Improved multiplicity-editing of HMBC NMR spectra
Andrew J Benie1, Ole W Sørensen
1Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500 Valby, Denmark.
Abstract:
A new improved multiplicity-edited HMBC experiment is introduced that leads to better J cross-talk suppression in the even (i.e. C + CH2 groups) and odd (i.e. CH + CH3 groups) subspectra. By combining data recorded with three different pulse sequences J cross-talk becomes a second-order effect in Delta1J, i.e. the deviation of an actual 1J coupling constant from the value 1J0 used in setting delays tau = (1J0)(-1/2), which is adequate for most applications. As for the original multiplicity-edited HMBC experiment, the improved experiment can be performed with a single excitation delay or implemented in a broadband version similar to broadband HMBC.
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