HAT HMBC: a hybrid of H2BC and HMBC overcoming shortcomings of both

A new 2D NMR experiment, HAT HMBC, that is a hybrid of H2BC and HMBC aims at establishing two-bond correlations absent in H2BC spectra because of vanishing (3)J(HH) coupling constants. The basic idea is to create an additional pi phase difference in the multiplet structure in HMBC peaks with respect to the (n+1)J(HH) coupling constant between the proton(s) attached to a (13)C and a (1)H separated by n bonds. Thus HMBC peaks associated with small J(HH) will be the most attenuated in a HAT HMBC spectrum in comparison to a regular HMBC spectrum, i.e. peaks associated with (n+1)J(HH) and (n)J(CH) will for n>2 usually be strongly attenuated. The HAT HMBC pulse sequences contain the same number of pulses as regular HMBC and are only a few milliseconds longer.