Just one sec...
Hey! Sign in to get help with your study questionsNew here? Join for free to post

Proton NMR question help!!

Announcements Posted on
Take our short survey, £100 of Amazon vouchers to be won! 23-09-2016
    • Thread Starter
    Offline

    3
    ReputationRep:
    Need help with this question. Name:  xoxoxo.png
Views: 12
Size:  32.0 KB Have I counted the proton environments right here? I counted 5, so surely there are 5 carbon peaks but the answer says only 2.

    Thanks
    Offline

    1
    ReputationRep:
    I think the question's answer is right, if you look region 2 has a carbon connected to it with 3 hydrogens on it, but every other carbon has just 1 hydrogen coming off it, so it might be that you've got one carbon atom with 5 hydrogens attached to the other carbon atoms next to it and the others each have 2 on the adjoining carbon atoms. I think by 2 peaks it means 2 different peaks, i.e. if they've all got the same environment that would count as one peak. Don't trust me fully on that though, I could easily be wrong.
    Online

    3
    (Original post by RallySPORT)
    I think the question's answer is right, if you look region 2 has a carbon connected to it with 3 hydrogens on it, but every other carbon has just 1 hydrogen coming off it, so it might be that you've got one carbon atom with 5 hydrogens attached to the other carbon atoms next to it and the others each have 2 on the adjoining carbon atoms. I think by 2 peaks it means 2 different peaks, i.e. if they've all got the same environment that would count as one peak. Don't trust me fully on that though, I could easily be wrong.
    Yeah you're wrong.

    There are 5 environments. Here is the (simulated) 13C NMR of TNT:



    Here's a quick simulated NMR I did myself (don't pay too much attention to the shifts, just to the distinct peaks):



    However for proton environments, there are two (as only the methyl and 3 carbons have protons attached):

    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by RallySPORT)
    I think the question's answer is right, if you look region 2 has a carbon connected to it with 3 hydrogens on it, but every other carbon has just 1 hydrogen coming off it, so it might be that you've got one carbon atom with 5 hydrogens attached to the other carbon atoms next to it and the others each have 2 on the adjoining carbon atoms. I think by 2 peaks it means 2 different peaks, i.e. if they've all got the same environment that would count as one peak. Don't trust me fully on that though, I could easily be wrong.
    Hey, I realise where I have gone wrong now. Thanks. So does this molecule have 5 carbon environments?
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by alow)
    Yeah you're wrong.

    There are 5 environments. Here is the (simulated) 13C NMR of TNT:

    Where can you find this app to check the no of environments?
    So No of H environments : 2 No of carbon envirnonment : 5 or 7?

    Thanks again
    Offline

    1
    ReputationRep:
    (Original post by alow)
    Yeah you're wrong

    well rip me
    Online

    3
    (Original post by coconut64)
    Where can you find this app to check the no of environments?
    So No of H environments : 2 No of carbon envirnonment : 5 or 7?

    Thanks again
    I use ChemDoodle to generate NMRs, but it's not that good at predicting shifts (although they're not too far off), only for showing the number of environments.

    I edited my last post to include a simulated 1H NMR, there are 2 environments.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by alow)
    I use ChemDoodle to generate NMRs, but it's not that good at predicting shifts (although they're not too far off), only for showing the number of environments.

    I edited my last post to include a simulated 1H NMR, there are 2 environments.
    So there are 7 carbon environments in total? Why isn't the carbon environment the same on the carbon atom attaching to NO2 ?? I don't quite get it... This is very annoying but pls help me!!

    THXX
    Online

    3
    (Original post by coconut64)
    So there are 7 carbon environments in total? Why isn't the carbon environment the same on the carbon atom attaching to NO2 ?? I don't quite get it... This is very annoying but pls help me!!

    THXX
    There are 5 carbon environments. There are 5 peaks in the NMR.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by alow)
    There are 5 carbon environments. There are 5 peaks in the NMR.
    Why does your stimulated image show 7? Is my labelling right here? Name:  hhhh.png
Views: 14
Size:  27.4 KB
    Online

    3
    (Original post by coconut64)
    Why does your stimulated image show 7? Is my labelling right here? Name:  hhhh.png
Views: 14
Size:  27.4 KB
    It doesn't. It shows 5.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by alow)
    It doesn't. It shows 5.
    Right, so there are 5 peaks but why is there a 7 labelled next to the molecule?

    Also have I labelled my molecules right??
    Online

    3
    (Original post by coconut64)
    Right, so there are 5 peaks but why is there a 7 labelled next to the molecule?

    Also have I labelled my molecules right??
    That's just counting the carbons... Look at the spectrum...

    Your labelling is fine.
    • Thread Starter
    Offline

    3
    ReputationRep:
    (Original post by alow)
    That's just counting the carbons... Look at the spectrum...

    Your labelling is fine.
    Cool, thats more reassuring. Also I have just downloaded that chemdoodle thing but I am so clueless as to how to use it. So just wondering if you know other apps that can do the same thing?

    Thank you so much
    Online

    3
    (Original post by coconut64)
    Cool, thats more reassuring. Also I have just downloaded that chemdoodle thing but I am so clueless as to how to use it. So just wondering if you know other apps that can do the same thing?

    Thank you so much
    ChemDraw might be able to but imo it's more difficult to use.
    Offline

    2
    ReputationRep:
    (Original post by alow)
    ChemDraw might be able to but imo it's more difficult to use.
    Chemdraw can do it, but I don't like it as a piece of software :biggrin:
    Online

    3
    (Original post by MexicanKeith)
    Chemdraw can do it, but I don't like it as a piece of software :biggrin:
    Yeah I'm not a fan of it either. And last time I used it drawing Bezier curves was stupidly difficult for mechanisms.

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: September 18, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Poll
Which would you rather be...?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22

Registered Office: International House, Queens Road, Brighton, BN1 3XE

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.