[AMMRL] Help Needed: Broad/Missing ¹³C NMR Signals

From: Muhammad Adil Raees via groups.io <adil.raees=lums.edu.pk_at_groups.io>
Date: Wed, 01 Oct 2025 07:38:00 -0700

Hi all,

I’m seeking advice on improving ¹³C NMR spectra that show
broad or missing signals.
Sample KB-P19-NO₂ in CDCl₃ had broad/missing signals,
but in DMSO it became sharp with good intensity.

Sample HY-VI-135-HH in CDCl₃ is also showing broad/missing signals
and is insoluble in Acetone, DMSO, and MeOD. We specifically want to improve
the ¹³C signals for HY-VI-135-HH.

For these experiments, I used zgpg or zgpg30 pulse programs. NMR instrument
is working fine — standard tests in CDCl₃ (ethyl benzene)
show all signals clearly. The FID files and molecular structures are attached 
for reference.

It seems sample-related, but I’m wondering:
* Could the broad signals be due to acquisition parameters?
* Are there ways to improve the signals for HY-VI-135-HH?
* Could the broadening be inherent to the molecule’s chemistry?

Any tips or shared experience would be greatly appreciated!

Thanks,
--
Muhammad Adil Raees, Ph.D.
Manager NMR Facility
The Central Laboratory
Syed Babar Ali School of Sciences and Engineering
Lahore University of Management Sciences
Opposite Sector-U, D.H.A. 54792, Lahore
+92-330-2866755
adil.raees_at_lums.edu.pk


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Received on Wed Oct 01 2025 - 07:53:07 MST