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 (1)J(HC) and (1)J(HN) splittings into different subspectra. The alpha/beta-half-filter elements are of the same duration as the (SCT)-C-3 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 (1)J(HC) coupling constants of (CH)-H-alpha 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.