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(SiMe3)(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))](2) 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 H-1 and F-19 NMR spectroscopy, which has revealed equilibria between isomers with different ligand coordination topologies cis-alpha, cis-beta 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)(mu-O)] or [{Fe(salan(x))(L)}(2)(mu-O)]. The lack of catalytic activity of the iron(II) salan and bapen complexes in the oxidation of cyclohexane with H2O2 as the oxidant is attributed to the rapid formation of stable and catalytically inactive oxo-bridged iron(III) complexes.