Instructions

The NMR Spec RMN online tool that you are preparing to use was designed to help you learn to analyse NMR spectra in a thorough and methodical manner.

To begin your session, select one or several level of difficulty (Level 1 and/or Level 2 and/or Level 3) and the response mode (Rookie or Pro). Then click on start.

Pro Mode

In Pro mode, you must draw the molecule corresponding to the spectrum, using the Marvin^TM sketch applet. Then click on submit your response. If your structure is correct, you will see a pop up window confirming your correct response and giving the name of the molecule. You can then advance to the next spectrum by clicking on next question.

If your structure is not correct, you will be able to try again. After three incorrect responses, you will have the option to switch to Rookie mode for the same spectrum by clicking on rookie mode, or to pass to the next spectrum in Pro mode by clicking on skip question.

Rookie Mode

In Rookie mode, the analysis of a spectrum takes place in three steps:

STEP 1: Signal Analysis

1. Click on a signal in the spectrum. In the window that appears you must select, using the dropdown menus, the number and type of fragment giving rise to the signal and the number of neighbouring protons, and lastly select the final motif corresponding to your choices.

2. Click on set. A window will appear summarizing your chosen motif. The part of the motif giving rise to the signal is indicated in blue and any neighbouring protons are shown in black. Your choices should be based on the intensity of the signal, which indicates the number of equivalent proton having the same chemical shift and the same coupling. You should also consider the multiplicity of the signal, which indicates the number of neighbouring protons (N) to which the protons of the signal are coupled, giving rise to a signal having N+1 peaks.

   You can see which signal corresponds to which summary window by passing your cursor over the "eye" symbol () located in the top right of the window. You can also erase the analysis completely by clicking on the "X" symbol () located in the top right corner of the window.

3. Repeat (1) and (2) for each signal on the spectrum.
4. Click on submit response to see if your assignments are correct.
1. If your assignments are correct, click on proceed to step 2.
2. If you have one or more errors, the online tool will ask you to try again, without offering any hints. Re-analyse the signals and re-submit your response.
3. If after your second attempt you still have one or more errors, the online tool will show you which signals were analysed correctly (indicated with the symbol ) and which were not (indicated with the symbol ). Re-analyse the mis-assigned signals and re-submit your response.
4. After three unsuccessful attempts, the online tool will offer to show you the correct response (click on show correct response) in order to pass to Step 2. However, may continue to analyse the signals until you arrive at the correct assignments yourself.

When all signals have been correctly assigned, you may advance to Step 2.

STEP 2: Motif Arrangement

This step allows you to calculate the number of unsaturations in the molecule and to copy into a sketch pad all the fragments necessary to complete a plausible structure corresponding to the NMR spectrum. To do this:

1. Indicate the number of unsaturations in the molecule by analysing the molecular formula on the spectrum, and selecting the right number from the dropdown menu following the prompt "Number of unsaturations in the molecule:"

2. Copy the relevant fragments identified in Step 1 into the sketch pad of Step 2 by clicking on the motifs shown above the sketch pad. You can move them around the page. By double clicking on them you can also turn them (), flip them into their mirror image () or erase them ().

   Be careful‼! Certain motifs (presenting both the signal protons and the neighbouring protons) may appear more than once in the list above the sketch pad. Pay attention to the colour coding to correctly identify the complete fragments.

3. Click on the images below the sketch pad to select fragments that are present in the molecule but do not bear a proton (non-protonated fragments).
4. Use the mouse to turn and move the molecular fragments in the sketch pad, in order to align them in the way they may be connected in the final structure, respecting both the multiplicity of the signals and their chemical shifts.
5. Click on submit response to see if you have correctly identified the right number of unsaturations as well as all the fragments necessary to construct the final molecule.
1. If your number of unsaturations is correct and all the non-protonated fragments are copied to the sketch pad, click on proceed to step 3.
2. If you have one or more errors, the online tool will allow you to try again, without giving any hints. Re-evaluate the number of unsaturations and/or the non-protonated fragments in the molecule.
3. If you still have one or more errors after your second attempt, the online tool will indicate if your errors are in the number of unsaturations and/or in the non-protonated fragments. Re-evaluate your responses by taking account of this feedback.
4. After three unsuccessful attempts, the online tool will offer to show you the correct answer (click on show correct response) in order to pass to Step 3. However, may continue to analyse the unsaturations and non-protonated fragments until you identify them correctly yourself.

When the right number of unsaturations and all the non-protonated fragments necessary to construct the final structure have been correctly identified, and you are satisfied with the rough alignment of the fragments in the sketch pad, you may advance to Step 3.

STEP 3: STRUCTURE DRAWING

1. In the Marvin^TM sketch applet, draw the final structure of the molecule, based on your sketch from Step 2.
2. Click on submit response to see if your structure is correct.
1. If your structure is correct, you will see a pop up window confirming your correct response and giving the name of the molecule. You can then advance to the next spectrum by clicking on next question.
2. If your structure is not correct, you will be able to try again.
3. After three incorrect responses, you will have the option to see the correct structure (click on show correct response) and then to pass to the next spectrum by clicking on next question.

Remember that protons that are near electronegative atoms are deshielded (higher PPM) compared to those that are not (lower PPM).