2D NMR: HC Correlation




Two-dimensional HSQC (Heteronuclear Single Quantum Coherence) proton-carbon COSY (COrrelation SpectroscopY) experiments allow you to determine the connectivity of a molecule by determining which protons are correlated with which carbons.  In these examples, “correlated” means directly bonded.

HSQCGP is an inverse-detection experiment observing protons while utilizing magnetic gradients along the bore of the sample. There are many advantages to this approach; this experiment will yield superior signal-to-noise ratios in shorter times than traditional experiments.

In the spectrum below, the proton spectrum appears across the top, while the “imputed” carbon spectrum appears along the left-hand side. Peaks within the grid arise from correlations between a given proton and carbon signal. For example, the methyl protons seen at 1 ppm on the proton axis are coupled to the methyl carbon at 16 ppm on the carbon axis.

Spectrum of Ethyl Benzene:

(Click on the spectrum to obtain a magnified view.)