Research Abstract


Regulating proton-coupled electron transfer for efficient water splitting by manganese oxides at neutral pH

2014年6月30日 Nature Communications 5 : 4256 doi: 10.1038/ncomms5256 (2014)


山口 晃1, 犬塚 理子1, 高嶋 敏宏2, 林 徹1, 橋本 和仁1 & 中村 龍平3

  1. 東京大学大学院 工学系研究科
  2. 山梨大学 クリーンエネルギー研究センター
  3. 理化学研究所 環境資源科学研究センター 生体機能触媒研究チーム

Manganese oxides have been extensively investigated as model systems for the oxygen-evolving complex of photosystem II. However, most bioinspired catalysts are inefficient at neutral pH and functional similarity to the oxygen-evolving complex has been rarely achieved with manganese. Here we report the regulation of proton-coupled electron transfer involved in water oxidation by manganese oxides. Pyridine and its derivatives, which have pKa values intermediate to the water ligand bound to manganese(II) and manganese(III), are used as proton-coupled electron transfer induction reagents. The induction of concerted proton-coupled electron transfer is demonstrated by the detection of deuterium kinetic isotope effects and compliance of the reactions with the libido rule. Although proton-coupled electron transfer regulation is essential for the facial redox change of manganese in photosystem II, most manganese oxides impair these regulatory mechanisms. Thus, the present findings may provide a new design rationale for functional analogues of the oxygen-evolving complex for efficient water splitting at neutral pH.