Two Anderson-type polyoxometalate-based hybrids constructed with different bis(pyrazine)-bis(amide) ligands: Efficient adsorption dyes and electrocatalytic activities

Abstract

By regulating the spacer lengths of the ligands, two Anderson-type polyoxometalate-based metal-pyrazinamide hybrids, namely, {HCu(L1)[AlMo6(OH)6O18]}·4H2O (1), {HCu(L2)(H2O)2[AlMo6(OH)6O18]}·4H2O (2) (L1 = N,N′-bis(2-pyrazinecarboxamide)-1,2-ethane, L2 = N,N′-bis(2-pyrazinecarboxamide)-1,4-butane) were prepared through hydrothermal methods, and characterized by powder X-ray diffraction, IR spectra, gravimetric analyses and single-crystal X-ray diffraction analysis. Crystal analysis demonstrates that 1 is a 2D network composed of the μ2-bridging L1 ligands and the bidentate bridging Anderson anions [AlMo6(OH)6O18]3− (AlMo6). Complex 2 is a 3D supramolecular architecture consists of the AlMo6 anions and the metal-organic chains [Cu(L2)]n2n+via hydrogen bonds. The result demonstrates that both 1 and 2 display adsorption capacities toward methylene blue (MB) and gentian violet (GV) in aqueous solutions and possess reusability. In addition, the electrocatalytic reduction performances of the title complexes were explored.