X-nucleus Heteronuclear Correlation (HETCOR)

The Heteronuclear chemical shift Correlation experiment (HETCOR) is similar to the COSY experiment with the exception that it concerns two different nuclei. This method is generally used to correlate proton resonances with those of other directly bonded nuclei. The axes of the contour plot represent the proton and other X-nucleus chemical shift ranges and signals occur at coordinates corresponding to the shifts of the bonded pairs of nuclei. In this experiment, X-nucleus signals are detected instead of those of the protons. Modification of the delays in HETCOR can provide long range coupling information (couplings between proton and X-nucleus through 2-3 bonds).

In common multidimensional NMR experiments for studies of biological macromolecules in solution, magnetization transfers via spin–spin couplings [insensitive nuclei enhanced by polarization transfer (INEPT)] are key elements of the pulse schemes.

Sample: Dow 704 Diffusion Pump Fluid                  Concentration: neat

• 1D proton spectrum

• data acquired and processed in about 11 seconds

• near integer values for the integrals

• ²⁹Si  XPT spectrum (top)

• data acquired using the same parameters as 1D experiment

• data acquired and processed in < three  minutes

• S/N = 74.0 using 32 scans
   

• ²⁹Si  1-D spectrum (bottom)
• data acquired and processed in < three  minutes

• S/N = 29.6 using 32 scans

• ²⁹Si HETCOR Spectrum

• data acquired and processed in less than ten minutes.

• Experimental value of J_SiH ~20 Hz