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# Complex splitting

Learn how to predict the splitting pattern when a proton has two different kinds of neighboring protons by using a splitting tree. Created by Jay.

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• Does it matter if you split with the higher or lower frequency first?
• No, the peaks will appear the same regardless of the order.
• For the second example, why do the two center peaks cross over? why wouldn't it make a quintet?
• So, for the last example with Jab = 12hz and Jac = 7 Hz (arbitrary letters), what would the ratio of the peak heights look like?

I imagine that it'd be like 1:2:3:2:1 or something similar due to overlapping coupling, but I'm not sure. Could someone clarify this for me?
• If the peaks are sharp and well-separated, the six peaks should be in the ratio 1:2:1:1:2:1, with peaks 1, 2, and 4 belonging to H(b) and peaks 3, 5, and 6 belonging to H(a).
However, the two middle peaks might overlap and look like a single peak. Then the signal would look like five peaks in the ratio 1:2:2:2:1.
• Shouldn't the second part of the splitting tree diagram be split 3.5 Hz both way rather than 7? The way it is shown is for 14 Hz and 14 Hz again, correct?
• No, J = 7 Hz, so the distance between each component of the triplet is 7 Hz. The distance between the two outer peaks of the triplet will then be 14 Hz.
• origin of NMR signal?
• The protons behave as if they are little magnets.
They can line up either parallel or antiparallel to external magnetic field, with the antiparallel arrangement being higher in energy.
When you irradiate the protons with a radiofrequency of the right energy (frequency), the protons will absorb energy and be excited to the higher energy level.
When the protons drop back to the lower energy level, they emit the energy at a characteristic frequency, which is detected by an internal receiver.
The signal is amplified and is displayed as a peak on a graph.
• General Question--> If there are two different neighbouring environments, and you have to do (n+1)(n+1), how do you know which environment to start with for example it could be a doublet of triplets or a triplet of doublets.
• It doesn't really matter.
If the doublet has the larger J value, we call it a doublet of triplets.
If the triplet has the larger J value, we call it a triplet of doublets.
• What happens if you have an H and an OH on the same carbon. Does the H on the OH count as a neighbor to the other hydrogen (since it is attached to the O and not the C)? How does it effect the other H on the same carbon?

For reference, I am trying to construct the H-NMR spectrum of Borneol.