Dear All,
First, thanks to all of you who answered to my question. I got over
20 answers!!!! And, thank you for the follow-up by some of you.
When I posted my message, I made 2 mistakes: first, I did not say that
here are Queen's University Belfast we have Bruker NMR spectrometers and,
second, that the splitting observed was along the 1H dimension. Most of
the time it was doublets but also sometimes multiplets. The presence of
multiplets can easily be explained by two factors, first 1H-1H long range
couplings and incomplete or unefficient 13C decoupling with the GARP sequence.
The presence of doublets can be explained by incomplete of inefficient 13C
decoupling and I needed to recalibrate the 13C decoupling pulse to solve
the problem.
If the problem appears in the 13C dimension, it could be due to the fact that
the 180 degrees pulse between the two INEPT blocks is not doing its job and
the shaped pulse can easily be replaced by a hard 180 degrees pulse or to
a processing problem.
Anyway, the problem is now solved and thanks again to all of you who replied.
Pierre Kempgens.
Received on Tue Nov 29 2022 - 04:50:39 MST