Signal intensity affected by long-range proton coupling?

i like this post (click again to cancel)

i dont like this post (click again to cancel)

remove favorite mark from this question (click again to restore mark)

Hi, I'm looking for a theoretical explanation for the effect of long-range (proton) couplings on the signal intensity of the coupled peak. For example, we have a series of compounds in which we have two 2H 'triplets', one of which is also involved in long-range (5J) coupling - this 'triplet' is consistently shorter and broader than the other. We've confirmed the long-range coupling on moving to a higher field instrument and through a long-range COSY (COSYLR). Thanks in advance!

long-range; coupling

asked Apr 11 '14 at 01:25

doodlebugs
1

One Answer:

oldest newest most voted

i like this answer (click again to cancel)

i dont like this answer (click again to cancel)

Could this just be that the long range coupling is not resolved, and so is just broadening the lines a bit? That would reduce the peak height.

If you integrate the two triplets, are the integrals significantly different?

link

answered Apr 14 '14 at 05:32

Pete Gierth
401

Perhaps that's just it. The integrals are exactly the same for both. The finer coupling is visible once we move to the higher field instrument. - doodlebugs (Apr 14 '14 at 06:45)

Here (once you log in) you will be able to sign up for the periodic email updates about this question.

Your answer

Please start posting your answer anonymously - your answer will be saved within the current session and published after you log in or create a new account. Please try to give a good answer, for discussions, please use comments and please do remember to vote (login to vote)

toggle preview

Tags:

coupling ×3
long-range; ×1

Asked: Apr 11 '14 at 01:25

Seen: 5,016 times

Last updated: Apr 14 '14 at 06:45

Related questions