Chemical Shift and Integration in the NMR

Reading: pp. 440-459 in McMurry text (7th edition).

For this experiment, we will be examining approximately 10 compounds by 13C and/or 1H NMR. This week we will be focusing on the chemical shift of the signals in the NMR and the reasons for the chemical shift. We will also use 1H NMR to determine the number of hydrogens that give rise to a signal. The compounds we will be examining are shown below, grouped based on the type of NMR (carbon or proton) we will be using. We may study a few of the compounds by both types of NMR. As a pre-lab exercise, determine the number of carbon signals in each compound in the first set. Then determine the number of proton signals in the second set. The easiest way to show the number of different signals is to label the different carbons or hydrogens with lower case letters. For example, 1-bromohexane has six carbon signals and the structure has been labeled a-f. If the carbons/hydrogens are the same, they get the same letter.

Compounds for 13C NMR

Compounds for 1H NMR

Lab Report

Redraw the first set of compounds shown below on another sheet of paper. Perform the following for each compound:

  1. State how many signals will be seen in the 13C NMR.
  2. Label the carbons in the structure with lower case letters (a, b, c, etc.) corresponding to the number of signals in the NMR spectrum. In other words, if you have five signals, you should have five different letters. If the carbons are identical, they will have the same letter.
  3. For each signal, give the range of chemical shift values, which are expected, using the table in your textbook as a reference.

An example:

For the next set of compounds, do the same things as above, labeling all of the hydrogens. (You do not need to draw out each hydrogen atom.) In addition, give the integration for each signal.

An example: