Abstract
In this article, we have synthesized two new heteropolytungstate-based compounds [EMIM]4[SiW12O40] (1) and [EMIM]6[P2W18O62] · 4H2O (2) using the ionic liquid (IL) [EMIM]Br (EMIM = 1-ethyl-3-methylimidazolium) as a solvent and characterized them by infrared (IR) and ultraviolet (UV) spectra, thermogravimetric (TG) and elemental analyses, electrochemistry, and single-crystal X-ray analyses. Compound 1 is constructed from one [SiW12O40]4− and four [EMIM]+. In the structure, [SiW12O40]4− and [EMIM]+ are connected by hydrogen bonds with the surface oxygens of the polyoxoanion to form a 3-D supramolecular framework. The heteropolyanion of 2 is a classical Dawson-type structure [P2W18O62]6− and connected with six cations through hydrogen bonds. The structures of these two heteropolyanions are consistent with those synthesized by traditional methods, indicating that ionothermal synthesis is an effective method for the preparation of heteropolyoxometalates. The photocatalytic properties of these compounds have also been investigated.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (no. 20701005/20701006); the Science and Technology Development Project Foundation of Jilin Province (no. 20060420); the Postdoctoral station Foundation of Ministry of Education (no. 20060200002); the Testing Foundation of Northeast Normal University (NENU); Science and Technology Creation Foundation of NENU (NENU-STC07009) and Science Foundation for Young Teachers of NENU (no. 20070302/20070312); and the Program for Changjiang Scholars and Innovative Research Team in University.