高自旋非血红素（烷基过氧）铁（III）中间体的X射线吸收光谱研究。
X-ray absorption spectroscopic studies of high-spin nonheme (alkylperoxo)iron(III) intermediates.
作者信息
Shan Xiaopeng, Rohde Jan-Uwe, Koehntop Kevin D, Zhou Yuming, Bukowski Michael R, Costas Miquel, Fujisawa Kiyoshi, Que Lawrence
机构信息
Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, Minnesota 55455, USA.
出版信息
Inorg Chem. 2007 Oct 1;46(20):8410-7. doi: 10.1021/ic700649w. Epub 2007 Sep 1.
The reactions of iron(II) complexes [Fe(T(pt-Bu,i-Pr))(OH)] (1a, Tp(t-Bu,i-Pr) = hydrotris(3-tert-butyl-5-isopropyl-1-pyrazolyl)borate), [Fe(6-Me2BPMCN)(OTf)2] (1b, 6-Me2BPMCN = N,N'-bis((2-methylpyridin-6-yl)methyl)-N,N'-dimethyl-trans-1,2-diaminocyclohexane), and Fe(L8Py2)(OTf) (1c, L8Py2 = 1,5-bis(pyridin-2-ylmethyl)-1,5-diazacyclooctane) with tert-BuOOH give rise to high-spin FeIII-OOR complexes. X-ray absorption spectra (XAS) of these high-spin species show characteristic features, distinct from those of low-spin Fe-OOR complexes (Rohde, J.-U.; et al. J. Am. Chem. Soc. 2004, 126, 16750-16761). These include (1) an intense 1s --> 3d preedge feature, with an area around 20 units, (2) an edge energy, ranging from 7122 to 7126 eV, that is affected by the coordination environment, and (3) a 1.86-1.96 A Fe-OOR bond, compared to the 1.78 A Fe-OOR bond in low-spin complexes. These unique features likely arise from a flexible first coordination sphere in those complexes. The difference in Fe-OOR bond length may rationalize differences in reactivity between low-spin and high-spin FeIII-OOR species.
铁（II）配合物[Fe(T(pt-Bu,i-Pr))(OH)]（1a，Tp(t-Bu,i-Pr) = 氢三（3-叔丁基-5-异丙基-1-吡唑基）硼酸酯）、[Fe(6-Me2BPMCN)(OTf)2]（1b，6-Me2BPMCN = N,N'-双（（2-甲基吡啶-6-基）甲基）-N,N'-二甲基反式-1,2-二氨基环己烷）和Fe(L8Py2)(OTf)（1c，L8Py2 = 1,5-双（吡啶-2-基甲基）-1,5-二氮杂环辛烷）与叔丁基过氧化氢反应生成高自旋FeIII-OOR配合物。这些高自旋物种的X射线吸收光谱（XAS）显示出特征，与低自旋Fe-OOR配合物不同（罗德，J.-U.等人，《美国化学会志》2004年，126卷，16750 - 16761页）。这些特征包括：（1）一个强烈的1s→3d预边特征，面积约为20个单位；（2）边能量范围为7122至7126 eV，受配位环境影响；（3）Fe-OOR键长为1.86 - 1.96 Å，而低自旋配合物中的Fe-OOR键长为1.78 Å。这些独特特征可能源于这些配合物中灵活的第一配位层。Fe-OOR键长的差异可能解释低自旋和高自旋FeIII-OOR物种之间反应性的差异。
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