Skip To Content

ACD/Labs Blog

Arvin Moser
Proton-proton couplings arise from influences on the proton’s magnetic field from the magnetic field of neighbouring protons. Being capable to recognize among the vast array of coupling patterns can facilitate the time spent on interpreting a 1H NMR. The diagram below illustrates two coupling patterns: a triplet of doublets (td) and a doublet of triplets...

Arvin Moser
I got some great comments from Tony and Gary on the “Dealing with a Mixture…” post that I decided to do a follow-up post. http://acdlabs.typepad.com/elucidation/2008/02/dealing-with-a.html In my lab days, I would routinely workup a newly acquired 1H NMR for an unknown sample prior to acquiring a 2D NMR dataset. One of my goals was to examine...

Arvin Moser
As would-be elucidators dive into an elucidation for an organic unknown, narrowing down a single molecular formula (MF) becomes vital in simplifying the elucidation. However, one hurdle quickly leads into another. As the total atom count adds up, the number of possible isomers increases just as much (See Table and Graph below). I can’t imagine...

Arvin Moser
One of the hardest parts of interpreting an NMR dataset is separating peaks from a mixture of compounds. To illustrate this point, below are the aromatic regions of two 75 MHz 13C NMR run on a mixture of methylbenzene and ethylbenzene in CDCl3. If the mixture exists at an approximate 1:1 ratio (top figure), then...