Assembly of two new polyoxometalate-templated supramolecular compounds by utilizing flexible 1,4-bis(pyrazol-1-ylmethyl)benzene ligand

Two new polyoxometalate-templated supramolecular compounds, [Cu-4(I)(bpmb)(4)][(PMo11MoO40)-Mo-VI-O-V] (1) and [Cu-4(I)(bpmb)(4)SiW12O40] (2) (bpmb=1,4-bis(pyrazol-1-ylmethyl)benzene), have been synthesized under hydrothermal conditions and characterized by routine methods. Structural analysis shows that in 1, there exist crown-like [Cu-4(I)(bpmb)(4)] coordination macrocycles, and the Keggin polyanions [PMo (11MoO40)-Mo-VI-O-V](4-) (abbr. as PMo12), which direct the crown-like macrocycle to form a 3-D supramolecular framework. In 2, there exist unusual meso-helix chains, and these chains are mutually interlaced in a wave-trough pattern, but without intersection resulting in a multi-cavity layer, in which the [SiW12O40](4-) (abbr. as SiW12) clusters as guest molecules occupy the cavities of the layers. The distinct structural features of the two compounds suggest that Keggin polyanions should play a significant role in the process of assembly. Electrocatalytic properties of 1 and 2 were investigated.