[Sheikia]

I am currently taking a coordination chemistry class so I am mildly comfortable with the idea of good ligands(ie good sigma donors and good pi acceptors) vs bad ligands

for example, I know that CO is a poor ligand as it is a poor sigma donor and only remains on a metal centre if there is significant pi backdonation (ie. you will not get a d0 metal with CO ligands on it)

So what I am wondering is how azides act as ligands in coordination complexes. I am doing a project on inorganic azides (boom) and I would like to have a better idea.

My prediction is that they are similar to CO in that they are good pi acceptors (they have a delocalized pi system to throw electrons into) and are poor donors because they are electronegative nitrogens. That being said, the bonded nitrogen does have two extra lone pairs that could make it a great donor.


I guess a secondary question would be, how would the electron richness of the metal affect the strength of the N-N bonds? Presumably as the metal becomes more electron rich, it is able to backdonate more into an antibonding orbital on the azide which would cause it to weaken the N-N bonds? I don't even really know because I cant find an MO diagram for an azide.


Am I just completely wrong in all of this? Are my speculations full of crap? any help is appreciated. If anyone has an MO diagram of an azide that would also be helpful. I am really bad at coming up with those on my own. Would it be similar to an allyl MO?