The Picket fence-oxygen Biomimetic Complex

The Picket-fence-oxygen Biomimetic Complex 3.3.2.1 Interplay Structure/Electronic State 

A small displacement of the porphyrin substituents away from the 02 molecule occurs during full relaxation of the molecular 

This electron distribution follows the semiempirical model proposed by Hoffman et al. in the late nineteen-seventies, with some variation because of the spin polarization [51]. In this example one can clearly differentiate these orbitals as having either iron or oxygen character [52] (although a small dZ2 component appears in the third orbital, 7r s, its relative contribution is very small). It follows from the above orbital assignment (A) that the Fe-02 bond can be formally described as FeIH-02. 

The electron distribution in the Fe-O-O linear conformation follows instead the scheme  

because of the strong Fe/02 mixing, classification of these orbitals as Fe or 02 character is not straightforward. Hence, neither the FeIH-02 nor the Fen-02 formal description is applicable here. The change in electronic configuration (A - B), 

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