Two new polyoxometalate-based organic-inorganic hybrids: synthesis, crystal structure and characterization

Abstract

Two new organic-inorganic hybrids, (4,4′-bipy)[Cu^I(2,2′-bipy)₂]₂[W₆O₁₉] (2,2′-bipy = 2,2′-bipyrine, 4,4′-bipy = 4,4′-bipyrine) (1) and (C₆H₅NO₂)₄{Mn^III(H₂O)}[As^IIIW₉O₃₃]₂{W(OH)}- {W(H₂O)}•∼18H₂O (2), have been synthesized and characterized by elemental analysis, IR, TG, UV–Vis, XRPD, XPS, electrochemical analysis and single-crystal X-ray diffraction. Single crystal X-ray diffraction analysis shows that 1 is a new Lindqvist-type polyoxoanion bisupported by copper(I) coordination cations and 2,2′-bipy ligands and exhibits a three-dimensional (3-D) supermolecular framework by aromatic π–π stacking interactions. Compound 2 is constructed from a manganese(III)-substituted sandwich-type polyoxoanion based on [α-AsW₉O₃₃]⁹⁻ units and dissociative, protonated pyridine-4-carboxylic acid molecules, which act as the charge compensation cations. The cyclic voltammogram of 2 shows an irreversible redox process for Mn³⁺ ions.

Keywords:

• Polyoxometalate
• Organic-inorganic hybrid
• π–π Stacking interaction
• Lindqvist
• Sandwich-type

Acknowledgements

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 Analysis and 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); the Program for Changjiang Scholars and Innovative Research Team in University.