The nickel–iron hydrogenase enzymes efficiently and reversibly interconvert protons, electrons, and dihydrogen. These redox proteins feature iron–sulfur clusters that relay electrons to and from their active sites. Reported here are synthetic models for nickel–iron hydrogenase featuring redox-active auxiliaries that mimic the iron–sulfur cofactors. The complexes prepared are Ni^II(μ-H)Fe^IIFe^II species of formula [(diphosphine)Ni(dithiolate)(μ-H)Fe(CO)₂(ferrocenylphosphine)]⁺ or Ni^IIFe^IFe^II complexes [(diphosphine)Ni(dithiolate)Fe(CO)₂(ferrocenylphosphine)]⁺ (diphosphine = Ph₂P(CH₂)₂PPh₂ or Cy₂P(CH₂)₂PCy₂; dithiolate = ^–S(CH₂)₃S^–; ferrocenylphosphine = diphenylphosphinoferrocene, diphenylphosphinomethyl(nonamethylferrocene) or 1,1′-bis(diphenylphosphino)ferrocene). The hydride species is a catalyst for hydrogen evolution, while the latter hydride-free complexes can exist in four redox states – a feature made possible by the incorporation of the ferrocenyl groups. Mixed-valent complexes of 1,1′-bis(diphenylphosphino)ferrocene have one of the phosphine groups unbound, with these species representing advanced structural models with both a redox-active moiety (the ferrocene group) and a potential proton relay (the free phosphine) proximal to a nickel–iron dithiolate.

镍铁氢酶有效且可逆地相互转化质子，电子和二氢。这些氧化还原蛋白具有铁硫簇，可将电子往返于其活性位。此处报道的是镍铁氢化酶的合成模型，其特征在于具有氧化还原活性的助剂，可模拟铁硫辅助因子。制备的复合物为Ni ^II（μ-H）的Fe ^II的Fe ^II物种式[（二膦）镍（二硫醇）（μ-H）的Fe（CO）₂（二茂铁）] ⁺或Ni ^II的Fe^我铁^II络合物[ （二膦基）Ni（二硫代硫酸盐）Fe（CO）₂（二茂铁基膦）] ⁺（二膦基= Ph₂ P（CH ₂）₂ PPh ₂或Cy ₂ P（CH ₂）₂ PCy ₂；二硫代盐=  ^– S（CH ₂）₃ S ^–; 二茂铁基膦＝二苯基膦基二茂铁，二苯基膦基甲基（九甲基二茂铁）或1，1′-双（二苯基膦基）二茂铁。氢化物是氢释放的催化剂，而后者的无氢化物络合物可以四个氧化还原态存在-铁二茂铁基团的引入使这一特征成为可能。1,1'-双（二苯基膦基）二茂铁的混合价络合物具有一个未结合的膦基团，这些物种代表具有氧化还原活性部分（二茂铁基团）和潜在质子继电器（游离的）的高级结构模型磷化氢），靠近二硫化镍铁。