An Overview of the HETCOR Experiment

We can thus assign carbon atoms on the basis of known proton chemical shifts, or we can assign protons on the basis of known carbon chanical shifts. For example, we might have a crowded proton spectrum but a carbon spectrum that is well resolved (or vice versa). This approach makes the 

HETCOR experiment particularly useful in the interpretation of the spectra of large, complex molecules. An even more powerful technique is to use results from both the HETCOR and COSY experiments together. 

As we did in the COSY experiment, we want to allow the magnetization vectors of the protons to process according to different rates, as dictated by their chemical shifts. Therefore, we apply a 90° pulse to the protons, then include an evolution time (ti). This pulse tips the bulk magnetization vector into the Z F plane. During the evolution period, the proton spins process at a rate determined by their chemical shifts and the coupling to other nuclei (both protons and carbons). Protons bound to atoms experience not 

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