Is the ability of distant iron ions to activate dioxygen specific only for zeolite materials? Dioxygen can be split in between two iron ions

• O2 activation by the model binuclear Fe(II) site of [Fe(Por)]2 is studied. • O2 can be bound by one of the Fe(II) ion. • O2 can also be split to form two iron-oxo species with energy cost of 35 kcal/mol. • Binuclear Fe(II) sites are shown to activate O2 despite the nature of the Fe host. We present a Density Functional Theory (PBE+D3/def2-TZVP) study on the applicability of the binuclear Fe(II) site composed of the two iron porphyrins (Fe(Por)) placed one opposite the other for the activation of dioxygen molecule. The O 2 molecule placed in between two Fe(Por) species can either be bound by one of the Fe(II) ions forming Fe-O 2 group or can be split to form two iron-oxo species. The latter process requires to overcome the 35.5 kcal/mol energy barrier. The comparison of the computed height of the energy barrier with those reported for binuclear Fe(II) sites incorporated in various zeolites shows that the process is feasible in experimental conditions. Therefore, we demonstrate the ability of distant binuclear Fe(II) sites to activate dioxygen by its splitting despite the nature (aluminosilicate, organic) of the “matrix” employed for the stabilization of Fe(II) ions. Our study opens the possibility for a development of new systems for oxygen activation which can be used for oxidation reactions.