Functional models of α-keto acid dependent nonheme iron oxygenases: synthesis and reactivity of biomimetic iron(II) benzoylformate complexes supported by a 2,9-dimethyl-1,10-phenanthroline ligand
Functional models of α-keto acid dependent nonheme iron oxygenases: synthesis and reactivity of biomimetic iron(II) benzoylformate complexes supported by a 2,9-dimethyl-1,10-phenanthroline ligand
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DOI：
10.1007/s00775-013-0984-6
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发表时间：
2013-03-01
影响因子：
3
通讯作者：
Paine, Tapan Kanti
中科院分区：
文献类型：
--
作者：
Das, Oindrila;Chatterjee, Sayanti;Paine, Tapan Kanti
以铁（II）-二氯配合物[（LFeCl 2）-Cl-II]（1）为原料，合成了两种仿生苯甲酰甲酸铁配合物[LFeII（BF）（2）]（2）和[LFeII（NO3）（BF）]（3）（L为2，9-二甲基-1，10-菲咯啉，BF为单阴离子苯甲酰甲酸）.所有的铁（II）配合物的结构和光谱特征。2中的铁（II）中心由双齿NN配体（2，9-二甲基-1，10-菲咯啉）和两个单阴离子苯甲酰甲酸盐配位以形成扭曲的八面体配位几何结构。其中一个苯甲酰甲酸酯通过两个羧酸氧与2中的铁结合，但另一个通过一个羧酸氧和酮氧以螯合双齿的方式结合。另一方面，铁（II）中心在3是由一个NN配体，一个双齿硝酸盐，和一个单阴离子螯合苯甲酰甲酸。这两个铁（II）苯甲酰甲酸络合物表现出在其固态结构的面NNO供体环境。配合物2和3在惰性气氛下在非配位溶剂中是稳定的，但在环境条件下与分子氧反应以高产率进行苯甲酰甲酸酯到苯甲酸酯的氧化脱羧。通过拦截和标记实验获得了苯甲酰甲酸氧化脱羧后形成铁（IV）-氧代中间体的证据。铁（II）苯甲酰甲酸络合物代表α-酮酸依赖性加氧酶的功能模型。
Two biomimetic iron(II) benzoylformate complexes, [LFeII(BF)(2)] (2) and [LFeII(NO3)(BF)] (3) (L is 2,9-dimethyl-1,10-phenanthroline and BF is monoanionic benzoylformate), have been synthesized from an iron(II)-dichloro complex [(LFeCl2)-Cl-II] (1). All the iron(II) complexes have been structurally and spectroscopically characterized. The iron(II) center in 2 is coordinated by a bidentate NN ligand (2,9-dimethyl-1,10-phenanthroline) and two monoanionic benzoylformates to form a distorted octahedral coordination geometry. One of the benzoylformates binds to the iron in 2 via both carboxylate oxygens but the other one binds in a chelating bidentate fashion via one carboxylate oxygen and the keto oxygen. On the other hand, the iron(II) center in 3 is ligated by one NN ligand, one bidentate nitrate, and one monoanionic chelating benzoylformate. Both iron(II) benzoylformate complexes exhibit the facial NNO donor environment in their solid-state structures. Complexes 2 and 3 are stable in noncoordinating solvents under an inert atmosphere, but react with dioxygen under ambient conditions to undergo oxidative decarboxylation of benzoylformate to benzoate in high yields. Evidence for the formation of an iron(IV)-oxo intermediate upon oxidative decarboxylation of benzoylformate was obtained by interception and labeling experiments. The iron(II) benzoylformate complexes represent the functional models of alpha-keto acid dependent oxygenases.