Heteronuclear Multiple Quantum Coherence (and HSQC and Het-Cor) detect correlations between nuclei of two different types that are separated by one bond. In typical H-C HMQC, a 13 C spectrum is displa...Heteronuclear Multiple Quantum Coherence (and HSQC and Het-Cor) detect correlations between nuclei of two different types that are separated by one bond. In typical H-C HMQC, a 13 C spectrum is displayed on f2 axis and a 1 H spectrum on the f1 axis. “Cross-peaks” show which hydrogens are attached to which carbons. Typical tables show a letter assignment, the carbon shift, and then the shift of the hydrogen attached to that carbon.
Just as COSY spectra show which protons are coupled to each other, HMBC (and the related HMQC) give information about the relative relationships between protons and carbons in a structure. In an HMQC ...Just as COSY spectra show which protons are coupled to each other, HMBC (and the related HMQC) give information about the relative relationships between protons and carbons in a structure. In an HMQC spectrum, a 13 C spectrum is displayed on one axis and a 1 H spectrum is displayed on the other axis. Instead of seeing which carbon is directly attached to a hydrogen, we see which carbon is next to that one, so that we begin to see how the molecule connects.
