How Do You Apply Pople Notation to Complex Spin Systems Like in 1-Bromobutane?

[scarecrow]

NMR "Pople Notation" HELP!

All the examples in my textbook show molecules that have only three sets of multiplets (AX, AB, ABX, or AMX first oder spin systems). But what if I have a molecule with more than 3 spin systems, for example in 1-bromobutane:

CH3-CH2-CH2-CH2-Br (there is a triplet, sextet, quintet, and triplet).

Each proton is unique, i.e., no chemically equivalent shift H's, no magnetically equivalent protons, enantiotopic or diastereotopic protons.

For this example, there is 4 spin systems, so do I have to describe it using 4 letters, but that seems impossible. I'm confused.

So far, I think it is this (reading left to right of the molecule): A3 B2 B2 X2

Someone please explain to me Pople notation. Thank you.

 

[ChemistHans]

All the examples in my textbook show molecules that have only three sets of multiplets (AX, AB, ABX, or AMX first oder spin systems). But what if I have a molecule with more than 3 spin systems, for example in 1-bromobutane:

CH3-CH2-CH2-CH2-Br (there is a triplet, sextet, quintet, and triplet).

Each proton is unique, i.e., no chemically equivalent shift H's, no magnetically equivalent protons, enantiotopic or diastereotopic protons.

For this example, there is 4 spin systems, so do I have to describe it using 4 letters, but that seems impossible. I'm confused.

So far, I think it is this (reading left to right of the molecule): A3 B2 B2 X2

Someone please explain to me Pople notation. Thank you.

You can see a detailed description of the Pople system at: http://www.chem.wisc.edu/areas/reich/nmr/05-hmr-07-pople.htm and http://www.chem.wisc.edu/areas/reich/nmr/05-hmr-08-symmetry.htm Any number of letters may be used.

The proper designation of 1-bromobutane is A3BB'CC'DD'. One could also use A3BB'CC'XX' since the CH2Br protons are quite far away from the others. The primes (BB') are there becasue the two B, two C and two D(X) protons are magnetically inequivalent. See: http://www.chem.wisc.edu/areas/reich/nmr/05-hmr-14-a2b2.htm