Synthesis of Three Novel Polyoxometalate–based Helical Hybrids from Simple to Complicated Helixes via Turing Metal Salt

Three novel helical compounds, [Ag3(H2O)2(btpe)2](HMo8O26)⋅2H2O (1), [Cu3(btpe)4(ac)2](Mo8O26) (2), and [Co(btpe)2]2(Mo8O26) (3) (btpe=1,5-bis(1,2,4-triazol-1-yl)pentane and ac=acetate) have been synthesized under the same hydrothermal conditions. Structural characterizations by single-crystal X-ray diffraction show that compounds 1 and 2 possess a pair of the right- and left-handed double helixes with communal entanglement nodes, whereas compound 3 represents the first example of POM-based double helical compound that consists of three pair of the right- and left-handed double helixes, containing two pairs of the right- and left-handed double helixes with communal entanglement nodes and a pair of the right- and left-handed double helixes without entanglement nodes. Also, the photocatalytic experiment indicates that the title compounds present a good degradation activity and may be potential photocatalysts to decompose the Methylene Blue dye.