imported>Fadesga: /* References */

2023-07-18T19:21:23Z

References

New page

The '''Pople notation''' is named after the Nobel laureate [[John Pople]] and is a simple method of presenting second-order spin coupling systems in [[NMR]].<ref>{{cite journal|last=Pople|first=J.A.|author2=Bernstein, H. J. |author3=Schneider, W. G. |title=The Analysis of Nuclear Magnetic Resonance Spectra|journal=Can. J. Chem.|year=1957|volume=35|pages=65–81|doi=10.1139/v57-143 }}</ref>

The notation labels each (NMR active) nucleus with a letter of the alphabet. The difference in [[chemical shift]], δ, relative to the [[J-coupling]] between nuclei mirrors the separation of the letter labels in the [[Latin alphabet]]. The letters used tend to be limited to A,B,M,N,X,Y.

For example, '''AB''' indicates two nuclei which have similar chemical shifts (Δδ similar to or smaller than J), whereas '''AX''' indicates two which lie further apart on the spectrum (Δδ significantly larger than J). '''A2B''' would similarly indicate a spin system containing two equivalent nuclei (A) and a third, inequivalent one (B). Nuclei which are in equivalent ''chemical'' environments (that is, symmetry-related), but inequivalent ''magnetic'' environments are distinguished with a prime; e.g. '''AA''''. This key aspect of the notation, i.e., using a prime to differentiate between chemical equivalence only compared to full magnetic equivalence, was introduced by Richards and Schaefer in 1958. <ref>{{cite journal|last=Richards|first=R.E.|author2=Schaefer, T. |title=High Resolution Hydrogen Resonance Spectra of Trisubstituted Benzenes|journal=Mol. Phys.|year=1958|volume=1|issue=4 |pages=331–342|doi=10.1080/00268975800100411 |bibcode=1958MolPh...1..331R }}</ref>

The notation can be used to represent systems of more than two nuclei, for example '''AMX''' represents three nuclei, each moderately separated from the others, and '''ABX''' represents two nuclei whose peaks are closely spaced and one other nucleus which is more distant.

Examples:
PHCl2 is an AX system whereas
CH3CH2F is an A3M2X system,

==References==
{{Reflist}}

[[Category:Nuclear magnetic resonance]]

{{NMR-stub}}

Pople notation - Revision history

imported>Fadesga: /* References */