2-D NMR

This experiment was developed by S.E. Van Bramer for Chemistry 465 at Widener University.

Introduction:

There are a wide range of NMR experiments available for solving structural problems in NMR. Many of these experiments are very complex and include a large number of different pulse sequences. With a modern NMR, however, these experiments are easily run. In this experiment we will acquire a run a variety of different experiments and use them to identify an unknown compound. The experimental details outlined here are in addition to the basic steps outlined in the documents listed below. This page should be treated as a supplement to those documents.

  1. Introduction to MacNMR
  2. MacNMR Experiment Setups
  3. NMR Operations for QE 300 with Tecmag Data System
  4. Data Processing with Nuts (brief) (detailed)

Experimental:

Safety

  1. DO NOT ENTER KB 421 if you have a pacemaker or other metal implant.

  2. DO NOT place any magnetic material near the magnet.

  3. DO NOT drop small metal material in the room.

  4. DO NOT bring large metal objects into KB 421.

  5. Credit Cards, Computer Diskettes, and ATM cards can be erased inside the yellow warning rope.

  6. DO NOT work unsupervised

  7. Follow Directions and Ask questions. The NMR costs about $150,000, be careful

  8. Sign-in the logbook

Sample Preparation

Sample Loading

Setup the Magnet For The New Sample

Run a Proton Spectrum

Run a 13C spectrum

  1. Turn the decoupler off in the control panel using the frequency control panel.

Run a DEPT spectrum.

  1. Load DEPT Experiment
  2. Set the number of sweeps and the acquisition delay as appropriate for the sample.
  3. NOTE: The Decoupler Pulse angle may need to be fine tuned in the Pulse Program Setup by changing the values in the T2 table. The current settings are based on 41 µs for 90° pulse.
    1. For 45° DEPT (All carbons +) 20.5 µs
    2. For 90° DEPT (Only CH carbons) 41 µs
    3. For 135° DEPT (CH2 - ; CH and CH3 +) 61.5 µs
    4. 1/(2*J), ie: 4.0 ms for 125 Hz
    5. As appropriate for P2 and T1 relaxation time
    6. 41 µs (Proton decoupler 90° pulse)
    7. 82 µs (Proton decoupler 180° pulse)

Run a COSY spectrum.

  1. Load the COSY Experiment.
  2. Turn the spinner off. Use the Control Panel for Frequency Control to turn the spinner air off.
  3. Set the spectral window as appropriate for sample
  4. Set the number of acquisitions for S/N required
  5. Set the Recycle delay (Short)
  6. Enter a file name

Run a NOESY spectrum.

  1. Load the NOESY Experiment.
  2. Turn the spinner off. Use the Control Panel for Frequency Control to turn the spinner air off.
  3. Set the spectral window as appropriate for sample
  4. Set the number of acquisitions for S/N required
  5. Enter a file name

Run a Hetcor spectrum.

  1. Open the Hetcor Setup.
  2. Turn the spinner off. Use the Control Panel for Frequency Control to turn the spinner air off.
  3. Set proton window in the Pulse Program settings, using the Pulse Acquisition Settings button.
    1. Set F2 so that left edge of H-1 window is F2 = (ppm * 300.148502) + 300148502
    2. Set SW so that SW = 2*ppm*300.15
    3. Useful settings
      F2 (MHz)SW (Hz)Left (ppm)Right (ppm)
      300.1515036000100
      300.15300050
      300.15060450007 -1
    4. Then reset the T2 table by entering 1u and calculating values.
  4. Set the number of acquisitions for S/N required
  5. Run the experiment

Laboratory Write-up:

Your Laboratory write-up should include the following information.
  1. (5 pts) An Abstract of your experiment.

  2. (40 pts) Interpret your spectra and assign all peaks in your spectra. Explain how you arrived at this identification, what information did you use from the spectra.

  3. (5 pts) The Carbon pages from your laboratory notebook.

This page is maintained by
Scott Van Bramer
Department of Chemistry
Widener University
Chester, PA 19013

Please send any comments, corrections, or suggestions to svanbram@science.widener.edu.

This page has been accessed times since 1/5 /96 .
Last Updated Tuesday, January 08, 2002 10:43:49 AM