ヒドロゲナーゼ活性中心のモデル構築をめざしたニッケルー鉄二核錯体の合成と反応

为了阐明由[NiFe]氢化酶介导的二氢活化过程，我从事了该酶催化过程中可能的中间体的模型研究。一系列新的二硫代杂茂桥联Ni-Fe（羰基/氰化物）络合物，[（18-冠-6）K]2[（CO）（CN）2Fe（pdt）Ni（CO）（PPh3）]（1; pdt =丙烷-1，3-二硫醇盐），[（18-冠-6）K]2[（CO）（CN）2Fe（ndt）- Ni（CO）（PPh3）]（二）; ndt = norborane-exo-2，3-dithiolate）和间氢化物配合物[（18-Crown-6）K][（CN）（CO）2Fe（pdt）（mu-H）- Ni（CN）（PCy 3）]（3），分别作为Ni-L和Ni-R态的模型。通过Ni（PPh 3）4与Fe（II）硫醇配合物[（CO）2（CN）2Fe（pdt）]（2-）和[（CO）2（CN）2Fe（ndt）]（2-）反应，合成了Fe（II）-Ni（0）配合物1和2。通过Fe（II）硫醇配合物与Ni（II）-氢化物配合物Ni（H）（Cl）（PCy 3）2的类似反应获得μ-氢化物配合物3。配合物1和2具有~2.5 A的Ni-Fe距离，因此它们用作新的合成模型配合物天然Ni-L状态和Ni中心保持四面体几何形状。Ni-Fe距离为2.6A的μ-氢化物配合物3是[Ni-Fe]氢化酶催化循环中非常重要的中间模型配合物，称为Ni-R态，其中Fe与CO/CN配位，Ni具有扭曲的四面体构型。虽然Rauchfuss报道了具有用刘易斯酸保护的CN配体的模型配合物，但配合物3是第一个Ni-Fe（CO/CN）μ-氢化物配合物。

For the purpose to elucidate the dihydrogen activation process mediated by [NiFe] hydrogenase, I was engaged in the model study of plausible intermediates associated during catalysis by the enzyme. A series of new heterobimetallic dithiolate-bridged Ni-Fe(carbonyl/cyanide) complexes, [(18-Crown-6)K]2[(CO)(CN)2Fe(pdt)Ni(CO)(PPh3)] (1; pdt = propane-1,3-dithiolate), [(18-Crown-6)K]2[(CO)(CN)2Fe(ndt)- Ni(CO)(PPh3)] (2; ndt = norborane-exo-2,3-dithiolate), and the m-hydride complex [(18-Crown-6)K][(CN)(CO)2Fe(pdt)(mu-H)- Ni(CN)(PCy3)] (3), were synthesized as models of the different states named Ni-L and Ni-R states. The Fe(II)-Ni(0) complexes 1 and 2 were synthesized by the reaction of Ni(PPh3)4 with Fe(II) thiolato complexes [(CO)2(CN)2Fe(pdt)](2-) and [(CO)2(CN)2Fe(ndt)](2-), respectively. The mu-hydride complex 3 was obtained via a similar reaction of the Fe(II) thiolato complex with Ni(II)-hydride complex Ni(H)(Cl)(PCy3)2. Complexes 1 and 2 has Ni-Fe distances of ~2.5 A, and thus they serve as the novel synthetic model complexes native Ni-L state and Ni center retain tetrahedral geometry. The mu-hydride bimetallic complex 3 with Ni-Fe distance ~2.6 A represents the very important intermediate model complex in the catalytic cycle of [Ni-Fe] hydrogenase termed as Ni-R state where Fe is coordinated by CO/CN and the Ni possesses a distorted tetrahedral geometry. While a model complex having CN ligand protected with Lewis acid was reported by Rauchfuss, complex 3 is the first Ni-Fe (CO/CN) mu-hydride complex.