Azanone nitrosyl complexes

On the other hand, (case ii) if the reaction of the donor with the metalloporphyrin is faster than its spontaneous decomposition rate, the metalloporphyrin reacts directly with the donor, accelerating its decomposition rate and forming the corresponding nitrosyl complex by azanone transfer to the metal center. For these cases, almost no free HNO is produced, as evidenced by the quantitative formation of the nitrosyl product even for equimolar metalloporphyrin to donor ratios. In these cases, the Uobs against [Donor] plot gives a straight line from which the bimolecular cat(Donor) rate constant can be obtained. 

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