Iron(II) Complexes of a Hemilabile SNS Amido. Ligand: Synthesis, Characterization, and Reactivity
Iron(II) Complexes of a Hemilabile SNS Amido. Ligand: Synthesis, Characterization, and Reactivity
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DOI：
10.1021/acs.inorgchem.7b01802
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发表时间：
2017-11-20
影响因子：
4.6
通讯作者：
Baker, R. Tom
中科院分区：
文献类型：
--
作者：
Das, Uttam K.;Daifuku, Stephanie L.;Baker, R. Tom
我们报告了一种易于制备的双（硫醚）胺配体 (SNHSme)-N-me，以及顺磁性铁 (II) 双（酰胺）络合物 [Fe(K-3-(SNSme)-N-me)2] (1) 的合成、表征和反应性。两种不同的硫醚与Fe的结合生成五元环和六元环，其中五元环中的Fe-S键（av 2.54埃）明显短于六元环中的Fe-S键（av 2.71埃（）），表明后者硫醚具有半稳定性。与这一假设一致，磁圆二色性 (MCD) 和计算 (TD-DFT) 研究表明，溶液中的 1 包含五配位组分 [Fe(K-3-(SNSme)-N-me)(K-2-(SNSme)-N-me)] (2)。通过 1 与 2,2'-联吡啶、1,2-双(二甲基膦基)乙烷和 2,6-二甲基苯基异腈的反应性研究进一步证明了这种配体半稳定性，得到铁 (II) 络合物 [L2Fe(k(2)-(SNSme)-N-me)(2)] (3-5)。将布朗斯台德酸 HNTf2 添加到 1 中会产生顺磁性铁 (II) 胺氨基阳离子 [Fe(K-2-3-S-(NSme)-N-me)(k(3)-(SNHSme)-N-me)](NTf2) (6; Tf = SO2CF3)。阳离子 6 很容易被三磷进行胺配体取代，得到 16e(-) 络合物 [Fe(k(2)-(SNSme)-N-me)(K-3-三磷)](NTf2) (7；三磷 = 双(2-二苯基膦乙基)苯基膦)。这些配合物通过元素分析进行表征； H-1 NMR、穆斯堡尔光谱、红外光谱和紫外可见光谱；和单晶X射线衍射。胺硼烷脱氢催化的初步结果表明配合物7是一种选择性且特别稳定的预催化剂。
We report an easily prepared bis(thioether) amine ligand, (SNHSme)-N-me, along with the synthesis, characterization, and reactivity of the paramagnetic iron(II) bis(amido) complex, [Fe(K-3-(SNSme)-N-me)2] (1). Binding of the two different thioethers to Fe generates both five- and six-membered rings with Fe-S bonds in the five membered rings (av 2.54 angstrom) being significantly shorter than those in the six membered rings (av 2.71 angstrom()), suggesting hemilability of the latter thioethers. Consistent with this hypothesis, magnetic circular dichroism (MCD) and computational (TD-DFT) studies indicate that 1 in solution contains a five-coordinate component [Fe(K-3-(SNSme)-N-me)(K-2-(SNSme)-N-me)] (2). This ligand hemilability was demonstrated further by reactivity studies of 1 with 2,2'-bipyridine, 1,2-bis(dimethylphosphino)ethane, and 2,6-dimethylphenyl isonitrile to afford iron(II) complexes [L2Fe(k(2)-(SNSme)-N-me)(2)] (3-5). Addition of a Bronsted acid, HNTf2, to 1 produces the paramagnetic, iron(II) amine amido cation, [Fe(K-2-3-S-(NSme)-N-me)(k(3)-(SNHSme)-N-me)](NTf2) (6; Tf = SO2CF3). Cation 6 readily undergoes amine ligand substitution by triphos, affording the 16e(-) complex [Fe(k(2)-(SNSme)-N-me)(K-3-triphos)](NTf2) (7; triphos = bis(2-diphenylphosphinoethyl)phenylphosphine). These complexes are characterized by elemental analysis; H-1 NMR, Mossbauer, IR, and UV vis spectroscopy; and single-crystal X-ray diffraction. Preliminary results of amine borane dehydrogenation catalysis show complex 7 to be a selective and particularly robustprecatalyst.