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[摘要]：We have succeeded in constructing a metalorganic framework (MOF), [Cu(bpdc)(H2O)2]n (H2bpdc=2,2'-bipyridyl-3,3'-dicarboxylic acid, 1), and two poly-POMMOFs (POM=polyoxometalate), {H[Cu(Hbpdc)(H2O)2]2[PM12O40]center dot n-H2O}n (M=Mo for 2, W for 3), by the controllable self-assembly of H2bpdc, Keggin-anions, and Cu2+ ions based on electrostatic and coordination interactions. Notably, these three compounds all crystallized in the monoclinic space group P21/n, and the Hbpdc- and bpdc2- ions have the same coordination mode. Interestingly, in compounds 2 and 3, Hbpdc- and the Keggin-anion are covalently linked to the transition metal copper at the same time as polydentate organic ligand and as polydentate inorganic ligand, respectively. Complexes 2 and 3 represent new and rare examples of introducing the metal N-heterocyclic multi-carboxylic acid frameworks into POMs, thereby, opening a pathway for the design and the synthesis of multifunctional hybrid materials based on two building units. The Keggin-anions being immobilized as part of the metal N-heterocyclic multi-carboxylic acid frameworks not only enhance the thermal stability of compounds 2 and 3, but also introduce functionality inside their structures, thereby, realizing four approaches in the 1D hydrophilic channel used to engender proton conductivity in MOFs for the first time. Complexes 2 and 3 exhibit good proton conductivity (10-4 to ca. 10-3 Scm-1) at 100 degrees C in the relative humidity range 35 to about 98%. |
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