical shifts with high sensitivity and accuracy. Although the changes with the original experiment (I) are relatively small, they are helpful for reliable and convenient use of the experiment. Twodimensional heteronuclear chemical-shift correlation (6-10) has proven to be a powerful tool for the assignment of 13C spectra. However, in practice, sensitivity of the two-dimensional experiment is at best about a factor of three lower (10) than that of a regular protondecoupled 13C spectrum. Moreover, large data matrices are usually required in this type of 2D experiment and minimum data acquisition plus processing time often exceeds one hour. Recently, there has been a renewed interest in alternative one-dimensional experiments that provide essentially the same information as the 2D experiment by transfer of magnetization from a preselected proton to its coupled 13C nucleus (11-14) or by suppression of the resonance of a 13C that is coupled to a preselecte