Four novel polytungstate compounds built up of paradodecatungstate clusters and transition-metal complexes/transition metal: Synthesis, structure, and electrochemical properties

A series of novel polytungstates, [{Cu(bim)(H2O)2}4(H4W12O42)]·14H2O 1, (Himi)6[{Mn(imi)(H2O)}(H4W12O42)]·2H2O 2, [{Cu0.5(H2O)}2{Cu0.5(H2O)2}2{Cu (bim)(H2O)2}2(H4W12O42)]·10H2O 3 and [{Na(H2O)4}2{Cu0.5(H2O)}4{Cu0.5 (H2O)1.5}2(H4W12O42)]·3H2O 4 (imi = imidazole; bim = 2,2′-biimidazole), have been obtained by the routine synthetic reactions in aqueous solution and characterized by IR, X-ray powder diffraction, UV, elemental analysis, TG and X-ray single-crystal diffraction. All the compounds contain the [H4W12O42]8− polyanions as building units. Compound 1 is isolated structure, which is modified with four {Cu(bim)(H2O)2}2+ fragments. The compound 2 exhibits an infinite 1D “wave-like” chain based on the interaction between the [H4W12O42]8− polyanion and [Mn(imi)(H2O)]2+ complex. The 2D layered structure of the compound 3 is formed by the interconnection 1D [{Cu0.5(H2O)}2(H4W12O42)]6− and [{Cu0.5(H2O)2}2(H4W12O42)]6− chains. While compound 4 can be abstracted of structural topology with (6,2)-connected 3D network. In addition, the electrochemical properties of these compounds are investigated.