- Pople Notation
The Pople notation is named after the Nobel laureate
John Pople and is a simple method of presentating spin coupling systems inNMR .The notation labels each (NMR active) nucleus with a letter of the alphabet. The difference in
chemical shift relative to theJ-coupling between nuclei mirrors the separation of the letter labels in thelatin alphabet . The letters used tend to be limited to A,B,M,N,X,Y.For example, AB indicates two nuclei which are strongly coupled to each other, and AX two which are only weakly coupled. For nuclei which are in equivalent "chemical" environments, but in-equivalent "magnetic" environments are differentiated with a prime; e.g. AA'.
The notation can be used to represent systems of more than two nuclei, for example AMX represents three nuclei each weakly coupled, and ABX represents two strongly coupled nuclei and one other, more weakly coupled nucleus.
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