Saturday, 20 September 2014

From NMR multiplets reports to synthetic spectra

I admit that I was never a fan of the traditional way in which NMR spectra are usually reported in organic chemistry journals, something like:

1H NMR (300 MHz, CDCl3) 7.91 (d, J=8.2 Hz, 2H), 7.31 (d, J=8.2 Hz, 2H), 3.65 (t, J=6.3 Hz, 2H), 3.13 (t, J=6.9 Hz, 2H), 2.95 (p, J=6.9 Hz, 1H), 2.20 (p, J=6.6 Hz, 2H), 1.26 (d, J=6.9 Hz, 6H)

It is not only that there is not a standard format that is strictly followed by all journals. It is also that it does not convey all the NMR information contained in the actual spectrum (reducing a spectrum into a multiplet report results in an irreversible loss of important information) and facilitates the job to those willing to cheat ( see this and this).

Today, in the 21st century, I don’t see any reason why the experimental raw data (i.e. FID+metadata) should not be an integral part of any article where NMR spectra have been used to characterize a chemical structure. In any event, there are millions of articles with NMR spectra in the form of those old fashioned multiplet reports and we thought that it would be a good idea to implement some tools to facilitate the analysis of those reduced spectra.

That is why we developed the Mnova script “Multiplet Report to Spectrum”, a tool which is available in Mnova from the scripts menu:

It is very easy to use: Once this command is issued, you only need to copy to the clipboard your multiplet report from the article (PDF, Word document, etc) and paste it into the Multiplet report edit box at the top of the dialog:

As soon as it is pasted, this application will parse the multiplets and the different fields (chemical shifts, number of protons, multiplicity, solvent, nucleus, etc) will be automatically populated. If for any reason some of those values are not correctly parse, you can manually amend them.
Once you are happy with those values, you can press OK so that Mnova will synthesize a spectrum with those values.

We believe that this is a very useful tool, in particular for organic chemists. It can be used to easily compare an experimental spectrum with a multiplet report from a journal, for example.