I-spin n-quantum coherences in InS spin systems employed for E.COSY-type measurement of heteronuclear long-range coupling constants in NMR

We propose a general NMR pulse scheme for conversion of I-spin multiple-quantum coherence to I-spin single-quantum coherence in InS spin 12 systems that exploit large single-bond JIS coupling constants and employs rf pulses on the S spin which, however, is fully restored to its original state after the process. This is essential for application in multidimensional pulse experiments for E.COSY-type extraction of heteronuclear long-range coupling constants. The new pulse scheme is derived in a systematic way, by first considering an energy level diagram in which selective rotations are required to achieve the desired effect and then deriving nonselective pulse sequences that produce the same effect.