Multiplet analysis

[schatzsc]

The multiplet analysis function does not work as I would expected and I'm not sure if this is a bug or a functionality issue.

For example, with 2-substituted pyridine rings, we often have a doublet-of-a-doublet-of-a-doublet (ddd) single which - when sufficiently resolved, consists of 8 peaks of equal intensity.

Sometimes, it has the additional difficulty that the peaks #4 and #5 of the two innermost doublets overlap by chance and therefore you only see seven peaks instead of the eight normally expected for a ddd peak.

In Topspin I can manually mark these peaks twice and then combine that different sub-peaks to extract the three coupling constants (3J, 4J, and 5J) but the Chemotion spectrum editor only labels this as a multiplet (m) and furthermore
only gives the "center position" (here as 7.858 ppm) while normally a multiplet (m) is given as a range, like 7.89-7.83 ppm

I also tried various ways to combine the peaks step by step to the intended ddd pattern but it all did not work.

Is this a bug or just the functionality not obviously enough documented?

A very good and pictorial introduction to advanced multiplet interpretation is given in the following book:

Roman A. Valiulin
NMR Multiplet Interpretation: An Infographic Walk-through
de Gruyter 2019
ISBN ‎ 978-3110608359