Chalcogens as terminal ligands to iron: synthesis and structure of complexes with Fe(III)-S and Fe(III)-Se motifs.
Chalcogens as terminal ligands to iron: synthesis and structure of complexes with Fe(III)-S and Fe(III)-Se motifs.
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硫属元素作为铁的末端配体：具有 Fe(III)-S 和 Fe(III)-Se 基序的配合物的合成和结构。
DOI：
10.1021/ja049118w
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发表时间：
2004
影响因子：
15
通讯作者：
Borovik,AS
中科院分区：
文献类型：
--
作者：
Larsen,PeterL;Gupta,Rajeev;Powell,DouglasR;Borovik,AS
具有末端硫族配体的金属配合物以早期过渡金属配合物而闻名，但对于较重的同系物（例如硫基和硒基），晚期 3d 金属离子没有类似的例子。本文报道了含有硫基和硒基配体的单体铁(III)配合物的分离和表征；使用三足配体三[(N'-叔丁基脲基)-N-亚乙基]氨基([H3buea]3-)完成分离。 FeIII−E(E=S2-,Se2-) 配合物由铁(II) 前体[FeII(H3buea)]2- 和硫元素的元素形式制备。 [FeIIIH3buea(S)]2- 和 [FeIIIH3buea(Se)]2- 与 Fe−E 单元的单体配合物的配方得到了光谱、分析和 X 射线衍射研究的支持。例如，X 波段 EPR 谱包含分辨率良好的轴向信号，这与具有 S= 5/2 基态的每个复合体一致。固态分子结构显示 [FeIIIH3buea(S)]2- 和 [FeIIIH3buea(Se)]2- 的 FeIII−Ebond 长度分别为 2.211(1) 和 2.355(1) Å。每个配合物的主配位层还包含来自[H3buea]3-的三个去质子化脲氮原子；顶端胺氮原子与铁中心的相互作用距离大于 2.6 Å。末端硫族配体似乎与 [H3buea]3- 的脲 NH 基团形成弱氢键；然而，[FeIIIH3buea(S)]2-和[FeIIIH3buea(Se)]2-观察到开放的氢键空穴，这可能导致它们观察到的长期不稳定性。
Metal complexes with terminal chalcogenido ligands are known for the early transition-metal complexes, yet for the heavier congeners (e.g., sulfido and selenido), there are no analogous examples for the late 3d metal ions. Reported herein is the isolation and characterization of monomeric iron(III) complexes containing sulfido and selenido ligands; isolation was accomplished using the tripodal ligand tris[(N‘-tert-butylureaylato)-N-ethylene]aminato ([H3buea]3-). The FeIII−E(E=S2-,Se2-) complexes were prepared from the iron(II) precursor, [FeII(H3buea)]2-, and the elemental forms of the chalogen. The formulation of [FeIIIH3buea(S)]2-and [FeIIIH3buea(Se)]2-as monomeric complexes with Fe−Eunits is supported by spectroscopic, analytical, and X-ray diffraction studies. For instance, X-band EPR spectra contain well-resolved axial signals, which are consistent with each complex havingS= 5/2 ground states. The solid-state molecular structures reveal FeIII−Ebond lengths of 2.211(1) and 2.355(1) Å for [FeIIIH3buea(S)]2-and [FeIIIH3buea(Se)]2-, respectively. The primary coordination sphere for each complex also contains three deprotonated urea nitrogen atoms from [H3buea]3-; the apical amine nitrogen atom weakly interacts with the iron centers at distances of greater than 2.6 Å. The terminal chalcogenido ligands appear to weakly hydrogen-bond with the urea NH groups of the [H3buea]3-; however, open H-bond cavities are observed for [FeIIIH3buea(S)]2-and [FeIIIH3buea(Se)]2-, which may contribute to their observed long-term instability.