Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AY, United Kingdom.
Inorg Chem. 2010 Dec 6;49(23):11106-17. doi: 10.1021/ic1016998. Epub 2010 Nov 9.
Tetradentate bis(aminophenolate) ligands H(2)salan(X) and H(2)bapen(X) (where X refers to the para-phenolate substituent = H, Me, F, Cl) react with [Fe{N(SiMe(3))(2)}(2)] to form iron(II) complexes, which in the presence of suitable donor ligands L (L = pyridine or THF) can be isolated as the complexes [Fe(salan(X))(L)(2)] and [Fe(bapen(X))(L)(2)]. In the absence of donor ligands, either mononuclear complexes, for example, [Fe(salan(tBu,tBu))], or dinuclear complexes of the type Fe(salan(X)) are obtained. The dynamic coordination behavior in solution of the complexes [Fe(salan(F))(L)(2)] and [Fe(bapen(F))(L)(2)] has been investigated by VT (1)H and (19)F NMR spectroscopy, which has revealed equilibria between isomers with different ligand coordination topologies cis-α, cis-β and trans. Exposure of the iron(II) salan(X) complexes to O(2) results in the formation of oxo-bridged iron(III) complexes of the type [{Fe(salan(X))}(2)(μ-O)] or [{Fe(salan(X))(L)}(2)(μ-O)]. The lack of catalytic activity of the iron(II) salan and bapen complexes in the oxidation of cyclohexane with H(2)O(2) as the oxidant is attributed to the rapid formation of stable and catalytically inactive oxo-bridged iron(III) complexes.
四齿双（氨苯甲酸盐）配体 H(2)salan(X) 和 H(2)bapen(X)（其中 X 指对苯二酚取代基 = H、Me、F、Cl）与 [Fe{N(SiMe(3))(2)}(2)] 反应，形成铁(II)配合物，在合适的给体配体 L（L = 吡啶或 THF）存在下，可分离为配合物 [Fe(salan(X))(L)(2)] 和 [Fe(bapen(X))(L)(2)]。在没有给体配体的情况下，得到单核配合物，例如 [Fe(salan(tBu,tBu))]，或双核配合物，例如 Fe(salan(X))。通过 VT（1）H 和（19）F NMR 光谱研究了配合物 [Fe(salan(F))(L)(2)] 和 [Fe(bapen(F))(L)(2)] 在溶液中的动态配位行为，发现了具有不同配体配位拓扑结构 cis-α、cis-β 和 trans 的异构体之间的平衡。将铁(II)salan(X) 配合物暴露于 O(2) 会导致形成氧桥联铁(III)配合物，例如 [{Fe(salan(X))}(2)(μ-O)] 或 [{Fe(salan(X))(L)}(2)(μ-O)]。铁(II) salan 和 bapen 配合物在 H(2)O(2)作为氧化剂氧化环己烷时没有催化活性，这归因于稳定和无催化活性的氧桥联铁(III)配合物的快速形成。
