Dear All
Thank you very much for all reply.
It seems difficult to observe HNCH correlation.
I will change the temperature for my measurement.
Regards.
Takahiro Kusukawa
>From Clemens Anklin
Any experiment involving N and C in natural abundance will be very
insensitive as you are looking at 1.1% * 0.37% or ca 41 parts per million
of your molecules.
I would rather try to sharpen the NH resonance by sloving the dynamic
process that broadens it. Lower temperatures or different pH might do it.
>From Matthias Findeisen
in my opinion this would work only on full 15N/13C labelled compounds.
>From Craig McElroy
The broad NH signal is due to exchange broadening (the proton is exchanging
with the solvent at an intermediate timescale)… you could try using a
different solvent and/or different temperature. Something that hydrogen
bonds like DMSO is usually good to see NH protons and allow them to COSY. An
HNCH COSY would not work in a small molecule because of the insensitivity of
the nitrogen, the low natural abundance of N15, and because you would have
to have a 15N next to a 13C which would be incredibly unlikely. Hope that
helps.
Have you tried sharpening the NH signal by changing the temperature?
Sent from my Verizon Wireless BlackBerry
>From David Redwine
For organic molecules we use HMBC experiments to get this information.
Received on Tue Jan 28 2014 - 01:26:02 MST