Four synthetic manganese complexes in which Mn atoms have different coordination environments and valence states were used to reconstitute water-oxidizing complex (WOC) in Mn-depleted photosystem 2 preparations. Three Mn-complexes restored a significant rate of electron transfer and oxygen evolution except one complex in which Mn atom ligated to the O-atoms within the ligands by covalent linkage. The effect of coordination environment of the Mn-atom within the Mn-complexes on their efficiencies in reconstituting the electron transport and oxygen evolution was analysed. and G. Y. Chen ... [et al.].