The Protonation Mechanism of Ferric-Dioxygen 5 to Cpd

BPW91 DFT calculations showed that 5 is an extremely strong base with a proton affinity of 422 kcalmol , and as such it may undergo protonation by a water molecule. This study was pursued by Guallar et a/. who carried out a QM(DFT)/MM investigation of the protonation mechanism, leading from 5 to Cpd 0 (6) in P450jryF- followed by a full quantum 

The computed energy profile changed gradually from an endothermic one (+20 kcal mol ) 

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