Oxygen atom transfer mediated by an iron(IV)/iron(II) macrocyclic complex containing pyridine and tertiary amine donors

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• 作者：Wanhua Ye ; Richard J. Staples ; Elena V. Rybak-Akimova
• 关键词：Non-heme iron ; Macrocyclic complex ; X-ray crystal structure ; Oxidation ; Olefin epoxidation ; Kinetics
• 刊名：Journal of Inorganic Biochemistry
• 出版年：2012
• 出版时间：October, 2012
• 年：2012
• 卷：115
• 期：Complete
• 页码：1-12
• 全文大小：1136 K

文摘

A new non-heme iron model complex containing a high-spin iron(II) complexed with N-methylated pyridine-containing macrocycle was synthesized and crystallographically characterized. The complex generates peroxo- and high-valent iron-oxo intermediates in reactions with tert-butylhydroperoxide and isopropyl 2-iodoxybenzoate, respectively, allowing to gain insight into the formation and reactivity of enzyme-like intermediates related to biological oxygen activation. The formation and reactivity of these intermediate species were investigated by the stopped-flow methodology. The mechanism of oxygen transfer to organic substrates involving reaction of oxoiron(IV) intermediate was elucidated on the basis of spectroscopic and kinetic data. Incorporation of a pyridine ring into the macrocycle increased the reactivity of the Fe^IVO intermediates in comparison with polyamine tetraaza macrocyclic complexes: ferryl (Fe^IVO) species derived from 3 demonstrated electrophilic reactivity in transferring an oxygen atom to substituted triarylphosphines and to olefins (such as cyclooctene). However, iron(III) alkylperoxo intermediate was unreactive with cyclooctene.