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 π 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 13C and a 1H 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.