The ge-2D Multiplicity-edited ADEQUATE (Adequate sensitivity DoublE-QUAnTum spEctroscopy) experiment is a simple variant of the ADEQUATE experiment that affords the carbon multiplicity information as an extra bonus with similar sensitivity ratios.

Implementation on any AVANCE spectrometer equipped with pulsed field gradients (PFGs) and inverse probehead.

Carbon multiplicity can be also included in ADEQUATE experiments allowing the the exact skeleton structure of C-C systems to be extracted. Thus, from a multiplicity-edited 1,1-ADEQUATE spectrum, CH-CH and C-CH2 correlations have positive intensity whereas C-CH and CH-CH2 have negative intensity ( 98MRC715 ). Recently,an improved multiplicity-edited ADEQUATE sequence has been reported for this same purpose ( 04JMR123-166 ). The basic building block is: and the implementation in the conventional 1,1-ADEQUATE and refocused ADEQUATE is as follows:

The ge-2D ADEQUATE experiment can be recorded in routine and automation modes. Minor changes are required if a predefined parameter set is available. Important parameters are:

• The user must define the strength, the duration, and the shape of the gradients and the recovery delay.
• Proton and carbon evolution periods must be optimized.
• Number of scans as a function of samples concentration.

More details on practical implementation of ge-2D ADEQUATE experiments on AVANCE spectrometers can be found in

Tutorials: 2D gradient-based inverse experiments

The ADEQUATE spectrum correlates double quantum frequencies of the J-coupled C-C heteronucleus (F1 dimension) and proton chemical shifts (F2 dimension) via the successive J(CH) and J(CC) mechanisms. The effective suppression of unwanted 1H-12C magnetization by means of PFGs allows to obtain ultra-clean 2D spectra from which clear analysis can be done. Full bonding topologies can be extracted from these experiments.

In the case of conventional edited-ADEQUATE the multiplet pattern is:

On the other hand, in the refocused version, the analysis is different:

Related experiments:

2D Inverse gradient-enhanced experiments