Water Oxidation at a Tetraruthenate Core Stabilized by Polyoxometalate Ligands: Experimental and Computational Evidence To Trace the Competent Intermediates

摘要

Stabilization of adjacent transition metal centers through multiple-μ-hydroxo/oxo bridging units, is a powerful strategy adopted by Nature to effect multiple/cascade transformations.In particular, the photosynthetic conversion of water into dioxygen is performed by photosystem II, using a polynuclear metal cluster, with four manganese and one calcium atom (Mn_4Ca).The natural oxygen evolving complex (OEC) is able to mediate the required four-electron-four-proton process while undergoing a stepwise oxidation to a series of states S_i (i = 0-4), whereby the substrate waters are proposed to react when bound as terminal ligands.