Assembly of two new polyoxometalate-templated supramolecular compounds by utilizing a ligand with a combination of rigidness and flexibility

Abstract

Two new polyoxometalate-templated compounds, (bix)[Cu(bix)]₃[PW₁₂O₄₀]·4H₂O (1), and [Cu(bix)]₃[PMo₁₂O₄₀] (2) (bix = 1,4-bis(imidazol-1-ylmethyl)benzene), were hydrothermally synthesized, and characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses, and single X-ray diffraction. In compound 1, the Keggin polyanions [PW₁₂O₄₀]³⁻ direct the [Cu(bix)] coordination polymeric chains to form a 3D supramolecular framework with grid-like 2D channels. By changing the polyanions into [PMo₁₂O₄₀]³⁻, compound 2 is obtained, in which the [Cu(bix)] coordination polymeric chains array around the polyanions to construct a 3D supramolecular framework with 1D hexagon-like channels. Their different structures show the template effect of the polyanions. Additionally, the cyclic voltammetry measurements indicate that the supramolecular compounds keep the redox properties of their parent polyanions.