The selective 1D ROESY experiment permit to obtain 1D ROESY spectra from which accurate ROE enhancements can be easily extracted and analyzed.Similar information can be extracted from a selective 1D NOESY experiment. Improved results are obtained from the gradient-based selective ge-1D ROESY experiment.

Easy implementation on AVANCE spectrometers with selective excitation using shaped pulses.

The selective ge-1D ROESY experiment ( 84JACS811 ) consists of three parts:

Selective excitationof the selected resonance.

Mixing period that in its basic form consists of a low-power continuous-wave irradiation block for in-phase polarization transfer to other spins via NOE in the transverse plane (see ROESY Block, T-ROESY Block, and Off-resonance ROESY Block).

Proton detection as usual.

Similar modified approaches have been reported:

• Selective excitation using a gaussian shape ( 86JMR106-70 ), half-gaussian shape ( 89JMR1-85 ), a DANTE ( 91JACS363 , 92JMR185-96 and 96CONC119 ) and DANTE-z ( 90JMR221-90 ) have also been used.
• Use of pulsed-field-gradients (see selective ge-1D ROESY experiment).
• 1D ROESY experiments can also be applied on overlapped resonances by applying some pseudo-3D experiment as, for instance, the selective 1D TOCSY-ROESY ( 92JMR185-96 , 93JMRB107-102 , and 95JMRB186-107 ) and selective 1D RELAY-ROESY ( 93JB367 ) experiments.

The selective 1D ROESY experiment can be run with minor changes from a predefined parameter set. Detailed description of the experiment can be found in the original publication ( 86JMR106-70 ). Two important parameters to consider are:

Selectivity of the selective excitation pulse: the user must define the shape, the duration and the power level needed for a defined excitation profile.

Optimization of the ROESY mixing time as a function of the sample under study.

For further details on practical implementation of selective 1D ROESY experiments on AVANCE spectrometers see Tutorial: selective 1D ROESY experiment.

In selective 1D ROESY spectra, through-space NOE connectivities from a selected spin can be trace-out in a very simple way. Undesired TOCSY peaks between J-coupled spins can be present. The use of alternative mixing schemes can improve the final result. An example is the use of the T-ROESY mixing consisting of a train of phase-inverted 180º pulses.

An excellent review describing selective excitation in 1D and multidimensional NMR experiments was published ( 91MRC527 ).