Ground-state electronic structure of the dimer-of-dimers complex ((Mn2O2)2(tphpn)2)4+: potential relevance to the photosystem II water oxidation catalyst

The electronic structure description of the tetrameric dimer-of-dimers complex ((Mn2O2)2(tphpn)2)4+ was reported. This complex displays a parallel polarization electron paramagnetic resonance signal that resembles that associated with the S1 state of the photosystem II manganese water oxidation catalyst. Each Mn(III, IV) dimer is strongly antiferromagnetically exchanged coupled with S' = 1/2, and the two dimers are weakly exchange coupled resulting in a low-lying singlet and triplet state.