The selective 1D INADEQUATE (SELINQUATE) experiment is the selective version of the 1D INADEQUATE experiment. This experiment allows to measure carbon-carbon coupling constants and to assign ¹³C-¹³C connectivities.

Easy implementation on AVANCE spectrometers with selective excitation using shaped pulses. However, the signals due to ¹³C-¹³C couplings are 1/200 the intensity of the signal from a single ¹³C. For this reason, the INADEQUATE experiment has a very low sensitivity and high sample concentrations are usually required

The selective ge-1D INADEQUATE pulse sequence can easily derived of the  1D INADEQUATE pulse sequence by converting the last ¹³C pulse of the sequence selective for a selected ¹³C resonance ( 88ANG1196 ). The sequence is based on the creaction of homonuclear multiple-quantum coherences.

Similar modified approaches have been reported:
 
• Using a DANTE pulse train ( 96CONC119 ) as a selective excitation scheme.
• Improved sensitivity by using multiple-selective excitation ( 92MRC1247 and 93JMRA42-102 ).
• Selective version using a heteronuclear-chemical-shift-filter to measure ¹J(CC) ( 87MRC798 and 92MRC68 ). It has also been used to measure ⁿJ(CC) ( 91MRC561 ). Improved results can be obtained from gradient-enhanced experiments as, for instance, the GRECCO experiment.
• Selective 1D DEPT-INADEQUATE expriment ( 91MRC561 ).
• A related selective 1D ¹³C COSY experiment has also been applied to ¹³C-labeled compounds ( 90MRC149 ).

The selective 1D INADEQUATE 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 J-coupling evolution delay as a function of 1/(2*J(CC)), in order to get the anti-phase magnetization of the selected carbon suitable for transfer polarization.

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

The selective INADEQUATE spectrum only shows the ¹³C nuclei directly and/or long-range J-coupled to the selected ¹³C nucleus. These signals appear as anti-phase doublets from which ¹J(CC) and ⁿJ(CC) can be measured.

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