In this study, we report the synthesis and characterization of [Fe(T1Et4iPrIP)(2-OH-AP)(OTf)](OTf) (2), [Fe(T1Et4iPrIP)(2-O-AP)](OTf) (3), and [Fe(T1Et4iPrIP)(DMF)₃](OTf)₃ (4) (T1Et4iPrIP = tris(1-ethyl-4-isopropyl-imidazolyl)phosphine; 2-OH-AP = 2-hydroxyacetophenone, and 2-O-AP^– = monodeprotonated 2-hydroxyacetophenone). Both 2 and 3 serve as model complexes for the enzyme–substrate adduct for the nonheme enzyme 2,4′-dihydroacetophenone (DHAP) dioxygenase or DAD, while 4 serves as a model for the ferric form of DAD. Complexes 2–4 have been characterized by X-ray crystallography which reveals T1Et4iPrIP to bind iron in a tridentate fashion. Complex 2 additionally contains a bidentate 2-OH-AP ligand and a monodentate triflate ligand yielding distorted octahedral geometry, while 3 possesses a bidentate 2-O-AP^– ligand and exhibits distorted trigonal bipyramidal geometry (τ = 0.56). Complex 4 displays distorted octahedral geometry with 3 DMF ligands completing the ligand set. The UV–vis spectrum of 2 matches more closely to the DAD-substrate spectrum than 3, and therefore, it is believed that the substrate for DAD is bound in the protonated form. TD-DFT studies indicate that visible absorption bands for 2 and 3 are due to MLCT bands. Complexes 2 and 3 are capable of oxidizing the coordinated substrate mimics in a stoichiometric and catalytic fashion in the presence of O₂. Complex 4 does not convert 2-OH-AP to products under the same catalytic conditions; however, it becomes anaerobically reduced in the presence of 2 equiv 2-OH-AP to 2.

中文翻译：

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使用仿生铁配合物探索2,4'-二羟基苯乙酮双加氧酶的作用机制

在这项研究中，我们报告了 [Fe(T1Et4iPrIP)(2-OH-AP)(OTf)](OTf) ( 2 ), [Fe(T1Et4iPrIP)(2-O-AP)](OTf)的合成和表征( 3 )和[Fe(T1Et4iPrIP)(DMF) ₃ ](OTf) ₃ ( 4 )(T1Et4iPrIP=三(1-乙基-4-异丙基-咪唑基)膦；2-OH-AP=2-羟基苯乙酮，和2-O-AP ^– = 单去质子化 2-羟基苯乙酮）。既2和3作为用于酶-底物加合物的非血红素酶2,4'- dihydroacetophenone（DHAP）双加氧酶或DAD模型复合物，而4个用作用于三价铁形式DAD的模型。复合体2 – 4已通过 X 射线晶体学表征，显示 T1Et4iPrIP 以三齿方式结合铁。配合物2还包含一个双齿 2-OH-AP 配体和一个单齿三氟甲磺酸配体，产生扭曲的八面体几何形状，而3拥有一个双齿 2-O-AP ^-配体并表现出扭曲的三角双锥几何形状 (τ = 0.56)。复合物4显示扭曲的八面体几何形状，其中 3 个 DMF 配体完成了配体组。的UV-vis光谱2个紧密地比DAD-基板光谱匹配3，并且因此，可以相信，对于DAD基板在质子化形式结合。TD-DFT 研究表明，可见吸收带2和3是由于 MLCT 频带。配合物2和3能够在 O ₂存在下以化学计量和催化方式氧化配位底物模拟物。配合物4在相同催化条件下不会将 2-OH-AP 转化为产物；然而，它在 2 当量 2-OH-AP 存在下厌氧还原为2。