Teaching and Learning by Spectral Example ... Part 1

There are many ways to teach the process of elucidating unknown structures. Offering a student a visual guide, such as seeing firsthand a spectral dataset, can enhance the learning process and better equip the student on future work.

Presented below is a typical elucidation question from a university test. The numerical values have been extracted from a 1H NMR spectrum and the student is basically left to focus on elucidating the unknown.

If a 1H NMR spectrum is presented with the question, as shown below, the student is faced with the tasks of interpreting the spectrum and elucidating the unknown.

Although both approaches can serve a purpose, the latter approach enhances the experience of learning how to elucidate an unknown.

Teaching and Learning by Spectral Example ... Part 1

There are many ways to teach the process of elucidating unknown structures. Offering a student a visual guide, such as seeing firsthand a spectral dataset, can enhance the learning process and better equip the student on future work.

Presented below is a typical elucidation question from a university test. The numerical values have been extracted from a 1H NMR spectrum and the student is basically left to focus on elucidating the unknown.

If a 1H NMR spectrum is presented with the question, as shown below, the student is faced with the tasks of interpreting the spectrum and elucidating the unknown.

Although both approaches can serve a purpose, the latter approach enhances the experience of learning how to elucidate an unknown.

Distinguishing Impurities … Conclusion

In the blog series entitled Distinguishing Impurities, several types of NMR experiments were outlined to offer some insight into what to be on the look out for. Although there is no set guideline in this process, the best advice I may offer is to keep track of all the solvents, be aware of the possibility for sample degradation or side products, and finally if a signal does not look right, trial and error may be the only safe bet to ensure nothing is overlooked.

Below is a summary of the each part in the series:

Part 1 covered the aspects a 1H NMR whereby 2 singlets seemed out of place in relation to the remaining 1H signals.

Part 2 described some prep work to check for differences in the integrals of the 1H signals.

Part 3 depicted a 1H-13C HSQC with no obvious indicators that any of the 1H signals were impurities.

Part 4 illustrated how a 1H-1H DQF COSY was a bad choice when dealing with 1H singlets.

Part 5 had a 1H-1H TOCSY spectrum lacking any long range correlations with the 1H singlets.

Part 6 explained how the 1H-13C HMBC lacked any correlation trails with the 1H singlets.