There is a significant 13C-19F isotope shift.
Kirk Marat
Victoria, BC
On Wed., Jul. 12, 2023, 11:22 Holmes, Daniel, <holmesd5_at_msu.edu> wrote:
> The 13C satellites are not symmetric about the 19F-12C peak due to the
> heavy isotope effect. See Glen Facey’s excellent post about it.
> http://u-of-o-nmr-facility.blogspot.com/2012/10/isotope-effects-and-19-f-13-c-hmqc.html
>
> Dan
>
>
> *From: *main_at_ammrl.groups.io <main_at_ammrl.groups.io> on behalf of Weidong
> Hu via groups.io <whu=coh.org_at_groups.io>
> *Date: *Wednesday, July 12, 2023 at 1:54 PM
> *To: *main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> *Subject: *[AMMRL] Unexpected peaks of 19F NMR from CF3CH2OH
>
> Hi All,
>
> I acquired 1D-19F NMR of CF3CH2OH dissolved in CDCl3/CD3OD(2:1 v/v) on CP
> TCI 700 H&F-C/N-D probe (without 1H decoupling), and the spectrum is very
> confusing.
>
> In addition to main triplet peaks, there are three minor triplet peaks
> (about 0.5% of main triplet). The positions of minor peaks are not
> symmetric to the main triplet, and thus should not come from natural
> abundance of 13C-19F J coupling. It is reasonable to see four minor peaks
> generated from one and two-bond J couplings between 13C-19F, but they
> should be symmetric to the main peak. I don't know how to explain the
> observed spectrum. Any suggestions as what is going on? The spectrum is
> attached below.
>
> Thank you,
>
> Weidong
>
> Dr. Weidong Hu
> Department of Immunology & Theranostics
> Beckman Research Institute
> 1450 E. Duarte Rd., Duarte, CA 91010
> Tel: 626 256 4673, Ext: 63416
> Fax: 626 301 8186
>
>
> ------------------------------
>
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Received on Wed Jul 12 2023 - 12:01:49 MST