AMMRLers,
I have a researcher that got me to do some 59Co NMR recently, and we
observed a strange line shape for the standard when summing multiple scans.
I believe that the strange broadening I get of the signal from the K3Co(CN)6
is due to a quadrupolar effect, but a quick search of the web only generated
hits for solid state 59Co NMR work, which would obviously give spectra with
none or at least very little motional averaging of the quadrupolar, dipolar
and chemical shift tensors.
So my question is, why would I get a broader line (even with the 2H lock on)
when I scan more than once on my standard in d2o. I am running at about 95
MHz on a Bruker AVANCE (DPX) 400 with a broadband probe, proton decoupling
(I modified the 13C parameters and just used eda to change the transmitter
nucleus).
Even with a single scan the line appears as if there are horrendous z4
shimming problems, but I suspect this is not a shimming problem (beating on
z4 didn't make a hump on the right more anywhere).
Any comments are much appreciated. A summary will be sent out if there is
sufficient interest.
Thanks for your time,
Jeff
Jeff Simpson, Director
Department of Chemistry Instrumentation Facility
Massachusetts Institute of Technology
77 Massachusetts Avenue, 18-0090
Cambridge, MA, 02139
617-253-2016 (1806 lab)
Received on Thu Sep 03 2009 - 10:09:28 MST