Dear AMMRLs:
Having fun doing 103Rh for the first time. Want to observe in
samples that are not so soluble, so we're using 31P excite/detect
in HMQC and HSQC type experiments. No problems see the 103Rh
chem shifts, but are having two problems I'm hoping this group
can assist with:
1. We want to see 31P coupling in the 103Rh dimension, so we can
count # phosphorous bound to 103Rh. 31P would almost certainly
be sufficient, but the Prof. would like to get the hetero-coupled
multiplet from the 103Rh F1 traces. So interesting problem:
how to get a heteronuclear J to show in the t1/F1 dimension.
I'm trying a couple obvious ideas, but would like to know of
publications/experiments that tackle this problem.
2. Probe is a 1H observe + lock on the inner coil, and 31P fixed +
X (nominal 13C-109Ag tunable) on the outer coil. We modified the
probe so X could tune down to 15.8MHz for 103Rh. We're
delivering 400 watts and have Q=52 at 103Rh. I find pw90=150us.
Ouch... Even though 103Rh is on the outer coil on this newer
style Nalorac probe, I definitely thought we would do better.
Had our engineer look at the probe in some detail on a spectrum
analyzer, but he insists everything is ok (e.g., no close-by
resonances).
Any of you that work down at these frequencies: I know the pw90
is coil/probe dependent, but what pw90's are you getting?
Any suggestions what we should check? The probe does not show
symptoms that would normally show up for arcing.
Thanks,
Charlie
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Charles G. Fry, Ph.D. Tel: (608)262-3182
Director, MR Facility Fax: (608)262-0381
Chem. Dept., Univ. Wisconsin
Madison, WI 53706 USA email: fry_at_chem.wisc.edu
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Received on Fri Aug 11 2000 - 14:57:02 MST