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3 questions about proton nmr, alevel.

I have 3 questions.
1.Do high resolution nmr give 1 peak per proton environment just like low resolution?
2. Apart from hydrogen bonded to carbon, which other hydrogens give split peaks?
3. What would the high resolution peak of 2,2 dimethylpropane look like? I think it would be 1 peak because of just 1 environment for all protons and the peak is not split because for all the protons, the adjacent carbon is the central carbon which has no protons bonded to it - am I right?
Reply 1
Avatar for alow
alow
19
Original post by thebrahmabull
I have 3 questions.
1.Do high resolution nmr give 1 peak per proton environment just like low resolution?
2. Apart from hydrogen bonded to carbon, which other hydrogens give split peaks?
3. What would the high resolution peak of 2,2 dimethylpropane look like? I think it would be 1 peak because of just 1 environment for all protons and the peak is not split because for all the protons, the adjacent carbon is the central carbon which has no protons bonded to it - am I right?


1. As long as there's no coupling, yes.

2. Any hydrogen which has a reasonably small number of bonds connecting it to a nucleus with non-integer spin.

3. I would guess just a singlet with satellites.
Original post by thebrahmabull
I have 3 questions.

3. What would the high resolution peak of 2,2 dimethylpropane look like? I think it would be 1 peak because of just 1 environment for all protons and the peak is not split because for all the protons, the adjacent carbon is the central carbon which has no protons bonded to it - am I right?


If you think about it dimethylpropane is analogous to TMS, which of course only gives one peak.
Original post by alow
1. As long as there's no coupling, yes.

2. Any hydrogen which has a reasonably small number of bonds connecting it to a nucleus with non-integer spin.

3. I would guess just a singlet with satellites.


Thanks! I didnot understand 2. Is it safe to think only carbon bonded hydrogens exhibit split peaks and that oxygen and nitrogen bonded hydrogens give a singlet?

About 3- what are satellites?
Original post by charco
If you think about it dimethylpropane is analogous to TMS, which of course only gives one peak.

Good point!
Reply 5
Avatar for alow
alow
19
Original post by thebrahmabull
Thanks! I didnot understand 2. Is it safe to think only carbon bonded hydrogens exhibit split peaks and that oxygen and nitrogen bonded hydrogens give a singlet?

About 3- what are satellites?


They're the little peaks you get either side from some of the molecules present containing carbon 13 (about 1%), which the protons can couple with.

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