Fe-N Bond Energy in Heme Group of Haemoglobin

[fomenkoa]

I've been searching far and wide and simply cannot find any info on the BOND ENERGY of a Fe- N coordinate-covalent bond, like that found in the heme group of haemoglobin.


it looks like this:
... N
... |
N -- Fe2+ -- N
... |
... N

The Fe2+ ion also has 2 coordination sites perpendicular to that plane.

Where can I possibly find the bond energy/length of those coordinate covalent bonds?

Anton

 

[Astronuc]

In addition, the calculations show a rather large difference in the short Fe-N bond distance, giving optimized Fe-N bond distances of 1.61 Å and 1.74 Å for the doublet and quartet states, respectively.

from http://www-ssrl.slac.stanford.edu/research/highlights_archive/fev.html

Abstract - Structure-function relations in hemoglobin as determined by x-ray absorption spectroscopy.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1061148&dopt=Abstract

The ligated forms of hemoglobin, and cytochrome c at high pH, gave spectra which were very similar to the bis-imidazole complex, where the average Fe-N bond distance is known to be 1.98 A. By comparison it was possible to determine that the average Fe-N bond distances were 1.99 A in oxyhemoglobin, 1.98 A in carbonmonoxyhemoglobin, and 1.98 A in cytochrome c at pH less than 10.5, with an experimental accuracy of +/-0.02 A.

Don't know if this is of use -
http://www.udel.edu/chem/bahnson/Chem641/chime/HemeFe_2.htm

 

[fomenkoa]

Wow thanks you are a research genius!

Anton