光合作用放氧反应

Photosynthetic oxygen-evolving reaction

光合作用放氧中心(OEC)是植物光系统Ⅱ(PSⅡ)中利用太阳能高效、安全地将水氧化,释放出电子、质子和氧气的生物催化剂。OEC的合成、结构和催化机理及其仿生模拟一直是光合领域广受关注的研究热点和难点。近年PSⅡ高分辨率晶体结构研究揭示出OEC是一个特殊的Mn_(4)CaO_(5)-簇合物,这一重要进展使人类可以在原子水平上探讨光合放氧反应的微观机理,同时也为OEC的人工合成提供了重要依据。我们近年来成功合成出结构和理化性能均与生物OEC类似的系列仿生Mn_(4)CaO_(4)簇合物,为研究OEC的微观机理提供了理想的化学模型,同时也为发展高效、廉价人工光合作用水裂解催化剂奠定了基础。目前无论是自然光合放氧研究,还是人工光合放氧研究都有大量重要的科学问题亟待深入研究。

Photosynthetic oxygen-evolving center in photosystem II(PSII)of plant is a unique biological catalyst that catalyzes the water oxidation into electrons,protons and dioxygen in high efficiency and high safety using solar energy.Its synthesis,structure and catalytic mechanism are great challenge in photosynthetic research.Recently,the high-resolution crystal structure of PSII has revealed the detailed structure of the unique Mn_(4)CaO_(5)-cluster of this natural catalyst.This advance provides a solid basis for the further investigation of the catalytic mechanism of photosynthetic oxygen-evolving reaction at an atom level,which is also a blueprint for the chemical synthesis of the OEC in laboratory.We have succeeded in synthesizing a series of artificial Mn_(4)CaO_(4)-clusters that closely mimic both the structure and physicochemical properties of the natural OEC in PSII.These synthetic Mn_(4)CaO_(4)-clusters provide a good chemical model to investigate the catalytic mechanism of the OEC and open a new direction for the development of high efficiency and low-cost artificial catalysts for the water-splitting reaction in future.Notably,there are still many scientific questions urgent to be answered in both natural and artificial photosynthetic oxygen evolution.