Imine Metathesis Catalyzed by a Silica-Supported Hafnium Imido Complex
Imine Metathesis Catalyzed by a Silica-Supported Hafnium Imido Complex
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DOI：
10.1021/acscatal.8b01395
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发表时间：
2018-10-01
期刊：
影响因子：
12.9
通讯作者：
Basset, Jean-Marie
中科院分区：
文献类型：
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作者：
Aljuhani, Maha A.;Barman, Samir;Basset, Jean-Marie
采用表面金属有机化学方法合成了具有良好结构的单位二氧化硅负载杂氮杂环己烷配合物[(Si-O-)Hf(ETA(2)/pi，7-c-MeNCH2)(ETA(1)，NMe2)(ETA(1)-HNMe2)]。经高真空热处理后，接枝物种转化为前所未有的Hfnimido双-氨基配合物[(Si-O-)Hf(=NME)(ETA(1)-NMe2)]。用元素分析和光谱技术对其进行了表征：红外光谱、固态单量子和多量子核磁共振、先进的DNP-SENS和扩展的X射线吸收精细结构。[(Si-O-)Hf(=NME)(ETA(1)-NMe2)]在温和的条件下催化亚胺歧化反应，反应活性表征表明，亚胺与N-(4-苯亚甲基)苯甲胺的亚胺交换生成了[(Si-O-)Hf(=NCH2Ar)(ETA(1)-NMe2)]，证明了亚胺和亚胺基团的2+2机理，DFT计算也支持该反应机理.
The well-defined single-site silica-supported hafniaaziridine complex [( Si-O-)Hf(eta(2)/pi,7-c-MeNCH2)(eta(1),NMe2)(eta(1)-HNMe2)] was prepared using surface organometallic chemistry. Upon thermal treatment under high vacuum, the grafted species was converted into the unprecedented hafnium imido bis-amido complex [( Si-O-)Hf(=NMe)(eta(1)-NMe2)]. The surface complexes were characterized by elemental analysis and the following spectroscopic techniques: infrared, solid-state single and multiple quantum NMR, advanced DNP-SENS, and extended X-ray absorption fine structure. [( Si-O-)Hf(= NMe)(eta(1)-NMe2)] catalyzed imine metathesis under mild conditions, and characterization of the reactivity showed that the imido exchange with N-(4-phenylbenzylidene)benzylamine yielded [( Si-O-)Hf (=NCH2Ar)(eta(1)-NMe2)], demonstrating a kind of 2 + 2 mechanism involving the imine and the imido groups; the proposed reaction mechanism is also supported by DFT calculations.