THE REACTION BETWEEN FERROUS POLYAMINOCARBOXYLATE COMPLEXES AND HYDROGEN-PEROXIDE - AN INVESTIGATION OF THE REACTION INTERMEDIATES BY STOPPED FLOW SPECTROPHOTOMETRY
THE REACTION BETWEEN FERROUS POLYAMINOCARBOXYLATE COMPLEXES AND HYDROGEN-PEROXIDE - AN INVESTIGATION OF THE REACTION INTERMEDIATES BY STOPPED FLOW SPECTROPHOTOMETRY
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DOI：
10.1016/0162-0134(87)80027-2
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发表时间：
1987-03-01
影响因子：
3.9
通讯作者：
KOPPENOL, WH
中科院分区：
文献类型：
--
作者：
RUSH, JD;KOPPENOL, WH
研究了 Fe(II)EDTA、Fe(II)DTPA 和 Fe(II)HEDTA 在中性 pH 值附近与过氧化氢的反应。所有这些反应均假设通过活性中间体 I1: Fe(II)pac + H2O 进行。**图形**。和 I1 + Fe(II)pac。**图形**。 2 Fe(III)pac + 2OH-，（其中 pac 是上述三种聚氨基羧酸盐之一）。 I1，是否.cntdot。 OH 自由基或铁络合物以相对于 k2 的速率与乙醇、甲酸盐和其他清除剂反应，除了叔丁醇和苯甲酸盐外，与 .cntdot 预期的速率相似但不相同。 OH自由基。相反，在pH 3时，在没有配体的情况下，I1与Fe2+的反应被乙醇和叔丁醇抑制，并且I1对这两种清除剂相对于亚铁离子的反应性与羟基自由基所表现出的反应性相同。当pac = HEDTA时，第一个反应的中间体与甲酸离子反应形成亚铁HEDTA配体自由基络合物，其特征在于在295 nm（ε = 2,640 M-1 cm-1）和420 nm（ε = 620 M-1 cm-1）处有最大吸收。对于 Fe(II)HEDTA 与 H2O2 的反应，提出了以下机理：Fe(II)HEDTA- + H2O2 .**图形**。 Fe(II)(H2O2)HEDTA-； Fe(II)(H2O2)HEDTA- + Fe(II)HEDTA- .**图形**。 [Fe(III)HEDTA(OH)]22-；和 [Fe(III)HEDTA(OH)]22- .**图形**。 2Fe(III)HEDTA(OH)-，其中 k17 = 4.2 ×。 104 M-1 sec-1 且 k19 = 5 .+-。 0.2 秒-1。
The reactions of Fe(II)EDTA, Fe(II)DTPA, and Fe(II)HEDTA with hydrogen peroxide near neutral pH have been investigated. All these reactions have been assumed to proceed through an active intermediate, I1: Fe(II)pac + H2O .**GRAPHIC**. and I1 + Fe(II)pac .**GRAPHIC**. 2 Fe(III)pac + 2OH-, (where pac is one of the three polyaminocarboxylates mentioned above). I1, whether .cntdot. OH radical or an iron complex, reacts with ethanol, formate, and other scavengers at rates relative to k2 that, with the exception of t-butanol and benzoate, are similar, but not identical, to those expected for the .cntdot. OH radical. In contrast, at pH 3, in the absence of ligands the reaction of I1 with Fe2+ was inhibited by ethanol and t-butanol and the reactivity of I1 towards these two scavengers relative to ferrous ion is identical to that exhibited by the hydroxyl radical. When pac = HEDTA, the intermediate of the first reaction reacts with formate ion to form the ferrous HEDTA ligand radical complex, which is characterized by absorption maxima at 295 nm (.epsilon. = 2,640 M-1 cm-1) and 420 nm (.epsilon. = 620 M-1 cm-1). For the reaction of Fe(II)HEDTA with H2O2, the following mechanism is proposed: Fe(II)HEDTA- + H2O2 .**GRAPHIC**. Fe(II)(H2O2)HEDTA-; Fe(II)(H2O2)HEDTA- + Fe(II)HEDTA- .**GRAPHIC**. [Fe(III)HEDTA(OH)]22-; and [Fe(III)HEDTA(OH)]22- .**GRAPHIC**. 2Fe(III)HEDTA(OH)-, where k17 = 4.2 .times. 104 M-1 sec-1 and k19 = 5 .+-. 0.2 sec-1.