Solvent-free heterogeneous catalysis for cyanosilylation in a dynamic cobalt-MOF
Solvent-free heterogeneous catalysis for cyanosilylation in a dynamic cobalt-MOF
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动态钴-MOF 中氰基硅烷化的无溶剂多相催化
DOI：
10.1039/c5dt01456e
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发表时间：
2015-01-01
影响因子：
4
通讯作者：
Zhang, Xian-Ming
中科院分区：
文献类型：
--
作者：
Cui, Xin;Xu, Mei-Chen;Zhang, Xian-Ming
基于蝶形四核钴簇的3D MOF [Me 2NH 2][Co-2（bptc）（mu（3）-OH）（H2O）（2）]（1）经由Co-O-水弱化的中间体1a经历可逆的热触发单晶到单晶转变以产生部分脱水相[Me 2NH 2][Co-2（bptc）（mu 3-OH）（H2O）]（2），这通过单晶X射线衍射证实，粉末X射线衍射、热重分析和IR光谱。在脱水过程中，Co ~（2+）离子的配位环境由饱和八面体转变为配位不饱和四方锥，晶体颜色由红色变为紫色。与水合的1相比，脱水的2在室温下无溶剂条件下对羰基化合物的氰硅烷化反应具有高效和可回收的催化活性，其原因在于Co 2+作为催化活性中心在多相催化过程中发挥了重要作用.
The butterfly-like tetranuclear cobalt cluster based 3D MOF [Me2NH2][Co-2(bptc)(mu(3)-OH)(H2O)(2)] (1) underwent a reversible thermally triggered single-crystal-to-single-crystal transformation via Co-O-water weakened intermediate 1a to produce a partly dehydrated phase [Me2NH2][Co-2(bptc)(mu 3-OH)(H2O)] (2), which was confirmed by single-crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, and IR spectroscopy. During the dehydration course, the local coordination environment of one Co2+ ion was changed from the saturated octahedron to a coordinately unsaturated square-pyramid, accompanied by a crystal color change from red to purple. Compared with pristine hydrated 1, dehydrated 2 exhibits highly efficient and recyclable catalytic activity for cyanosilylation of carbonyl compounds with a low catalyst loading of 0.1 mol% Co at room temperature under solvent-free conditions, which due to the open Co2+ sites as catalytically activated sites played a significant role in the heterogeneous catalytic process.