Spin-state selection filters for the measurement of heteronuclear one-bond coupling constants.

Novel alpha/beta-half-filter elements are proposed for the separation of the high-field and low-field component of 1JHC and 1JHN splittings into different subspectra. The alpha/beta-half-filter elements are of the same duration as the S3CT pulse sequence element and, like this, are less sensitive to cross talk between different subspectra than the original shorter alpha/beta-half-filters. The filter elements are demonstrated with the measurement of 1JHC coupling constants of C alpha H groups in 2D and 3D experiments and the subspectral editing of the four different multiplet components observed in two-dimensional alpha/beta-HSQC-alpha/beta spectra recorded without heteronuclear decoupling in either dimension.