A High-Spin Iron(IV)鈥揙xo Complex Supported by a Trigonal Nonheme Pyrrolide Platform

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• 作者：Julian P. Bigi ; W. Hill Harman ; Benedikt Lassalle-Kaiser ; Damon M. Robles ; Troy A. Stich ; Junko Yano ; R. David Britt ; Christopher J. Chang
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 25, 2012
• 年：2012
• 卷：134
• 期：3
• 页码：1536-1542
• 全文大小：382K
• 年卷期：v.134,no.3(January 25, 2012)
• ISSN：1520-5126

文摘

We report the generation and characterization of a new high-spin iron(IV)鈥搊xo complex supported by a trigonal nonheme pyrrolide platform. Oxygen-atom transfer to [(tpa^Mes)Fe^II]^{鈭?/sup> (tpaAr = tris(5-arylpyrrol-2-ylmethyl)amine) in acetonitrile solution affords the Fe(III)鈥揳lkoxide product [(tpaMes2MesO)FeIII]鈭?/sup> resulting from intramolecular C鈥揌 oxidation with no observable ferryl intermediates. In contrast, treatment of the phenyl derivative [(tpaPh)FeII]鈭?/sup> with trimethylamine N-oxide in acetonitrile solution produces the iron(IV)鈥搊xo complex [(tpaPh)FeIV(O)]鈭?/sup> that has been characterized by a suite of techniques, including mass spectrometry as well as UV鈥搗is, FTIR, M枚ssbauer, XAS, and parallel-mode EPR spectroscopies. Mass spectral, FTIR, and optical absorption studies provide signatures for the iron鈥搊xo chromophore, and M枚ssbauer and XAS measurements establish the presence of an Fe(IV) center. Moreover, the Fe(IV)鈥搊xo species gives parallel-mode EPR features indicative of a high-spin, S = 2 system. Preliminary reactivity studies show that the high-spin ferryl tpaPh complex is capable of mediating intermolecular C鈥揌 oxidation as well as oxygen-atom transfer chemistry.}