Chemical Forums

Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: AussieKenDoll on August 21, 2020, 12:33:25 PM

Title: Is there any atoms that do not couple even if they are magnetically inequivalent
Post by: AussieKenDoll on August 21, 2020, 12:33:25 PM

Does I and F couple in F-19 NMR? If not why?

Title: Re: Is there any atoms that do not couple even if they are magnetically inequivalent
Post by: Babcock_Hall on August 21, 2020, 04:11:19 PM

I don't know the specific answer to your question.  But let me offer you food for thought.  Do we observe Cl-35 coupling to H-1 or to C-13 in chloroform?

Title: Re: Is there any atoms that do not couple even if they are magnetically inequivalent
Post by: AussieKenDoll on August 21, 2020, 04:21:53 PM

no because C-13 and H-1 are not quadroupole active?

Title: Re: Is there any atoms that do not couple even if they are magnetically inequivalent
Post by: Babcock_Hall on August 22, 2020, 09:48:26 AM

C-13 and H-1 couple to H-2, which is quadrupolar; therefore, we know that in general spin-1/2 nuclei can couple with quadrupolar nuclei.  I think it has to do with the relaxation rate of the Cl-35 nucleus being very fast.  It has been some time since I looked into this over.