The ligand N,N′-bis(6-methyl-2-pyridylmethyl)-N,N′-bis(2-pyridylmethyl)ethane-1,2-diamine (L622M) has allowed to prepare the new FeII complex [(L622M)FeCl2] (1), and to compare its structural and spectroscopic characteristics with [(L622M)FeCl]PF6 (2). The molecular structure of 1, resolved by X-ray diffraction, exhibits the ligand tetracoordinated with the two non-methylated pyridine rings coordinated. As shown by UV/Vis spectroscopy and cyclic voltammetry, upon dissolution in methanol or acetonitrile, one chloride ion is released and replaced by a pyridine group. Therefore, complexes 1 and 2 adopt identical structures in solution, i.e. [(L622M)FeCl+. However, upon oxidation complex 1 gives several ferric complexes with the ligand L622M pentacoordinated, or tetracoordinated with two chloride ions. This peculiar behaviour is due to the presence of chloride ions in solution in the case of 1. Upon reaction with H2O2 in methanol, complex 2 leads to the formation of low-spin [(L622M)FeIII(OOH)2+, whereas it is not observed in the case of 1. Based on the presence or not of chloride ions in solution, a mechanism is proposed for the reactivity of complexes 1 and 2 toward H2O2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

中文翻译：

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含有配体 N,N-Bis(6-methyl-2-pyridylmethyl)-N,N-bis(2-pyridylmethyl)ethane-1,2-diamine 的铁配合物：结构、光谱和电化学研究，与过氧化氢的反应性以及低自旋 Fe-OOH 配合物的形成

配体 N,N'-双(6-甲基-2-吡啶基甲基)-N,N'-双(2-吡啶基甲基)乙烷-1,2-二胺 (L622M) 已允许制备新的 FeII 复合物 [(L622M )FeCl2] (1)，并将其结构和光谱特征与 [(L622M)FeCl]PF6 (2) 进行比较。通过 X 射线衍射解析的 1 的分子结构显示出与两个非甲基化吡啶环配位的四配位配体。如紫外/可见光谱和循环伏安法所示，溶解在甲醇或乙腈中后，一个氯离子被释放并被吡啶基团取代。因此，配合物1和2在溶液中采用相同的结构，即[(L622M)FeCl+。然而，在氧化时，配合物 1 产生了几种三价铁配合物，配体 L622M 与两个氯离子五配位或四配位。这种特殊的行为是由于在 1 的情况下溶液中存在氯离子。在甲醇中与 H2O2 反应时，配合物 2 导致形成低自旋 [(L622M)FeIII(OOH)2+，而它是在 1 的情况下未观察到。基于溶液中氯离子的存在与否，提出了复合物 1 和 2 与 H2O2 反应的机制。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)