Institut de Chimie Moléculaire et des Matériaux d'Orsay, Laboratoire de Chimie Inorganique, Université Paris Sud 11, 91405, Orsay Cedex, France.
Dalton Trans. 2009 Nov 21(43):9587-94. doi: 10.1039/b913470k. Epub 2009 Sep 8.
The new ligand L(6)(2)4E (N,N,N',N'-tetrakis(5-ethyl-2-pyridylmethyl)ethane-1,2-diamine) was designed as a more robust analog of TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine) for which the ability at stabilizing high valent Fe-Oxo and Fe-(hydro)peroxo has been reported. With respect to the latter, the pyridyl beta-substituents in L(6)(2)4E do not modify the Fe coordination chemistry. From the Fe(II) precursor, FeO and Fe(III)-(hydro)peroxo intermediates are prepared using the same synthetic methods as those reported for the TPEN analogs. The spectroscopic characteristics of all L(6)(2)4E-Fe complexes are very similar to their TPEN analog. However, (L(6)(2)4E)FeO has a greater lifetime than that of (TPEN)FeO. This can be explained by a restricted bimolecular autodegradation due to the bulkiness provided by the ethyl substituents. Regarding small organic molecule oxidation, (L(6)(2)4E)FeO and (L(6)(2)4E)FeOOH exhibit behaviours that seem to be general for the complexes built with ligands of the TPEN family: FeO appears to be efficient to epoxidize olefins, whereas FeOOH hydroxylates the aromatic ring of anisole with efficacy.
新配体 L(6)(2)4E（N,N,N',N'-四（5-乙基-2-吡啶甲基）乙二胺）被设计为 TPEN（N,N,N',N'-四（2-吡啶甲基）乙二胺）的更稳定类似物，后者具有稳定高价 Fe-Oxo 和 Fe-（氢）过氧化物的能力。就后者而言，L(6)(2)4E 中的吡啶 β-取代基不会改变 Fe 配位化学。从 Fe(II)前体出发，使用与 TPEN 类似物报道的相同合成方法制备 FeO 和 Fe(III)-(氢)过氧化物中间体。所有 L(6)(2)4E-Fe 配合物的光谱特性都与它们的 TPEN 类似物非常相似。然而，(L(6)(2)4E)FeO 的寿命比 (TPEN)FeO 更长。这可以解释为由于乙基取代基提供的体积庞大，限制了双分子自动降解。关于小分子氧化，(L(6)(2)4E)FeO 和 (L(6)(2)4E)FeOOH 表现出的行为似乎是与 TPEN 配体家族构建的配合物通用的：FeO 似乎有效地将烯烃环氧化，而 FeOOH 有效地将苯甲醚的芳环羟基化。
