Nonheme iron(II) complexes of macrocyclic ligands in the generation of oxoiron(IV) complexes and the catalytic epoxidation of olefins

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• 作者：Yumi Suh ; Mi Sook Seo ; Kwan Mook Kim ; Youn Sang Kim ; Ho G. Jang ; Takehiko Tosha ; Teizo Kitagawa ; Jinheung Kim and Wonwoo Nam
• 关键词：Biomimetic oxidation ; Nonheme iron complex ; Oxoiron(IV) intermediate ; Oxygen activation ; Olefin epoxidation
• 刊名：Journal of Inorganic Biochemistry
• 出版年：2006
• 出版时间：April 2006
• 年：2006
• 卷：100
• 期：4
• 页码：627-633
• 全文大小：251 K

文摘

Mononuclear nonheme oxoiron(IV) complexes bearing 15-membered macrocyclic ligands were generated from the reactions of their corresponding iron(II) complexes and iodosylbenzene (PhIO) in CH₃CN. The oxoiron(IV) species were characterized with various spectroscopic techniques such as UV–vis spectrophotometer, electron paramagnetic resonance, electrospray ionization mass spectrometer, and resonance Raman spectroscopy. The oxoiron(IV) complexes were inactive in olefin epoxidation. In contrast, when iron(II) or oxoiron(IV) complexes were combined with PhIO in the presence of olefins, high yields of epoxide products were obtained. These results indicate that in addition to the oxoiron(IV) species, there must be at least one more active oxidant (e.g., Fe^IV-OIPh adduct or oxoiron(V) species) that effects the olefin epoxidation. We have also demonstrated that the ligand environment of iron catalysts is an important factor in controlling the catalytic activity as well as the product selectivity in the epoxidation of olefins by PhIO.