Thank you for your help Alan, Andrew, David, Jane, Jeff, John, Karol,
Michael, Richard, Rudi, and Xi An!
I was able to record magnitude COSY for Ni(II) complex. We could observe
beautiful cross-peaks for signals of linewidths in 50 - 80 Hz range. The
spectrum (0 - 60 ppm) was obtained with an acquisition time of 20 ms and
256 points in F1 and 1024 data points in the F2 dimension. It probably
wasn't necessary, but I used relaxation delay of 0.1 s. However, it was
necessary to use quite high number of scans - 128 (S/N for 1D spectrum
of our sample is already satisfactory after just 8 scans). An unshifted
sine-bell squared weighting function and zero-filling were applied prior
to FT in both dimensions.
Thank you again.
Piotr
-----Original Message-----
> From: Piotr Dobrowolski [mailto:piotrd_at_cc.usu.edu]
> Sent: Thursday, August 28, 2003 12:11 PM
> To: AMMRL (ammrl_at_chemnmr.colorado.edu)
> Subject: COSY of paramagnetic complexes
Hello,
We are trying to record magnitude 1H COSY spectra of Fe(II) and Ni(II)
complexes (in acetonitrile) on our ARX-400. The major obstacles here are
of course broadening of the spectral lines and very large range of
chemical shifts (>150ppm). Our 1D spectra don't look that bad. However,
on COSY spectrum we can hardly see ANY cross-peaks. How should we
approach this problem to be able to detect these cross signals?
Have a nice long weekend!
Piotr
Piotr Dobrowolski
NMR/EPR Manager
Department of Chemistry and Biochemistry
Utah State University
0300 Old Main Hill, Logan UT 84322-0300
telephone: (435) 797-1673
fax: (435) 797-3390
Received on Tue Sep 09 2003 - 17:51:31 MST