Construction And Characterization Of Polyoxometalates Directed By N-containing Organic Cations

Polyoxometalates which are endowed with unique structures and special physical and chemical properties are an important research field of inorganic chemistry. In recent years, based on the thought of supramolecular self-assembly and organic-inorganic hybrid materials, many research team take polyoxometalate compounds as inorganic building units in order to design and synthesize new organic-inorganic hybrid materials through the introduction of organic groups. Such materials have a good prospect in catalysis, molecular recognition, optical and magnetic properties, biological conductive materials, biomimetic materials, molecular sieve as a result of combining of the advantages of the organic components and in organic components.In this paper, five organic-inorganic polyoxometalate supramolecular compounds have been prepared through hydrothermal synthesis methods. In addition, a binuclear complex has been synthesized with the self assembly of 1, 6-bis(triethylmethylammonium)xylol with CuI by solvent evaporation method. These six compounds are [bphx][Mo6O19] (1), [bphx]2[Mo8O26] (2), [bphx]3[H2W12O40]·3H2O (3), [py]2[Hpy]3[PMo12O40]·H2O (4), [btx]2[Mo8O26]·H2O (5), [btx]Cu2I4 (6). These compounds have been characterized by single crystal X-ray diffraction and IR spectroscopy. The results indicate that these compounds are composed of isolated organic cation and inorganic anion by electrostatic interaction. For the introduction of different organic cations, the molybdenum oxide cluster [Mo6O19]2- anion in compound 1 is Lindqvist structure, the molybdenum oxide cluster [Mo8O26]4- anion in compound 2 shows one-dimensional chain structure, the tungsten oxide cluster anion in compound 3, phosphomolybdenum oxide cluster anion in compound 4 and molybdenum oxide cluster anion in compound 5 are all cage structure and compound 6 is a dinuclear structure. Meanwhile, the thermal analysis of compound 2,3 and 5 have been studied and the fluorescence spectra and UV-Vis spectroscopy of compound 6 are measured. Finally, through the investigation of the oxidation reaction of acetaldehyde to acetic acid, it is showed that they have certain catalytic activities.