Friedle Simone, Lippard Stephen J
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
Eur J Inorg Chem. 2009 Nov 5;2009(36):5506-5515. doi: 10.1002/ejic.200900821.
In this study, diiron(II) complexes were synthesized as small molecule mimics of the reduced active sites in the hydroxylase components of bacterial multicomponent monooxygenases (BMMs). Tethered aromatic substrates were introduced in the form of 2-phenoxypyridines, incorporating hydroxy and methoxy functionalities into windmill-type diiron(II) compounds [Fe(2)(μ-O(2)CAr(R))(2)-(O(2)CAr(R))(2)(L)(2)] (1-4), where (-)O(2)CAr(R) is a sterically encumbering carboxylate, 2,6-di(4-fluorophenyl)- or 2,6-di(p-tolyl)benzoate (R = 4-FPh or Tol, respectively). The inability of 1-4 to hydroxylate the aromatic substrates was ascertained. Upon reaction with dioxygen, compounds 2 and 3 (L = 2-(m-MeOPhO)Py, 2-(p-MeOPhO)Py, respectively) decompose by a known bimolecular pathway to form mixed-valent diiron(II,III) species at low temperature. Use of 2-(pyridin-2-yloxy)phenol as the ligand L resulted in a doubly-bridged diiron complex (4) and an unprecedented phenoxide-bridged triiron(II) complex (5) under slightly modified reaction conditions.
在本研究中，合成了二价铁配合物，作为细菌多组分单加氧酶（BMMs）羟化酶组分中还原活性位点的小分子模拟物。以2-苯氧基吡啶的形式引入了连接的芳香族底物，将羟基和甲氧基官能团引入风车型二价铁化合物[Fe(2)(μ-O(2)CAr(R))(2)-(O(2)CAr(R))(2)(L)(2)]（1-4）中，其中（-）O(2)CAr(R)是空间位阻较大的羧酸盐，分别为2,6-二（4-氟苯基）-或2,6-二（对甲苯基）苯甲酸酯（R分别为4-FPh或Tol）。确定了1-4无法使芳香族底物羟化。与氧气反应时，化合物2和3（L分别为2-（间甲氧基苯氧基）吡啶、2-（对甲氧基苯氧基）吡啶）在低温下通过已知的双分子途径分解，形成混合价态的二价铁（II,III）物种。在稍微修改的反应条件下，使用2-（吡啶-2-基氧基）苯酚作为配体L，得到了一个双桥连二价铁配合物（4）和一个前所未有的苯氧基桥连三价铁（II）配合物（5）。
