Date: Mon, 21 Mar 2016 14:07:05 +0000
jfxiang,
Since 25Mg is quadrupolar, and based on the structures that you have showed, I would suspect the linewidths in proton spectra be really broad. Have you tried to pulse the experiments very fast?
Just my two cents.
Good luck.
S. W. Simon Sham, Ph.D.
EPR/NMR Manager
Department of Chemistry and Biochemistry
Utah State University
Logan, Utah 84322
Office: 435-797-1673
NMR Lab:435-797-0529
________________________________
From: jfxiang_at_iccas.ac.cn <jfxiang_at_iccas.ac.cn>
Sent: Friday, March 18, 2016 8:47 PM
To: ammrl_at_ammrl.org
Subject: AMMRL: about the proton spectrum of Mg complexes
Hey, friends
Recently, a Ph D candidate just consulted with me for the proton spectrum of a Mg complex. It is very surpising that the Mg complex is NMR inactive in CD2Cl2, CD3CN, CD3COCD3 at room temperature and low temperature (insoluble in C6D6), but the ligand showed a NMR spectra in C6D6 and CD2Cl2 at low temperature. For the clarity at the beginning, I am a little worried about the success of this complex because Mg is not a strong metal ion. I have asked him to check the proton, carbon and nitrogen contribution by elementary analysis. It turned out the complex indeed contain these elements. Then the problem come: Why I cannot observe any NMR signals for this compound? Any suggestion is appreciated.
The possible molecular structure is listed below:
[cid:_Foxmail.1_at_34f2543f-45af-8a08-a452-56321ed56823]
Best regards
Junfeng Xiang
ICCAS, Beijing, China
(image/png attachment: clip_image002.png)