Reactivity of MnII with superoxide.: Evidence for a [MnIIIOO]+ unit by low-temperature spectroscopies
Reactivity of MnII with superoxide.: Evidence for a [MnIIIOO]+ unit by low-temperature spectroscopies
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DOI：
10.1021/ic062063
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发表时间：
2007-03-19
影响因子：
4.6
通讯作者：
Anxolabehere-Mallart, Elodie
中科院分区：
文献类型：
--
作者：
Groni, Sihem;Blain, Guillaume;Anxolabehere-Mallart, Elodie
锰超氧化物歧化酶在Mn-III和Mn-II状态之间循环以从超氧化物产生氧和过氧化氢。已提出形成加合物，但其性质仍有疑问，因为已提出[（MnOO-）-O-II]和[（MnOO 2-）-O-III]氧化还原态。超氧化物与锰配合物反应性的研究是当前的兴趣。本文研究了[（L）Mn-II]（2+）[L = N-甲基-N，N '，N'-三（2-吡啶甲基）乙烷-1，2-二胺]与K_2O_2在低温无水溶剂中的反应。在添加CA。2当量的过氧化钾，[（L）Mn-II]（2+）无色溶液变为蓝色，并且紫外-可见光谱显示在590 nm（165 M-1 cm（-1））处的带和在430 nm（100 M-1 cm（-1））处的肩。电喷雾电离质谱显示归属于[（L）MnO 2]（+）的峰（m/z = 434.1）。X-波段电子顺磁共振谱平行模式显示六线信号，间隔为6.6 mT，中心为86 mT（g = 8.1）。这些结果支持[（MnO）-O-III]（+）加合物的形成。
Manganese superoxide dismutase cycles between the Mn-III and Mn-II states to produce oxygen and hydrogen peroxide from superoxide. The formation of an adduct has been suggested, but its nature remains questionable because both [(MnOO-)-O-II] and [(MnOO2-)-O-III] redox states have been proposed. Study of the reactivity of superoxide with manganese complexes is of current interest. The reaction of [(L)Mn-II](2+) [L = N-methyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine] with potassium superoxide has been investigated at low temperature in an anhydrous solvent using various techniques. Upon the addition of ca. 2 equiv of potassium superoxide, the [(L)Mn-II](2+) colorless solution turned blue and the UV-vis spectrum displayed a band at 590 nm (165 M-1 cm(-1)) and a shoulder at 430 nm (100 M-1 cm(-1)). Electrospray ionization mass spectrometry showed a peak (m/z = 434.1) assigned to [(L)MnO2](+). The X-band electron paramagnetic resonance spectrum parallel mode displayed a six-line signal separated by 6.6 mT and centered at 86 mT (g = 8.1). These results support the formation of an [(MnOO)-O-III](+) adduct.