NMR Spectroscopy : Please help me understand the peaks and put together a molecule from those peaks..?

Question

I understand how to look up the ppm and get the various parts of the compound. I just don't understand how to link those parts togther.

Answer 1

If you give me an example I can show you but it's hard to explain all by itself.

Basically, the amount of peaks tells you how many different types of hydrogen you have, and the splitting within the peaks shows you how many hydrogens within each type. The distance from the 0 point, (TMS) tells you what the hydrogens are attached to. For example if you have the molecule C3H7I, and the NMR spectrum had 2 peaks, you would know that you have two different types of Hydrogens. If the first peak was split into 2, and the second peak was split into 7, you know that the ratio of 1 type of hydrogen to the other is 6:1, because the splitting is n+1. Then, If the peak that was split into 7 is further down that the one split into 2, then you know that those hydrogens (7 peak ones) are not attached to the electronegative atom (which causes chemical shift) therefore you can conclude that the structure would be 2-iodo-propane because the Carbon that has the Iodine attached to it can only have one Hydrogen attached to it, so you know it must be on the second Carbon.

Hope this helps. If you had an example with a picture I could explain it better.