Assembly of Six Polyoxometalate-Based Hybrid Compounds from a Simple Supramolecule to a Complicated Pseudorotaxane Framework via Tuning the pH of the Reaction Systems

Abstract

Three pairs of inorganic–organic hybrid compounds respectively based on [Mo6O19]2–/[Mo8O26]4–, [PW12]3– and [P2W18]6– anions were obtained at different pH values under hydrothermal conditions, namely, [H2bib][Mo6O19] (1), CuII(bib)1.5(H2O)(β-Mo8O26)0.5 (2), [Hbib]2[HPW12O40] (3), [bib0.5][CuII(bib)3CuI(bib)0.5(PW12O40)] (4), [H2bib][CuII(bib)2.5(H2O)(H2P2W18O62)]·2H2O (5), and [CuIbib][(CuIbib)2(H2KP2W18O62)]·4H2O (6), (bib = 1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene). Their structures have been determined by single-crystal X-ray diffraction analyses and characterized by infrared spectra (IR), elemental analyses, and powder X-ray diffraction (PXRD) patterns. Compounds 1 and 3 are zero-dimensional (0D) monomers, in which the protonated bib ligands as countercations combine with [Mo6O19]2–/[PW12O40]3– anions by the intermolecular hydrogen bonding interactions forming a supramolecular layer. In 2, the (4, 4) two-dimensional (2D) layer is formed by β-[Mo8O26]4– anions as double-dentate inorganic ligands to l...