DISTINGUISHING 2-BOND AND 3-BOND C-13-H-1 CONNECTIVITIES BY 2D BIRD-DECOUPLED DIFFERENCE SPECTRA - THE DODO PULSE

A modified BIRD pulse, called the DODO pulse, was developed and incorp orated into one version of the FLOCK sequence. Addition of the two-dim ensional spectra obtained with this modified sequence and with the unm odified FLOCK sequence produces a normal indirectly bonded C-13-H-1 sh ift correlation spectrum. Subtraction of one spectrum from the other g enerates a difference spectrum which allows a clear distinction betwee n two-bond and three-bond C-13-H-1 connectivities among protonated car bons.