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

Two new organic-inorganic hybrids, (4,4′-bipy)[CuI(2,2′-bipy)2]2[W6O19] (2,2′-bipy = 2,2′-bipyrine, 4,4′-bipy = 4,4′-bipyrine) (1) and (C6H5NO2)4{MnIII(H2O)}[AsIIIW9O33]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.