ANALYSIS OF COSY CROSS PEAKS BY DECONVOLUTION OF THE ACTIVE SPLITTINGS

Various numerical techniques for alleviating crowding in two-dimensional NMR correlation spectra are investigated with a view to facilitating the measurement of spin-spin coupling constants. The following strategy for the analysis of cross sections through COSY cross peaks is developed: The active coupling constant is determined by J doubling (McIntyre and Freeman, J. Magn. Reson.96, 425, 1992). The active splitting is then removed (J deconvolution) by the maximum-entropy method. Estimates of the passive coupling constants are next obtained from the deconvolved spectrum. Finally, the values of all coupling constants are refined, if necessary, by model fitting to the original spectrum. This approach is shown to be successful for complex, congested cross peaks, whose multiplet structures are far from obvious. © 1993 by Academic Press, Inc.