A family of 1D methods are described using a combination of HSQC-type (or HMQC-type) heteronuclear preparation blocks with homonuclear transfer schemes, such as COSY, n-step RELAY, TOCSY, ROESY, and NOESY, in order to reveal direct or long-range heteronuclear connectivities, as well as relayed (scalar or dipolar) interproton connectivities. Two essential features of this approach are: (i) selective carbon excitation simultaneous with a proton spin-lock period, to avoid dephasing during the selective carbon pulse length; and (ii) coherence selection by pulsed field gradients of the desired coherences, to improve time performance and get cleaner spectra devoid of artifacts usually produced by imperfect subtraction when using phase-cycling methods. The resulting high-quality 1D spectra allow the easy extraction of accurate values for the relevant homo- and heteronuclear coupling constants. This approach is particularly useful when strongly overlapped proton systems prevent the application of conventional 1D experiments based on proton-selective excitation. Results are presented for sucrose. © 1995 Academic Press, Inc.
|Journal||Journal of Magnetic Resonance, Series A|
|Publication status||Published - 1 Jan 1995|