Evans-Showell-type polyoxometalate-based metal-organic complexes with novel 3D structures constructed from flexible bis-pyrazine-bis-amide ligands and copper metals: syntheses, structures, and fluorescence and catalytic properties.

摘要: Two new Evans–Showell-type polyoxometalate (POM)-based metal–organic complexes, namely {Cu3(L1)1.5(H2O)5[Co2Mo10H4O38]}·5H2O (1), {[Cu(L2)0.5(H2O)2]2[Co2Mo10H4O38]}·6H2O (2) (L1 = N,N′-bis(2-pyrazinecarboxamide)-1,4-butane, L2 N,N′-bis(2-pyrazinecarboxamide)-1,6-hexane), were successfully synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, powder diffraction (PXRD) thermogravimetric analyses (TGA). In complex 1, the adjacent [Co2Mo10H4O38]6− polyoxoanions are linked CuII ions to form a 1D Cu–[Co2Mo10H4O38]6− inorganic chain, which is further ligand L1 polyoxoanions, forming 3D framework. 2, link generate 2D layer, connected with bidentate ligands obtain The structural diversities of compounds 1 2 showed that spacer lengths flexible bis-pyrazine–bis-amide play important roles in tuning structures title complexes. Compounds represent first examples frameworks based on Cu-bis-pyrazine–bis-amide coordination Moreover, was introduced into POM system. electrochemical fluorescence properties discussed. As heterogeneous catalysts, have good catalytic activity for oxidation benzyl alcohol. compound has higher performance 100% conversion 98.0% selectivity benzoic acid at 10 h. difference their may be mainly due structures. catalysts can recovered reused without displaying any significant loss activity.