Hydrogenation reactions in biology are usually carried out by enzymes with nicotinamide adenine dinucleotide (NAD(P)H) or flavin mononucleotide (FAMH₂)/flavinadenine dinucleotide (FADH₂) as cofactors and hydride sources. Industrial scale chemical transfer hydrogenation uses small molecules such as formic acid or alcohols (e.g. propanol) as hydride sources and transition metal complexes as catalysts. We focus here on organometallic half-sandwich Ru^II and Os^II η⁶–arene complexes and Rh^III and Ir^III η⁵–Cp^x complexes which catalyse hydrogenation of biomolecules such as pyruvate and quinones in aqueous media, and generate biologically important species such as H₂ and H₂O₂. Organometallic catalysts can achieve enantioselectivity, and moreover can be active in living cells, which is surprising on account of the variety of poisons present. Such catalysts can induce reductive stress using formate as hydride source or oxidative stress by accepting hydride from NAD(P)H. In some cases, photocatalytic redox reactions can be induced by light absorption at metal or flavin centres. These artificial transformations can interfere in biochemical pathways in unusual ways, and are the basis for the design of metallodrugs with novel mechanisms of action.

中文翻译：

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细胞中的转移氢化催化

生物学中的氢化反应通常由酶以烟酰胺腺嘌呤二核苷酸 (NAD(P)H) 或黄素单核苷酸 (FAMH ₂ )/黄腺嘌呤二核苷酸 (FADH ₂ ) 作为辅因子和氢化物来源进行。工业规模的化学转移氢化使用小分子如甲酸或醇（例如丙醇）作为氢化物来源，使用过渡金属配合物作为催化剂。我们在这里关注有机金属半夹心 Ru ^II和 Os ^II η ^{6 -}芳烃配合物以及 Rh ^III和 Ir ^III η ⁵ -Cp ^x催化水介质中丙酮酸和醌等生物分子的氢化反应，并生成重要的生物学物质，例如 H ₂和 H ₂ O _{2 的配合物}。有机金属催化剂可以实现对映选择性，而且可以在活细胞中具有活性，由于存在多种毒物，这令人惊讶。这种催化剂可以通过接受来自 NAD(P)H 的氢化物，使用甲酸盐作为氢化物源来诱导还原应力或氧化应力。在某些情况下，金属或黄素中心的光吸收可以诱导光催化氧化还原反应。这些人工转化可以以不寻常的方式干扰生化途径，并且是设计具有新作用机制的金属药物的基础。