Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
Department of Chemistry, Technische Universität Berlin, Straβe des 17. Juni 135, 10623 Berlin, Germany.
J Am Chem Soc. 2020 Apr 1;142(13):5924-5928. doi: 10.1021/jacs.9b13756. Epub 2020 Mar 18.
In soluble methane monooxygenase enzymes (MMO), dioxygen (O) is activated at a diiron(II) center to form an oxodiiron(IV) intermediate that performs the challenging oxidation of methane to methanol. An analogous mechanism of O activation at mono- or dinuclear iron centers is rare in the synthetic chemistry. Herein, we report a mononuclear non-heme iron(II)-cyclam complex, -, that activates O to form the corresponding iron(IV)-oxo complex, -, via a mechanism reminiscent of the O activation process in MMO. The conversion of - to - proceeds via the intermediate formation of an iron(III)-superoxide species , which could be trapped and spectroscopically characterized at -50 °C. Surprisingly, is a stronger oxygen atom transfer (OAT) agent than -; performs OAT to - or PPh to yield - quantitatively. Furthermore, - oxidizes the aromatic C-H bonds of 2,6-di--butylphenol, which, together with the strong OAT ability of , represents new domains of oxoiron(IV) and superoxoiron(III) reactivities.
在可溶性甲烷单加氧酶（MMO）中，氧气（O）在二价铁（II）中心被激活，形成一个氧代二价铁（IV）中间体，该中间体完成了甲烷到甲醇的挑战性氧化。在合成化学中，单核或双核铁中心的 O 激活类似机制很少见。在此，我们报告了一种单核非血红素铁（II）-环戊二烯复合物-，通过类似于 MMO 中 O 激活过程的机制，将 O 激活形成相应的铁（IV）-氧合复合物-。-到-的转化通过铁（III）-超氧化物物种的中间形成进行，该物种可以在-50°C 下捕获并通过光谱学进行表征。令人惊讶的是，-是比-更强的氧原子转移（OAT）试剂；-定量地进行 OAT 到-或 PPh 以生成-。此外，-氧化 2,6-二--丁基苯酚的芳族 C-H 键，这与-的强 OAT 能力一起，代表了氧代铁（IV）和超氧代铁（III）反应性的新领域。
