Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction Engineering, School of Chemistry and Chemical Engineering , Hefei University of Technology , Hefei , 230009 , P. R. China.
Department of Chemistry , Texas A&M University , College Station , Texas 77843-3255 , United States.
Inorg Chem. 2018 Nov 5;57(21):13912-13919. doi: 10.1021/acs.inorgchem.8b02434. Epub 2018 Oct 9.
In this study, we demonstrate a bottom-up assembly of a monomeric copper complex and a two-dimensional (2-D) heterometallic metal-organic framework (MOF) from a carboxylate-functionalized tridentate Schiff base ligand and metal ions. The obtained 2-D MOF features a unique bimetallic copper center which is different from its monometallic precursor and acts as an efficient heterogeneous catalyst for the Friedel-Crafts reaction and Henry reaction. The MOF catalyst shows a remarkably superior activity compared to its homogeneous counterparts in a wide range of substrates. It is presumably ascribed to the dual activation of the substrates by the active bimetallic copper center confined in the MOF network, which is supported by the significant changes in catalytic activity at low catalyst/substrates ratios when using the 2-D MOF and its precursor as catalysts, respectively. Moreover, the MOF catalyst also shows an excellent stability and recyclability. Our work, therefore, provides a stepwise strategy to design a heterogeneous cooperative catalyst, by taking advantage of the modulated structure of MOF and tunable functionality of the tridentate Schiff base, with high performance in a variety of organic synthesis.
在这项研究中，我们展示了一种由羧酸官能化的三齿席夫碱配体和金属离子自下而上组装单体铜配合物和二维（2-D）异金属金属-有机骨架（MOF）的方法。所得的 2-D MOF 具有独特的双金属铜中心，与单金属前体不同，可作为 Friedel-Crafts 反应和 Henry 反应的高效多相催化剂。与均相对应物相比，MOF 催化剂在广泛的底物中表现出显著更高的活性。这可能归因于受限在 MOF 网络中的活性双金属铜中心对底物的双重活化，这一点通过在使用 2-D MOF 和其前体作为催化剂时，在低催化剂/底物比下催化活性的显著变化得到了支持。此外，MOF 催化剂还表现出优异的稳定性和可回收性。因此，我们的工作提供了一种逐步策略，通过利用 MOF 的调制结构和三齿席夫碱的可调功能，设计出在各种有机合成中具有高性能的异相协同催化剂。
