Abstract
Two organic–inorganic hybrid polyoxometalates {[V2W4O19{Cu(2,2′-bipy)2}2] · (4,4′-bipy)} n (1) and [Co(2,2′-bipy)3][W6O19] · H2O (2) (2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), constructed by Lindqvist polyanions and transition metal coordination cations, have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, UV spectra, thermogravimetric (TG) analyses, X-ray photoelectron spectroscopy (XPS), and single- crystal X-ray diffraction. Compound 1 is a neutral molecule and consists of a di-VV substituted Lindqvist-type polyanion [V2W4O19]4−, two supporting copper cations [Cu(2,2′-bipy)2]2+ and one free 4,4′-bipy. Neutral molecules of 1 are extended to a 2-D grid-like network by π–π stacking interactions between pyridine groups. The molecular structure of 2 contains one [W6O19]2− cluster polyanion and a [Co(2,2′-bipy)3]2+. Inductively coupled plasma (ICP) analysis and XPS spectrum of 1 prove the presence of VV. TG curves of 1 and 2 indicate two weight loss steps.
Acknowledgements
This work was financially supported by the National Natural Science Foundation of China, Program for New Century Excellent Talents in University of Henan Province, the Foundation of Education Department of Henan Province, and the Natural Science Foundation of Henan Province.