A thiourea-functionalized metal-organic macrocycle for the catalysis of Michael additions and prominent size-selective effect
A thiourea-functionalized metal-organic macrocycle for the catalysis of Michael additions and prominent size-selective effect
复制标题
硫脲官能化金属有机大环化合物用于催化迈克尔加成并具有显着的尺寸选择性效应
DOI：
10.1039/c6dt04299f
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发表时间：
2017
影响因子：
4
通讯作者：
Duan Chunying
中科院分区：
文献类型：
--
作者：
Yang Lu;Zhao Liang;Zhou Zhen;He Cheng;Sun Hui;Duan Chunying
通过有机配体和镍离子的自组装，合成了一种大尺寸的四核硫脲基金属有机大环化合物。将硫脲基团作为氢键供体引入到金属-有机络合物体系中导致了用于合成官能化非均相催化剂的新方法，因为这不仅引入了用作螯合剂的配位位点，而且还克服了通常在均相体系中发生的通过分子间H-键合的自缔合问题。该材料的堆积结构形成了一个适合于底物分子通过硫脲基团的强氢键相互作用而进入的封闭环境，从而在硝基苯乙烯与硝基烷烃的Michael加成反应中实现了高催化性能，在非均相中具有显着的产率和尺寸选择性。此外，Ni-SPT的IR光谱与丙二酸二甲酯和β-硝基苯乙烯浸渍的Ni-SPT的光谱的比较表明，两种底物分子β-硝基苯乙烯和丙二酸二甲酯都能够进入三聚体亚基的空腔。
A discrete tetranuclear thiourea-based metal–organic macrocycle (MOM) with a large size was constructed by a well-designed organic ligand and nickel(II) ions via self-assembly. Incorporating thiourea groups as hydrogen-bond donors into a metal–organic complex system leads to a new approach for synthesizing functionalized heterogeneous catalysts, as this not only introduces coordination sites serving as chelators, but also overcomes the issues of self-association via intermolecular H-bonding, often occurring in homogeneous systems. The packing structure of this material formed a confined environment suitable for the access of substrate molecules dragged by the strong hydrogen-bond interactions from the thiourea groups, thus achieving a high catalytic performance in Michael additions of nitrostyrenes to nitroalkanes, with remarkable yields and size-selectivity in heterogeneous phase. Moreover, a comparison of the IR spectrum of Ni–SPT with the spectra of dimethyl malonate- and β-nitrostyrene-impregnated Ni–SPT indicated that both substrate molecules, β-nitrostyrene and dimethyl malonate, were able to access the cavity of the trimeric subunit.