Nonheme FeIVO complexes that can oxidize the C-H bonds of cyclohexane at room temperature
Nonheme FeIVO complexes that can oxidize the C-H bonds of cyclohexane at room temperature
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DOI：
10.1021/ja037288n
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发表时间：
2004-01-21
影响因子：
15
通讯作者：
Que, L
中科院分区：
文献类型：
--
作者：
Kaizer, J;Klinker, EJ;Que, L
合成了两个五齿配体N_4Py（N，N-双（2-吡啶基甲基）-双（2-吡啶基）甲胺）和Bn-tpen（N-苄基-N，N ′，N ′-三（2-吡啶基甲基）-1，2-二氨基乙烷）的非血红素氧合铁（IV）配合物，发现其光谱性质与之前报道的四齿TPA（三（2-吡啶基甲基）胺）配合物相似.然而，与TPA络合物不同，五齿络合物在室温下具有相当长的寿命。这种更高的热稳定性使得具有C-H键的烷烃的羟基化在室温下可以观察到高达99.3 kcal/mol。此外，在氘的氧化中发现了大的氘KIE值。这些观察结果提供了强有力的可信度假设的机制，单核nonheme铁酶，调用oxoiron（IV）物种的中间。
Nonheme oxoiron(IV) complexes of two pentadentate ligands, N4Py (N,N-bis(2-pyridylmethyl)-bis(2-pyridyl)methylamine) and Bn-tpen (N-benzyl-N,N‘,N‘-tris(2-pyridylmethyl)-1,2-diaminoethane), have been generated and found to have spectroscopic properties similar to the closely related tetradentate TPA (tris(2-pyridylmethyl)amine) complex reported earlier. However, unlike the TPA complex, the pentadentate complexes have a considerable lifetime at room temperature. This greater thermal stability has allowed the hydroxylation of alkanes with C−H bonds as strong as 99.3 kcal/mol to be observed at room temperature. Furthermore, a large deuterium KIE value is found in the oxidation of ethylbenzene. These observations lend strong credence to postulated mechanisms of mononuclear nonheme iron enzymes that invoke the intermediacy of oxoiron(IV) species.