Abstract：
[FeFe] hydrogenases demonstrate remarkable catalytic efficiency in hydrogen evolution and oxidation processes. However, susceptibility of these enzymes to oxygen-induced degradation impedes their practical deployment in hydrogen-production devices and fuel cells. Recent investigations into the oxygen-stable (Hinact) state of the H-cluster revealed its inherent capacity to resist oxygen degradation. Herein, we present findings on Cl- and SH-bound [2Fe-2S] complexes, bearing relevance to the oxygen-stable state within a biological context. A characteristic attribute of these complexes is the terminal Cl-/SH- ligation to the iron center bearing the CO bridge. Structural analysis of the t-Cl demonstrates a striking resemblance to the Hinact state of DdHydAB and CbA5H. The t-Cl/t-SH exhibit reversible oxidation, with both redox species, electronically, being the first biomimetic analogs to the Htrans and Hinact states. These complexes exhibit notable resistance against oxygen-induced decomposition, supporting the potential oxygen-resistant nature of the Htrans and Hinact states. The swift reductive release of the Cl-/SH-group demonstrates its labile and kinetically controlled binding. The findings garnered from these investigations offer valuable insights into properties of the enzymatic O2-stable state, and key factors governing deactivation and reactivation conversion. This work contributes to the advancement of bio-inspired molecular catalysts and the integration of enzymes and artificial catalysts into H2-evolution devices and fuel-cell applications.
摘要：
[FeFe]氢化酶在析氢和氧化过程中表现出显著的催化效率。然而,酶对氧诱导降解的敏感性阻碍了它们在制氢设备和燃料电池中的实际应用。最近对H簇的氧稳定（Hinact）状态的研究揭示了其抵抗氧降解的固有能力。在这里，我们提出了关于Cl-/SH结合的[2Fe-2S]配合物的发现，在生物学背景下与氧稳定状态相关。这些复合物的特征属性是末端Cl-/SH-连接到带有CO桥的铁。t-Cl的结构分析表明与DdHydAB和CbA5H的Hinact态惊人相似。t-Cl/t-SH表现出可逆氧化，两种氧化还原物种，电子,是Htrans和Hinact状态的第一个仿生类似物。这些配合物对氧诱导的分解表现出显著的抗性，支持Htrans和Hinact状态的潜在耐氧性质。Cl-/SH-的快速还原释放证明了其不稳定和动力学控制的结合。从这些研究中获得的发现为酶促O2稳定状态的特性提供了有价值的见解，以及控制失活和再激活转换的关键因素。这项工作有助于促进生物激发的分子催化剂的发展，并将酶和人工催化剂集成到H2释放装置和燃料电池应用中。
