Dioxygen reactivity of mononuclear heme and copper components yielding a high-spin heme-peroxo-Cu complex
Dioxygen reactivity of mononuclear heme and copper components yielding a high-spin heme-peroxo-Cu complex
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DOI：
10.1021/ja010602y
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发表时间：
2001-06-27
影响因子：
15
通讯作者：
Zuberbühler, AD
中科院分区：
文献类型：
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作者：
Ghiladi, RA;Hatwell, KR;Zuberbühler, AD
在本报告中，我们描述了一个五配位高自旋血红素-过氧化物-铜配合物的形成，[(F8TPP) FeIII-(O2 2-)- cuii (TMPA)]+(2)， 1在还原血红素配合物（F8TPP） FeII （1a）和铜配合物[(TMPA) CuI (CH3CN)]+(1b){方案1}的混合物中加入O2形成。值得注意的是，双氧与Fe和Cu单核组分的混合会产生异双核配合物2，而不是同双核的微过氧或微氧血红素3,6或纯铜产物。目前的体系为血红素- cu体系的双氧化学研究提供了重要的电子、结构和机理方面的新进展。获得的见解可能与血红素-铜氧化酶o2结合和还原有关，8-11其他化学或涉及金属二氧结合的生物化学，8、12、13 o2活化（例如，细胞色素P-450单加氧酶，14铜络合物o2反应性，5、15、16和Cu单加氧酶15,17,18），以及OO还原裂解。（F8TPP） FeII (1a) 3,19和[(TMPA) CuI (CH3-CN)](ClO4)(1b) 4的等摩尔溶液中加入在MeCN溶剂中-40℃的二氧{还原谱：λmax) 414 (sh), 421 (Soret), 526 nm}，紫外可见光谱（图1）揭示了新物质{λmax) 412 (Soret)， 558 nm}的形成。我们将该O2-加合物作为过氧配合物[(F8TPP)- feiii -(O2 2-)- cuii (TMPA)]+(2)，基于以下因素：(1)2的共振拉曼光谱（图2A）在808 cm-1处呈现过氧OO拉伸振动，在18o标记的双氧（图2B）下下降46 cm-1（图2B）。在打乱同位素实验中，16O-18O拉伸对应于785 cm-1的单一组分（图2C），表明过氧化物以对称方式结合。(2)在MeCN溶剂中形成的2的MALDI-TOF-MS在m/z 1239 {(m - clo4 -+ MeCN)+}处有一个母峰。当18O2， m/z 1243形成2时，可以观察到4的预期质量增加。(3)二氧摄取测量{分光光度滴定法：MeCN，-40℃}显示了氮
In this report, we describe the formation of a pentacoordinate high-spin heme-peroxo-Cu complex,[(F8TPP) FeIII-(O2 2-)-CuII (TMPA)]+(2), 1 formed upon addition of O2 to a 1: 1 mixture of the reduced heme complex (F8TPP) FeII (1a) and copper complex [(TMPA) CuI (CH3CN)]+(1b){Scheme 1}. Remarkably, mixing of dioxygen with Fe and Cu mononuclear components2-5 leads to the heterobinuclear complex 2, in preference to homobinuclear µ-peroxo or µ-oxo heme-only3, 6 or copper-only products. 4, 5, 7 The present system provides significant new electronic, structural, and mechanistic advances into the dioxygen chemistry of heme-Cu systems. Insights obtained may have relevance to heme-copper oxidase O2-binding and reduction, 8-11 other chemistries or biochemistries involving dioxygen-binding to metals, 8, 12, 13 O2-activation (eg, cytochrome P-450 monooxygenase, 14 copper complex O2-reactivity, 5, 15, 16 and Cu monooxygenases15, 17, 18), and OO reductive cleavage.Upon addition of dioxygen at-40 C in MeCN solvent to an equimolar solution of (F8TPP) FeII (1a) 3, 19 and [(TMPA) CuI (CH3-CN)](ClO4)(1b) 4 {reduced spectrum: λmax) 414 (sh), 421 (Soret), 526 nm}, UV-visible spectroscopy (Figure 1) reveals the formation of a new species {λmax) 412 (Soret), 558 nm} We formulate this O2-adduct as the peroxo complex [(F8TPP)-FeIII-(O2 2-)-CuII (TMPA)]+(2) based upon the following:(1) The resonance Raman spectrum of 2 (Figure 2A) presents a peroxo OO stretching vibration at 808 cm-1 that downshifts by 46 cm-1 with 18O-labeled dioxygen (Figure 2B). In the scrambled isotope experiment, the 16O-18O stretch corresponds to a single component at 785 cm-1 (Figure 2C), and indicates that the peroxide species is bound in a symmetric fashion.(2) MALDI-TOF-MS of 2 (formed in MeCN solvent) gives a parent peak at m/z 1239 {(M-ClO4-+ MeCN)+} when 16O2 is employed. 20 The expected increase in mass of 4 is observed when 2 forms from 18O2, m/z 1243.(3) Dioxygen-uptake measurements {spectrophotometric titration: MeCN,-40 C} revealed an