[science123]

I tried predicting the structure and checked using the n+1 rule. All the H comply with the rule except for the H on the middle carbon . It is supposed to give 24 lines [ (n+1)*(n+1)*(n+1) --> (2+1)(3+1)(1+1) = 24 lines] since all the neighboring protons are non-equivalent to each other. Any suggestions?

http://img13.imageshack.us/img13/6717/nmry.jpg

[opuktun]

The middle atom has five neighbours...

So the (5+1)=6 peaks is correct.

What's with the 24?

If the scanning resolution of NMR is not sensitive enough, you would not see further splitting.

[science123]

The middle atom has five neighbours...

So the (5+1)=6 peaks is correct.

What's with the 24?

If the scanning resolution of NMR is not sensitive enough, you would not see further splitting.

It's not 24 my bad! You are right that the resolution of NMR is not sensitive enough so i could see the max theoritical peaks but my prof. told me that only non-equivalent protons split and the protons counting towards N should be equal to each other to apply N+1 rule but if they aren't like in this problem (ch2 and ch3 ) then (n+1)(n+1) rule applies.

(2+1)(3+1) = 12 peaks theoretically.