Vela Javier, Cirera Jordi, Smith Jeremy M, Lachicotte Rene J, Flaschenriem Christine J, Alvarez Santiago, Holland Patrick L
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
Inorg Chem. 2007 Jan 8;46(1):60-71. doi: 10.1021/ic0609148.
Six of the seven iron atoms in the iron-molybdenum cofactor of nitrogenase display an unusual geometry, which is distorted from the tetrahedral geometry that is most common in iron-sulfur clusters. This distortion pulls the iron along one C3 axis of the tetrahedron toward a trigonal pyramid. The trigonal pyramidal coordination geometry is rare in four-coordinate transition metal complexes. In order to document this geometry in a systematic fashion in iron(II) chemistry, we have synthesized a range of four-coordinate iron(II) complexes that vary from tetrahedral to trigonal pyramidal. Continuous shape measures are used for a quantitative comparison of the stereochemistry of the Fe atoms in the iron-molybdenum cofactor with those of the presently and previously reported model complexes, as well as with those in polynuclear iron-sulfur compounds. This understanding of the iron coordination geometry is expected to assist in the design of synthetic analogues for intermediates in the nitrogenase catalytic cycle.
固氮酶铁钼辅因子中的七个铁原子中有六个呈现出不寻常的几何结构，这种结构与铁硫簇中最常见的四面体几何结构不同。这种畸变将铁沿着四面体的一条C3轴拉向一个三角锥。这种三角锥配位几何结构在四配位过渡金属配合物中很少见。为了在铁（II）化学中系统地记录这种几何结构，我们合成了一系列从四面体到三角锥变化的四配位铁（II）配合物。连续形状测量用于定量比较铁钼辅因子中Fe原子与目前和先前报道的模型配合物以及多核铁硫化合物中的Fe原子的立体化学。对铁配位几何结构的这种理解有望有助于设计固氮酶催化循环中间体的合成类似物。
