Dinuclear Cp*Co Amido and Alkoxo Complexes: Synthesis, Structures, and Reactivity
Dinuclear Cp*Co Amido and Alkoxo Complexes: Synthesis, Structures, and Reactivity
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DOI：
10.1021/om101065z
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发表时间：
2011-02
期刊：
影响因子：
2.8
通讯作者：
S. Takemoto;T. Honma;H. Matsuzaka
中科院分区：
文献类型：
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作者：
S. Takemoto;T. Honma;H. Matsuzaka
通过[Cp*Co(μ-Cl)]2(1)与Lix反应，合成了新的氨基和烷氧基桥联双核钴配合物[Cp*Co(η-X)]2(X=NHTol(2)，NHBoc(3)，OBn(4)；Cp*=μ5-C5Me5；TOL=对甲苯基；Boc=t-BuOCO；Bn=CH2Ph)。氨基配合物2和3是抗磁性的，具有折叠的Co_2N_2蝶形结构和Co-−-Co单键。相反，烷氧基配合物4是顺磁性的，包含一个平面的Co2O2核心，具有长的Co····Co分离。用核磁共振谱研究了化合物2和3的动态立体化学过程，确定了化合物2的顺式−反式异构化和化合物2和3的Co2N2环反转。配合物2和4分别与一氧化碳反应生成N，N‘-二对甲苯基脲和碳酸二苄酯，并与[Cp*Co(CO)2]和[Cp*Co(μ-CO)]2反应生成Co(III)配合物[(Cp*Co)2(μ-I)(μ-nHTol)2]I(5)和[(Cp*Co)2(μ-OH2)(μ-nHTol)2][OTf]2(6)。
New amido- and alkoxo-bridged dinuclear cobalt complexes [Cp*Co(μ-X)]2 (X = NHTol (2), NHBoc (3), OBn (4); Cp* = η5-C5Me5; Tol = p-tolyl; Boc = t-BuOCO; Bn = CH2Ph) have been prepared by the reaction of [Cp*Co(μ-Cl)]2 (1) with LiX and characterized by X-ray analysis. The amido complexes 2 and 3 are diamagnetic and feature a folded Co2N2 butterfly structure with a Co−Co single bond. In contrast, the alkoxo complex 4 is paramagnetic and contains a planar Co2O2 core with a long Co···Co separation. Dynamic stereochemical processes in 2 and 3 were investigated by NMR spectroscopy, and cis−trans isomerization in 2 and Co2N2 ring inversion in 2 and 3 were identified. Complexes 2 and 4 reacted with carbon monoxide to give N,N′-di-p-tolylurea and dibenzyl carbonate, respectively, along with [Cp*Co(CO)2] and [Cp*Co(μ-CO)]2. Oxidation of 2 with iodine and ferrocenium triflate afforded the Co(III) complexes [(Cp*Co)2(μ-I)(μ-NHTol)2]I (5) and [(Cp*Co)2(μ-OH2)(μ-NHTol)2][OTf]2 (6), respectively, the latter being charac...