Department of Chemistry, Texas A & M University, College Station, Texas 77845, USA.
J Am Chem Soc. 2010 Jul 7;132(26):8870-1. doi: 10.1021/ja103774j.
The hydrophobic cavity of the active site of [FeFe]-Hydrogenase is mimicked by two cyclodextrin molecules which surround a 2Fe2S synthetic analogue of the active site, outfitted with an aryl sulfonate to promote inclusion into beta-cyclodextrin. The X-ray crystal structure of the clathrate shows an increased torsion angle between the apical CO ligands indicating that the supramolecular cage destabilizes the eclipsed geometry typical of diiron model complexes. Inclusion in the model second coordination sphere also has important effects on the electrochemical properties of the model complex including an approximately 80 mV shift of the Fe(I)Fe(I)/Fe(I)Fe(0) reduction and a change in the potential at which electrocatalytic reduction of protons by the diiron complex occurs.
活性位点的疏水性空腔由两个环糊精分子模拟，它们包围着一个 2Fe2S 的活性位点合成类似物，并配备了一个芳基磺酸盐以促进其包含在β-环糊精中。笼合物的 X 射线晶体结构显示出轴向 CO 配体之间的扭转角增加，表明超分子笼破坏了典型的二铁模型配合物的重叠几何形状。在模型的第二配位层中的包含也对模型配合物的电化学性质有重要影响，包括 Fe(I)Fe(I)/Fe(I)Fe(0)还原的约 80 mV 位移以及电催化还原二铁配合物发生的位置的变化。
