Hints

 

For those molecules find the number of different signals. We give you the molecular formula in order to guess what are the impurities.

In 1H NMR spectroscopy we often have signals that are composed on many peaks (multiplet) and therefore based on the symmetry and the distance we need to try to guess where is a signal and how many there are.

In order to determine if it is an impurity it is often useful to integrate the spectrum. To integrate press the 'ALT' key and then click on the starting point and click on the ending point of the integral.

 

In CDCl3, water is around 1.5ppm and CHCl3 at 7.27.

In DMSO-d6, water is at around 3.5 and DMSO-d5 at 2.5..

Acetone is often an impurity in NMR spectra. It is used to clean the NMR tubes.

If the solvent is not specified, it is CDCl3.

Instructions

 

1. Select one exersise from the left table(click)

2. Analyse the spectrum and). Consider the chemical shifts, integrals(displayed on the top of each signal) and multiplicities.

3. Analyse the molecular formula of the target molecule (displayed over the spectrum viewer). Calculating the degree of unsaturation helps. 

3. Draw your proposed structure in the JSME Molecular Editor.

4. The correctness of the solutions is evaluated each time that the structure is changed. If the rigth strucuture is drawn, the row of the table is inmediately highlighted in green.