Submitted by Dr. Vishakha Monga / University of British Columbia on Mon, 09/01/2014 - 02:36

Hello Everyone,

I teach the labs for the introductory inorganic chemistry course at our institution.  For one of the experiments,my students prepare a Co(III) complex, trans-[Co(en)2(NO2)2]NO3 . I would like them to use FTIR spectroscopy to characterize this compound. 

However, I am unable to find a resource which discusses Co-N stretches.  I wanted to get my students to identify the difference between the unbound ligand with the bound ligand in a metal complex.  However, all I can find are C-N stretches or N-O stretches in the complex.  I don't believe these are clearly diagnostic.

If anyone has any suggestions where I can find FTIR stretches for the metal-ligand bond for this complex or other similar complexes, please let me know.



Sheri Lense / University of Wisconsin Oshkosh


There is a discussion of metal-N stretches, including Co-N stretches, in complexes containing ethylenediamine ligands in the book Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part B, Applications in Coordination, Organometallic, and Bioinorganic Chemistry, 6th Ed., by Kazuo Nakamoto, pp.14-22.  I hope that helps!


Mon, 09/08/2014 - 16:15 Permalink
Dr. Vishakha Monga / University of British Columbia

Hi Sheri,

Yes, I had seen that and all the papers related to these complexes as well.  I was hoping for something that did not fall in the Far IR region but I guess those stretches don't exist for such complexes. Mo and V are much more diagnostic with their respective Metal-ligand bonds. 

Thanks anyways.


Mon, 09/08/2014 - 19:22 Permalink