Linear and T-Shaped Iron(I) Complexes Supported by N-Heterocyclic Carbene Ligands: Synthesis and Structure Characterization.
Linear and T-Shaped Iron(I) Complexes Supported by N-Heterocyclic Carbene Ligands: Synthesis and Structure Characterization.
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DOI：
10.1021/acs.inorgchem.5b01522
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发表时间：
2015-09-08
影响因子：
4.6
通讯作者：
Deng L
中科院分区：
文献类型：
--
作者：
Ouyang Z;Du J;Wang L;Kneebone JL;Neidig ML;Deng L
N-杂环卡宾（NHC）配体1，3-双（2′，6 ′-diethylphenyl）-4，5-（CH2）4-imidazole-2-ylidene（cyIDeg），1，3-bis（2′，6 ′-二乙基苯基）-咪唑啉-2-亚基（sDeep）及其N-异亚丙基类似物sIMes能够制备双配位的均配型铁（I）-NHC配合物[（cyDeep）2Fe][BArF 4]（3，ArF表示3，5-二（三氟甲基）苯基）和[（sIDep）2Fe][BArF 4]（4）以及T形铁（I）-NHC络合物[（sIMes）2Fe（THF）]-[BPh 4]（5，THF =四氢呋喃）。配合物3-5通过在相应的NHC配体存在下通过KCl 8控制还原二卤化铁（II），然后用NaBAr 4进行卤化物提取的顺序方案制备。光谱表征，包括单晶X射线衍射研究和57 Fe穆斯堡尔谱，结合密度泛函理论计算，表明它们的高自旋性质。溶液性质研究（吸收光谱和循环伏安法）表明，3和5在THF溶液中保持其相应的二配位和三配位性质，4可能可逆地与THF分子配位形成T形物种[（sIdep）2Fe（THF）][BArF 4]. 3和4的分离证明了均配二配位铁（I）-NHC络合物的可及性。
The use of the N-heterocyclic carbene (NHC) ligands 1,3-bis(2′,6′-diethylphenyl)-4,5-(CH2)4-imidazol-2-ylidene (cyIDep), 1,3-bis(2′,6′-diethylphenyl)-imidazolin-2-ylidene (sIDep), and its N-mesityl analogue sIMes enables the preparation of the two-coordinate homoleptic iron(I)-NHC complexes [(cyIDep)2Fe][BArF4] (3, ArF denoted for 3,5-di(trifluoromethyl)phenyl) and [(sIDep)2Fe][BArF4] (4) and the T-shaped iron(I)-NHC complex [(sIMes)2Fe(THF)]-[BPh4] (5, THF = tetrahydrofuran). Complexes 3–5 were prepared via the sequential protocol of control reduction of iron(II) dihalides by KC8 in the presence of the corresponding NHC ligands followed by halide-abstraction with NaBAr4. Spectroscopic characterization, including single-crystal X-ray diffraction studies and 57Fe Mössbauer spectroscopy, in combination with density functional theory calculations, suggest their high-spin nature. Solution property study (absorption spectroscopy and cyclic voltammetry) indicates that 3 and 5 keep their corresponding two- and three-coordinate nature in THF solution, and 4 might reversibly coordinate a THF molecule to form, presumably, the T-shaped species [(sIDep)2Fe(THF)][BArF4]. The isolation of 3 and 4 demonstrates the accessibility of homoleptic two-coordinate iron(I)-NHC complexes.