Highly Efficient Bioinspired Molecular Ru Water OxidationCatalysts with Negatively Charged Backbone Ligands.

The oxygen evolving complex (OEC) of the naturalphotosynthesis system II (PSII) oxidizes water to produce oxygen andreducing equivalents (protons and electrons). The oxygen releasedfrom PSII provides the oxygen source of our atmosphere; the reducingequivalents are used to reduce carbon dioxide to organic products,which support almost all organisms on the Earth planet. The firstphotosynthetic organisms able to split water were proposed to be cyanobacteria-likeones appearing ca. 2.5 billion years ago. Since then, nature has chosena sustainable way by using solar energy to develop itself. Inspiredby nature, human beings started to mimic the functions of the naturalphotosynthesis system and proposed the concept of artificial photosynthesis(AP) with the view to creating energy-sustainable societies and reducingthe impact on the Earth environments. Water oxidation is a highlyenergy demanding reaction and essential to produce reducing equivalentsfor fuel production, and thereby effective water oxidation catalysts(WOCs) are required to catalyze water oxidation and reduce the energyloss. [ABSTRACT FROM AUTHOR]