Isolation and Characterization of a Dihydroxo-Bridged Iron(III,III)(μ-OH)<sub>2</sub> Diamond Core Derived from Dioxygen
作者:Michael K. Coggins、Santiago Toledo、Julie A. Kovacs
DOI:10.1021/ic4010906
日期:2013.12.2
indicate that the oxygen and proton of the μ-OH bridges of 2 are derived from dioxygen and acetonitrile. Deuterium incorporation (from CD3CN) suggests that an unobserved intermediate capable of abstracting a H-atom from CH3CN forms en route to 2. Given the high C–H bond dissociation energy (BDE = 97 kcal/mol) of acetonitrile, this indicates that this intermediate is a potent oxidant, possibly a high-valent
with no easily substituted ligand. On the other hand, other Fe(II) complexes with unsaturated coordination or an easily substituted ligand had high SOD activity (IC50=0.4–20 μM). The results indicate that the substitution reaction of a ligand with superoxide or the coordination of superoxide is essential for Fe(II)TPEN analogue complexes to have SOD activity. Moreover, we examined the effect of steric
Structural characterization of manganese and iron complexes with methylated derivatives of bis(2-pyridylmethyl)-1,2-ethanediamine reveals unanticipated conformational flexibility
作者:Cristina M. Coates、Kenton Hagan、Casey A. Mitchell、John D. Gorden、Christian R. Goldsmith
DOI:10.1039/c0dt01556c
日期:——
manganese(II) and iron(II) compounds with bispicen and five increasingly methylated derivatives. The extent and sites of methylation strongly impact the optical and electrochemical properties of the manganese and ironcomplexes. Increased methylation is correlated with more positive M(III/II) reduction potentials. Structural analysis of the Mn(II) series reveals two ligand conformations that have never been
铁和锰配合物的衍生物 双(2-吡啶基甲基)-1,2-乙二胺先前已经发现(bispicen)是烃氧合的有效催化剂。甲基化可能会影响金属中心周围的配体构象和结合的金属离子的电子特性;这些因素反过来都会影响反应性。报告的是单核锰(II)和铁(II)化合物,含有双吡啶和五个甲基化程度更高的衍生物。甲基化的程度和部位强烈影响锰和铁配合物的光学和电化学性质。增加的甲基化与更多的正M(III / II)还原电位相关。Mn(Ⅱ)的结构分析)系列揭示了除了常见的顺式-α构象外,对于二聚体构架从未观察到的两个配体构象,顺式-β和反式。结构上表征的铁化合物的1 H NMR光谱与这些构象异构体的混合物一致,这表明二picen配位比以前认为的更灵活,更动态。