Assembly of a new circle connecting circle chain through exerting the template role of a Keggin polyoxometalate

By using the flexible bis(triazole) ligand 1,2-bis(1,2,4-triazol-1-yl) ethane (bte), a polyoxometalate-templated compound, [Zn-2(bte)(4)(SiW12O40)]center dot 2H(2)O (1), was synthesized under hydrothermal conditions. The compound was characterized by single-crystal X-ray diffraction, elemental analyses, IR spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. Compound 1 is constructed from two motifs: the [SiW12O40](4-) polyanion and a bi-nuclear metal-organic circle [Zn-2(bte)(2)](4+). The polyanion exerts a template role, inducing the formation of the bi-nuclear circle. The circles build a 1-D circle connecting circle chain through sharing the same Zn ions. Adjacent circles in the chain are vertical with each other. The template polyanion is surrounded by four circles from four different 1-D chains, forming a 3-D supramolecular structure.