NMR "Pople Notation" HELP!

[scarecrow]

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