Coordinating functional groups chelate formation

Porous polymers containing various metal chelates bound to nitrogen functionalities have been used to separate oxygen from argon, nitrogen, and carbon monoxide [25]. The porous polymer is synthesized with pyridyl functional groups, which serve as an axial base for the metal chelate in coordinate bond formation between the metal chelate and the polymer. It also serves to activate the metal complex for oxygen coordination. 

These results indicate that the catalytic activity of a metal chelate is very dependent on the number and arrangement of the electron donor groups of the substrate, since combination with the substrate can take place in such a manner as to interfere with the freedom of the functional groups of the ligand to form a reactive intermediate or a transition state complex. This type of interaction could also occur with metal ions, but would lead to the formation of a complex that would itself have catalytic activity because of the presence of unsubstituted positions in the coordination sphere of the metal ion. 

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