[FeFe]氢酶活性中心6Fe氢簇的化学模拟：Fe-S簇簇耦合和氰根配位

The [FeFe]-hydrogenases have displayed efficient catalysis activities for H2 production. The chemical methods have been used to mimic the active-sites of [FeFe]-hydrogenases, so-called "H-clusters", so as to make new artificial H2-production catalysts. The [2Fe2S] subsites of the H-clusters have took direct roles in hydrogen reactions and motivated major researches on the chemical models. Most of the chemical models are included in the issues of dithiolate-bridge modification, CO/donor substitution, protons association, and functional application. Problems which are still need to be studied are now addressed on the understanding of the overall electron structures of the hex-iron cores in the H-clusters. This project proposes to investigate electronic effects of two structure factors. The designs of coupling of Fe-S clusters are intended to mimic the [4Fe4S] subsites as the electron transferor for the H-reactions. The designs of coordination of cyanides will stable the [2Fe2S] core structures and improve the association of protons. The new models which combine the two subsites by S-bridges will be studied with electrochemistry and spectrographic characterizations. The project proposal also involves the evaluation of the influence of structure factors on the entire electron structure, and the illumination of the importance of overall electronic structures of H-clusters to the H2-production activities of the chemical models. The research will promote the development of H2-production catalyst research and train young scholars in the technical, intellectual and practical challenges.

[FeFe]氢酶高效地催化质子还原放氢的性能启发了运用化学模拟手段、合成新型制氢催化剂的研究。现在，研究完整6Fe氢簇的电子传输环境对[2Fe2S]亚基双铁核心活性的影响已成为[FeFe]氢酶活性中心模拟研究迫切需要解决的方向。本项目设计合成类半胱氨酸配体配位的Fe-S簇结构以模拟[4Fe4S]亚基的电子供体作用，合成具有CN-配位的[2Fe2S]亚基模拟结构以稳定双铁核心，运用μ-S配位等桥连模式以模拟[4Fe4S]亚基和[2Fe2S]亚基共存的完整氢簇结构。我们将通过谱学表征及电化学等研究手段，研究两种亚基模拟结构之间Fe-S簇的耦合作用和电子传递过程，揭示模拟结构中CN-配位、Fe-S簇耦合等结构因素与电子传输环境之间的关联规律，及对双铁核心催化活性的影响规律。本项目将以[FeFe]氢酶活性中心氢簇6Fe簇核结构的化学模拟，及还原质子放氢催化性能的研究积累，促进催化制氢研究的发展。

利用太阳能光催化分解水制氢是一项极具挑战同时具有重大战略意义的工作。由于利用太阳能光催化制氢的效率仍有待进一步提高，同时贵金属材料也不适合于可持续地大规模实际应用，因此，[FeFe]氢酶等廉价金属催化酶所表现的高效的催化性能，使得它们或是以它们为原型的化学模拟物成为生物科技中富有吸引力的重要方向。.本项目着眼于对高分辨率解析的氢酶活性中心结构进行化学模拟，结合氢酶活性中心结构模拟物的设计合成、光化学驱动的质子还原研究和光电化学制氢催化性能的研究，通过人工合成体系模拟自然界氢酶中H2的氧化还原过程，得到廉价、高效的氧化还原催化剂，有可能替代贵金属催化剂制备清洁能源氢。.本项目设计合成新的[2Fe2S]亚基模拟结构和异金属核模拟化合物等具有优良化学还原质子性质的[FeFe]氢酶活性中心模拟结构，通过化学键合、吸附担载等连接手段与合适的电子供体基团、多官能团拓展结构、光致活化金属化合物以及其他光敏材料相结合，并进一步寻找更高效的连接方式，生成[2Fe2S]模拟物与光敏化合物或电化学活性结构的偶联产物，融合光生电子与化学还原质子反应，实现对[2Fe2S]模拟化合物、异金属核模拟化合物等[FeFe]氢酶活性中心模拟结构在光驱动条件下，还原质子放氢的催化性能的研究、探索和积累。