NMR at HMC
HMC Chemistry Department
2D NMR: HC Correlation
2D NMR: HC Correlation
Experiment:
HMCHCCOSW
HMCINV4GSSW
Discussion:
Two-dimensional 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.
The two experiments listed above differ in their means of detection. HMCHCCOSW detects 13C, whereas HMCINV4GSSW is an inverse-detection experiment observing protons while utilizing magnetic gradients along the bore of the sample. There are many advantages to this approach; the later experiment will yield superior signal-to-noise ratios in shorter times than the former experiment.
In the spectrum below, the proton spectrum appears across the top, while the 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:
