Crystallographic Evidence for a Sterically Induced Ferryl Tilt in a Non‐Heme Oxoiron(IV) Complex that Makes it a Better Oxidant
Crystallographic Evidence for a Sterically Induced Ferryl Tilt in a Non‐Heme Oxoiron(IV) Complex that Makes it a Better Oxidant
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非血红素氧铁 (IV) 复合物中空间诱导的费基倾斜使其成为更好的氧化剂的晶体学证据
DOI：
10.1002/anie.201804836
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Telser, Joshua
中科院分区：
文献类型：
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作者：
Rasheed, Waqas;Draksharapu, Apparao;Banerjee, Saikat;Young, Jr., Victor G.;Fan, Ruixi;Guo, Yisong;Ozerov, M.;Nehrkorn, Joscha;Krzystek, J.;Telser, Joshua
含氧铁（IV）单元通常涉及作为非血红素铁加氧酶和氧化酶的催化循环中的中间体。这些中间体的最具反应性的合成类似物由具有N-甲基苯并咪唑或喹啉供体的四齿三足配体支撑，但它们的不稳定性妨碍了结构表征。在这里，我们报告了两个[FeIV（O）（L）]2+配合物的晶体结构支持的五齿配体纳入这些杂环，这表明较长的平均Fe-N距离比只有吡啶供体的配合物。这些较长的距离与O-和H-原子转移速率的logk 2 ′值线性相关，表明配体场的减弱增加了Fe=O中心的亲电性。还发现空间体积较大的喹啉供体使Fe=O单元从线性N-Fe =O排列倾斜10°。
Oxoiron(IV) units are often implicated as intermediates in the catalytic cycles of non‐heme iron oxygenases and oxidases. The most reactive synthetic analogues of these intermediates are supported by tetradentate tripodal ligands withN‐methylbenzimidazole or quinoline donors, but their instability precludes structural characterization. Herein we report crystal structures of two [FeIV(O)(L)]2+complexes supported by pentadentate ligands incorporating these heterocycles, which show longer average Fe–N distances than the complex with only pyridine donors. These longer distances correlate linearly with logk2′ values for O‐ and H‐atom transfer rates, suggesting that weakening the ligand field increases the electrophilicity of the Fe=O center. The sterically bulkier quinoline donors are also found to tilt the Fe=O unit away from a linear N‐Fe=O arrangement by 10°.