Skip To Content

Logic Puzzle #4: Correlating to the Correct 13C Signal … Solution

July 5, 2010
by Arvin Moser, Team Manager, Application Scientists, ACD/Labs

The goal of this puzzle is to resolve the ambiguity exhibited within a 2D NMR spectrum and thus provide the correct signal correlation. Although this exercise may seem a trivial one, it is important to go over the rationale when correlating one signal to another.

For the following 1H-13C HSQC-DEPT NMR spectrum it is important to note that the 2 correlations are phased positively (red) and thus represent either a CH or CH3 group and not a CH2. Next, one must ensure that the carbons at 61.5 and 62.2 ppm are 1 carbon each. Although this detail is not certain, we will assume this to be the case. Finally, it is best to start with the easy part first. The 1H signal at 3.50 ppm is correlated to the 13C signal at 62.2 ppm. By process of elimination, one can conclude that the 1H signal at 2.73 ppm is correlated to the 13C signal at 61.5 ppm (see this post for more details).

Logic#4OnHSQCAssignment_Jun282010

 

Ambiguity in correlating 1D and 2D NMR data can routinely occur. Some extra steps that can help avoid this issue are re-aligning the data and/or re-processing the ‘raw’ data with different parameters.

 

 


Join our newsletter!

Keep up-to-date with our quarterly newsletter that brings you the latest educational webinars, resources, tips, and tricks.

This field is for validation purposes and should be left unchanged.

Comments

Your email address will not be published. Required fields are marked *

Join our newsletter!

Keep up-to-date with our quarterly newsletter that brings you the latest educational webinars, resources, tips, and tricks.

This field is for validation purposes and should be left unchanged.