Two polyoxometalate-based metal–organic complexes constructed from a pyridine-polyazole: Assembly, structures, electrochemistry and adsorption properties

Abstract

Two new polyoxometalate-based metal–organic complexes, namely, [Ni3(Htyptz)2(γ-Mo8O26)(H2O)8]·4H2O (1) and [Ni3(H2typtz)2(TeMo6O24)(H2O)8]·6H2O (2) [H2typtz = 3-(tetrazol-5-yl)-5-(pyrid-3-yl)-1,2,4-triazole] have been successfully synthesized under hydrothermal conditions. Their structures have been identified by single crystal X-ray diffraction, and further characterized by elemental analysis, infrared spectra (IR), and powder X-ray diffraction (PXRD). In complex 1, the [Ni(Htyptz)2] mononuclear unit link the adjacent 1D Ni-γ-Mo8O26 inorganic chains conducing to the formation of the 2D layer, then the adjacent 2D layers are connected through hydrogen bonds to construct a 3D supramolecular network. Complex 2 is a 2D coordination network, which is constructed from 1D [Ni3(H2typtz)2] chains and TeMo6 anions. The different polyoxometalates play important roles in tuning the structures of the title complexes. In addition, the adsorption activities of complexes 1 and 2 for methylene blue (MB), neutral red (NR), rhodamine 6G (R6G), Orange II (OrII) have been investigated. Moreover, their electrochemical behaviors and electrocatalytic properties have also been studied.