A DFT/B3LYP study of the mechanisms of the O2 formation reaction catalyzed by the [(terpy)(H2O)MnIII(O)2MnIV(OH2)(terpy)](NO3)3 complex: A paradigm for photosystem II

The reaction pathway of dioxygen formation catalyzed by the [(terpy)(H2O)MnIII(O)2MnIV(OH2) (terpy)](NO3)3 (terpy = 2,2′:6′,2″-terpyridine) complex is presented based on DFT-B3LYP calculations. Key findings include solution acetate acting as the sole proton acceptor, and a partial oxido radical at the beginning of the reaction, subsequently delocalized toward the outermost Mn of the μ-oxo bridge.151