Mirica Liviu M, Vance Michael, Rudd Deanne Jackson, Hedman Britt, Hodgson Keith O, Solomon Edward I, Stack T D P
Department of Chemistry, Stanford University, California 94305, USA.
J Am Chem Soc. 2002 Aug 14;124(32):9332-3. doi: 10.1021/ja026905p.
The activation of dioxygen (O(2)) by Cu(I) complexes is an ubiquitous process in biology and industrial applications. In tyrosinase, a binuclear copper enzyme, a mu-eta(2):eta(2)-peroxodicopper(II) species is generally accepted to be the active oxidant. Reported here is the characterization and reactivity of a stable mu-eta(2):eta(2)-peroxodicopper(II) complex at -80 degrees C using a secondary diamine ligand, N,N'-di-tert-butyl-ethylenediamine (DBED). The spectroscopic characteristics of this complex (UV-vis, resonance Raman) prove to be strongly dependent on the counteranion employed and not on the solvent, suggesting an intimate interaction of the counteranions with the Cu-O(2) cores. This interaction is also supported by solution EXAFS data. This new complex exhibits hydroxylation reactivity by converting phenolates to catechols, proving to be a functional model of tyrosinase. Additional interest in this Cu/O(2) species results from the use of Cu(I)-DBED as a polymerization catalyst of phenols to polyphenylene oxide (PPO) with O(2) as the terminal oxidant.
铜（I）配合物对双氧（O₂）的活化在生物学和工业应用中是一个普遍存在的过程。在酪氨酸酶（一种双核铜酶）中，μ-η²:η²-过氧二铜（II）物种通常被认为是活性氧化剂。本文报道了使用仲二胺配体N,N'-二叔丁基乙二胺（DBED）在-80℃下对一种稳定的μ-η²:η²-过氧二铜（II）配合物的表征及反应活性。该配合物的光谱特征（紫外可见光谱、共振拉曼光谱）被证明强烈依赖于所使用的抗衡阴离子，而不是溶剂，这表明抗衡阴离子与Cu-O₂核心之间存在紧密的相互作用。溶液扩展X射线吸收精细结构（EXAFS）数据也支持了这种相互作用。这种新的配合物通过将酚盐转化为儿茶酚表现出羟基化反应活性，证明是酪氨酸酶的功能模型。对这种Cu/O₂物种的更多兴趣源于使用Cu（I）-DBED作为酚类以O₂作为终端氧化剂聚合为聚亚苯基氧化物（PPO）的催化剂。
